Two’s Company

April 28, 2021 by grahamrob in Broadband, Deep Sky Objects, General Astronomy, Globular Cluster, Imaging and tagged Globular Clusters, M53 | Leave a comment

For good reason spring is known as “galaxy season” by astronomers but during this period, shortly before astronomical darkness inevitably disappears for summer, there’s also another show in town. Closer to home in the denser extremities of our galaxy, over 150 globular clusters have so far been identified orbiting above and below the plane of the Milky Way within the galactic halo. Globular clusters consist of hundreds of thousands of tightly packed stars that are surely one of the more enigmatic features of astronomy, as we now know that similar clusters also are associated with other galaxies throughout the Universe. Whilst the formation of globular clusters is poorly understood, we do know that at 10.0 to 13.5 billion years they are very old. Given their age, location and density, it seems that globular clusters formed under very different circumstances to the more recent dispersed star clusters.

Sagittarius and Ophiuchus brim with globular clusters but at the higher latitude here at Fairvale Observatory it is necessary to view those around the regions of Canes Venatici, Virgo or Coma Berenices; the Great Cluster of M13 and others such as M92 and NGC 6229 located in the aforesaid Hercules constellation move into a better view later during early summer. Having previously imaged a number of these clusters in the past, this spring I looked around for something new and different, which I found in the name of M53 (Above + left of centre – main image top of the page) . In this case it turned out to be two for the price of one, as with careful framing it was possible to include a second globular cluster, NGC 5053 (Below + right of centre – main image top of the page).

True Orientation (top = North) + 30% crop – Image Rotated 90 degrees clockwise

Located in the southern area of the Coma Berenices constellation, M53 (Above left of centre – main image, top of the page) is some 58,000 light years from Earth. Containing some 500,000 metal-poor stars, the cluster equates to 13 arc minutes of sky or about 220 light years in diameter, with an estimated age of 12.67 billion years. Just over 1^o east of M53, NGC 5053 is 53,500 light-years away, with an apparent size of 10.5 arc minutes or 160 light-years. Although classified as a globular cluster, NGC 5053 is more irregular and dispersed in nature without a distinct bright core and is therefore dimmer than its neighbour, making it more difficult to image.

All-in-all I believe these two globular clusters, combined with the star studded background that just includes the binary Diadem star (Upper edge + right of middle – main image, top of the page) southwest of M53, altogether makes for a rich and interesting final image.

	IMAGING DETAILS
Object	M53 & NGC 5053
Constellation	Coma Berenices
Distance	Approx.. 58,000 & 53,000 light-years
Size	13.0 & 10.5 arc minutes
Apparent Magnitude	+8.33 & +10.00

Scope	William Optics GT81 + Focal Reducer FL 382mm f4.72
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	William Optics 50mm guide scope
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600MM-Cool mono CMOS sensor
	FOV 2.65^o x 2.0^o Resolution 2.05”/pix Max. image size 4,656 x 3,520 pix
EFW	ZWOx8 EFW & 31mm Chroma LRGB filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker, PixInsight v1.8.8-7, Photoshop CS3, Topaz Denoise
Image Location & Orientation	Centre RA 13:13:59.405 DEC +18:01:48.627 Lower Left Corner = North Top = South West
Exposures	55 x 180 sec L , 34 x 180 sec R, 30 x 180 sec G&B Total Integration Time: 7hr 27 min
	@ 139 Gain 21 Offset @ -20^oC
Calibration	10 x 60 sec Darks 15 x LRGB Flats & Dark Flats @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	13^th, 15^th & 16^th April 2021 @ +21.00h
Weather	Approx. <5^oC RH >55% 🌙 6% waxing

Galactic Stepping Stones

April 20, 2021 by grahamrob in Broadband, Deep Sky Objects, Galaxy, General Astronomy and tagged Coma Berenices, Filters, Virgo | Leave a comment

The Virgo Cluster consists of more than 2,000 galaxies, which unfortunately are optically too much for my small William Optics GT81 telescope individually. However, one of several sub-groups within the Virgo Cluster forms a striking J-curve shape that does make for a pleasing LRGB image. Discovered and named after the Armenian astrophysicist Benjamin Markarian, Markarian’s Chain is a string of bright galaxies that share a common motion through space. I first imaged the Chain in April 2015 using a modded DSLR and then again in April 2017, as my first LRGB image with the then new ZWO ASI1600MM-Cool camera but with integration times of less than 1-hour on both occasions, the resulting images were far from ideal. On this occasion using my new Chroma LRGB filters for the first time I was determined to do better.

The new filters and nearly 7-hours integration time has resulted in a much more dynamic and detailed image, which I believe now does justice to this spectacular group of galaxies. Analysis of the image using Astrometry.net shows just how crowded this area of Virgo is with galaxies (see annotated image above) but it is Markarian’s Chain that inevitably stands out together with a few other adjacent galaxies.

Large 10^th magnitude M84 & M86 galaxies at the western end of the Chain dominate the image. M84 is the object with the highest blue shift in the Messier catalogue, which is a result of its rapid movement (244km/sec) towards the centre of the Virgo Cluster and us. At the centre of M84 is a 1.5 billion solar mass black hole.
NGC 4420 & NGC 4388 – by comparison these edge-on galaxies together with even smaller NGC 4413 & NGC 4425 seem to frame the larger M84 and M86.
Next along the Chain is a pair of interacting galaxies, the smaller round shaped NGC 4435 and NGC 4438 with its distorted disk, known as “The Eyes”.
As the Chain starts to turn, some 20’ along is NGC 4458 and its partner, the 11th magnitude elliptical NGC 4461.
The final section of the Chain consists first of NGC 4473, its brightness generated by a supermassive black hole – at 100 million solar masses its diameter of 4.46au which would stretch from the Sun to the asteroid belt! Thereafter the 11.4 magnitude barred lenticular galaxy NGC 4477 defines the north eastern extremity of Markarian’s Chain.
As previously noted, there are many other galaxies in this part of the Virgo Cluster. Perhaps most notable though is M87, from which the first ever image of a black hole was the obtained in 2019 – consisting of some 6.5 billion solar masses.

All-in-all Markarian’s Chain makes for a rewarding image using my small telescope combined with the new Chroma filters. Such is the nature of the image the galaxies might also suggest a string of pearls or perhaps galactic stepping stones – metaphorically leading to the next phase of my astroimaging journey.

	IMAGING DETAILS
Object	Markarian’s Chain
Constellation	Virgo & Coma Berenices
Distance	50 – 55 million light-years
Size	~2.5^o total
Apparent Magnitude	Varies +10 to +12 approx.

Scope	William Optics GT81 + Focal Reducer FL 382mm f4.72
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	William Optics 50mm guide scope
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600MM-Cool mono CMOS sensor
	FOV 2.65^o x 2.0^o Resolution 2.05”/pix Max. image size 4,656 x 3,520 pix
EFW	ZWOx8 EFW & 31mm Chroma LRGB filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker, PixInsight v1.8.8-7, Photoshop CS3, Topaz Denoise
Image Location & Orientation	Centre RA 12:27:46.65 DEC +13:03:06.44 @21.30h Left = North
Exposures	100 x 60 sec L , 54 x 60 sec R, 55 x 60 sec G&B Total Integration Time: 6hr 44 min
	@ 139 Gain 21 Offset @ -20^oC
Calibration	10 x 60 sec Darks 15 x LRGB Flats & Dark Flats @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	5^th & 6^th April 2021 @ +21.00h
Weather	Approx. <2^oC RH >=45% 🌙 30% waning

Reflections 2020

December 29, 2020 by grahamrob in Autoguiding, Broadband, Deep Sky Objects, Equipment, Imaging, Narrowband, Nebula, Processing, Software, Viewing, Widefield Imaging and tagged PixInsight, Starnet++, Topaz Denoise AI | Leave a comment

After starting astronomy in 2014, Watch This Space (Man) was launched shortly thereafter as a personal record of my then nascent astronomy journey. Apart from the main blog about my progress or otherwise, links to other astrophotographers, astronomy tools, astronomy weather, scientific papers etc. can also be found on this website; I was suprised to see that to-date 152 items have been published on this site.

I always like to hear from others – comments, questions, help or just to say hello – and can be contacted via: graham.s.roberts@gmail.com or just leave a comment at the end of any item if you prefer.

Vistor map 2020: In this most difficult of years for everyone, it’s especially heartening to see so much interest from all corner’s of the world and hope to see you and others again in 2021 – Clear Skies!

REFLECTIONS is a review of my astronomy and astrophotography during the past year, together with some thoughts on possible future developments.

2020 Overview, Images & Goals for 2021

For the world 2020 was a year like no other. Notwithstanding the obvious problems and dire consequences of Covid-19 for everyone, there have been surprising benefits for astronomy. Although I am retired, under lockdown there was even more time available for hobbies. Furthermore, as I live close to Gatwick and Heathrow airports + underneath numerous high altitude long-haul overflight paths, a massive reduction in air travel resulted in a very obvious improvement in seeing conditions, which was confirmed by guiding results. Located in a Bortle 5 to 6 area I ordinarily achieve at best average RMS error guiding of 0.90” to 1.50”/pixel, guiding improved markedly during lockdown to between 0.50” to 0.75”/ pixel. Of course such seeing conditions also resulted in better quality imaging itself and on a number of occasions I was able to achieve integration times of 10-hours or much more over a number of nights. The result was better images but less of them and inevitably, a lot more cloud throughout the rest of the year!

Having previously got to grips with plate solving, using the new CdC planning function I intended to develop the use of mosaics this year. However, such is the weather in the UK (see above) that it’s obvious to me that creating mosaics is probably not the best use of what imaging time we get. Undeterred, during January I planned and shot a 15x panel mosaic of Barnard’s Loop in Ha-wavelength. Unfortunately the unpredictable occurrence of patchy cloud invalidated some of the panels, though I was finally able to compile a 7x panel mosaic of the upper easterly section of Barnard’s Loop – see below. Notwithstanding, there were lessons learned: (i) restrict mosaics to one or two panels and / or (ii) where wider view images are required use a wide FOV set-up rather than a large mosaic.

Most of my other objectives for 2020 turned out to be pipedreams e.g. a new observatory or perhaps a larger telescope or dual rig. Despite this there were important developments on other fronts.

After eventually coming to the conclusion that mosaics were probably an unwise way to go considering UK conditions, it became clear that a suitable high-quality camera lens might produce similar coverage with less imaging time and hassle. Thus also inspired by the images of others on the SGL Forum using such equipment, I set out to build a new rig based around the excellent Samyang 135 f2 lens. This project remains work-in-progress but so far using the lens with a bespoke 3D printed rig and micro focuser made by Astrokraken and a modded DSLR, it’s apparent that this lens produces excellent widefield images in a relatively short time.

Initial Samyang 135 f2 set-up with modded DSLR

With the time and ‘opportunity’ afforded by lockdown throughout most of the year, I finally decided to do something about improving my processing, namely learning PixInsight. Unfortunately the rumours were correct – it is a steep learning curve and altogether a less than user friendly software. However, after many weeks of toil and expletives I’m pleased to say I can now process an entire image with PixInsight, the impact of which has been nothing less than profound. However, whilst PixInsight is an excellent processing facility, I’ve come to the conclusion that it is often best used together with other process software where appropriate for specific tasks:

Deep Sky Stacker for calibration, alignment and stacking; the equivalent PixInsight process is just too complicated and time consuming;
Photoshop can be very helpful finessing colours and stretching (Levels & Curves);
Starnet++ is useful for creating starless images, which then help to get the best from processing nebula separately before re-combining with the stars;
Topaz AI Denoise has been very effective and easy to use for noise reduction and sharpening at any point during the workflow.

This combination for processing has turned out to be something of a game changer and almost certainly was the most important astrophotography development of the year for me, which augurs well for 2021 and beyond.

Favourite Images

Continuing with the theme of less is more, I imaged just 13 objects this year – of which three were experimental & three with a DSLR – but still with a total integration time of 80 hours (2019 17 objects & 65 hours, 2018: 25 objects & 43 hours). Having worked through many of the astronomer’s favourites by now, images in 2020 consisted of: a new approach to old favourites, difficult / small objects for my equipment e.g. galaxies or less popular and widefield targets.

I’m pleased to say that most of these images turned out well and it’s difficult to choose a favourite. The so-called ‘favourites’ below therefore represent those images from this year that portray an important development in my astrophotography journey. More detailed reviews of these and all other images from 2020 can be found in specific articles that can be accessed using the links found below or via the Blog Index, located under the dropdown menu ABOUT.

Heart Nebula: Although imaged in 2018, this version has been re-processed using mainly PixInsight, thus transforming the original SHO Hubble Palette image from something rather dull to one with warm, vibrant colours, as well as much great detail – demonstrating the significant impact of my new PixInsight based processing abilities.

LBN 325: Numerous emission nebulae populate this small part of a very extensiveHII-Region, which forms an exciting LRGB image. Processing was complex and difficult, in order to bring out exciting features that abound in this spectacular but less popular area of the Cygnus constellation. Integration time of 10-hours was obtained over three nights and is my first LRGB image processed using PixInsight.

M63 Sunflower Galaxy: At 12.6’ x 7.2’and apparent magnitude of +9.3,this small flocculent galaxy in the Canes Venatici constellation is a challenge for my equipment. However, with 8 hours 20 minutes exposure over three nights in April and careful processing, the all-important detail within the galactic disc is clear. Topaz Denoise AI and Gigapixel software played an important role in maintaining the colour and delicate detail in this +50% cropped image.

Taken from last year’s REFLECTIONS 2019:

“Although you never know, I don’t see any major breakthroughs in the coming year”. Just goes to show what I know, fewer but better images were obtained in 2020:

RECORD CARD 2020

Goal	Specifics / Results	Outcome
Improve image capture	Further Improvements in overall quality + much longer integration times + better guiding accuracy = less but better images.	MUCH BETTER
*Better processing*	Using PixInsight software combined with Photoshop, Starnet++ and Topaz Denoise AI has led to major processing improvements and much better final images.	MUCH MUCH BETTER
Widefield Imaging	Initial results from new imaging rig based around Samyang 135 f2 lens were very promising but there’s more to do.	BETTER

My main objectives for 2020 were largely fulfilled (see above), so what about 2021?

Imaging: Other than maintaining the aforesaid improvements achieved over the past two years – guiding & longer integration times – two items that still need to be addressed are: (i) upgrade filters to remove star bloating and all round better images, (ii) improved focussing.

Widefield: Complete Samyang-rig build and switch from DSLR to CMOS mono camera.

Consolidate processing improvements: Whilst the move to PixInsight and other software was very successful in 2020, I’m still only scratching the surface of what’s possible.

Upgrade mono camera – there’s a new generation of colour CMOS cameras starting to appear, hopefully soon to be followed by their mono equivalents !

Hardly a year I and the rest of the world will want to remember, though more than ever astrophotography played a big role in providing relief from the trauma going on around us all.

The major increase of integration times achieved and the use of PixInsight has proved transformative for my astrophotography and will justify returning to reimage some old favourites in future years. I had often thought about upgrading my OTA to something bigger but given the lack of a permanent observatory here at Fairvale Observatory, combined with long periods of bad / cloudy weather, the penny finally dropped and I now have high hopes for the little wonder that is the Samyang 135 f2 lens when I complete its set-up in 2021.

Looking back I have to be happy with my astrophotography in 2020 but more importantly, look forwards to an even better year which holds great promise building on the positive developments of the past 24-months. Moreover, I hope for the sake of everyone that we will be able to deal with Covid-19 soon and return to something of a normal life once again. These are big ambitions and I hope that WTSM’s Reflections 2021 will record such success.

Watch this space!

ASTROPHOTOGRAPHY INDEX OF 2020

To access each blog, click on the title required below highlighted in RED:

JANUARY & FEBRUARY – Jinxed: Barnard’s Loop Mosaic (+ NGC 1333 reflection nebula & LDN 1622 Bogeyman Nebula)

MARCH – Nice but Dim: Medusa planetary nebula / Abell 21

MARCH & APRIL – Return of the Lion: Leo Triplet M65, M66 & NGC 3628

MAY – Galactic Bloom: M63 Sunflower Galaxy

JUNE – Canine Capers: M51 Whirlpool Galaxy

AUGUST & SEPTEMBER – The Big Picture: First Light Samyang 135 f/2 NAN, Cygnus & Veil Nebula

OCTOBER – Reach For The Sky: LBN 325 emission nebula

NOVEMBER – Swan Adventures: NGC 6914 reflection nebula

DECEMBER – Image Redux: HST re-processing – Pacman, Heart, Rosette, NAN & California Nebula

Image Redux

December 8, 2020 by grahamrob in Broadband, Deep Sky Objects, General Astronomy, Narrowband, Nebula, Processing, Software | 1 Comment

An astrophotography image is clearly the sum of its parts, which can broadly be defined as: Equipment – Image Capture – Processing. Much attention and money is given to the first two items but it’s easy to overlook the importance of processing, I should know I’ve done it for years! With time on my hands this year during Covid-19 & lockdown, I have at last turned my attention to this most critical of items to very good effect. Hitherto I’ve used Deep Sky Stacker (DSS) for calibration & stacking, before moving to Photoshop for all other processing, which has usually produced satisfactory results. However, I’ve often thought more might be obtained from the data by using more powerful software combined with an improvement of my overall skills.

On taking up astrophotography it’s a shock when first looking at the camera’s data, which will usually produce a dark almost featureless image, represented by a very narrow, steep image histogram – a graphical representation of the tone and light collected by the exposures. This is because most of the image of the night sky will of course be dark, with precious few photons arriving from distant objects being photographed contained only within the said narrow histogram – the trick is to tease them out during processing in the so-called digital darkroom, thereby revealing the image within.

In the right hands Photoshop is an excellent tool for post processing but it’s no coincidence that most accomplished astrophotographers are using PixInsight (PI), for good reason: it is dedicated to astrophotography, is very powerful, whilst at the same time being very flexible. Unfortunately the learning curve for PixInsight is steep but from my recent experience very much worth the effort. Metaphorically speaking, I’m in the foothills of using PixInsight but now with sufficient knowledge to process images from start to finish, I have already successfully tackled complex LRGB images LBN 325 and NGC 6194. Subsequently I’ve turned my attention to re-processing old narrowband data, which first time round produced unsatisfactory results using Photoshop; this being as much the user as anything else.

Whilst PixInsight was the principal software for this re-processing, it was used in conjunction with Photoshop to achieve certain affects and other newly acquired dedicated software for specific tasks: Starnet++ to produce starless images and Topaz Denoise AI for noise reduction and sharpening. Using the HST palette in all cases, the workflow (see table at the end) was adapted for each image depending on the characteristics of the object. Before (top) and after (below) images are shown beneath, together with links to the original blogs for more background and imaging information.

NGC 281 Pacman Nebula, August 2019: Whilst the initial HaOO bicolour image looked good I struggled to do the same with the SHO version. However, the transformation after re-processing with PI is, as they say – a whole new ballgame. Vibrant colours have emerged from the previous somewhat gloomy image, together with detailed internal structures. Although somewhat artistic in character, I particularly like the starless version which is shown at the top of the page.

IC 1805 Heart Nebula, August 2018: Like Pacman the original bicolour processing was also successful but SHO much less so. Re-processing has brought out warm colours and details around the inner edge of the heart-shaped nebulosity but it is the striking blue inner region which highlights Melotte-15 at the centre that steals the show. Here fierce stellar forces associated with superhot, young open star clusters, model the adjacent dust clouds into features analogous to those of the Eagle Nebula’s Pillars of Creation.

NGC 2244 Rosette Nebula, February 2018: The Rosette was the most difficult data to re-process and therefore turned out to be the most satisfying. Similar to the Heart Nebula, the rose-like dark nebulous outer region and bright inner edge frames the dramatic, somewhat translucent pale blue inner area. Therein billowing, cloud-like blue nebulosity shows off various internal features, which include an open star cluster at the centre and the so-called Carnival of Animals marching across the lower right quadrant. Altogether new processing has transformed this image into something rather special.

NGC 7000 North America Nebula, August 2017: Although very happy with the original SHO image processed using Photoshop, the revised version is not so much better but different. Use of the SCNR function and subsequent PI and Photoshop colour adjustments have introduced greater detail overall, as well as produced more delicate colours, especially the diaphanous blue nebulosity around the ‘Gulf of Mexico’

NGC 1499 California Nebula, October 2017: In this case re-processing has brought out greater structure throughout the nebula and, to a lesser degree, improved the overall colour. However, the nature of the object, limited integration time and relative lack of what is faint OIII and SII data has probably limited the final impact.

Frankly I found PixInsight a complete pain to understand and use initially, however, with the help of online videos, tutorials and the recently published excellent Mastering PixInsight book, I believe the results more than justify the effort and speak for themselves; overall I’m very pleased with the outcome, which far exceeds my expectations. Notwithstanding, going forwards I can’t see PixInsight being my only processing software (though it could be) but it almost certainly will now become my main choice for post processing, where necessary supplemented by Photoshop and other packages dedicated to specific tasks. It’s a case of using the right tool for the job and the wider combination outlined provides much more flexibility, as well as producing excellent results. All I need now are clear skies!

OUTLINE HST NARROWBAND WORKFLOW*

ACTION	COMMENT
Alignment & Stacking	Deep Sky Stacker
NON-LINEAR PRE-PROCESSING
Dynamic Crop	All stacks
Dynamic Background Extraction (DBE)	Gradient removal
RGB Combination	SHO Hubble palette
Linear Fit
Background Neutralisation
Colour Calibration-1
Deconvolution (sometimes)	Not used here but can be if necessary
Noise Reduction	Use ACDNR or Topaz DeNoise AI
Histogram Transformation	Non-linear stretch
LINEAR PROCESSING
Curves Transformation (CT)	Preliminary to bring out colours but not too strong
Colour Calibration-2
SCNR	Remove Green Hue
Magenta star adjustment	If present + use PixelMath script
*Starnet++*	Separate Nebula & Stars
(a) Curves Transformation & / or (b) Colour Saturation	Colour punch Apply Range Mask to accentuate specific areas
Photoshop – selective colours	Further specific colour adjustment
Re-combine starless & stars images	PixelMath script + experiment with proportions
Final adjustments where necessary	DBE + CT + ACDNR or DeNoise AI + Linear / Curves adjustment

* PixInsight processing unless stated otherwise

Swan Adventures

November 12, 2020 by grahamrob in Broadband, Deep Sky Objects, Nebula, Widefield Imaging and tagged Cygnus | 2 Comments

I first visited the constellation of Cygnus soon after starting astrophotography, inevitably to image the Veil Nebula and North America (NAN) & Pelican Nebula, or parts thereof. As my abilities and equipment improved I’ve often returned to each of these popular targets, in the hope of obtaining a better image each time and I’m sure I will continue in this pursuit. However, such is the draw of these iconic objects that it’s easy to overlook other equally exciting targets within the same constellation.

Last year (2019) my attention was drawn to such a target in the form of DWB 111 or the Propeller Nebula, which I successfully imaged and thereby ignited my interest in the rich, very large HII-region of Cygnus (see above), within which imaging possibilities are almost endless. I therefore recently went back during this September to image two less popular targets located within the aforesaid HII-region; I had already imaged the NAN and Veil Nebula again in early September, on which occasion using my new Samyang 135mm f2 lens set-up to obtain wide-field shots.

After first imaging LBN 325 and other emission nebulae across the adjacent area, I turned my attention to a neighbouring part of the said HII-region of Cygnus, likewise found in the quadrant of Cygnus defined by the stars Deneb – Sadr – Delta Cygni. Similarly this area is full of numerous emission nebulae but furthermore here strikingly intercalated with dark nebula, star clusters and in particular reflection nebulae. Most prominent of these near the centre of the image is NGC 6914, vdB 131 & vdB32 (Main image top-of-the-page), which are conspicuously highlighted by associated bright blue nebulosity. Dotted throughout the rest of the image the use of HaLRGB picks out many other blue and rare yellow refection nebula and stars that all together make for an exciting image (Ha starless image above). Such is the quality and vastness of this part of Cygnus for potential image targets that I feel sure I’ll be coming back to this region for many years to come.

	IMAGING DETAILS
Category / Object	Reflection Nebula NGC 6914
Constellation	Cygnus
Distance	6,000 light-years
Size	2.5^o x 1.90^o
Apparent Magnitude	?

Scope	William Optics GT81 + Focal Reducer FL 382mm f4.72
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	William Optics 50mm guide scope
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600MM-Cool mono CMOS sensor
	FOV 2.65^o x 2.0^o Resolution 2.05”/pix Max. image size 4,656 x 3,520 pix
EFW	ZWOx8 + ZWO LRGB & Ha OIII SII 7nm filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker + PixInsight + Photoshop CS3 + Topaz AI Denoise
Image Location & Orientation	Centre: RA 20h 25’ 23.097” DEC +42^o 22’ 41.092” Top of image = approximately North
Exposures	36 @ 300 sec Ha + 37 x LGB 36 x R @ 180 sec Time: Ha 3hr LRGB 7hr 21min = Total 10hr 21 min
	@ 139 Gain 21 Offset @ -20^oC
Calibration	5 x 300 sec Ha + 10 X 180’ LRGB Darks, 20 x 1/4000 sec Bias 10 x HaLRGB Flats @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	17^th 20^th 21^st September 2020 @ +21.00h
Weather	Approx. 15^oC RH = 45- 70% 🌙 New – 22% waxing

Reach For The Sky

October 16, 2020 by grahamrob in AstroBin, Broadband, Deep Sky Objects, Narrowband, Nebula, Processing, Software and tagged Cygnus, LBN325, PixInsight | 3 Comments

In September I returned to the Cygnus constellation, popular for The North America and Veil Nebula at this time of the year but elsewhere often overlooked by astrophotographers. In particular the vast HII-region that is located around the Deneb-Sadr area which contains an abundance of exciting imaging opportunities, this time my target was LBN325 which contains numerous Ha emission nebulae, a dark nebula and a supernova remnant. To capture these features at their best, I chose to shoot, process and then combine separate HaOO narrowband and RGB images for the first time.

Integrating RGB data for better star colours and narrowband data for nebulosity turned out to be tricky but by removing the stars from the narrowband nebulosity and then processing the starless image before combining with RGB image manually eventually worked out well (see top-of-the-page image). However, the narrowband and broadband data had respectively been taken either side of the Meridian without plate solving and unfortunately my manual alignment was on this occasion poor. However, with careful cropping I was eventually able to able to align and combine each of the images, though at the cost of losing 25% of the overall field-of-view which did not overlap; see full size Ha-image below with interesting features along left and right edges which had to be cropped out to align the final narrowband and broadband images.

In addition to LBN325 there are a large number of other notable features (see Image Details table at the end & Nico Carver’s annotated image below – green outline delineates areas of my image). In addition to the many Ha emission nebulae, the most noteworthy are the dark nebula Barnard 345 and a large section of the Supernova Remnant G082.2+53. Some 100 light-years in total diameter, this OIII-rich feature is unfortunately too faint to be picked out in my image, which would require significantly more OIII data to be seen. Looking further afield of the image the continuing richness of the adjoining area cannot be overstated, which is beautifully seen in Nico Carver’s accompanying image (Northwestern Cygnus by Nico Carver is licensed under a CC BY-SA 4.0 License) – an 8-pannel 46-hour mosaic! I can only dream of such work but certainly hope to return to this area again when possible, in order to enjoy more of the exquisite objects that can be found across this truly exciting area of Cygnus. But for now there’s another story about this image.

For some time I’ve known that I had to improve my processing skills and to this end purchased PixInsight software at the beginning of the year. Very few of the best astrophotographers do not use this processing software but PixInsight has a notoriously steep learning curve and no doubt like many others I gave up after a few days! I can unequivocally say that PixInsight is by far the most user unfriendly software I’ve come across in nearly four decades; there’s no denying it’s abilities but the developers clearly gave very little thought to its users. Nonetheless, spurred on by the need to improve my images and the ‘opportunity’ of more time that Covid-19 has provided us all recently, I returned to PixInsight a number of times over the summer and slowly made progress.

Cropped HaLRGB M101 practice image from scratch – using Pixel Math to add Ha has worked within the galaxy but unfortunately seems to have spread into other areas too!

Using my existing data for M101, I first spent many days working through the calibration and integration process, which can only be described as exhausting! Undeterred and in an effort to speed up matters, I moved on to Batch Processing, which though helpful only partially assists the overall task of pre-processing and inevitably put PixInsight aside again in order to find renewed enthusiasm to continue. From this initial experience I had already come to one conclusion – that I would not be using PixInsight for calibration and integration, continuing for now with Deep Sky Stacker and possibly later switching to either Astro Pixel Processor (APP) or Astro Art, both of which get good user reviews.

From the results of others it’s clear that PixInsight is a route to better images and there is no shortage of online tutorials and books but hitherto I’d not found one that worked well for me. Online tutorials by Light Vortex Astronomy are an excellent learning aid but tricky to work with on screen and Harry’s Astro Shed video tutorials were also helpful but I needed a book on the matter to read, thumb through and casually refer to when needed. Then I got lucky!

It was my good fortune that in May a new text by Rogelio Bernal Andreo (AKA ‘RBA’) Mastering PixInsight became first digitally available and then in September was published as a book. The work is divided into two well thought out and presented volumes:

A comprehensive, easy-to-follow and understand description of how to use PixInsight
A reference guide providing more in-depth information on specific PixInsight processes

The two volumes come as a boxed set, are well bound and illustrated and for the first time (from my point-of-view) form an accessible, easy to use and helpful text on PixInsight. RBA deserves every success with this outstanding book(s) which I believe will transform the otherwise torrid experience of learning PixInsight. Armed with RBA’s Mastering PixInsight, Light Vortex Astronomy online tutorials, Harry’s Astro Shed and a other online videos, I’m pleased to say that I am now at last able to use PixInsight for processing and LBN325 is my first image; I should also mention Shawn Nielsen’s excellent Visible Dark YouTube channel, which demonstrates a number of very useful techniques.

As my first attempt to use PixInsight for processing, I’m pleased with the outcome of LBN 325 but realise there’s still much more to learn and, aside from the framing error, it’s clear that even more integration time is needed to get the best of LBN325 and its companions. Going forwards PixInsight and Photoshop both have their respective strengths and weaknesses and judicious use of various techniques from each is probably going to yield the best results. For now, at least, I feel the considerable time put into learning PixInsight is starting to pay off and I’ve finally turned a corner with my processing.

	IMAGING DETAILS
Object	LBN325 & 326 + Barnard 345 & SNR G082.2+5.3 DWB 156, 167, 165, 168, 170, 176,
Constellation	Cygnus
Distance	5,000 light-years?
Size	>2^o
Apparent Magnitude	NA

Scope	William Optics GT81 + Focal Reducer FL 382mm f4.72
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	William Optics 50mm guide scope
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600MM-Cool mono CMOS sensor
	FOV 2.65^o x 2.0^o Resolution 2.05”/pix Max. image size 4,656 x 3,520 pix
EFW	ZWO x8 + ZWO LRGB & Ha OIII SII 7nm filters
Capture & Processing	APT + PHD2 + DSS + PixInsight + Photoshop CS3 + Topaz Denoise AI
Image Location	Centre RA 20h 18’ 42.55” DEC +46 25’ 03.12”
Exposures	NB 300 sec x 53 Ha & x 38 OIII BB 60 sec x 49 R, x 35 G & x 50 B Time: NB 7hr 58 min BB 2hr 14 min TOTAL 9hr 49 min
	@ 139 Gain 21 Offset @ -20^oC
Calibration	Darks 5 x 300 sec & 10 X 60’ 20 x 1/4000 sec Bias 5 x Ha & OIII Flats 10 x LRGB Flats @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	9^th 13^th & 14^th September 2020 @ +21.00h
Weather	Approx. 15-20^oC RH <=60% 🌙 20% waning

Reflections 2019

December 21, 2019 by grahamrob in Broadband, Deep Sky Objects, Galaxy, General Astronomy, Imaging, Mosaic, Narrowband, Nebula, Processing, Software, Solar system, Widefield Imaging and tagged Andromeda, Horsehead Nebula, M101, M42 Great Orion Nebula, M51, M74, M78, Milky Way, Wizzard Nebula | Leave a comment

The website Watch This Space (Man) began in 2015 as I started out in astronomy and is a record of my personal journey, comments and thoughts. Apart from the main blog, the website also contains links to other astrophotographers, astronomy tools, astronomy weather, and scientific papers etc., which can be accessed from the top menu.

Whilst there is a photo gallery of my work in this website, an overview of the better images can be found in the My Astrophotography FLICKR album, which can be found in the GALLERY menu. Furthermore, this year I took the plunge and joined the Astrobin community, where my images can be found using the appropriate link also in the GALLERY menu.

Heat Map 2019

During the past year the site was visited from 64 different countries, literally from every corner of the world. I always like to hear from anybody out there – comments, questions, help or just to say hello – and can be contacted via details given in the ABOUT menu section or just leave a comment on any item if you prefer.

Reflections is compiled at the end of each year as a review of my astronomy and astrophotography during the previous twelve months, together with some thoughts on possible future developments.

Overview, Images & Goals for 2020

The past year’s plan was simple: build-on and experiment with developments from the previous year, in particular using Plate Solving to achieve longer integration times and explore further the north sky, which I could now see from the new Shed Observatory and operates during the spring and summer months.

By routinely using Plate Solving integration times, now obtained over a number of nights or even months, have increased by up to four-fold compared to previous years. As a result I concentrated on less objects but for longer time, achieving between 6 to 8 hours of subs on some occasions, the limiting factor as ever being British weather. Although quite modest compared to those able to use fixed observatories, or in clear, dry climates with Bortle 1 or 2 skies, I was very pleased with the positive impact this had on my images.

Starting astronomy and astrophotography somewhat late in the day a few years ago, like many others after retirement, the learning curve was steep and often frustrating. There were times I’ve almost considered giving up but with perseverance I’ve made progress and often get great pleasure from some of the results, as well as just enjoying and learning about this wonderful subject. For me it is just a hobby but recognising some of my achievements and abilities acquired since starting out in 2014, I was especially proud this year to be elected a Fellow of the Royal Astronomical Society. For all the help in reaching this point, I’d like to thank all those who have helped me from the astronomy community, wherever they are.

Favourite Images

My weakness in astrophotography remains processing but having at last obtained some good integration times, this year I made a greater effort to improve these techniques – with some success. Adopting the theme less is more, I imaged just 17 different objects this year – of which nine were full narrow or broadfband images, with the rest being experimental or DSLR – with a total integration time of 65 hours (2018: 25 objects & 43 hours). The resulting images turned out well, achieving Picture of the Week on the British Astronomical Association website on six occasions. It’s therefore difficult to choose favourites from this select group based on merit alone, so this year’s favourites (see below) represent those good images that also mark a significant milestone in my astrophotography. Detailed reviews of these and all other images from 2019 are discussed in dedicated articles that can be found via the Blog Index under the ABOUT dropdown menu.

SHO2 CompF (Large)

Horsehead & Flame Nebula: Usually imaged in LRGB broadband, this narrowband SHO version produced a very different affect and colours, whilst also showing the beauty of the accompanying clouds of interstellar gas and dust. Taken over three nights, at nearly 7-hours, this image was also one of my longest integration times to date.

M101 HaLRGB final Closeup

M101 Pinwheel Galaxy: Given Bortle 5-6 skies, being on the Gatwick Airport flightpath and a using a small refractor, I struggle to image galaxies and often LRGB images in general from Fairvale Observatory. However, on this occasion the combination of 5-hours HaLRGB subs and new processing techniques to enhance the colours, M101 proved the exception and is perhaps my first decent classic spiral galaxy imaged from home. Moreover, the HII regions light up along the spiral arms with the addition of Ha wavelength, producing a dazzling and dynamic image.

Picture saved with settings embedded.

Heart & Soul Nebula: Combining existing data from 2018 of the Heart Nebula and new 2019 data of the Soul Nebula + the intervening space, this is my first albeit modest mosaic, which promises to open up significant possibilities in the future.

RECORD CARD – 2019
Goal	Specifics / Results	Outcome
Improve broadband and narrowband imaging	Achieved major increase of image integration times and overall quality.	MUCH, MUCH BETTER
*Improve processing*	Continuing to make slow improvements, with greater use of new Photoshop techniques.	BETTER
Expand & Improve Widefield Imaging	Despite some good images of the Milky Way in the USA, I never used the Vixen Polarie tracking mount and did not make it to any other dark sky sites = disappointing.	FAILED

My objectives in 2019 mostly went well in (see above), so here goes for 2020:

Imaging: There’s always scope to improve imaging techniques but probably most of all I still need to improve guiding quality and increase exposure and image integration times even further.

Mosaic: Expand the use of mosaic imaging using Plate Solving and new CdC planning software.

Improve processing: I expect this will continue to be something of a challenge for some time to come unless I go to the dark side and adopt software such as PixInsight & / or APP.

New Observatory: Unfortunately this will not be a fixed obsy whilst I continue to live here at Fairvale which is unsuitable. However, I’m hopeful that another location between the Main (North) Observatory and the Shed Observatory might open up the north sky better and by getting away from the high hedges that surround the garden allow longer imaging sessions than can be currently obtained at the Shed.

Other: My mind is always thinking about larger telescopes or a dual rig and / or a new high-end encoded mount but probably not until I make further progress with the above goals and / or move to a better dark sky location – dreaming is part of astrophotography = watch this space!

Although you never know, I don’t see any major breakthroughs in the coming year but more of the same – revisiting familiar objects in order to obtain new image versions based on greater integration time and hopefully using mosaic techniques to build-out images in order to encompass wider areas of the sky. This year I was surprised to discover objects that I had hitherto considered out of reach from my location (M101, M51 etc.), as well as exciting features that were completely new to me and still hold great promise e.g. DWB 111 AKA the Propeller Nebula.

Looking back I’m very happy to say 2019 was an excellent year for astronomy and astrophotography, almost certainly my best yet. You can’t ask for more than that and I hope that WTSM’s Reflections 2020 will record further such success.

Watch this space!

2019 CHRONICLE

Below is a quarter by quarter summary of my astronomy and astrophotography for the year, followed by an imaging record.

JANUARY TO MARCH

Towards the end of 2018 I decided to undertake a project, with the prime objective to gather a much longer period of integration than hitherto achieved by using my newly developed skill of Plate Solving. I’d previously imaged the Horsehead and Flame Nebula in the more traditional colour palette, either with a modded DSLR or by LRGB broadband. However, I’d recently seen this iconic image undertaken using the Hubble Palette to great affect and was inspired to do the same myself. Thereafter, for more than 2-months the clouds rolled in and I thought my project would then be impossible, not least because by now Orion had crossed the Meridian in the early evening and imaging times were at best limited. But as is often the case with astrophotography everything suddenly changed and it was game on!

The first evening of clear skies since 11^th November 2018 coincided with the full lunar eclipse on 21^st January, which I was therefore able to image once again. Then six days later a very untypical clear and quite warm period of weather arrived and I was able to complete my intended project after all, with further time to image both the Great Orion Nebula and the reflection nebula M78 + Barnard’s Loop (see images below).

HaLRGB2FINALcrop (Large)

Combined +180 degrees 3+5min HaLRGB (Large)

Achieving much longer integration times of between 5 and nearly 8-hours, the impact on the resulting images was transformative. I was especially pleased with the outcome of the Horsehead project in SHO (see Favourites Images section) but found the Ha-only starless version of the same scene (see below) particularly mesmerising, as the large HII structures throughout this region bring the image to life.

NGC 2024 Ha Starless2

By the end of February the night sky at 51^o latitude has moved inexorably on to the so-called Galaxy Season, which provides something of a dearth of imaging opportunities for my 81mm telescope. However, with a good patch of weather at the end of March, whilst experimenting with the Leo Group I noticed that small areas of Ursa Major region could be seen directly above for a couple of hours, which to my surprise opened up a whole new world of possibilities hitherto considered unavailable. Shortly after I managed to obtain almost 5-hours of data on M101 the Pinwheel Galaxy, which is one of my best galaxy images taken from Fairvale Observatory (see Favourite Images section).

APRIL TO JUNE

Having discovered the albeit limited possibilities of seeing Ursa Major, I moved to the Shed Observatory early in April, which by then afforded slightly better views of the same area of sky and thereby to my great joy provided the possibility of imaging the wonderful Whirlpool Galaxy, M51. Unfortunately time was somewhat limited but it was better than nothing and I was thrilled to obtain an image of this wonderful object for the first time. Weather permitting I’ll be back for more data in 2020 with which to build on the promising result obtained this year.

LRGB Image FINALX2 (Large)

By the end of April just 8-weeks away from the summer solstice astronomical darkness is in short supply. Fortunately having moved earlier to the Shed Observatory this year, I was in a good position to return to inaging the Bodes and Cigar Galaxies (see below), which had been my first ever image of north sky objects in 2018.

LRGBFinal (Large)

JULY TO SEPTEMBER

From May until late July the absence of Astronomical darkness makes astronomy difficult and frankly having progressed from the time of being a beginner, it is quite refreshing to take a break. Therefore it was only after an evening viewing the partial eclipse on 16^th July and a brief experiment with the Wizzard Nebula (something for the future) at the beginning of August, that much later I returned to astrophotography seriously.

SHO2SCcrop (Large)

Having messed up imaging the Soul Nebula with poor framing in 2018 and being at the Shed Observatory, I decided to re-image the Soul properly, together with some of the adjacent sky in order to combine the new data with last year’s adjacent Heart Nebula to form a mosaic of both objects. I don’t know why but this was my first attempt at a mosaic. Only very recently has integrated software for mosaic planning combining Cartes de Ciel and Astrophotography Tool for image capture has been released. However, on this occasion I planned and implemented the said mosaic imaging manually, with a satisfying outcome (see Favourite Images section) but with the new software now available I hope to embark on more extensive mosaic projects in the near future.

This year’s astrophotography has followed two themes, the aforementioned ‘less is more’ with the aim of producing better images using much greater integration times. The second has been largely determined by chance, being the discovery of new objects that had hitherto either been unknown to me or considered to be out of view from Fairvale Observatory; the combination of my house, very high hedges + trees and adjacent houses obscures large swathes of the night sky. Earlier in the year such chance had led me to the M101 and M51 galaxies and in the autumn it was first the iconic Pacman Nebula and then an exciting area of Cygnus constellation.

Pacman is not particularly large for my equipment but nevertheless produced a decent narrowband image, my last from the Shed Observatory for this year. Not until late September did the clouds again relent for my next project that initially seemed something of a long shot but actually turned out very well. The Propeller Nebula is located in a vast HII region of the Cygnus Constellation, which from my point-of-view was a complete surprise. At some 25 arc seconds the nebula is again on the small side for my equipment but the complexity of the adjacent HII region transforms the wider image into something really spectacular (SHO version below), which I certainly intend to visit again next year to build on the current data and explore further afield the HII region which presents exciting possibilities.

SHO F HLVG (Large)

A subsequent long trip to the USA stopped all astronomy in Surrey but a couple of evenings out in Wyoming and Utah produced some incredible dark skies and DSLR Milky Way images (see below). Despite the remoteness of Spilt Mountain in the UTAH section of the Dinosaur National Monument – designated a Dark Sky Area – whilst imaging at 20 second exposures only one-in-ten images were without a plane track, very sad.

IMG_2345 ComboX

OCTOBER TO DECEMBER

Prior to the arrival of Orion and other fun objects of the mid-winter night skies, imaging opportunities are sparse with my equipment but it’s been a couple of years since I last imaged M31 the Andromeda Galaxy and therefore for two evenings in late October it was time to give our neighbour the extended integration treatment. At 7½ hours data acquisition went well but although the processed image is probably my best yet of this object, there’s room for improvement, which I suspect will require a move to more advanced processing software?

HaLRGBx5b (Large)

ASTROMINAGING RECORD 2019

No	Date	Type	Object	Name

1	21/01/19	DSLR	Full Lunar Eclipse

2	27/01/19*	NB	Barnard-33 & NGC 2024	Horsehead & Flame Nebula

3	23/02/19*	Combo	M42	Great Orion Nebula

4	25/02/19*	Combo	M78	Reflection Nebula Orion

5	12/03/19	BB	NGC443/444	Jellyfish Nebula

6	24/03/19	Combo	M95/96/105	Leo-1 Group

7	29/03/19*	Combo	M101	Pinwheel Galaxy

8	10/04/19	Combo	M51	Whirlpool Galaxy

9	13/04/19	BB	M81 & m82	Bodes & Cigar Galaxies

10	16/07/19	DSLR	Partial Lunar Eclipse

11	02/08/19	NB	NGC 7380	Wizzard Nebula

12	23/08/19*	BB	IC 1848	Soul Nebula + Mosaic Link

13	26/08/19	NB	NGC 281	PacMan Nebula

14	05/09/19*	NB	DWB 111	Propeller Nebula

15	Sept	DSLR	Milky Way	Split Mountain Utah

16	22/10/19*	Combo	M31	Andromeda Galaxy

17	18/11/19	BB	M74	Galaxy

18	18/11/18	NB	SH2-240	Spaghetti Nebula

*multiple evenings Combo = HaLRGB Underlined = BAA published

POSTSCRIPT

The ones that got away – imaged but not seen in WTSM this year – warts and all

RHB_2ajelly (Medium)

I saw some wonderful narrowband versions of the supernova remnant IC 443 Jellyfish Nebula this year, in particular adopting a wider view to incoporate its sentinel-like parner stars Tejat (Mu Geminorum) left and the tripple star Propus (Eta Geminorum) right, together with the reflection nebula IC 444 in the background. As an experiment I think it may hold promise but will require a lot more integration time to improve the quality, colour and bring out more of IC 444.

M95_96_105 (Medium)

I’ve tried the Leo-1 group (M95/96/105) before but, as they say, if you don’t succeed try again. Unfortunately the passage of time didn’t help – I need a larger telescope to do these critters justice!

IMG_2336 (Large)

Dinosaur National Monument – Split Mountain, Utah. Even at this wonderfully remote location, which is one of the darkest places in the USA, passing planes still get in the way of a good image – just like at Fairvale Observatory!

M74 LRGBx (Medium)

At <=10 arc minutes the spiral galaxy M74 is too much for my equipment.

SH2-240 AB combined Ha Stretch (Large)

Located between the constellations Auriga and Gemini, SH2-240, Simeis 147 AKA the Spaghetti Nebula is a very large (+3 degrees) supernova remnant but it’s very low brightness makes imaging extremely difficult. In fact prior to and during capture in Ha-wavelength, I had no idea if it was even within the image frame. Aggressive stretching shows that it was there but only much darker skies and probably longer exposure time is likely to produce a more viable picture.

One In A Trillion

December 7, 2019 by grahamrob in Broadband, Deep Sky Objects, Galaxy, Narrowband and tagged Andromeda, Milky Way | 1 Comment

HaLRGBx5b (Large)

Since the early twentieth century when Edwin Hubble recognized that the Milky Way was not the only galaxy, it has been estimated that there are some two hundred billion galaxies in the observable Universe; the Milky Way is thought to contain about 250 billion stars +/- 150 billion. Research in 2016 now suggests this might significantly underestimate the number of galaxies, which could exceed more than two trillion!

Perhaps the ultimate astrophotograph is the Hubble Ultra Deep field image. At just one seventeenth a degree of the sky in size it shows objects up to some 13 billion light-years away, which is the furthest visible light image ever taken and contains some 10,000 galaxies.

Somewhat closer to home at a mere 2.5 million light-years, is our nearest neighbour M31, AKA the Andromeda galaxy. Like the Milky Way, Andromeda is a spiral galaxy with a concentrated bulge of matter at the centre, surrounded by a disk of gas, dust and stars and an immense halo. Andromeda and the Milky Way are moving inexorably together on a collision course at the rate of about 70 miles per second and are expeted to meet in about 4.5-billion years. However, such is the space between the matter in each galaxy, the most likely outcome will not be a collision but the interaction of gravity between the opposing masses, leading to their eventual coalescence into a new giant galaxy.

Since starting astroimaging I’ve often returned to Andromeda at this time of the year ( 21/08/14 Meet the Neighbours, 09/10/15 Space Oddysey, 27/10/15 Overspill, 03/11/17 Galactic Neighbours), it is after all one of the magnificent features of the night sky. At some 3^o x 1^oin size, with an apparent magnitude of +3.44 the galaxy completely fills the field-of-view of my equipment but I’ve always found imaging and particularly processing to be somewhat challenging. As ever integration time is a major determinant of final image quality and this time I was able to obtain 7.5 hours over two nights, far greater than on previous occasions. However, the overwhelming brightness of the galaxy’s core is always difficult to control during capture and processing and this was again to be the case.

Notwithstanding, I’m pleased to say that after four previous occasions imaging Andromeda, the combination of much greater integration time and better processing is this time evident in an improved image, which is overall more powerful. Moreover, the galaxy’s internal structure has been enhanced with the addition of Ha-subs, which highlight large HII-areas of star formation that broadly follow the dust lanes. However, you can never have too many subs and I’ll inevitably return again to this object in order to add to this year’s data and hopefully further improve processing so as to tame the subtleties that make Andromeda such a wonderful feature for astrophptography.

	IMAGING DETAILS
Object	M31 the Andromeda galaxy.
Constellation	Andromeda
Distance	2.5 million light-years
Size	3.2^o x 1^o or 220,000 light-years
Apparent Magnitude	+3.44

Scope	William Optics GT81 + Focal Reducer FL 382mm f4.72
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	William Optics 50mm guide scope
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600M M-Cool mono CMOS sensor
	FOV 2.65^o x 2.0^o Resolution 2.05”/pix Max. image size 4,656 x 3,520 pix
EFW	ZWOx8 + ZWO LRGB & Ha OIII SII 7nm filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker & Photoshop CS3
Image Location & Orientation	Centre RA 00:42:44 DEC 41:16:04 Top = North
Exposures	L 44 x 180 sec R 26 x 180 sec G 26 x 180 B 27 x 180sec Ha 27 x 180sec (Total time: 7hr 30 minutes)
	@ 139 Gain 21 Offset @ -20^oC
Calibration	10 x 180 sec & 15 x 60 sec Darks 20 x 1/4000 sec Bias 10 x HaLRGB Flats @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	22^nd & 27^th October 2019 @ +/-19.00h
Weather	Approx. 7^oC RH >=75% 🌙 50% to 5% waning

Other Worlds

June 10, 2019 by grahamrob in Broadband, Galaxy, History, Imaging and tagged Canes Venatici, Ursa Major, Whirlpool Galaxy | 1 Comment

LRGB Image FINALX2 (Large)

Being galaxy season it was appropriate that the BAA spring meeting this year on 27^th April was all about – galaxies. This was my first BAA meeting and I’m pleased to say it was well attended and very worthwhile, I especially enjoyed the following presentations:

Prof. Richard Ellis: The Quest for “Cosmic Dawn”;
Prof. Chris Impey: Einstein’s Monsters: Black Holes at the Heart of Galaxies;
Stewart Moore: Galaxies: A Brief History of Discovery, and
Owen Brazell: Observing Galaxy Clusters.

It seems incredible that just 100-years ago the prevailing view was that Universe consisted entirely of the Milky Way, though that was soon about to change. Whilst Immanuel Kant had proposed the possibility of galaxies outside our own as long ago as 1755, it was not until Edwin Hubble’s work at the Mount Wilson Observatory, California that the existence of other worlds, in the form of galaxies, was proven and accepted during the period between 1924 and 1929.

Following Copernicus’s controversial theory in 1543 that the Earth orbited the Sun, the evidence this time that there was much, much more beyond the Milky Way was equally profound in its implications, if not more so. However, I was surprised to learn that it was Vesto Slipher and not Hubble who discovered the redshift of galaxies that was fundamental to understanding that galaxies existed outside the Milky Way that were moving away from us – it would seem to me that he deserves much greater credit as well as Hubble for this work. The current estimate is that there are some 100 to 200 billion galaxies in the observable universe but new research now estimates that the total number is likely to be at least ten times greater! Either way there are many other worlds out there.

After recently learning that I could after all see and image a few larger galaxies from Fairvale Observatory in-and-around the Ursa Major constellation, it was to my great delight when I then discovered that one of them was M51 AKA the Whirlpool Galaxy. I’ve seen many images of this wonderful object and was frustrated that it seemed to be completely out of sight from here but thankfully that is not the case. Armed with this knowledge, following an imaging session of M101 at the end of March, I therefore went on and immediately grabbed a single Luminance test sub of M51 (below) before it disappeared behind the roof of my house, (a) because I could, and (b) to see how it looked with my equipment. The answer was that it was almost certainly a viable target for another night when more time was available.

M51 KStar

While located just above the star Alkaid in Ursa Major, M51 is now included within the nearby constellation Canes Venatici; created by Johannes Hevelius in the 17^th Century, M51 was previously in Ursa Major. One of the more famous grand-design spiral galaxies i.e. with prominent well-defined spiral arms, the Whirlpool Galaxy forms a striking image as it interacts and distorts the dwarf galaxy NGC 5195 located at the tail of its outer second arm. The exquisite structure of M51 is further enhanced by large star-forming regions along the spirals, which are picked out by the associated hydrogen alpha gases.

Timing is everything: M51 is in a tricky position seen from Fairvale Observatory, obscured for much of the time at the north viewing location by the house and from the south location by a 20ft hedge – in between there’s a maximum window of no more than 2.5 hours for imaging!

The smaller dimensions of the M51 galaxy would normally place it at the limit of my equipment for imaging but is helped by its aforementioned clear-cut features, strong colours, favourable apparent magnitude and its location towards the zenith immediately above my observatory. This has long been in my top-10 ‘must-do’ imaging list but hitherto was thought to be out of view. Unlike M101, which lies below Alkaid i.e. south, being further north the imaging time of M51 from Fairvale Observatory North is even shorter before it too retreats behind the rooftop. However, this year I decided to move early to the summer location at the bottom of the garden – Fairvale Observatory South – where it was possible to gain a slightly longer view, though still only just over two hours before it disappears for the night, this time behind the adjacent 20-foot hedge!

It’s clear that the final LRGB image would be greatly enhanced with further integration time and the addition of Ha-wavelength but for now I’m content that at last I’ve managed to capture this spectacular object on camera. Skies permitting I hope to return to the Whirlpool and its companion NGC 5195 as soon as possible.

	IMAGING DETAILS
Object	M51 The Whirlpool Galaxy & NGC 5951
Constellation	Canes Venatici
Distance	23 million light-years
Size	11.2’ x 6.9’ or 43,000 light-years (M51 only)
Apparent Magnitude	+8.4

Scope	William Optics GT81 + Focal Reducer FL 382mm f4.72
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	William Optics 50mm guide scope
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600MM-Cool mono CMOS sensor
	FOV 2.65^o x 2.0^o Resolution 2.05”/pix Max. image size 4,656 x 3,520 pix
EFW	ZWO x8 ZWO LRGB & Ha OIII SII 7nm filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker & Photoshop CS3
Image Location & Orientation	Centre RA 13:30:03 DEC 47:11:43 Top = South Bottom = North
Exposures	(A) L 18 x 180 sec RG 9×180 sec B 10 x 180 (Total time: 2hr 18 minutes)
	@ 139 Gain 21 Offset @ -20^oC
Calibration	10 x 180 sec Darks 20 x 1/4000 sec Bias 10 x HaLRGB Flats @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	10^th April 2019 @ +22.00h
Weather	Approx. 6^oC RH 60% 🌙 ¼ waxing

Fireworks

May 23, 2019 by grahamrob in Broadband, Deep Sky Objects, Galaxy, General Astronomy, Imaging and tagged M101, Pinwheel Galaxy, Ursa Major | 2 Comments

HaLRGB final-denoise2-denoise-PS (Large)

At Fairvale Observatory North it’s normal that I struggle to find suitable objects when the so-called Galaxy Season arrives in late winter through spring. Despite the abundance of galaxies my William Optics 81mm aperture rules out all but a few for imaging as they are mostly just too small. However, smaller galaxies that make up features such as Markarian’s Chain and the Leo group do produce a pleasing widefield image full of the so-called faint-fuzzies but hitherto with the exception of M31 the Andromeda galaxy I’ve struggled to obtain the real thing – a decent, full-on spiral galaxy – they are there of course but are either obscured to the north by my house and trees or, as indicated, are too small for my equipment to resolve properly.

M95_96 Anotated

Nonetheless, this year after playing around imaging the aforesaid Leo Group (see above), I looked directly above the observatory and to my surprise discovered a new world of galaxies close to the Zenith that were just visible, briefly transiting along the southern edge of the house roof, which included a few large classics in-and-around the constellation Ursa Major. After 2-hours imaging the Leo group time was too short for a serious attempt at any of these galaxies but nonetheless was sufficient to experiment with what looked like a potential target, the wonderful M101 the Pinwheel Galaxy, which at over 28 arc seconds showed real potential with only 42 minutes of subs before it disappeared out of sight for the night. Moreover, large parts of Ursa Major and nearby galaxies also briefly appeared at other times on the night from behind the roof, tracking close to the gutter for nearly 2.5 hours before returning behind the roof in a similar manner to M101. Thus assuming full set-up could be achieved earlier in the evening, this seemed to provide a window of opportunity that I grasped over two subsequent evenings with a very satisfactory outcome.

With nearly 5-hours of subs, processing of M101 would be a challenge in order to bring out the galaxy’s colours and perhaps highlight the stellar nursery areas that are found along the spiral arms and are rich in Ha-light. To do this I first changed the RGB image stack to Lab Colour in Photoshop, increased the saturation in the (a) and (b) channels before returning to RGB mode. This had the desired effect of successfully enhancing the colours, which can otherwise look washed-out after stacking, stretching and combining. After this I split the RGB channels and pasted the Ha-stack into the Red channel, before re-combining again into an RGB image, at which point the H II regions along the spiral arms just lit up! These were both new processing techniques for me that greatly improved the final image and hold great promise for processing HaLRGB objects in the future.

M101 closeup data crop

M101 widefield data crop

The final image (top of the page + crop below) far exceeded my expectations in detail and colour, showing off much of the galaxy’s wonderful structure and the aforementioned HII regions. There’s no doubt that further integration time will benefit the faint extremities of the galaxy but for now it was a very satisfying outcome of a spectacular object that hitherto I thought was beyond my seeing at Fairvale Observatory. Also noteworthy, the image has caught a plethora of companion galaxies close to and around M101 (see annotated images above), most conspicuous of which is the classic side-view of NGC 5422 (left of M101) and the more unusual dwarf spiral galaxy NGC 5474 (right of M101), which has been noticeably distorted by gravitational interaction with the Pinwheel itself. All-in-all a fine display of galactic fireworks worthy of November 5^th.

M101 HaLRGB crop-denoise-denoisePS

	IMAGING DETAILS
Object	M101 Pinwheel galaxy
Constellation	Ursa Major
Distance	20.9 million light-years
Size	28.8’ x 26.9’ or 170,000 light-years
Apparent Magnitude	+7.86

Scope	William Optics GT81 + Focal Reducer FL 382mm f4.72
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	William Optics 50mm guide scope
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600MM-Cool mono CMOS sensor
	FOV 2.65^o x 2.0^o Resolution 2.05”/pix Max. image size 4,656 x 3,520 pix
EFW	ZWOx8 + ZWO LRGB & Ha OIII SII 7nm filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker & Photoshop CS3
Image Location & Orientation	Centre RA 14:03:15 DEC 54:20:46 Top = North
Exposures	(A) L 31 x 180 sec HaRGB each 16×180 sec (Total time:4hr 45 minutes)
	@ 139 Gain 21 Offset @ -20^oC
Calibration	10 x 180 sec & 15 x 60 sec Darks 20 x 1/4000 sec Bias 10 x HaLRGB Flats @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	29^th & 31^st March 2019 @ +22.00h
Weather	Approx. 8^oC RH <=70% 🌙 ¼ waning