The Journey

November 16, 2021 by grahamrob in Deep Sky Objects, Galaxy, General Astronomy, Imaging, Narrowband, Processing, Universe and tagged Andromeda | Leave a comment

A year after taking up astronomy as a hobby, at the behest of my elder daughter I started this blog in 2014. Describing the objective and content of the blog I adopted the strapline “A personal discovery of the Universe through astronomy and astrophotography”, which could also be described as a journey. In reality it’s been an adventure consisting of two threads: the knowledge and related science of astronomy and the challenge of astrophotography. As we on Earth pass through space whilst at the same time rotating 360^o each year around the sun our view of the night sky changes month-by-month, inevitably returning to the same perspective each 365-days. Against this background I therefore often return to certain objects every few years hopefully armed with new astrophotography skills in pursuit of an even better image.

Following such a path I’ve already imaged M31 the Andromeda Galaxy on four separate occasions since 2015, each time enthralled by the majesty and beauty of this barred spiral galaxy. Notwithstanding, it was clear to me that there was significant scope for improvement of the previous images with both better data and processing. Since the last attempt in October 2019 a myriad of positive developments have taken place of which perhaps three stand out: multi-star guiding, the purchase of Chroma filters and in particular the use of PixInsight image for processing – all have been game changers, so much so that reprocessing that image now also looks good – see below.

However, whilst the said progress has already been transformative to my astrophotography during the past year, inevitabky it is imaging conditions that play the most critical role, especially in England. Fortunately during this autumn in both October and November for once the new moon coincided with clear skies, providing no less than six nights over which I was able to obtain almost 12-hours of some of perhaps my best ever data. Based on this I’ve been careful to apply my best new processing skills and am thankful that the final HaLRGB image has turned out very well. In particular, the dust lanes stand out against the bright core and surrounding blue intergalactic dust and gases, which are themselves punctuated by the bright red regions rich in Ha light.

In the blogs that accompanied previous Andromeda images I’ve often referred to the galaxy as a neighbour of the Milky Way but really we are part of the same family known as the Local Group. Some 10-million light years in diameter, more than 30 galaxies form two collections around the two largest galaxies of Andromeda and the Milky Way. Gravitational forces play the central role in controlling this group, especially Andromeda which is itself moving towards the Milky Way at about 70 miles per second and is destined to merge in about +/- 4 billion years; recent studies indicate that an outer halo of stars extending up to 2-billion light years from Andromeda may be in the influence of the galaxy, suggesting this event may already have started!

Thereby my personal journey of astrophotography is set to continue somewhat in parallel with that of Andromeda, which will I am sure lead to further hopefully even better images of this exciting deep sky object that is perfect for my equipment – after all we’re getting closer at the rate of 2,207,520,000 miles each year!

	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 guide 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	ZWO x8 EFW + Chroma LRGB & Ha OIII SII 3nm filters
Capture & Processing	Astro Photography Tool , Deep Sky Stacker, PixInsight 1.8.8-8, Photoshop CS3 & Topaz AI Denoise
Image Location & Orientation	Original image centre RA 00:42:48 DEC 41:15:05 Final image rotated 180^o i.e. Bottom = North + 5% crop
Exposures	L 71 x 60 sec R17 G 20 B 27 x 300 sec Ha 35 x 600 sec Total time: 11hr 46 minutes
	@ 139 Gain 21 Offset @ -20^oC
Calibration	Darks 5 x 600 sec + 5 x 300 sec + 60 x 60 sec HaLRGB Flats & Dark Flats x15 each @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	1^st 5^th 6^th 8^th 9^th October & 4^th November 2021 @ +/-19.00h
Weather	Approx. 14^o to 5^oC RH >=65% to +85% 🌙 New Moon

Night Safari

November 2, 2021 by grahamrob in Deep Sky Objects, Equipment, Imaging, Narrowband, Nebula and tagged Cepheus | Leave a comment

A very large emission nebula, the so-called Elephant’s Trunk Nebula in the Cepheus constellation is rightly one of astrophotography’s most iconic images. Unfortunately my house obscures northern views of the sky from the main observatory and I’ve therefore only imaged this once before in 2018 with some success but definite room for improvement. However, using a Takahashi FSQ 106 located at the DSW observatory in New Mexico, USA during Q3 there were no such constraints, which has resulted in a 29.5 hour data set that forms the foundation of this exciting HaSHO image.

SH2-131 consists of glowing gases illuminated by an open star cluster, which is divided by lanes of dark interstellar dust clouds. The ‘trunk’ itself, designated IC 1396A, dominates the centre of this image and is spectacularly illuminated from behind by a bright star forming region; a longer focal length combined with the QSI camera and 30% crop has produced much closer view than previoulsy in 2018. Together with the Cave Nebula, Fyling Bat and Giant Squid Nebula, the dark nebula LDN-1250 and now the Elephant Trunk Nebula, Cepheus, has proved a very productive area for me this year.

	IMAGING DETAILS
Object	Elephant’s Trunk Nebula SH2-131 (IC 1396)
Constellation	Cepheus
Distance	2,400 light-years
Size	45’ Trunk only
Apparent Magnitude	+3.5 to 5.7

Scope	Takahashi FSQ 106 FL 530mm f/5 = Moonlight Crawler focuser
Mount	Paramount MyT
Guiding	Yes
Camera	QSI 683-WSGB KAF-8300 full frame CCD sensor 5.4nm pixels
	FOV 1.94o x 1.46o Resolution 2.1”/pix Image array 3326 x 2507 pix
Processing	Deep Sky Stacker, PixInsight 1.8.8-8, Photoshop CS3 Topaz AI Denoise
Image Location on	Centre RA 21:34:59.08 DEC +57:28:05.86
Exposures	22 Ha, 18 SII & 15 OIII x 1,800 sec Total Time: 27hr 30 min
Calibration	4 x 1,800 sec Darks 34 Ha SII OIII Flats 32 Flat Darks
Location & Darkness	Deep Sky West – amateur hosting facility near Rowe, New Mexico, USA SQM typically >= 21.7
Date & Time	5^th August to 27^th September 2021

The Well & The Butterfly

September 12, 2021 by grahamrob in AstroBin, Deep Sky Objects, General Astronomy, Imaging, Narrowband, Nebula and tagged Cygnus | Leave a comment

Located within the Orion Arm of the Milky Way galaxy is the Gamma Cygni nebula, a diffuse emission nebula that surrounds the star of the same name, otherwise better known as Sadr. Moreover, this large area forms part of an even bigger HII-region that is mainly (80%) located in the north and east quadrants of the so-called Cygnus Cross, which is defined by the stars Deneb – Sadr – Delta Cygni – Albireo – Aljanah (see below).

This vast area passes directly high overhead at this time the year before disappearing behind the house roofline in the early morning hours and has already provided many exciting imaging opportunities for me in the past. The heart (not the centre) of the region is the supergiant star Sadr and I first imaged this area in autumn 2015 using my modded DSLR camera. A return visit was therefore long overdue and this time I set out to better capture the so-called Butterfly Nebula in narrowband wavelengths.

The resulting data has been processed to good effect as an SHO image (see top-of-the-page) using the Hubble Palette techniques. Other than the dominant supergiant star Sadr and widespread colourful nebulosity, two significant features are worthy of note in the final image. Either side of the almost central dark rift that divides the image laterally, are two large bright areas which together form the ‘wings’ of the so-called Butterfly Nebula IC 1318-C (right = south) and IC 1318-B (left = north). Furthermore, just beyond the Butterfly’s left wing north of Sadr is the young, bright open star cluster NGC 6910.

Finished well with submersible water pump & floodlight (turned off for astronomy!)

I’m very pleased with this image, which is my first since the end of March, in part because nowadays I take an astronomy break during the long late spring / summer days when astronomical darkness is largely absent. However, this year the pause has been protracted as the patio on which Fairvale Observatory is situated was re-laid, during which a hitherto unknown water well was discovered. Thereafter one thing led to another and turned into a summer project to recommission the well, thus delaying completion of the patio. As a result I’ve only recently been able to reinstate the astronomy equipment, a job that is still ongoing. The new patio is firm and flat, providing a much better surface for the mount than before and I’m hopeful that once recalibration is completed will result in improved tracking results – watch this space!

	IMAGING DETAILS
Object	IC1318-B & IC1318-C Gamma Cygni Nebula or Butterfly Nebula NGC 6910 Open cluster
Constellation	Cygnus
Distance	3,700 light-years
Size	1Approximately 100 light-years
Apparent Magnitude	Varies

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 v1.8.8-8, Photoshop CS3, Topaz Denoise
Image Location & Orientation	Centre RA 20:25:20.492 DEC +40:11:20.970 Left = North
Exposures	21 x 300 sec Ha, OIII, SII Total Integration Time: 5hr 15 min
	@ 139 Gain 21 Offset @ -20^oC
Calibration	5 x 300 sec Darks 15 x Flats & 10 x Dark Flats Ha, OIII, SII @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	6^th & 7^th September 2021 @ +21.00h
Weather	Approx. >=17^oC RH >=45% 🌙 New Moon

Dark Art

August 17, 2021 by grahamrob in Broadband, Dark Nebula, Deep Sky Objects, General Astronomy, Imaging, Processing and tagged Cepheus, DSO Imaging, Lynds Dark Nebula | Leave a comment

Somewhat tongue-in cheek, astrophotography is often referred to as something of a dark art and to be fair it sometimes seems that way, particularly when it comes to processing. My main interests in astrophotography are Deep Sky Objects such as emission nebulae, galaxies and planetary nebula but have long aspired to capture a more elusive category that abounds throughout the Universe – dark nebula.

Popular with astrophotographers, emission nebulae consist of vast clouds of ionised gases and regions of interstellar dust which reflect light from the said gases and or from stars and stellar nurseries that lie within – depending on their make-up the results are colourful in both broadband and narrowband wavelengths. Dark or absorption nebulae are also a type of interstellar cloud but are so dense they completely obscure and / or soak-up visible light emitted from objects behind or within, which as a result contrasts with general light flux of the Universe forming large dark regions. Because of their darkness they are usually faint, hard to see and moreover, difficult to image, especially from locations with light pollution.

The Horsehead Nebula is a dark nebula that has formed a part of my previous images but I’ve only imaged an isolated dark nebula once before – Barnard 142-3, which for obvious reasons is also known as the E-nebula (see above & here). Larger more complex dark nebulae require much darker skies to image than prevail at Fairvale Observatory, such as in New Mexico, USA where the Deep Sky West observatory is located and on this occasion has produced my first ‘serious’ image of a stand-alone dark nebula.

Cepheus & the aproximate location of LDN 1250 image indicated by the red square

Lynds Dark Nebula (LDN) catalogue of dark nebulae was compiled by the eponymous Beverly T. Lynds in 1962 and is based on the study of red and blue photographic prints from the National Geographic-Palomar Observatory Sky Atlas. Situated in the north close to Polaris, the constellation of Cepheus has a number of dark nebulae, of which LDN 1250 is part of a huge complex of dark nebula surrounded by dust and scattered light from the stars of Cepheus.

LDN 1250 luminance – RGB wavelengths are also strong

Imaged here in LRGB the features come out well in all wavelengths, however, such are the subtleties of the dark nebula components I found processing difficult and required plenty of ‘dark art’ techniques. The final image at the top of the page shows to good effect the main dark nebula, togeher with widespread but less opaque nebulosity and star colours, as well as some distant galaxies lurking in the background that together has produced a satisfying and very interesting outcome.

	IMAGING DETAILS
Object	LDN 1250 & 1251
Constellation	Cepheus
Distance	1,000 light years
Size	Main nebula approximately 1^o ~ 17 light-years
Apparent Magnitude	–

Scope	Takahashi FSQ 106 FL 530mm f/5 + Moonlight Nightcrawler focuser
Mount	Paramount MyT
Guiding	Yes
Camera	QSI 683-WSG8 KAF-8300 full frame CCD sensor 5.4nm pixels
	FOV 1.94^o x 1.46^o Resolution 2.1”/pix. Image array 3326 x 2,507 pix
Processing	Deep Sky Stacker, PixInsight v1.8.8-7, Photoshop CS3, Topaz Denoise
Image Location & Orientation	Centre – RA 22:28:54.702 DEC +75:09:45.158 North = Up
Exposures	23L + 18R + 16G + 17B x 900 secs @ -15C Total Integration Time: 18hr 30min
Calibration	41 x 900 secs Darks x 50 Bias & x16 LRGB Flats
Location & Darkness	Deep Sky West – amateur hosting facility near Rowe, New Mexico – USA SQM Typically >= 21.7
Date & Time	Q4 2020

Cosmic Eruption

July 30, 2021 by grahamrob in General Astronomy, Imaging, Narrowband, Supernova and tagged Cassiopeia, DSO Imaging | Leave a comment

Originally thought to be a planetary nebula, Abell included this object in his catalogue as Abell-85 but later in 1971 it was revised as a supernova remnant (SNR) and renamed CTB-1, thus also denoting it as a radio source. The overall structure is a circular shell with a conspicuous rupture towards the north (bottom right of image). The main red Ha-shell is composed of multiple interlocking filament limbs, with a blue / green OIII arc along one side (see main image above).

I experimented extensively processing the data because of its overall complexity and is an interesting object, which is therfore also presented below as greyscale Ha-wavelength only and starless versions. The main Ha and OIII data is shot at long 1,800 second exposures, which together with RGB adds up to a whopping 29 hours of integration time. However, CTB-1 is an extremely faint object, which probably still requires considerably more time – I’ve seen somebody else’s 61-hour integration which they described as “not enough” and despite the quality of their image I’d probably have to agree.

CTB-1 is a very exciting object, which might have been what Douglas Adams had in mind when creating Milliways or The Restaurant At The End Of The Universe in the Hitchhiker’s Guide, from which such spectacular events could be ordered to view with your meal!

	IMAGING DETAILS
Object	CTB-1 (Abell-85)
Constellation	Cassiopeia
Distance	10,000 light-years
Size	35 arcminutes ~ 100 light-years
Apparent Magnitude	–

Scope	Takahashi FSQ 106 FL 530mm f/5 + Moonlight Nightcrawler focuser
Mount	Paramount MyT
Guiding	Yes
Camera	QSI 683-WSG8 KAF-8300 full frame CCD sensor 5.4nm pixels
	FOV 1.94^o x 1.46^o Resolution 2.1”/pix. Image array 3326 x 2,507 pix
Processing	Deep Sky Stacker, PixInsight v1.8.8-8, Photoshop CS3
Image Location & Orientation	Centre – RA 23:59:19.402 DEC +62:25:39.406 North = bottom right
Exposures	29 Ha & 20 OIII x 1,800 secs @ -15C 18 R 17 G 19 B x 300 secs Total Integration Time: 29hr
Calibration	48 x 1,800 secs Darks* x47 Bias & x16 HaOIII +LRGB Flats *RGB scaled to 300sec
Location & Darkness	Deep Sky West – amateur hosting facility near Rowe, New Mexico – USA SQM Typically >= 21.7
Date & Time	Q3 2020

The Bat & Squid

July 2, 2021 by grahamrob in Deep Sky Objects, Imaging, Narrowband, Nebula and tagged Cepheus | Leave a comment

Discovered as recently as 2011 by French astronomer Nicolas Outters, is the very faint OIII emission nebula Ou4. Located in the constellation of Cepheus , this somewhat elusive object requires very long exposures and integration time to successfully image. For obvious reasons Ou4 has become known more commonly as the Giant Squid Nebula and belongs to the difficult but must-do objects list of astrophotographers. Moreover, the Squid lies within the much larger SH2-129 HII emission region or the Flying Bat Nebula, only part of which is shown here. In this case some 40-hours of exposure, of which the Squid is 15-hours, combined with careful processing has produced a wonderful image of both these exciting objects.

Initially considered to be a Planetary Nebula, Ou4 is now thought to be a bipolar outflow that was discharged 90,000 years ago from the hot massive triple star system HR 8119 situated within the Sh 2-129 HII-region, which is also responsible for ionizing the red emission nebula itself. The Squid consists of two collimated lobes with arc-shaped tips of enhanced OIII emission that resemble bow-shocks seen in stellar outflows and a few bubbles and filamentary arcs. The bipolar Ou4 lobes measure some 50×8 light-years, which though faint forms one of astrophotography’s great spectacles.

	IMAGING DETAILS
Object	SH2-129 Flying Bat & Giant Squid Nebula
Constellation	Cepheus
Distance	2,300 light-years
Size	Approx. 100.0 arc minutes
Apparent Magnitude	–

Scope	Takahashi FSQ 106 FL 530mm f/5 + Moonlight Nightcrawler focuser
Mount	Paramount MyT
Guiding	Yes
Camera	QSI 683-WSG8 KAF-8300 full frame CCD sensor 5.4nm pixels
	FOV 1.94^o x 1.46^o Resolution 2.1”/pix. Image array 3326 x 2,507 pix
Processing	Deep Sky Stacker, PixInsight v1.8.8-7, Photoshop CS3, Topaz Denoise
Image Location	Centre – RA 21:12:37.077 DEC +59:53:50.801
Exposures	x51 Ha & x30 OIII x 1,800 secs @ -20C Total Integration Time: 40hr 30min
Calibration	24 x 1,800 secs Darks x70 Bias & 70 Ha & Flats
Location & Darkness	Deep Sky West – amateur hosting facility near Rowe, New Mexico – USA SQM Typically >= 21.7
Date & Time	Q3 2018

Photon Factory

June 15, 2021 by grahamrob in Deep Sky Objects, Equipment, Globular Cluster, Imaging, Narrowband and tagged Globular Clusters, Hercules | Leave a comment

About this time of the year as astronomical darkness is lost for a few months I tend to take it easy, astronomically speaking. However, this year’s an exception as I have a large backlog of image processing to complete courtesy of the Photon Factory. With continuously bad weather prevailing across Europe back in February, it was more than four months since I’d been able to undertake any astrophotography here at Fairvale Observatory – of course such problems go with the hobby but this was ridiculous and somewhat disheartening. There were three solutions to the situation: continue waiting, give up all together or look further afield where the skies are reliably clear and dark, which like many others nowadays is what I did and thus joined the ever increasing band of remote imagers.

About 2-years ago I considered establishing equipment at one of the growing number of astrophotography host sites in southern Europe. However, after some research I concluded that whilst such a facility would be great to have it was probably too expensive for now and moreover, I first needed to spend more time improving my processing techniques before embarking on such a plan. Thus having since taken steps towards this goal, which included learning PixInsight, I felt the time was right to sign-up with Deep Sky West (DSW) situated in the state of New Mexico, USA. DSW were one of the early remote hosting observatories established and have a good reputation, reasonable prices and a wide choice of quality equipment. I therefore signed up for one year’s imaging with the following set-up:

Takahashi FSQ 106 FL 530mm f/5 + Moonlight Nightcrawler focuser
QSI1683-WSGA camera 5.4 nm pixels & Astrodon 5nm filters
Paramount MyT mount

Deep Sky West is located about 35-miles south east of Santa Fe, at an elevation of 7,400ft on the Glorietta Mesa (see above map). Established by Lloyd Smith and Bruce Wright in 2015, there are now two large bespoke roll-off sheds (Alpha & Beta – see picture below) housing up to nearly forty rigs which are used by astrophotographers from across the world – you could call it a photon factory. DSW has since established a premier reputation as an observatory producing high quality data. Building on this success and the burgeoning demand for remote imaging, DSW are now expanding their service into Chile.

After imaging the globular cluster M53 from Fairvale Observatory in early April, it was opportune to be able to continue the same theme with my first two DSW images taken during Q1 and Q2 – the globular clusters M13 and M92, both located in the constellation of Hercules. With an angular separation of just 9^o 33’, spatially the two clusters appear as neighbours but in reality M13 is some 4,560 thousand light-years closer. Spanning some 145 light years in diameter, M13 consists of several hundred thousand stars and as the brightest globular cluster in our galaxy it is generally considered to be the finest in the Northern Hemisphere. Whilst somewhat overshadowed by its more famous neighbour, M92 is still one of the brightest globular clusters orbiting the Milky Way and at +11 billion years is one of the oldest.

Since moving to mono imaging in 2017 I’ve only used a CMOS camera and therefore this is my first experience of working with CCD data, hitherto considered as the best, though more recent development of CMOS sensors suggests this is now likely to be the way forwards for amateur astrophotography. Whilst most of the techniques are the same there are minor differences such as using bias frames instead of dark flats with my CMOS camera for calibration.

The DSW equipment combination produces a field-of-view nearly 50% less than my equipment at home but with a similar resolution, thus improving the magnification and image details of smaller and/or complex features such as globular clusters. Notwithstanding, I was pleased with my previous image of M13 (above) taken from Fairvale Observatory in 2018, which after cropping compares well with the new DSW version (see main image at the top of the page). This is my first image of M92 (below), which though OK probably needs more attention, as I’m not convinced the combination of the 600 secs + 300 secs + 60 secs data has worked to its full potential.

The Takahashi 106 is one of my dream scopes and with up to 250 clear nights a year historically, the DSW location in New Mexico provides an opportunity to work with top level equipment in outstanding night sky conditions – what’s not to like with remote imaging? However, with a growing cadre of remote imagers this has become a something of a contentious issue amongst astrophotographers – there’s no doubt it produces excellent data which leads to outstanding images but as a hobby it’s still good to be hands-on. So far I’m really enjoying working with the remote data produced under optimum conditions but strangely there’s much to be said for imaging in the backyard even with or perhaps because of the problems it involves. Funny old world!

	IMAGING DETAILS
Object	M13 The Great Globular Cluster in Hercules
Constellation	Hercules
Distance	22,180 light-years
Size	20.0 arc minutes
Apparent Magnitude	+5.8

Scope	Takahashi FSQ 106 FL 530mm f/5 + Moonlight Nightcrawler focuser
Mount	Paramount MyT
Guiding	Yes
Camera	QSI 683-WSG8 with KAF-8300 full frame CCD sensor and 5.4nm pixels
	FOV 1.94^o x 1.46^o Resolution 2.1”/pix. Image array 3326 x 2,507 pix
Processing	Deep Sky Stacker, PixInsight v1.8.8-7, Photoshop CS3, Topaz Denoise
Image Location	Centre – RA 16:41:41.701 DEC +36:27:34.927
Exposures	49 L 34R 36G 36 B x 300 secs @ -15C Total Integration Time: 12hr 55min
Calibration	48 x 900 secs Darks* x47 Bias & x20 LRGB Flats *scaled to 300sec
Location & Darkness	Deep Sky West – amateur hosting facility near Rowe, New Mexico, USA SQM Typically >= 21.7
Date & Time	Q1 2021

	IMAGING DETAILS
Object	M92 Globular Cluster
Constellation	Hercules
Distance	26,740 light-years
Size	14.00 arc minutes
Apparent Magnitude	+6.3

Scope	Takahashi FSQ 106 FL 530mm f/5 + Moonlight Nightcrawler focuser
Mount	Paramount MyT
Guiding	Yes
Camera	QSI 683-WSG8 with KAF-8300 full frame CCD sensor and 5.4nm pixels
	FOV 1.94^o x 1.46^o Resolution 2.1”/pix. Image array 3326 x 2,507 pix
Processing	Deep Sky Stacker, PixInsight v1.8.8-7, Photoshop CS3, Topaz Denoise
Image Location	Centre – RA 17:17:07.165 DEC +43:08:10.267
Exposures	20L 12R 12G 18B x 600 secs @ -15C 0L 23R 22G 23B x 300 secs30L 30R 30G 23B x 60 secs Total Integration Time: 17hr 53min
Calibration	48 x 900 secs Darks* x47 Bias & x20 LRGB Flats *scaled to 600, 300 & 60 secs
Location & Darkness	Deep Sky West – amateur hosting facility near Rowe, New Mexico, USA SQM Typically >= 21.7
Date & Time	Q2 2021

Last Chance Catch

May 7, 2021 by grahamrob in Deep Sky Objects, Imaging, Narrowband, Nebula and tagged Jellyfish Nebula | Leave a comment

Here at Fairvale Observatory, most of the exciting deep sky objects associated with the transit of the Milky Way during winter have disappeared over the western horizon by early spring. Notwithstanding, a brief period of decent conditions at the very end of March provided a late window of opportunity to image a core area of our galaxy, which being viewed above Oirion at a higher declination in the constellation of Gemini, helped to extend the limited imaging time available. Frankly after such a terrible period of weather since last November, I was desperate to get one last image from this rich part of the night sky and try out my new Chroma narrowband filters again, which thankfully worked out well after imaging IC443 the Jellyfish Nebula over four nights, despite there being less than two hours of suitable viewing and darkness each night.

The remnant of a supernova that occurred between 3,000 and 33,000 years ago, located in the Gemini constellation the Jellyfish Nebula is some 5,000 light years from Earth. With a diameter of 70 light-years, the angular view of the nebula is some 50 arcminutes or nearly twice the size of a full moon. Overall the nebula consists of at least three distinct shells reflecting the complex nature of this Type-II supernova, which is interacting with the surrounding area of molecular clouds.

*Red box indicates location and orientation of image*

Acknowledging the limited time available – compounded by lingering cloud each night – I chose to image The Jellyfish in narrowband bicolour, hoping to collect some SII photons on another day to add to the Ha & OIII. At the end I also added some short LRGB subs to improve the final star colours and during processing used Ha as a false luminance layer to help bring out the complex structure of the nebula further. The image has been deliberately framed by the adjacent large stars Propus (bottom) and Tejat (top), which caused plenty of problems during processing but in my opinion form an essential component when imaging this object. Whilst IC443 is undoubtedly the main act, it is set off well by the large adjacent area of detailed nebulosity and the smaller reflection nebula IC444 to the right which is easy to overlook. Despite many issues I am very pleased with the final image that beautifully shows off this spectacular DSO and the surrounding region in all its glory, which seems all the better being something of a last chance opportunity that I thought I’d missed for this season.

	IMAGING DETAILS
Object	IC443 Jellyfish Nebula & IC444
Constellation	Gemini
Distance	5,000 light-years
Size	50 arc minutes ~70 light years
Apparent Magnitude	+12

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 + 3nm Ha &OIII filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker, PixInsight v1.8.8-7, Photoshop CS3, +Starnet, Topaz Denoise
Image Location & Orientation	Centre RA 06:18:53.542 DEC +22:31:13.827 @21.30h Right = North
Exposures	NB 15 x 600 sec Ha , 12 x 600 sec OIII & BB 15 x L, 11 x R, 9 x G5, 11 x B x 120 sec Total integration time: 6hr 02 min
	@ 139 Gain 21 Offset @ -20^oC
Calibration	NB 5 x 600 sec Darks + 15 x Ha & OIII flats & dark flats BB 10 x 120 sec Darks + 15 LRGB Flats & Dark Flats @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	29^th & 30^th March + 4^th & 5^th April 2021 @ +21.00h
Weather	Approx. <5^oC RH >=30% 🌙 99% waning

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

Orion In A New Light

February 19, 2021 by grahamrob in Deep Sky Objects, DSLR, Equipment, General Astronomy, Nebula, Universe, Widefield Imaging and tagged Orion Constellation | Leave a comment

In ancient history Orion’s stars were considered to form a pattern that resembled a hunter holding a club above with his right arm and a shield in front with his left. The appearance of Orion each year marks the highlight of the astronomy for many including me but for the second year running months of continuous cloud have precluded any astronomy since October; I note from comments online far-and-wide that this phenomenon has prevailed across much of the northern hemisphere, no doubt resulting in a lot of unhappy astronomers.

Finally the clouds briefly relented over Fairvale Observatory in February but only for a few hours each time, thus eliminating the possibility of imaging with a CMOS mono camera. Faced with these problems I therefore returned to my somewhat neglected modded Canon 550D camera and suitable lenses for appropriate widefield compositions, in order to image some classic targets around the Orion constellation in a broader context. Having first whetted my appetite with the Samyang 135 f2 and its large 9.45^o x 6.30^o FOV to successfully image the iconic area that encompasses Orion’s belt, the Horsehead Nebula and M42 (see Going Big), it was time to go really big in order to capture the entire constellation literally and figuratively in a new light.

Seven bright stars define the area which outlines the torso and upper legs of Orion the Hunter: Betelgeuse, Bellatrix, Rigel and Saiph at the top and bottom, connected across the centre by his ‘belt’ formed from Alnitak, Alnilam and Mintaka. The H-shape thus created by these stars is a familiar sight over the winter months but like so many asterisms of the night sky all is not what it seems. Plotting the distance from Earth of each star it is immediately obvious that their spatial relationship significantly changes the shape of the constellation compared to what as we perceive by eye. It is a sobering thought that with the passage of time those asterisms familiar to astronomers today will look very different in the future as the stars move though space and therefore continue to change their relative positions, look and shape.

Star	Betelgeuse	Bellatrix	Rigel	Saiph	Alnitak	Alnilam	Mintaka
Distance from Earth* (light years)	643	243	772	724	800	1,359	900

*Source: Royal Greenwich Observatory

Click HERE for annotated version of the Orion Constellation in 3D ref. Space Science Telescope Instititue

The Canon ‘Nifty Fifty’ 50mm f1.8 fixed aperture lens is perfect for an ultra widefield image of Orion. Whilst the glass is excellent, focus leaves a lot to be desired and once achieved needs to be secured with tape

Aside from the said visual perspective of Orion, like so much of space we only see a fraction of what is really present in the Universe but can nevertheless often be disclosed by astrophotography. And so I next decided to image the entirety of Orion, this time with a basic Canon 1.8 50mm lens – the so called “nifty fifty”- with the purpose of capturing in one shot the constellation with which we are all familiar, together with vast spectacular HII-regions that encompass much of the constellation but usually remain unseen. This camera-lens combination provides an enormous 25.5^ox 17.0^o field-of-view (x7 > Samyang lens, x83 William Optics GT81!) albeit with lower resolution, which perfectly encompasses most of Orion and therefore the entire arc of Barnard’s Loop on the left and the Angelfish Nebula (Orion’s “head”) located above and between Betelgeuse and Bellatrix.

Above: Orion constellation from Fairvale Observatory 24th December 2014 (Left) compared with long exposure image + modded camera 10th February 2020 (right)

Barnard’s Loop is an emission nebula, forming part of the Orion Molecular Cloud Complex which also contains the dark Horsehead and bright Great Orion Nebulae M42. The Loop is believed to have originated from a supernova explosion about 2 million years ago, which is now ionized by stars from within and around the Orion Nebula and takes the form of a large arc centred approximately on the Orion Nebula. Discovered and photographed by E. E. Barnard in 1894, this vast feature extends over some about 600 arcminutes when viewed from Earth or physically up to 300 light years across, depending on the distance from Earth.

The Angelfish Nebula SH2-264 is centred on the young star cluster of Lamda Orionis, of which Meissa is the brightest. An HII-region with an apparent size of 5 degrees and actual size of 150 light years, it is also an emission nebula that is energised by the aforesaid star cluster and is considered to form the so-called head of Orion.

Having previously imaged notable parts throughout Orion, I’ve long wanted to capture the full extent of this wonderful constellation in all its glory and am very pleased with the outcome on this occasion.

DSLR IMAGING DETAILS*
Object	Orion Constellation
Constellation	Orion
Distance	243 to 1,360 light-years
Size	594^o2
Apparent Magnitude	Varies

Lens / Scope	Canon 50mm f1.8
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	No Guiding
Camera	Canon 550D modified
	FOV 25.5^o x 17.7^o Resolution 17.72”/ pixel
Capture & Processing	Astro Photography Tool + PHD2 Deep Sky Stacker, PixInsight, Photoshop CS3 & Topaz Denoise AI
Image Location & Orientation	Centre RA 05:37:37.3 DEC +00:48:50.26 Top = North Right = West
Exposures & Aperture	42 x 120 sec @ ISO800 Total: 1hr 24 min F1.8
Calibration	5 x 120’ Darks, 20 x 1/4000 sec Bias 20 x Flats
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	10^th February 2021 @ +21.00h
Weather	Approx. <=0^oC RH <=65% 🌙 NEW MOON