Avian Astronomy: Seagull Nebula

March 4, 2024 by grahamrob in AstroBin, Deep Sky Objects, Narrowband, Star Cluster and tagged astronomy, Astrophotography, deep-sky, DSO Imaging, Emission Nebula, Monoceros, Reflection Nebula | Leave a comment

Located 3,650 light-years from Earth, in the area between the Monoceros and Canis Major constellations, is the emission and reflection nebulae complex of the so-called Seagull Nebula. It’s been 8-years since I last briefly dabbled with imaging this exciting object and for good reason. From my position, this bird flies at a maximum 28^o above the southern horizon (-11 DEC) and, furthermore, spends much of its time behind houses, trees, and tall hedges, thus providing just two short windows for imaging; combined with this winter’s terrible weather it made for a tough but ultimately rewarding target.

*The Seagull’s approximate flight path seen from Fairvale Observatory makes imaging difficult*

Whilst popularly known as the Seagull Nebula, the bird consists of a number of fabulous objects spanning some 200 light-years in their entirety: the Seagull’s head (SH2-292) and wings (IC 2177), the large open star cluster along the leading edge of the left wing (NGC 2335) and a smaller cluster on the edge of the right wing (NGC 2327), the nebula at the tip of the right wing (Sh2-297), as well as many other named features (Sharpless and LBN) that are highlighted in the following plate solved image (below).

Despite the difficulties posed by the low transit of the bird in the night sky, each of the Ha, OIII and SII wavelengths are strong, making for good data acquisition and a very pleasing final SHO image.

	IMAGING DETAILS
Object	Seagull Nebula (SH2-292, IC2177 etc.)
Constellation	Monoceros
Distance	3,650 light-years
Size	Approx. 200 light-years
Apparent Magnitude	Various

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	ZWO ASI294MM CMOS sensor
	FOV 2.87^o x 1.96^o Resolution 2.50”/pix Max. image size 4,144 x 2,822 pix
EFW	ZWOx8 EFW & 31mm Chroma Ha, OIII, SII filters
Capture & Processing	Astro Photography Tool (APT), Deep Sky Stacker & PixInsight v1.8.9-2
Image Location & Orientation	Centre = RA 07:06:42.425 DEC -11:18:53.372 Left = North Top = West
Exposures	Ha x16 + OIII x13 + SII x14 @ 600 sec Total Integration Time: 7hr 10 min
	@ Gain 120 & 30 Offset 21 @ -15^oC
Calibration	5 x 300 sec Darks 10 x NB Flats & Dark Flats @ ADU 32,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	18^th 19th January 11^th 12^th February 2023 @ +20.30h
Weather	Approx. <2^oC RH >=70% 🌙 <+55% Waning

2023 The Year In Pictures

January 1, 2024 by grahamrob in Broadband, Dark Nebula, Deep Sky Objects, Equipment, Galaxy, General Astronomy, Globular Cluster, Imaging, Mosaic, Narrowband, Nebula, Other, Planetary Nebula, Processing, Samyang 135, Supernova, Widefield Imaging and tagged Aurora Borealis, DSO Imaging, Galaxies, Nebulae | Leave a comment

This Christmas marks the 10^th edition of my astrophotography calendar, consisting of my better images from the previous 12-months, which I produce for myself and members of the family. Wow doesn’t time fly? Based on these images, I also compile a video of the images set to music, which we all watch together before seeing the actual calendar. It’s become something of an occasion and is a great way to present the images, which look wonderful on today’s smart TV’s and is fun to watch and share with the family.

THE CALENDAR

Much longer imaging times (total of more than 145 hours), re-imaging old favourites in new ways and unusual, overlooked, or difficult objects, resulted in a very good 2023 astrophotography year and perhaps the best calendar yet? The calendar for 2024 on YouTube can be viewed by clicking HERE and below is a brief overview of each image. More detailed background information and imaging details for those interested can be found in relevant blogs I posted on this website. The background music is the track Appleshine from Underworld’s album Drift.

COVER	SH2-284: Close-up of April’s image – along the inside of the ring structure are many dark dust pillars and globules, which on the right seem to resemble a hand with a bony finger pointing inwards!
JANUARY	NGC 1333: Nestled within the western area of the Perseus Molecular Cloud, some 1,100 light-years from Earth is the colourful NGC 1333 reflection nebula, one of the closest and most active star-forming regions of the night-sky.
FEBRUARY	Spaghetti Nebula: Straddling the boundary of Taurus and Auriga constellations, is the giant supernova remnant (SNR) Simeis-147. The stellar explosion occurred 40,000 years ago, leaving a rapidly spinning neutron star or pulsar at the core of the now complex and the expanding SNR.
MARCH	Aurora Borealis: Situated just below the Arctic Circle, Iceland is well known both for its geology and views of the Aurora Borealis, which we saw in March on the south coast near Kirkjubaejarkklaustur.
APRIL	SH2-284: A star-forming region of dust and gases, sculpted by radiation and interstellar winds emanating from a young (3 to 4 million years) star cluster located near the centre.
MAY	M3 Globular Cluster*: Consisting of 500,000 stars and over 11 billion years old, M3 is one of150 globular clusters that orbit around the Milky Way Galaxy.
JUNE	*M27 Apple Core Nebula:** A planetary nebula, consisting of a glowing shell of ionized gas ejected from a red giant star in its late stage of life to become a white dwarf. Complex hydrogen (red) and oxygen (blue) fans form around the outer regions, with a pulsar-like beam transecting the nebula.
JULY	Monkey Head Nebula: Located 6,400 light years from Earth in the Orion constellation, the ‘Monkey’ is a so-called emission nebula, where new stars are being created within at a rapid rate.
AUGUST	SH2-115: This widefield image contains a richness of various emission nebulae, centred around the distinctive large blue SH2-115 region. Just to the left of SH2-115 is the small but enigmatic SH2-116 a faint, blue disc thought to be a planetary nebula.
SEPTEMBER	LDN-768 Black Cat Nebula: Close to M27 in the constellation of Vulpecula (“Little Fox”), is a dense region of stars broken-up by dark nebulae to create intriguing shapes. Here strung out from left-to-right, several of the dark nebulae seem to coalesce (visually) to create the form of a black cat.
OCTOBER		SH2-126 Great Lacerta Nebula: On the western edge of the Milky Way in the southern part of Lacerta, is the very large but faint emission nebula SH2-126. The red filament structures stretch over 3 degrees, to the right is the Gecko Nebula, a molecular cloud associated with bright young stars.
NOVEMBER		Flaming Star & Tadpoles Nebula: Two emission nebulae: dust & gas of the Flaming Star (below) combined with red ionized hydrogen gas produces a flame affect. Above, the stellar winds and radiation pressure from hot massive stars creates the Tadpoles ‘wriggling’ away from the centre.
DECEMBER		*M51 Whirlpool Galaxy:** As the smaller galaxy passes behind M51, joint gravitational forces are interacting, resulting in the misalignment of stars and unusually bright blue and pink areas across the Whirlpool galaxy. Their fates are inextricably linked and might eventually merge.
*Footnote:* All images taken from Redhill, Surrey or telescope at a dark sky site in New Mexico, USA shown by an asterisk*
*HAPPY NEW YEAR + CLEAR SKIES FOR 2024*

Monkey Business

May 3, 2023 by grahamrob in Broadband, Deep Sky Objects, Equipment, General Astronomy, Imaging, Narrowband, Nebula, Software and tagged Nebulae, Orion Constellation | Leave a comment

Constellation names mostly originated from ancient Middle Eastern, Greek, and Roman cultures, when they identified groups of stars and named them after their gods, goddesses, animals, and objects that were important to them. Other world-wide groups and throughout time – Native American, Asian, and African – have also made and named similar pictures from star groups based on their cultures and related beliefs. Given the number of stars observed when looking up into a clear dark sky, it is obviously helpful to ‘construct’ familiar patterns and adopt memorable names, which can then be used to identify areas of the sky in a way that can be easily identified by all. I have no problem with this long and well-established convention, which despite their antiquity works just as well in the modern world but I do have an issue with nicknames.

I’ve smiled at some of the nicknames given to popular, usually deep sky objects that have been well established by astronomers, but despite the possible use of describing their form, I am increasingly finding them a distraction when considering the merit of astrophotography images: Seagull Nebula, Running Man Nebula, Pelican Nebula etc. The problem is that they absolutely do look like the object they’re meant to depict but, like an earworm is to music, once seen they are difficult to view any other way.

With this partly in mind, for the first time in seven years I recently chose to image NGC 2174 again. I previously used the William Optics GT81 with a modded Canon 550D DSLR camera, which resulted in an image that wasn’t too bad, except it looked like a monkey! Given its nickname of the Monkey Head Nebula, this was to be expected but unfortunately, thereafter the picture of a monkey has remained with me ever since when I view NGC 2174 images. The challenge on this occasion was therefore to limit the monkey’s impact on the image, thereby showing the object for what it really is – an emission nebula.

Using the same OTA but with a mono CMOS camera and a good set of filters, the new data set obtained was much improved, and with better processing experience it was time to see the monkey (or not) in a new light. The first thing to do was present the image in an orientation that produces a more favourable perspective (less monkey like). Using a basic SHO palette in PixInsight the initial image was promising (see below) but with an alternative PixelMath dynamic SHO palette* and then processing with autocolor script, color saturation, Russell Croman’s XT-suites and other tweaks, I was pleased to see that the monkey was nowhere to be seen in the final image (see image at the top-of-the-page), or at least to my eye.

At last, it is now possible to look at NGC 2147 and see the inherent features of this interesting emission nebula, where new stars are being born at a rapid rate. Moreover, the inner details can now be clearly viewed within, thus also showing the associated open star cluster NGC 2175 and more. As a result of this monkey make-over, the NGC 2174 image now not only looks much better but critically, I no can longer see the ape! Now where’s that Seagull?

	IMAGING DETAILS
Object	NGC 2174
Constellation	Orion
Distance	6,400 light-years
Size	40 arc secs
Apparent Magnitude	+6.80

Scope	William Optics GT81 + Focal Reducer FL 382 mm 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	ZWO ASI294MM CMOS sensor
	FOV 2.87^o x 1.96^o Resolution 2.50”/pix Max. image size 4,144 x 2,822 pix
EFW	ZWOx8 EFW & 31mm Chroma HSO & LRGB filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker, PixInsight v1.8.9-1, Photoshop CS3
Image Location & Orientation	Centre = RA 6:09:39.801 DEC +20:29:12.851 Right = North Up = East
Image PI Processing: Dynamic Pixel Math*	R = (O^~O)S+~(O^~O)H G = ((OH)^~(OH))H+~((OH)^~(OH))O B = O
Exposures	Ha 36 x 300 sec (3hr), OIII 30 x 300 sec (2hr 30m), SII 32 x 300 sec (2hr 40m) Total Integration Time: 8hr 10 min
	@ 120 Gain 30 Offset @ -15^oC
Calibration	5 x 300 sec Darks 15 x HSO Flats & Dark Flats @ ADU 32,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	25^th + 26^th February + 2^nd March 2023 @ +19.00h
Weather	Approx. < 3^oC RH >=65% 🌙 +25 to +50%

The Unicorn’s Finger

March 14, 2023 by grahamrob in Deep Sky Objects, Narrowband, Nebula, Star Cluster and tagged Monoceros | Leave a comment

SH2-284 is an HII star forming region of dust and gases, sculpted by the radiation and interstellar winds emanating from the young (3 to 4 million years) open star cluster Dolidze 35 located near its centre. Along the inner edge of the main ring structure are numerous dark dust pillars and Bok Globules, not unlike those of the Elephant’s Trunk nebula, of which the largest seems to resemble a hand with a large bony finger at the end pointing inwards (see cropped + rotated image below).

Despite its close resemblance to the Elephant’s Trunk and the nearby Rosette nebula, the emission nebula SH2-284 is by comparison somewhat overlooked. Being some x8 times further away it’s apparent size is a good deal smaller and much fainter in nature but still forms an excellent late winter image target.

	IMAGING DETAILS
Object	SH2-284 or LBN 983
Constellation	Monoceros
Distance	18,000 light-years
Size	0.50^o
Apparent Magnitude	Faint

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	ZWO ASI294MM CMOS sensor
	FOV 2.87^o x 1.96^o Resolution 2.50”/pix Max. image size 4,144 x 2,822 pix
EFW	ZWOx8 EFW & 31mm Chroma LRGB filters
Capture & Processing	Astro Photography Tool + PHD2 + PixInsight v1.8.9-1
Image Location & Orientation	Centre = RA 06:45:20.506 DEC +00:18:12.758 Right = North Top = East
Exposures	Ha 53 x 300 sec, OIII 36 x 300 sec, SII 36 x 300sec = 11hr 30 min R 35 x 60 sec, G 35 x 35 sec, B 34 x 60 sec = 1hr 44min Total Integration Time: 13hr 14 min
	@ 120 Gain 30 Offset @ -15^oC
Calibration	5 x 300 sec & 20 x 60 sec Darks + 15 x LRGB & Ha, OIII, SII Flats & Flat Darks @ ADU 32,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	6th^th + 7^th + 8^th + 9^th + 13^th February 2023 @ +19.30h
Weather	Approx. <=3^oC RH >=70% 🌙 Full Moon – waning

Supernova Sensation

February 6, 2023 by grahamrob in Deep Sky Objects, Equipment, Imaging, Narrowband, Samyang 135, SNR, Supernova, Widefield Imaging and tagged Auriga | 2 Comments

Straddling the boundary of Taurus and Auriga, is the giant supernova remnant (SNR) Simeis-147 AKA SH2-240 or the Spaghetti Nebula. It is believed that the stellar explosion that created Simeis-147 occurred some 40,000 years ago, leaving behind a rapidly spinning neutron star or pulsar at the core of the now complex, expanding SNR; the nebulous area has an almost spherical shell consisting of numerous filamentary structures. With an apparent diameter of 3^othe SNR spans some 160 light-years, making it a very large astrophotography target.

I’ve long admired the spectacular SNR Simeis-147 AKA Spaghetti Nebula, which I first imaged with my standard William Optics GT81 scope in January 2022. The outcome (see image below) was pleasing but with the limited FOV it had to be just a nibble of this large object – something of an appetiser you might say. Therefore, ever since putting my Samyang rig together last summer I’ve had only one object in mind with this excellent widefield set-up, which had to be the full menu version of Simeis-147!

Apart from its size, Simeis-147 is very faint, making long exposure time essential, which is always difficult in the UK. However, a rare spell of cold, clear nights this January provided sufficient opportunity over five nights to obtain just over 20-hours integration and a complete image of this truly magnificent SNR.

Notwithstanding the favourable conditions and long-time achieved – a record for me at this location – the faint nature of this object made image processing difficult too. After experimenting, I eventually adopted a tone mapping technique: pre-processing each individual wavelength stack before removing the stars, stretching and processing each of the starless Ha and OIII images before combining using Pixel Math in the ratio: R – (Ha*1.70) + G – (OIII*0.80)+(Ha*0.20) + B- (OIII*0.80)+(Ha*0.20).

With further processing of the HOO starless combination I was able to obtain the desired result of marvellous SNR detail, together with pleasing Ha (red) and especially OIII (blue/green) colours, that altogether with the addition of the stars and some final tweaking produced a striking image with good depth. Moreover, I feel the widefield setting achieved using the Samyang 135 lens produces a striking setting for this fascinating object.

	IMAGING DETAILS
Object	Simeis 147 / SH2-240 AKA Spaghetti Nebula
Constellation	Taurus
Distance	3,000 light-years
Size	Approx. 3.0^o
Apparent Magnitude	Extremely faint

Scope / Lens	Samyang 135 @f2.8
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	Sky-Watcher EvoGuide 50ED
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600MM-Cool mono CMOS sensor
	FOV 7.5^o x 5.67^o Resolution 5.81”/pix Max. Image Size 4,656 x 3,520 pix
EFW	ZWOx8 EFW & 31mm ZWO LRGB & 7nm Narrowband filters
Capture & Processing	Astro Photography Tool + PHD2 + PixInsight v1.8.9-1
Image Location & Orientation	Centre: RA 05:41:15.081 DEC +28:05:32.778 Right = North Top = East
Exposures	60 x 600 sec Ha, 62 x 600 sec OIII Total Integration Time: 20 hr 20 min
	@ 139 Gain 21 Offset @ -15^oC
Calibration	5 x 600 sec Darks 20 x Flats & Flat Darks
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5 – 6
Date & Time	12^th 17^th 18^th 19^th & 21^st January 2023 @ +18.30h
Weather	Approx. <=0^oC RH >=80% 🌙 70% to 0^o New Moon

Cygnus Hat-Trick

October 21, 2022 by grahamrob in Deep Sky Objects, General Astronomy, Narrowband, Nebula, Widefield Imaging and tagged Cygnus, DSO Imaging | Leave a comment

The Cygnus constellation is rich in potential astrophotography targets and since the return of astronomical darkness I’ve bagged three objects from this area with my new widefield Samyang 135 rig: Cygnus Loop, Sadr Region & Crescent Nebula, and the Western Veil & Pickering’s Triangle. As the Cygnus season now draws to a close – in my case disappearing northwards behind my house – I was ready to snap one final Cygnus object using my main William Optics GT81 rig but then looked closer and realised using the Samyang 135 rig with careful framing there was another a more ambitious possibility.

The original object in question was SH2-119 AKA the Clamshell nebula, an emission nebula somewhat overlooked by photographers. Nevertheless, imaged in narrowband there’s plenty of structure to see throughout the nebulosity that makes up the two ‘shells’, whilst the bright magnitude +5 star 68 Cygni might be likened to the pearl at the centre, which would work well with the 81mm William Optics field-of-view. But deploying with care the much wider field-of-view of the Samyang 135 and it’s possible to include the North America and Pelican nebulae as well, just!

With some difficulty (weather) I finally managed to obtain 13-hours integration time over 6-nights, which has resulted in a pleasing SHO image (see main image at the top of the page – below is a dynamic version processed using PI PixelMath), once again demonstrating the capacity of this small but powerful lens. Personally, I find bringing all three objects together within a much larger field-of-view creates greater context, resulting in a more interesting image overall – in football parlance you might call it a hat-trick of nebulae!

	IMAGING DETAILS
Objects	North America Nebula (NGC7000) + Pelican Nebula (IC5070 & IC5067) + Clamshell Nebula (SH2-119)
Constellation	Cygnus
Distance	approx. 2,600 light-years
Size	3.0^o
Apparent Magnitude	approx. +4 to 8

Scope / Lens	Samyang 135 @f2.8
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	Sky-Watcher EvoGuide 50ED
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600MM-Cool mono CMOS sensor
	FOV 7.5^o x 5.67^o Resolution 5.81”/pix Max. Image Size 4,656 x 3,520 pix
EFW	ZWOx8 EFW & 31mm ZWO LRGB & 7nm Narrowband filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker, PixInsight v1.8.8-12, Photoshop CC, Topaz Denoise
Image Location & Orientation	Centre RA 21:06:17.698 DEC +43:58:35.414 Left = North Top =West (original rotated 90^o)
Exposures	Ha 61 x 300 sec, OIII 54 x 300 sec, SII 41 x 300 sec Total Integration Time: 13hr 00 min
	@ 139 Gain 21 Offset @ -10^oC
Calibration	Darks 10 x 300 sec, 15 x Ha OIII SII flats & flat darks
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	24^th 28^th 29^th September 2^nd 5^th 6^th October 2022 @ +20.30h
Weather	Approx. <=12^oC RH >=75% 🌙 +80%

Diaphanous Delectation

October 1, 2022 by grahamrob in Deep Sky Objects, Equipment, Imaging, Narrowband, Processing, SNR and tagged Cygnus, Cygnus Loop | 1 Comment

Following my routine summer break from astrophotography, I restarted in early August first using my new Samyang 135 + ZWO ASI1600MM-Cool rig, which immediately demonstrated its ability to produce excellent widefield images of very large objects, in this case the Cygnus Loop. However, also in late spring I had rejigged my William Optics GT81 telescope with the addition of a new ASI294MM camera, the successor to the ASI1600 which had been redeployed to the aforesaid Samyang rig. Having constructed, tested and briefly obtained First Light with this new combination, I then had to wait for the return of astronomical darkness and more suitable objects. Once again, I turned to the Cygnus Loop but this time concentrating on the western and central areas, generally known as the Western Veil and Pickering’s Triangle.

*Cygnus Loop Morphology, ID &*
*Approximate Image Location (Red Box)*

Located 1,500 light-years from Earth within the plane of the Milky Way in the constellation of Cygnus, this large supernova remnant (SNR) occurred between 5,000 and 8,000 years ago. In its entirety the debris cloud has been sculpted by the shock wave from the star’s explosion, to form the Cygnus Loop object that we see today. The coloured light is created by the excitement of hydrogen (red) and oxygen(blue) gasses of the SNR, which is still expanding at about 100 km (60 miles) per second; image integration times for OIII & Ha wavelengths are in the ratio of 2:1 to enhance the weaker oxygen signal. More than twice the width of the full moon and spanning 35 light-years, this section of SNR only just fits into my field-of-view but with careful framing it works perfectly.

The resulting image successfully brings out the exquisite nature of this exciting SNR, in particular highlighting the abundant waveforms that run throughout the entirety of this dynamic object. Furthermore, the combination of the new ASI294MM camera and 3nm Chroma filters, has produced a vibrant red-blue colour palette that further enhances the said structures. Altogether this diaphanous delectation convincingly demonstrates the power and beauty of the Universe whilst, moreover, pointing to a new level for my astrophotography.

	IMAGING DETAILS
Object	Cygnus Loop Section: Western Veil Nebula (NGC 6960), Pickering’s Triangle, NGC 6979 & 6974
Constellation	Cygnus
Distance	1,500 light-years
Size	~2.9^o total
Apparent Magnitude	+7.0

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	ZWO ASI294MM CMOS sensor
	FOV 2.87^o x 1.96^o Resolution 2.50”/pix Max. image size 4,144 x 2,822 pix
EFW	ZWOx8 EFW & 31mm Chroma LRGB filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker, PixInsight v1.8.8-12, Photoshop CC v23.5.0
Image Location & Orientation	Centre = RA 20:48:47.0 DEC +31:00:54.7 Left = North
Exposures	Ha 41 x 300 sec (3hr 25m), OIII 82 x 300 sec (6hr 50m) Total Integration Time: 10hr 15 min
	@ 120 Gain 30 Offset @ -15^oC
Calibration	5 x 300 sec Darks 15 x LRGB Flats & Dark Flats @ ADU 32,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	27^th + 29^th + 30^th + 31^st August 2022 @ +21.00h
Weather	Approx. <18^oC RH >=65% 🌙 0% New

Shrinking The Universe

September 5, 2022 by grahamrob in Deep Sky Objects, Equipment, Imaging, Narrowband, Nebula, Widefield Imaging and tagged Cygnus | 1 Comment

Hitherto, most of my astrophotography has concentrated on a variety of specific objects that work within the 2.65^o x 2.0^o field-of-view provided by the combination of my William Optics GT81 refractor and ZWO ASI1600MM-Cool camera. After recently pairing the aforesaid ZWO mono camera with a Samyang 135 lens (often marketed elsewhere as the Rokinon 135) my astrophotography world has expanded dramatically to an enormous 7.50^o x 5.67^o, some x8 larger than before. As a result, this excellent lens that also captures great detail, provides new opportunities to image some of the very large features that abound throughout the Universe without having to resort to a mosaic imaging; this a great advantage when working in UK weather conditions which usually provides less imaging time than required.

Above, Cygnus-X Region & notable nearby objects: The red box appproximately outlines the image area, which in this plan is presented upside-down compared to the main image. The numerous red shapes define the location of the HII objects that make up the DWB catalogue (19 is the Crescent nebula). Just beyond to the left is the North America Nebula (NGC7000) and below the SNR Cygnus Loop, AKA the Veil Nebula (NGC 6960 & 6992).

In this case I chose to frame the image in such a way as to encompass some familiar objects, such as the Butterfly Nebula (IC1318) and the Crescent Nebula (NGC6888) anchored by Sadr, the yellow-white supergiant star that stands out from within the very large Cygnus-X region. Processed here in HOO, with 6-hours integration time and full calibration (darks, flats & flat darks), the final image provides a magnificent view of this large, interesting region that augurs well for future widefield imaging with this new rig. I’m particulalry intrigued by the bluish feature at about 8.0 o’clock of the Crescent Nebula, which I now believe to be associated with WR-134: a bubble-like structure some 50 light-years in diameter consisting of OIII rich light formed by an intense wind emanating from the Wolf-Rayet star at it’s centre. The breadth of view it provides can encompass myriad of objects in exceptional detail, thereby providing a wider context that is simply awe-inspiring to see – it’s just like shrinking the Universe!

	IMAGING DETAILS
Object	Sadr Region
Constellation	Cygnus
Distance	+5,000 light-years
Size	Full FOV – see below
Apparent Magnitude	+/- 7.0

Scope / Lens	Samyang 135 @f2.8
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	Sky-Watcher EvoGuide 50ED
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600MM-Cool mono CMOS sensor
	FOV 7.5^o x 5.67^o Resolution 5.81”/pix Max. Image Size 4,656 x 3,520 pix
EFW	ZWOx8 EFW & 31mm ZWO LRGB & 7nm Narrowband filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker, PixInsight v1.8.8-12, Photoshop CC, Topaz Denoise
Image Location & Orientation	Centre RA 20:16:40.452 DEC +38:50:14.404 Right = North Top = East
Exposures	36 x 500 sec Ha, 36 x 300 sec OIII Total Integration Time: 6hr
	@ 139 Gain 21 Offset @ -10^oC
Calibration	5 x 300 sec Darks 15 x Flats & Flat Darks
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	10^th & 12^h August 2022 @ +22.00h
Weather	Approx. 25^oC RH 50 – 60% 🌙 100% Full Moon

A New Perspective

August 19, 2022 by grahamrob in Deep Sky Objects, Equipment, General Astronomy, Imaging, Narrowband, Supernova, Widefield Imaging and tagged Cygnus, DSO Imaging | 2 Comments

It’s been nearly two years since acquiring my Samyang 135 lens but since then it’s unfortunately only had limited use in combination with my modded 550D DSLR. Whilst impressed with the results from this set-up, my main objective has always been to combine it with my ASI1600 mono camera for some serious widefield astrophotography but as that was being used with my William Optics refractor it just didn’t happen, until now. After upgrading to a ASI294MM Pro camera in May, at last I was finally able spend the early part of this summer working on a new Samyang 135 + ASI1600 rig and now that astronomical darkness is (just) back I recently managed to catch a few photons with this new set-up of the large SNR Cygnus Loop.

I originally purchased a x2-ring Astrokraken 3D-printed clamping system for the lens + DSLR combination from Philippe in France but since then he’s tweaked the design. In particular x3 built-in M4 nuts have been incorporated on either side of each of the two main lens clamping rings, for the purpose of attaching ancillary equipment, which for me has been a game changer. I therefore bought a new x3-ring Astrokraken bracket, with the said bolt holes, around which to build my new rig:

The two main clamping rings that hold the lens have a shoe immediately above the lens, to which I’ve fitted a Sky-Watcher EvoGuide 50ED guidescope (not yet working), with the rear third ring holding the ASI1600 mono camera & EFW.
I swapped the Canon lens bayonet adapter for a bespoke M42 screw adapter, in order to ensure a more secure attachment, thus reducing any potential lens-camera movement at this critical point of the image train.
I’m continuing to use the excellent Astrokraken micro-focuser, which consists of a ring that clamps onto to the lens’ focus ring, with two small bolts above that make contact with either side of the guidescope shoe, so that when turned the focus ring can be adjusted either way to obtain focus, which is then locked when completed. So far I’ve found the micro-focuser to work very well with this lens, assisted by the addition of an Astrokraken Bahtinov mask which is inserted into the front of the lens casing.
Using this lens with the ZWO ASI1600MM-Cool camera and EFW, the backfocus guideline is 44mm, which I was able to achieve by adding an Altair T2 variable locking extension ring set to 17.5mm = 44mm minus 26.5 (camera + EFW).
With my Chroma filters now being used with the new ASI294MM Pro camera, I purchased another ZWO 31mm x8 EFW and brought my ZWO 31mm filters out of retirement.
Finally, using the new M4 nut holes I’ve added a Baader Skysurfer III RDF on the left-hand side of the Astrokraken bracket system to help with sky navigation and framing.

After bolting the Astrokraken with the lens, camera and said components to a Losmandy plate it makes a very nice compact rig, that is easy to handle and store. Notwithstanding, as they say – the proof of the pudding is in the eating: SEE top-of-the page for original image & below for 50% crop.

Whilst the recent heatwave produced clear skies, it was far from ideal here for astronomy and was further hampered by a full moon. However, with only just over two hours integration time and a few Dark calibration files, I’m still impressed with the outcome of this quite amazing lens. It is very pleasing to capture the entire Cygnus Loop comfortably sitting within the lens’ FOV – for information on this FOV and comparisons go to this previous WTSM blog HERE. For me context is important with astrophotography and in this regard the astronomical perspective this lens produces is outstanding, no wonder it is so popular. I just love working with this FOV and can’t wait for better conditions for greater integration time and more widefield targets to point this wicked little lens at.

	IMAGING DETAILS
Object	Cygnus Loop
Constellation	Cygnus
Distance	2,400 light-years
Size	3.0^o
Apparent Magnitude	+7.0

Scope / Lens	Samyang 135 @f2.8
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding – Not Used	Sky-Watcher EvoGuide 50ED
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600MM-Cool mono CMOS sensor
	FOV 7.5^o x 5.67^o Resolution 5.81”/pix Max. Image Size 4,656 x 3,520 pix
EFW	ZWOx8 EFW & 31mm ZWO LRGB & 7nm Narrowband filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker, PixInsight v1.8.8-12, Photoshop CC, Topaz Denoise
Image Location & Orientation	Centre RA 20:52:28.01 DEC +31:14:56.186 Right = North Top = East
Exposures	27 x 180 sec Ha, 20 x 180 sec OIII Total Integration Time: 4hr 21 min
	@ 139 Gain 21 Offset @ -10^oC
Calibration	5 x 180 sec Darks
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	9^th & 10^h August 2022 @ +22.00h
Weather	Approx. 27^oC RH <=50% 🌙 96% Full Moon

The Cone, Fox Fur & Christmas Tree

May 5, 2022 by grahamrob in Deep Sky Objects, Narrowband, Nebula and tagged DSO Imaging, Monoceros | Leave a comment

Projecting a line from Bellatrix to Betelgeuse a similar distance beyond to the east (left) by eye, to the northern extremity on Monoceros is one of late winter’s treats. Located about 2,500 light years from Earth is the star forming region NGC 2264, consisting of the Christmas Tree Cluster (an open cluster), the nearby so-called Cone Nebula and in between the Fox Fur nebula. I first imaged these objects in 2014 and again in 2018 but now armed with better skills and equipment, a return to this rich area of the night sky which is full of HII, reflection and dark nebula was long overdue + I had a plan to obtain greater detail and colour than was hitherto achieved.

*Location of NGC 2264 Christmas Tree Cluster et al based on Wikisky image*

Key to the plan was greater integration time and with 13h 25minutes obtained over three nights at the end of February, this established a solid data foundation. As ever with all broadband images, there’s an endless choice of permutations combining wavelengths to form a final image and inspired by the work of others, I used the popular SHO Hubble Palette but adapted here by using synthetic SII and OIII channels in PixInsight’s Pixel Math to enhance the related colours: SII = (Ha*0.30+SII*0.70) & OIII (Ha*0.40+SII*0.60+OIII). The resulting final image has exceeded my expectations, as the colours and details here now successfully highlight the aforesaid central objects as well as the wider complexity and beauty of flowing dust and gases that abounds in this region, which also includes NGC 2261 Hubble’s variable nebula, NGC 2259 open cluster and the emission nebula LBN 902.

*NGC 2264 starless version shows detail more clearly*

*Conventional HOO image version of NGC 2264 widefield*

	IMAGING DETAILS
Objects	NGC 2264 – Christmas Tree Cluster, Cone Nebula, Fox Fur Nebula + NGC 2261 Hubble’s variable nebula, LBN 902 emission nebula & NGC 2259 open star cluster
Constellation	Monoceros
Distance	2,500 light-years
Size	~2.5^o total
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	ZWO x8 EFW & 31mm Chroma Ha, SII & OIII filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker, PixInsight v1.8.8-12, Photoshop CC
Image Location & Orientation	Centre RA 06:40:55.725 DEC +09:53:45.407 Top is 280^o E of N i.e. Right = approx. North
Exposures	x39 Ha , x83 OIII, x39 SII @ 300 sec Total Integration Time: 13hr 25 min
	@ 139 Gain 21 Offset @ -20^oC
Calibration	5 x 300 sec Darks + 15 x Ha, OIII, SII Flats & Dark Flats @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	26^th, 27^th February & 7^th March 2022 @ +19.00h
Weather	Approx. <4^oC RH >=70% 🌙 approx.. New Moon