October | 2022 | WATCH THIS SPACE(MAN)

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%

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