Whilst the highlight is the alluring bright blue reflection nebula NGC 7023 AKA Iris Nebula, careful processing reveals that this celestial flower is enveloped within a vast region of interstellar dust, altogether making for a spectacular image. Strictly speaking NGC 7023 refers to an open cluster within the reflection nebula, which is itself illuminated by a magnitude +7.4 star designated HD 200775 – the cropped starless image shows the beautiful detail that makes up the Iris ‘flower’.
The first galaxies were identified in the 17th Century by the French astronomer Charles Messier, although at the time he did not know what they were. It was only when in 1924 American astronomer Edwin Hubble measured the distance to the Andromeda galaxy using cepheid variables, that the existence of other galaxies was finally established. One hundred years on it’s now estimated that there are between 200 billion and 2 trillion galaxies in the Universe; as Douglas Adams said in the Hitchhikers Guide to the Galaxy, “Space…….is really big”!
For astronomers this time of the year is generally referred to the ‘Galaxy Season’, as our view of the Milky Way from Earth changes from the winter sky of the Orion Spur and Perseus Arm to the summer view with Cygnus overhead down to Sagittarius in the south, in between we’re looking into deep space. With very few exceptions, galaxies are located very far from Earth, which from our perspective makes them small and therefore a challenge for my imaging equipment. However, this Spring I’ve been imaging the spectacular Leo Galaxy Cluster, a mere 330 million light-years from Earth (see cropped version of cluster at the top of the page).
Containing at least 70 major galaxies, the Leo Cluster unusually consists mostly of spiral galaxies, which are best seen here cropped from the original widefield image. The bright elliptical galaxy near the centre of the image, NGC 3842, has one of the largest known black holes in the universe, which is about 10 billion times more massive than our sun!
We have come a long way since Galileo Galilei published his astronomical treatise Sidereus Nuncius AKA Starry Messenger in 1610, the first scientific publication based on observations made through a telescope. Galileo’s work completely changed the way humanity understood the night sky and, by extension, our place in space, later leading to the acceptance of the heliocentric model of the planets. Profound as that was, our understanding of the Universe since 1924 has even greater implications. Moreover, the ability for an amateur to image something like the Leo Cluster from my back garden is exciting and very rewarding (see widefield version above+ image location + orientation where the red dot = top left of image).
IMAGING DETAILS
Object
Leo Galaxy Cluster
Constellation
Leo
Distance
330 million light-years
Size
Various
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 2.87o x 1.96o Resolution 2.50”/pix Max. image size 4,144 x 2,822 pix
EFW
ZWOx8 EFW & 31mm LRGB filters
Capture & Processing
Astro Photography Tool (APT), Deep Sky Stacker & PixInsight v1.8.9-2
Image Location & Orientation
Centre = RA 11:44:12.40 DEC +19:50:25.70 Right = North
Exposures
L x30 + R x31 + G x31 + B x 31 @ 180 sec Total Integration Time: 6hr 9min
@ Gain 120 & 30 Offset 21 @ -15oC
Calibration
10 x 180 sec Darks + 10 x BB Flats & Dark Flats @ ADU 32,000
Location & Darkness
Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
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 28o 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 2.87o x 1.96o 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 @ -15oC
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
18th 19th January 11th 12th February 2023 @ +20.30h
This Christmas marks the 10th 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: Located6,400 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*
Two months past the summer solstice in late August, shortly after the new moon, I was drawn to the constellation of Vulpecula (Latin for “little fox) and an interesting region of reflection and dark nebulae that provide good imaging possibilities. In particular, a vast area of stars in which the contrasting dark nebulae create some intriguing shapes.
At the centre of the resulting image, strung out from east to west (left to right), several of the dark nebulae seem to coalesce (visually) to create the form of a black cat: LDN 773, 774, 769 & 768; an alternative interpretation is that of the Loch Ness Montser. Further enhancing the image, the cat is adorned by two large, bright orange stars near its head and within the ‘body’ to the right, several various reflection nebulae created by hot blue stars (VdB 126 / LBN 133 & 134 etc.).
Moreover, above the cat’s head another group of dark nebula form what I’d describe as a furled umbrella (LDN 781, 782, 783 & 779). Finally, towards the lower right edge of the image (below the cat’s rear leg) is the open star cluster of NGC 6793.
Apart from its obvious beauty, the inspiration for this image was my four-year old granddaughter who just loves cats – especially her own one-eyed black cat!
IMAGING DETAILS
Object
LDN 768, LDN 772, LDN 781, Vdb 126, LBN 133
Constellation
Vulpecula
Distance
Various
Size
Various
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 2.87o x 1.96o Resolution 2.50”/pix Max. image size 4,144 x 2,822 pix
A popular object at this time of the year, the planetary nebula M27 consists of a glowing shell of ionized gas, which has been ejected from a red giant star in its late stage of its life to become a white dwarf. Like many planetary nebulae, the main inner shell exhibits numerous dark and light knots, of which red ionized hydrogen areas form two bright lobes that together make the shape of an apple- core / dumbbell, which are M27’s two nicknames. There also seems to be different bi-polar influences occuring, that have resulted in complex Ha (red) and OIII (blue) fans around the outer regions and a pulsar-like beam transecting the nebula (see cropped version at the top of the page).
Despite the good data quality and long integration time, the complicated nature of the planetary nebula made processing very difficult, in particular, teasing out the aforesaid but very faint outer fans. In this case it was necessary to carry out individual soft stretches of the Ha and OIII stacks before combining them into an HOO image, from which a starless colour image was created and then processed further to bring out the fans. Thereafter, Pixelmath was used to amalgamate this image with two other starless HOO and RGB versions that emphasized the main part of the nebula, before finally adding back RGB stars and finishing off.
After considerable experimentation to obtain this result, I’m happy with the final image, which I hope shows off the said apple core / dumbbell and its outer fans to good effect (see above).
IMAGING DETAILS
Object
M27 AKA Dumbbell or Apple Core Nebula or NGC 6853
Constellation
Vulpecula
Distance
1,360 light-years
Size
8.0 x 5.7 arc-minutes (core) 15 arc-minutes (total) or 5 light-years (actual)
As our closest galactic neighbour, I’ve imaged M31 the Andromeda Galaxy five times since beginning my personal astrophotography journey in 2014, each time using my William Optics GT81 apo refractor – first with a DSLR, then a ASI1600mm-Cool and most recently ASI294MM cameras. Andromeda is perhaps the perfect object for my equipment, as it just fits the field-of-view of the aforesaid set-up, which produces something of an up-close-and-personal image of this alluring galaxy. But despite the success of these images, perhaps there’s an alternative view?
This year, I therefore deployed my Samyang 135 + ASI1600MM-Cool rig to capture 6 ½ hours of Andromeda, the result of which shows a whole new perspective of M31. The widefield format of this lens produces greater context than previous images, whilst still obtaining excellent details and colours of the galaxy itself. As a result, this final image (see above) better reveals the galaxy in its true glory deep in space, which in some ways I believe can be more powerful than the more popular close-up renditions of this impressive object (M31 with star reduction applied to the image below).
IMAGING DETAILS
Object
M31 Andromeda Galaxy
Constellation
Andromeda
Distance
2.5 million light-years
Size
3.2o x 1o or 220,000 light-years
Apparent Magnitude
+3.44
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 7.5o x 5.67o Resolution 5.81”/pix Max. Image Size 4,656 x 3,520 pix
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
3.0o
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 7.5o x 5.67o Resolution 5.81”/pix Max. Image Size 4,656 x 3,520 pix
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 SkysurferIII 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
3.0o
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 7.5o x 5.67o Resolution 5.81”/pix Max. Image Size 4,656 x 3,520 pix
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
~2.5o 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 2.65o x 2.0o 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 280o 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 @ -20oC
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
