The Flame & Frogs

February 26, 2023 by grahamrob in AstroBin, Deep Sky Objects, Imaging, Nebula, Processing, Widefield Imaging and tagged Auriga | 1 Comment

There’s a lot going on in and around the Auriga constellation and this winter I’ve been mainly imaging in this region, almost exclusively using the Samyang 135 widefield rig. Here with the whopping 7.50^ox 5.67^ofield-of-view this set-up provides, it easily incorporates both emission nebulae IC405, AKA the Flaming Star Nebula and it’s nearby (visually) neighbour IC410, the Tadpoles Nebula, as well as much more.

Hydrogen gas ionized by the central AE Auriga star produces the dominant strong red colour, which combined with the rippling dust and gas lanes that run through the head of IC405 leads to a ‘flame affect’ and thus the nebula’s popular nickname.

The structures in IC410 are illuminated by radiation from the open star cluster NGC1893, located at the centre of the nebula. Hot, massive, young stars abound, especially around Simeis 129 & 130, the two tadpoles. These structures are ‘wriggling away’ from the centre of the nebula, because of the prevailing stellar winds and radiation pressure from the stars in NGC 1893.

This image is the cornerstone of a series of covering a wider area completed during January, which I intend to first present individually before, hopefully, bringing them together as an HOO mosaic later.

This image has been processed as two SHO versions of the Hubble Palette: (i) a basic mix above and (ii) using a dynamic mix ( main cropped image at top-of-the page). Once more I have been impressed by the ability of this small camera lens to produce exceptional detail and colours, but especially here with the starless Ha version of IC410, where the signature features or so-called tadpoles have been captured to great effect (see cropped starless Ha version of IC410 below).

	IMAGING DETAILS
Object	IC 405 The Flaming Star Nebula + IC 410 The Tadpoles Nebula
Constellation	Auriga
Distance	1,500 & 12,000 light-years
Size	Approx. 37’ x 10’ & 40’ x 30’
Apparent Magnitude	+6.0 & +10

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 05:19:54.329 DEC +33:47:12.699 Right = North Top = East
Exposures	24 x 300 sec Ha & OIII, 18 x 300 sec SII Total Integration Time: 5 hr 30 min
	@ 139 Gain 21 Offset @ -15^oC
Calibration	10 x 300 sec Darks 20 x Flats & Flat Darks
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5 – 6
Date & Time	2^nd & 9^th January 2023 @ +18.30h
Weather	Approx. <=2^oC RH >=80% 🌙 +80%

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

Playing With Fire

May 3, 2018 by grahamrob in Narrowband and tagged Auriga | Leave a comment

RGB (Large)

When possible my current repertoire has continued with DSO targets previously imaged with a modded DSLR and now revisited using the ZWO1600MM-Cool camera. In general I’ve found the outcome with the new camera has been noticeably better in detail and colour but I’m still learning and know I can do better in time. Last imaged in December 2015 with a DSRL camera, the larger FOV comfortably encompassed both the Tadpole (IC410) and adjacent Flaming Star (IC405) nebulae, resulting in an exciting composition. However, this time the ZWO CMOS sensor could only accommodate the latter in the image but with improved resolution.

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IC 405 (right) The Flaming Star Nebula & IC 410 The Tadpole Nebula: WO GT81 & modded Canon 550D + FF | 15 x 180 sec @ ISO 1,600 & full calibration | 8th December 2015

The Flaming Star is an emission / reflection nebula, which surrounds the bright blue variable star AE Aurigae. Imaging in narrowband produced decent Ha data but was very weak in OIII and SII wavelengths and even with 2-hours integration time is somewhat lacking in colour both in SHO (top-of-the-page) & HOO (below). Notwithstanding, it’s an exciting object that at some point in the future will obviously require much longer imaging time and perhaps even a mosaic in order to include its neighbour the Tadpole once again.

HOO (Large)

	IMAGING DETAILS
Object	The Flaming Star Nebula IC405
Constellation	Auriga
Distance	1,500 light-years
Size	37’ x 19’
Apparent Magnitude	+6.0

Scope	William Optics GT81 + Focal Reducer FL 382mm f4.72
Mount	SW AZ-EQ6 GT + EQASCOM computer control
Guiding	William Optics 50mm guide scope
	+ Starlight Xpress Lodestar X2 guide camera & PHD2 control
Camera	ZWO1600MM-Cool (mono) CMOS sensor
	FOV 2.65^o x 2.0^o Resolution 2.05”/pix Max. image size 4,656 x 3,520 pix
EFW	ZWOx8 + ZWO LRGB & Ha OIII SII 7nm filters
Capture & Processing	Astro Photography Tool, Deep Sky Stacker & Photoshop CS2
Exposures	300 sec x12 Ha, x6 SII & x6 OIII (Total time: 120 minutes)
	@ 139 Gain 21 Offset @ -20^oC
Calibration	5 x 300 sec Darks 20 x 1/4000 sec Bias 10 x Flats Ha, OIII & SII @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5
Date & Time	24^th February 2018 @ 20.30h approx.

It’s all in the stars

February 24, 2016 by grahamrob in Deep Sky Objects, General Astronomy, Imaging, Universe and tagged Auriga, DSO Imaging, Hitchhiker's Guide to the Galaxy, Milky Way, Nebulae, Star Clusters | 2 Comments

After 24-weeks I have just completed Imagining Other Earths, a Coursera MOOC presented by David Spergel, Charles A. Young Professor of Astronomy at Princeton University – soon to become Director of the new Computational Centre of Astrophysics, NY – and cannot speak too highly of the course. In my quest to better understand what I am seeing and imaging, I have participated in five astronomy courses and this is by a country mile the best; how many country miles in a parsec I wonder? There was very little not covered about astronomy in the course, including related geology and life itself but it was outstanding for three reasons:

Frequent use of easy-to-understand equations to explain and link various processes responsible for the Universe and everything in it;
It is very comprehensive, thorough and well produced, and…
David’s lecturing is just very good – easy to understand and well delivered.

For some while now the trend in my astrophotography has been increasingly directed towards seeing the big picture and by coincidence the course followed a similar scientific theme in order to Imagine Other Earths throughout the Universe; a metaphor for life itself and possibilities across the Universe.

The ultimate question starts at the beginning – where do we come from? Moby and astrophysicists seem to have the answer: we are all made of stars. How we get from that to here may be an even bigger question and like the philosophers in The Hitchhikers Guide to the Galaxy looking for the meaning of life (answer = 42!), should keep many astrophysicists gainfully employed for aeons.

In the meantime there is strong evidence that we do indeed come from stars and their evolution through the process of nucleosynthesis, which is responsible for all but a few man-made elements that we find on Earth. Through the action of nuclear fusion a star burns its way through the periodic table, first from hydrogen to helium then carbon-oxygen-magnesium-silicon and eventually iron. Thereafter the other, heavier elements require even more extreme conditions – heat & pressure – that can only be found in the late or final stage of a star’s life such as a Super Nova.

When the Periodic Table was initially formulated in 1863 by Dimitri Mendeleev there were 53 elements, which through subsequent discovery have now grown to 118. I find it wonderful and exciting that almost all of these can be attributed to stellar evolution, which can be viewed and imaged in the night sky.

At this time of the year the Milky Way is a dominant feature passing across the winter night sky which provides numerous, sometimes spectacular objects that are favourable for imaging. Located close to the western edge of the Milky Way in the constellation of Auriga about 1,500 light-years from Earth, is IC 405 or Flaming Star Nebula and nearby (visually) IC 410 or Tadpole Nebula, itself at 12,000 light-years distance. Located across the central area between these objects is a star field, notable of which and actually within the IC 405 is the O-type blue variable star of AE Aurigae, that is responsible for illuminating the nebulae.

IC 405 is formed of two sections, consisting of an emission and reflection nebula. Radiation from the variable star AE Aurigea, that is located in the lower part of upper-east (left) lobe, excites the hydrogen gas of the nebula which then glows red, while carbon-rich dust also creates a blue reflection from the same star.

IC 405 (right)-The Flaming Star Nebula inc AE Aurigae varibale star & IC 405-The Tadpole Nebula: WO GT81 & modded Canon 550D + FF | 15 x 180 sec @ ISO 1,600 & full calibration | 8th December 2015

Located within the nebula IC 410 and partly responsible for its illumination is an open cluster of massive young stars, NGC 1893. Being just 4-million years old these bright star clusters are the site of new star formation and therefore are just starting their creation of new elements. The so named ‘tadpoles’ are filaments of cool gas and dust about 10 light-years long.

IC 410-The Tadpole Nebula: Illuminated from within by the NGC 1839 star cluster. Image cropped and forced to highlight the two ‘tadpoles’, which can just be seen indicated in the green ellipses (‘tails’ upwards)

Each nebula is large, respectively 30’ x 20’ and 40’ x 30’, with an apparent magnitude of +6.0, which combined with the star AE Aurigae makes an excellent target for the William Optics GT81. I find it thrilling to consider the processes taking place in these objects that I have captured in the photograph, which surely represents the ultimate Big Picture?