Monthly Archives: February 2023

The Flame & Frogs

by in AstroBin, Deep Sky Objects, Imaging, Nebula, Processing, Widefield Imaging and tagged | 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 7.50o x 5.67o field-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
ObjectIC 405 The Flaming Star Nebula + IC 410 The Tadpoles Nebula
ConstellationAuriga
Distance1,500 & 12,000 light-years
Size  Approx. 37’ x 10’ & 40’ x 30’
Apparent Magnitude+6.0 & +10
  
Scope  / LensSamyang 135 @f2.8  
MountSW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel  
GuidingSky-Watcher EvoGuide 50ED
 + Starlight Xpress Lodestar X2 camera & PHD2 guiding
CameraZWO1600MM-Cool mono  CMOS sensor
 FOV 7.5o x 5.67o Resolution 5.81”/pix  Max. Image Size 4,656 x 3,520 pix   
EFWZWOx8 EFW & 31mm ZWO LRGB & 7nm Narrowband filters  
Capture & ProcessingAstro Photography Tool + PHD2 + PixInsight v1.8.9-1  
Image Location              & OrientationCentre: RA 05:19:54.329      DEC +33:47:12.699                         Right = North   Top = East 
Exposures24 x 300 sec Ha & OIII, 18 x 300 sec SII Total Integration Time: 5 hr 30 min     
 @ 139 Gain   21 Offset @ -15oC    
Calibration10 x 300 sec Darks 20 x Flats & Flat Darks  
Location & DarknessFairvale Observatory – Redhill – Surrey – UK        Typically Bortle 5 – 6  
Date & Time2nd & 9th January 2023 @ +18.30h   
WeatherApprox. <=2oC   RH >=80%                  🌙 +80%  

Supernova Sensation

by in Deep Sky Objects, Equipment, Imaging, Narrowband, Samyang 135, SNR, Supernova, Widefield Imaging and tagged | 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 3o the 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
ObjectSimeis 147 / SH2-240  AKA Spaghetti Nebula
ConstellationTaurus
Distance3,000 light-years
Size  Approx. 3.0o
Apparent MagnitudeExtremely faint  
  
Scope  / LensSamyang 135 @f2.8  
MountSW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel  
GuidingSky-Watcher EvoGuide 50ED
 + Starlight Xpress Lodestar X2 camera & PHD2 guiding
CameraZWO1600MM-Cool mono  CMOS sensor
 FOV 7.5o x 5.67o Resolution 5.81”/pix  Max. Image Size 4,656 x 3,520 pix   
EFWZWOx8 EFW & 31mm ZWO LRGB & 7nm Narrowband filters  
Capture & ProcessingAstro Photography Tool + PHD2 + PixInsight v1.8.9-1  
Image Location              & OrientationCentre: RA 05:41:15.081      DEC +28:05:32.778                         Right = North   Top = East 
Exposures60 x 600 sec Ha, 62 x 600 sec OIII Total Integration Time: 20 hr 20 min     
 @ 139 Gain   21 Offset @ -15oC    
Calibration5 x 600 sec Darks 20 x Flats & Flat Darks  
Location & DarknessFairvale Observatory – Redhill – Surrey – UK        Typically Bortle 5 – 6  
Date & Time12th 17th 18th 19th & 21st January 2023 @ +18.30h   
WeatherApprox. <=0oC   RH >=80%                  🌙 70% to 0o New Moon