Rosette Nebula 16/2/2021 – HOO narrowband

My first attempt ever at the Rosette Nebula.

This is an HOO narrowband image (as I had only 3 subs of sulphur when clouds rolled in!)

  • Altair Astro 183M camera
  • Sky Watcher Equinox Pro 80mm OTA
  • NEQ6 mount
  • Lichfield, UK
  • 2 hours of data – 1/3 luminence, 1/3 hydrogen alpha, 1/3 oxygen, (3 frames of sulphur!)
  • This picture from hydrogen and oxygen only.
  • PixInsight, Photoshop, Topaz DeNoise and SharpenAI plug-ins.


What’s in a name? Surely, all filter wheels are the same?

I feel that my role in RAG is to do all the stupid things that make people laugh of cringe – whether it is my history of dropping Ethos eyepieces (and getting away with it), walking into my French doors with my scope and denting dew tube because I didn’t realise the door was closed (yes I really did that) or watching as someone else’s scope topples and falls off my Equatorial platform (got away with that too without damaging scope boy was I lucky!)
My latest experience has occurred this week – you may remember that on Wednesday night I had a fruitless few hours trying to take any photo in that very clear and very cold weather. Although there are probably several contributing factors, one particular aspect really annoyed me at the time – which was that my filter wheel would not work. For some reason APT had dropped the automatic selection of the filter wheel which it did normally, so I had to choose the wheel again and the Atik driver would not connect to the EFW2 filter wheel. I decided to tackle this problem this morning…….and realised my filter wheel is a ZWO one! No wonder the Atik driver didn’t work! Selecting ZWO has sorted the problem out…….


The Crab

I made the most of a short clear spell last Wednesday. This is the Crab Nebula- the first object in Messier’s catalogue. I captured it with my ASI 1600mm and 8 inch Newtonian – its first use since last September- with 30 minutes of RGB on the stars and then half an hour each on Ha and Oiii. Not really enough, but there was intermittent cloud throughout the evening and I rejected more of the narrowband subs than I kept.

I’m really fond of this object for several reasons: I love its place in history, with clear records in China in 1054 observing the actual supernova, it’s a good observing challenge and really jumps out with an Oiii filter, and it’s one of only 2 natural phenomena (the other being a neutron star collision) that we know of that produces Gold. I always get a bit whimsical and hold my wedding ring when observing M1, as a direct physical link to a similar ancient astronomical event.

Doesn’t look much like a crab to me though!

Observing with Dob-Mounted SW250PDS

Wednesday night (3rd February 2021) was the first opportunity for 4 weeks that the sky has been clear enough for long enough at a reasonable time (I am fussy) to get in some observing. It was due to cloud over later so decided on the 10″ SW on the Dob. My target in January had been globular cluster M15, but it’s now too low in the murky West towards Burton on Trent. Orion was well placed so I focussed on multi-star system sigma Orionis, about 45 arcminutes south of zeta Ori, Alnitak, at the eastern end of Orion’s belt.

This is a 5 star system but I learned later only 4 are visible in amateur telescopes, that’s a lesson in planning that could have saved me a few eyepiece changes! The bonus with this target is that you get a triple star system in the same view, Struve 761. The image below was obtained using a Canon 60D 1/8s @ iso3200.

Auriga was high above, so I had a go at finding 1 of its 3 open clusters and found M37, the most impressive of the 3, suprisingly quickly, as I last observed it over a year ago using a GoTo mount. I do like star clusters and this was a real jewel, that was best at magnification of 100X. My image from 2020 below does not do it justice, of course.

Just time to slew over to Perseus to check out Mirfak and the Alpha Persei Cluster, using the 9×50 finder to view it all before the inevitable high clouds rolled in. Overall, I was pleased with what I had seen in just over an hour during only my 2nd session of 2021.

Atik 16200 – bad pixel map, bias and dark frames

Master dark and bad pixel maps (taken 4/2/2021):

Click below to download FITS files of master dark and bad pixel maps for this camera:

Atik16200 Master Dark 21x600sec @ -20C taken 4/2/2021 (ZIP)

Atik 16200 Bad Pixel Map-APP-taken 4/2/2021 (ZIP)

Bias and Dark Files (these are a bit older):

Download ZIP file with FITS versions of bias and dark files by clicking on next line:

Atik 16200 bias & dark frames (taken 2 years ago)

Below are JPEG versions of bias and dark frames:

Bias frame:

Dark frame 300 secs:

My first three months in Astrophotography

or how I came to love the cold, and lose feeling in my toes and fingers regularly

My name is Paul and I am trying to be an astrophotographer.  It has been 4 days since my last clear sky.

Time to document the progress that I have made with the help of the challenges set by the RAG Astrophotograhy Special Interest Group….  They have been really well set to cope with my limited kit

December meeting’s target – M31

I used my standard DSLR and a Redcat 51 to capture a widefield shot of the Andromeda Galaxy.   I used an iOptron Skyguider pro to keep me on target.  I obtained 40 90s 800 ISO subframes that were useful. Stacking was done in Deep Sky Stacker and processing was done in photoshop.

M31 – Andomeda Galaxy

As first serious efforts go, I was quite happy with that as obtaining the shots gave me an insight into may elements of acquisition and an introduction into what can be done in preprocessing and processing of images.

The discussion at the meeting in December included an introduction to Pixinsight – I had seen others use it tutorials,but thought it is a little expensive and was put off by the reports of a steep learning curve…..  But after the meeting I downloaded a trial version and started to play.  I found it logical once I realised that it is really not a single programme but an operating system for image processing…  SInce then DSS has been uninstalled and  photoshop has returned to its use in day time photography…..

January’s target – M42

Christmas eve was clear and I was able to roll out the Redcat 51 and sky guider pro, this time guided using a WO guidescope and ASi120.  I also dug out an old Canon EOS 600D from the cupboard to get it modded by Juan Fierros.  This set up is at the extreme of what the sky guider can hold, so balance and polar alignment were critical – SharpCap’s polar alignment procedure helped enormously, though I fear that I am a bit heavy handed with the set up when finding my targets…..  Anyway I was able to get a set of 90s subs before Dec drift produced noticible star trails.  Started to develop a work flow in pixinsight and get hooked!

M42 – Orion and De Mairan’s and Running Man Nebulae


I got the Astrophotographer of the year calendar for a present, and was inspired to try to emulate Ross Clark’s fab extremely widefield photo of the Orion area.  I used the modded 600D with my Samyang 135mm F2 lens and a Cokin on lens light pollution filter to take a load of very short subs at 200 ISO

February’s target – anything in Orion

WHAT A CLOUDY MONTH!  2 nights clear all month.  Probably my fault as I needed to try some more kit.  I’ve started to take narrowband images as the forthcoming new ZWO CMOS cameras are starting to get people to sell their ASI 1600’s at more and more reasonable prices.   Guess what – I got one with a filter wheel and a full set of broadband and narrowband filters.

After a lot of research  and a bit of trial and error, I found a reasonable balance between maximising exposure time, gain and limitations of the now totally at the limit skyguider to produce a first light of the Horsehead nebula.  The skyguider has been great as it has forced me to learn how to star hop, but I have been restricted to try easy to find targets!

Anyway as the moon was very close I took some subs of the horsehead nebula  in H alpha, waiting for darker skies for the LRGB….

The horsehead nebula

Then i went after another classic – The rosette in H alpha…..  42 90s subs at unity gain ( I almost sound as if I know what I am talking about!.), Well Monoceros is close to Orion…

Rosette nebula in H alpha

I am working on the oxygen and sulphur for the rosette, but these need loads more time!


So there you go, 3 months well spent I have learned loads and enjoying the cold!  Cloudy nights projects for me include a set of slides that I want to share on a load of optics questions like why are stars so big in astrophotographs?  How bad can focus be and still be good? What is this seeing thing anyway? Do I really need to guide if my mount is well calibrated?  What is an Airy ring when it it is at home and can I see one?  Watch this space and I will share a series of blogs on these plus a summary of a load of my ramblings on noise and calibration……

Clear skies.

HaRGB processing of Horsehead and Flame Nebulae from data 9/1/2021 and 21/1/2021

My next attempt at creating combined HaRGB image from my data from 9/1/2021 and 21/1/2021.
I think I am slowly getting there!

  • Sky Watcher Equinox Pro 80mm OTA
  • Altair Astro 183M camera
  • Baader filters
  • Sky Watcher Eq6 mount
  • Processed in PixInsight and Photoshop with Topaz plugins.


The two following versions are similar but I prefer the second …. but I am not sure if it is the better one of the two…..please post your thoughts!