Astrophotography – deep sky

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.


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!

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!


A Tipsy Dither

At last AP group meeting Neil suggested sharing bloopers, and I was thinking afterwards that it was a good idea- so here’s my submission…

Sods law dictated that the only clear night in weeks should coincide with a pre-arranged zoom drinks and quiz night with some local dads. I thought that at least I could get some imaging done whilst it was on. Trouble is, to avoid walking noise, I have to manually dither the mount.

Three rounds in, before my turn to be question master, I suggested we have a ten minute break and quickly hared into the garden. Unfortunately it’s quite a delicate procedure, involving a tiny couple of degrees on the slo-mo knob. I completely botched it and had to do a hasty re-alignment. Just about got it done and ran back in thinking ‘Phew- got away with that’.

No, I didn’t.

See below: imaging restarted with completely different framing and polar alignment knocked out, leaving the mount slewing drunkenly off track. A bit like myself!

Horsehead and Flame Nebula Hydrogen Alpha from 22/1/2021 and first attempt at combining that data with LRGB image same field from 9/1/2021

On evening 21/1/2021, I collected 100 minutes of data on the Horsehead and Flame Nebulae – first time even using just one narrowband image on an object in an evening – this was on advice of Ken Critchon – and it was excellent advice – as I obtained te image below! Minimal processing – stacked using weighted batch pre-processing script in PixInsight and Photoshop curves to make data visible.

Then I tried to combine this image with my previous LRGB one from 9/1/2021 in Photoshop – a less successful effort! Don’t really know how to do that.


Re-processing my Horsehead and Flame Nebula from 9/1/2021

I have further processed this data to see how much detail I could bring out.

The issue is that really bright star – when I used curves to bring out detail then the star became extremely bright and adversely effected the rest of the image. So, I addressed it by creating 2 copies of image, masking the star in one and other bright stars in image. I then increased curves on that image to bring out detail and the mask stopped star blowing out.


Horsehead Nebula data from 9/1/2021

Thanks to RAG members who have offered to have a go at processing my Horsehead and Flame data to see what you can make of it.

File can be downloaded by clicking on link below – comes with calibration data – ZIP file – WARNING! The file is 10GB in size!

Horsehead and Flame Nebula in Orion, light frames & calibration files, Altair Astro 183M/Sky Watcher Equinox 80+1.0x FF/LRGB 9/01/2021 (ZIP file, 10 GB)



Horsehead and Flame Nebulae from last night

My photo from last night:

  • 3 hours of data.
  • 80mm Sky Watcher Equinox Pro telescope.
  • Sky Watcher EQ6 mount.
  • Mono camera Altair Astro 183M – Baader LRGB 7-8.5nm filters.
  • Taken in Lichfield, UK.
  • Sky had some transparency issues & below zero temperature outside.
  • Telescope set up on garden.
  • Processed in PixInsight and Photoshop CS6 with GradientXterminator filter and Astroflat Pro filters; and Topaz AI Noise and AI Sharpen filters.


Which version of following two do you prefer?