Andrew Thornett

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?

Observing Log 9/1/2021

Orion UK 10 inch Dobsonian

Explore Scientific 9mm 100 degree AFOV eyepiece



Wow! I have just had my best ever view of M36, 37 and 38. Never expected that tonight. Using ten inch Dobo with Explore Scientific 9mm 100 degree FOV eyepiece, each cluster fills the field of view of the eyepiece. The views of M36 and M38 are extremely bright with that diamonds on velvet appearance that makes the Double Cluster in Perseus through a 10 inch Dobsonian scope such a wonderful view – it is just that I have never seen it before with these three open clusters, which often disappoint,  but not tonight! M36 is entirely different, with loads of fainter white stars, also filling the field from end to end. What a comparison! I guess this must be related to how high Auriga is riding tonight, at about 75 degrees for these clusters. Not the clearest of nights, but not too bad either – 7/10 on my personal “visibility of Orion’s sword” scale (I resort to this because the local seeing conditions are almost always poor so it is a question of how poor they are tonight….) There is minimal scintillation and, at this elevation, the constellation is above most of the light pollution.

Looking at Pleiades, can see that the sky has lot of moisture with halo around the brightest stars.

I have been photographing the Tadpoles with my imaging rig, but Orion now cleared the trees. At the RAG astrophotography SIG last night, Rob Leonard suggested this months target should be something in Orion, so I have now moved over to Orion to photograph the Horsehead and Flame Nebula. Only once have ever photographed those in colour and it is an awful picture. Since then I’ve taken a half-decent black and white photo – hopefully, if the clouds hold off, I can add a reasonable colour photo to that tonight…….although of course today’s reasonable becomes tomorrow’s awful as our standards improve with experience (I also very happy with my previous photo when I took it!)

I am quite excited about tonight. I must go for my Covid vaccine tomorrow at 9am so sadly can’t keep going so in a minute I am going to put the kit away. However I have managed 2 hours straight in Horsehead. This is first time that I have ever been able to keep imaging one object for that long on single night, either because of cloud or because the object I am imaging goes behind trees in my garden. And its a great object too – the Horsehead and Flame plus my stars look round(!) So hopefully I can produce something decent.

M42 LRGB 20/12/2020 re-processed 1/1/2021

My first processed image of 2021 is a re-process of my LRGB data on M42 from 20/12/2020.

I have used StarNet in PixInsight to extract the nebula, enhance it, and then added back the stars in Photoshop.

Although there isn’t more detail in this image compared to my last attempt, I think my background gradients are better dealt with, and the stars slightly improved – although my wife prefers the previous version! What do you think?


New version of M42:

Most of stars removed using StarNet in PI:

Mounting new rings on Sky Watcher 180

The SkyMax 180 came with a Vixen mounting bar which I have found difficult to use at night due to the the large bulk of the tube. Therefore, I thought it would be useful to change it to a Losmandy bar. I also wanted to add a handle to make the scope easier to handle in the dark.

I have been drilling and bolting my new Orion telescope rings to create a cradle with Losmandy bar and handle for my SkyMax 180 scope this New Year’s morning!

Below = finished product. When I removed Vixen bar there was big crunch as inside the student a nut and holding bar fell off thankfully not onto mirror or corrector plate. So I had to remove the corrector plate and cell to get them out of tube and remove second nut from other bolt golding Vixen bar – needed to get it off to give room for the rings. Then 4 old belts required to pad out the rings bit big for tube. I had bought an aluminium bar for top of rings which I drilled this morning for the rings and to create mounting holes for the handle I purchased from Germany. I bought that one particularly because it has a slot in the middle of the handle – convenient for mounting another mounting bracket onto which I can place a guidescope held centrally so it does not imbalance the scope in use.

2nd attempt at processing my narrowband image of M42 from 24/12/2020

Do you prefer one of these versions from today or the ones I posted previously?

In one respect these images are better – in my previous post I had stacked the frames using Nebulosity 4 and there was some misalignment of stars in corners. On this occasion, I used the automatic script in PixInsight to stack and it has done a far better job. I also think I have kept more detail in the fish-mouth/trapezium region. Leaving some of the green in the image (i.e. not using 100% on SCNR has also emphasised the Running Man nebula M43).

Regarding colour choices in narrowband imaging, this is in the eye of the beholder – not sure which I prefer…..

Versions 1 and 3 are very similar – Version 1 is really Version 3 with Topaz SharpenAI and DeNoiseAI filters applied.

All versions used 75% SCNR in PixInsight – in Version 2 I used Replace Colour in Photoshop to replace some of green with red to see if it looked nicer!

Version 4 is my Phoenix Version!