The Monkey Head and Pacman Nebulae

[Trev S]

The seeing has been very poor lately so (like Tim) I have been revisiting old data to see if I can improve my results. The attached images were taken on the nights of the 9th and 10th of January 2025 from my back garden in Surrey.

The Monkey Head Nebula, also known as NGC 2174 is an emission nebula located about 6400 lightyears away in the constellation Orion.

The Pacman Nebula, also known as NGC 281 is a bright emission nebula located about 9500 lightyears away in the constellation Cassiopeia.

One interesting thing about these two nebulae is that they are very similar in looks and apparent size, though the Pacman nebula is about 50% farther away than the Monkey head Nebula.

C9.25 SCT with 0.63 flattener/reducer
ZWO ASI1600M  camera cooled to -10C
AZ-EQ6GT mount
Antlia filters

Both images:
Ha (Red) 30x300s
Sii (Green) 25x300s
Oiii (Blue) 25x300s
RGB 40x60s (stars)

SGPro mount and camera control, PHD2 guiding
Processed with Pixinsight and PS2
(Stars processed from the RGB and added later)

Thanks for looking

[tcos...@gmail.com]

Hi Trev

These are lovely images. They show tremendous detail and your processing captures the cave-like structure of these objects very well. I never fail to be impressed by the quality of the images you get from your Celestron C9.25 scope.

Well done!

Tim C

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[drja...@aol.com]

Hi Trevor

Again, some fantastic detailed and noiseless images.

Given it's the same data, what processing changes do you think made the most difference to the results.  

James

Sent from my iPad

On 4 Oct 2025, at 20:22, Trev S <trevs...@gmail.com> wrote:

The seeing has been very poor lately so (like Tim) I have been revisiting old data to see if I can improve my results. The attached images were taken on the nights of the 9th and 10th of January 2025 from my back garden in Surrey.

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<PacManNebula.jpg>

<MonkeyHeadNebula.jpg>

[Trev S]

Thanks for the kind comments.

James, It is just my better understanding of Pixinsight proessing especially the gradient and noise correction tools including the newest additions.  I find that with Pixinsight there are several different ways to achieve the same result using its different tools, that when they introduce a new one or improve on an existing one it takes a while to learn how to use it to best advantage.  It's a constant learning process.  Still, it keeps the old grey matter working.  

[drja...@aol.com]

Thanks Trevor.  That's interesting.  The rate of change of Pixinsight seems to have been quite substantial over the last few years, with AI based tools as well.  And, so far, without it becoming an ongoing subscription service rather than a one off purchase with mostly free updates.

James 

Sent from my iPad

On 5 Oct 2025, at 17:54, Trev S <trevs...@gmail.com> wrote:



Thanks for the kind comments.

James, It is just my better understanding of Pixinsight proessing especially the gradient and noise correction tools including the newest additions.  I find that with Pixinsight there are several different ways to achieve the same result using its different tools, that when they introduce a new one or improve on an existing one it takes a while to learn how to use it to best advantage.  It's a constant learning process.  Still, it keeps the old grey matter working.  

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[Carly Harris]

Wow these photos are amazing! How wonderful a d thank you William for adding me in to these emails 

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