M33 at 400mm...

[ollypenrice]

Another one with Paul Kummer.

You wouldn't normally choose a scope with a 400mm focal length to shoot galaxies but , hey, pixels are getting smaller to match. Anyway, what happens if you do? Here we go:

This is quite a heavy crop of the starfield and has no additional Ha.  It's RASA 8, ASI2600MC, Avalon Linear. After DBE in PI it was processed in Ps and incorporated Russ Croman's StarXterminator in the workflow. Thanks to Ciaran for suggesting a better way of recombining the starfield. It worked a treat and is explained in this thread.  Merci Monsieur!  (At some point I'm going to try to work out what I'm actually doing when I follow this method but this time I just did as I was told.  )

 

Olly

Edited October 10, 2022 by ollypenrice
Forgot to un-flip image. Doh!

[gorann]

A lot of dust there Olly! As Ciaran suggested you can also download the Star XTerminator Unscreen action from RC-astro, it will do the same thing (giving you a starless image and a star image to blend in) so a bit simpler than the manual method. Download it here  https://www.rc-astro.com/StarXTerminator/UnscreenStars.atn.zip

[Xiga]

5 hours ago, ollypenrice said:

Another one with Paul Kummer.

You wouldn't normally choose a scope with a 400mm focal length to shoot galaxies but , hey, pixels are getting smaller to match. Anyway, what happens if you do? Here we go:

This is quite a heavy crop of the starfield and has no additional Ha.  It's RASA 8, ASI2600MC, Avalon Linear. After DBE in PI it was processed in Ps and incorporated Russ Croman's StarXterminator in the workflow. Thanks to Ciaran for suggesting a better way of recombining the starfield. It worked a treat and is explained in this thread.  Merci Monsieur!  (At some point I'm going to try to work out what I'm actually doing when I follow this method but this time I just did as I was told.  )

 

Olly

Glad you liked  the new method of adding back in the stars Olly 🙂 

I'll post a link to a video which helps to explain how it works (although i have to admit i don't think i fully get it myself!). I'll add it to the thread above for consistency. 

[ollypenrice]

11 hours ago, gorann said:

A lot of dust there Olly! As Ciaran suggested you can also download the Star XTerminator Unscreen action from RC-astro, it will do the same thing (giving you a starless image and a star image to blend in) so a bit simpler than the manual method. Download it here  https://www.rc-astro.com/StarXTerminator/UnscreenStars.atn.zip

Thanks Goran. I have that link but am unable to locate the PsCC program file on my PC. I also have, and want to keep, PsCS3 which I can find.  Anyway it's a 2 second job to write it as an action.

Olly

[ollypenrice]

Here's a hybrid combining my old TEC140 HaLRGB CCD  image with the RASA. Opinions welcome. The RASA went deeper, without any doubt, finding the smooth outer glow which looks slightly artificial, perhaps, but which I think is genuine. The RASA had 6.65 hours, the TEC about 30. Makes you think...

Olly

 

[gorann]

Very nice Olly, but as you say the outer glow looks slightly artificial. It ends very abruptly. I had a look at other RASA images on Astrobin and there is a tendency for that glow to have a relatively defined outer edge, at least more so than M31, but your edge appear to be at the sharper en of the spectrum. Here is one to compare with using identical equipment:

https://www.astrobin.com/1bvta1/

You can just search on Astrobin for M31 and then on the menu to the left write RASA :

https://www.astrobin.com/search/?q=m33&subject=&telescope=rasa&camera=&date_published_min=2011-11-09&date_published_max=2022-10-11&sort=

Edited October 11, 2022 by gorann

[ollypenrice]

4 hours ago, gorann said:

Very nice Olly, but as you say the outer glow looks slightly artificial. It ends very abruptly. I had a look at other RASA images on Astrobin and there is a tendency for that glow to have a relatively defined outer edge, at least more so than M31, but your edge appear to be at the sharper en of the spectrum. Here is one to compare with using identical equipment:

https://www.astrobin.com/1bvta1/

You can just search on Astrobin for M31 and then on the menu to the left write RASA :

https://www.astrobin.com/search/?q=m33&subject=&telescope=rasa&camera=&date_published_min=2011-11-09&date_published_max=2022-10-11&sort=

Some wild colours out there! I take your point about my relatively well defined outer glow but I'll say in defence of my image that I think there are hints of very faint spiral structure in that glow which I haven't seen elsewhere - though that will only be down to my random selection of views.

Olly

Edited October 11, 2022 by ollypenrice
typo

[tomato]

Here is my RASA8/QHY268c capture of M33 from January 21, just 126 mins integration, reprocessed with the RC tools. No distinct oval of outer nebulosity, but I think it is starting to come through?

[ollypenrice]

8 minutes ago, tomato said:

Here is my RASA8/QHY268c capture of M33 from January 21, just 126 mins integration, reprocessed with the RC tools. No distinct oval of outer nebulosity, but I think it is starting to come through?

I think it's there already though not as clear of the background sky. That's just a matter of exp. time.

Olly

[tomato]

Thanks Olly, as I read from my notes (as a FDA inspector once told me “if it ain’t written down, it’s just a rumour”) this was imaged under a full moon. I should change my handle to The Optimistic Imager.

[Louis D]

Please excuse me if it's inappropriate to create and post my own interpretation of someone else's image, but I wondered what I could do with some simple Photoshop Elements edits of the hybrid image above.  After some levels adjustments, increased saturation, and selective unsharp masking, I came up the following:

I'll admit I'm a sucker for colors that POP!

 

Edited October 11, 2022 by Louis D

[ollypenrice]

12 hours ago, Louis D said:

Please excuse me if it's inappropriate to create and post my own interpretation of someone else's image, but I wondered what I could do with some simple Photoshop Elements edits of the hybrid image above.  After some levels adjustments, increased saturation, and selective unsharp masking, I came up the following:

I'll admit I'm a sucker for colors that POP!

 

You can always do this in any graphics program but whether or not you do so is a matter of choice. You've done two things:

1) Cut out the faint signal which took a lot of capturing. That's to say the galaxy's faint outer glow. That's a net loss in any terms. This happens when you bring the black point in too far and clip the left hand side of the histogram. It also results in a flat, jet black sky.

2) Increased the colour saturation. This is a matter of taste but the truth is that M33 is not a very colourful galaxy, probably because of its astrophysics. It does not have particularly well defined spiral arms so is not as active as some spirals in terms of star formation. However, saturation is a matter of choice and my processing was something of a reaction against my original M33 which had higher saturation. I was also making a statement against the intense colour which is becoming the norm in AP. I probably over-did it (or under did it. )  Anyway, it's nice to know that the colour is there if the imager wants it!

Olly

[ollypenrice]

On reflection the earlier image was more milk shake than whisky so I dedicate this one to Louis D. 

Olly

[Rodd]

Just my .01 cents, but I think if you bring down the brightness in the galaxy much more detail would be visible.  There is so much signal it is almost blinding.  There is a lot of structure in M33 beyond Ha.

[ollypenrice]

18 minutes ago, Rodd said:

Just my .01 cents, but I think if you bring down the brightness in the galaxy much more detail would be visible.  There is so much signal it is almost blinding.  There is a lot of structure in M33 beyond Ha.

Yes, good point. I dithered over the overall brightness and will look again. Cheers, Rodd.

Olly