That is with a Celestron C925 with a Celestron 0.63 reducer/Corrector using a ZWO ASI294 OSC camera.
This is a stack of 13 ten minute, ten of five minutes, ten of four minutes, four of two minutes and a single 1 min sub. Stacked and stretched in Deep Sky stacker with a final tweak in GIMP as I have not gotten my head around Astro Pixel Processor yet.
Unfortunately I suspect that the reflection is an internal one in the corrector, so I am going to have a crack without that in the train tonight.
Good job there Paul; a couple of suggestions if I may. The core is blown out;
in DSS the bottom slider in the Luminance section is set to 50 by default.
You can reduce it until you can see the detail in the core, probably to
around 30-40. The image is lacking in colour; the galaxy has a strong medium brown appearance,[hence the name Cigar Galaxy], so I suggest you increase the saturation.
raymo
Looks great to me.
Maybe try a longish dew tube. I use a 2.5 foot baffled dew tube on my 80mm and I am sure it does wonders...but I have not done comparisons. ..if nothing else it works well as a dew tube...but if you look at the Hubble you will see they have similar baffle placement...and it makes sense...
Alex
Had another crack at processing, borrowed a machine with Photoshop on it (Old, CS6) and had a fiddle, though I am very far from competent with any image processing software at this point.
I think resizing this has not done wonders for it but here goes.
Last edited by The_bluester; 03-02-2019 at 04:04 PM.
Heaps better Paul.
Colours look good
I feel like reaching for an 'Old Port' and taking up smoking cigars again (not really).
I like using PS and probably because its all I've used!
To resize i use 'save for web ' in PS and keep adjusting the % until its about 2meg or under.
Cheers
Andy
Yeah, I have to say images are one thing I have never been all that happy with on this forum. I would much prefer to use img code to a file stored elsewhere. At least that way you can put up an image at decent resolution.
The problem with Astrobin is no embedding allowed, particularly for a paid service, even if the cost is pretty low.
Basically this forum is the odd one out image wise for me. To make it work I would need to upload the small image here and provide a link to an Astrobin full res version, and then upload the image elsewhere as well for the other forums (Which do permit [img] [/img] type embed tags and don't allow file upload directly)
I have never been able to grasp why IIS goes the other way, it must contribute quite a bit to storage and bandwith consumption, hence the low 200kb limit.
Good tracking on such a small image scale. I'm still trying to get the hang of much wider fields myself.
I notice the stars in the top left are a bit elongated - is that a collimation issue or a field flatness issue?
Also, the reflection is interesting in that it's not circular and seems almost elliptical? I wonder where that comes from? I'd be interested to hear if you find the cause.
The odd stars is a combination of things. Collimation was probably not perfect and I think I am really pushing a visual OTA close to the limit, even with a reducer/corrector fitted it shows some coma in the corners.
I suspect from my reading that the loop of light is an internal reflection off a transition from glass to air or air to glass inside the corrector. I plan to test it on a really bright off axis star without the corrector. The further off axis the star is, the longer the loop but it is there on bright stars well inside the FOV as well so it does not seem to be a reflection from the sides of a tube such as the baffles inside the OTA or the spacers in front of the cam.
I am using zero gain and subs up to 600 seconds. At the moment I am working on using the highest dynamic range I can get out of it. I am only using more gain than that to get quicker framing tests.
I was pleasantly surprised that the guiding was working well enough to get half decent stars out of 600 seconds.
