StarTools

Hi! Is there any way to check if I'm really bad at processing or if my data is too bad?

Here's an example of what I recently processed Here's some info about it:
18x10mins
CLS filter, Bortle Class 5 skies
Canon 80D

I'm not sure what's wrong with it. It just looks bad to me. Any tips on working with ST would be great! I am also be willing to upload my stacked image if anyone would like to try processing my data (which I would appreciate a lot!)

Hi,

Feel free to post the stack - it's indeed a little hard to say if this is all the dataset has to give, or if there is more that can be done.

It's a very faint target and you will need a lot of time on it with an unmodified camera.

Some more pre-processing and acquisition specs would help. How was this stacked, calibration frames, ISO, etc.

Thank you,

Hello,

Please ignore the previous image. My files got mixed up. That's from my ~10x4 mins data set. This one below is the 18x10mins data set:
better, but I still feel more can be done.

Here is my stack:

https://drive.google.com/file/d/1Yin_1_ ... sp=sharing

Here's some more info about it:
-No pre-processing done as far as I can tell.
-stacked in DSS. I also already followed the recommended settings for StarTools
-Taken at ISO200 on a Canon 80D with a CLS filter. Sensor temp is around 23-25 degC.
-Scope is a SW Quattro 200P on a SW AZEQ5
-I used Darks, flats, and dark flats. Though I had to reuse the flats from the night before because I forgot to take flats, though they are the same setup.

Thank you!

Hi Starnoob,

Well here's a quick but best I think I could do with your data, for now.

When I checked the linear stack it seemed the stars were a bit oblong in the up/down direction, maybe a little loose on the tracking or guiding? When processed things didn't seem bad though.

I used center option to open this, but I don't know anything about processing a CLS filter, so I don't know if that is proper or if I should have just chosen linear. I also don't quite know what that CLS is blocking out from the spectrum here (I'm sure I could look up the graph lol) so uncertain as to color balance and how complete the image is.

Coming from a Bortle 7-8, I wonder if CLS is even helpful in B5 or holding you back. Only other thing, you might look up the best astro ISO for your Canon. Most Canons I see discussed are shot at around 800-1600 ISO. 200 might not be in the best range, but, perhaps it is for your particular model?

I maybe could have stretched this some more to show the nebulosity off to the side better? Would have to try again. There also did seem to be some vignetting here, despite your flats, so I did use the vignetting preset in Wipe as a starting point.

@Mike in Rancho is fast becoming another ST greybeard around here.

As I wondered as well, the ISO may have been a bit low, but then I looked up the specs of the 80D, and it appears ISO 200 is indeed entirely reasonable.

(the way to interpret the Dynamic Range is to look for the first stop, from left to right, where the line becomes "straight" - this is the point where you get a linear relationship between signal collected and dynamic range used up).

You could try a higher ISO, say 400 next time, but I now doubt that would make any significant difference.

As I surmised, the biggest issue is probably just the object being faint, while imaging from a Bortle 5 location with an unmodified camera.

As Mike also commented, definitely check your flat frames, as there is definitely uneven lighting going on, even showing faint hints of dust donuts; if you are going for faint objects, your flats need to be impeccable. Without being able to trust whether something is faint detail or dust donut (or vignetting, etc.) it becomes impossible to rescue faint signal from the murk.

CLS filters pass through much of the visual spectrum, however will cause a notable absence of yellow. E.g. a "correct" visual spectrum rendering is pretty much out of the question. However, you could consider using the bi-color preset to create a nice, distinct separation between the emissions in the red part of the spectrum (S-II, Ha) and the emisisons in the blue+green parts of the spectrum (O-III, Hb).

So, all up, super quick process, just for demonstration purposes;

AutoDev, Bin, Crop, Wipe (Vignetting preset, increased Gradient Aggressiveness), AutoDev (defaults), then Color module (Bi-Color preset), finished off with the Isolate preset in the Super Structure module;
E.g. please embellish, tweak to taste, chop and change. It's just to give you an idea. The cyan an Ha corresponds reasonably well with that from Ha and O-III renditions (or even SHO renditions) on, for example AstroBin. The one major issue is your flats, which makes faint nebulosity "iffy".

Hope this helps!

Flats are the hardest calibration file get right , we all struggle at times especially with a big Newtonian, how are you doing your flats , I really struggled with flats on my newt 8” you really want a pretty even dim light source not too bright , I seem to have better results now I moved on to a Zwo533mc and use APT flats aid to determine exposure, I use an El panel with white cotton covering and a opaque acrylic sheet over that and my last flats were 3.3sec exposure for a I think a 20,000 adu value using a dslr with the El panel I couldn’t seem to get a long enough exposure and was getting issues from the el panel refresh rate which is only overcome with longer exposure which is recommended for El panels , if funds allow in the future ditch the dslr and move to a cooled set point camera it makes life sooooo much easier .

Regards Dave

A graybeard at 2 months in? Well, I did read here for many months before joining. Participating and trying out user data is more fun though, and better learning.

So you did a bicolor preset, but loading was probably open, not composite using OSC/DSLR bicolor? I guess that still locks B and G for color purposes, but the channels wouldn't be an identical blend sans the composite?

Hi @Mike in Rancho and Ivo,

Thank you for taking a look at my data. Yes, I am having issues with guiding. The flats were not taken on the same session because I got too excited taking down my setup. So, that's probably one cause of the dust donuts, though I think that's better than no flats at all.

I'll try these settings you've suggested. Thanks again!

Burly wrote: ↑Wed Aug 18, 2021 5:56 am Flats are the hardest calibration file get right , we all struggle at times especially with a big Newtonian, how are you doing your flats , I really struggled with flats on my newt 8” you really want a pretty even dim light source not too bright , I seem to have better results now I moved on to a Zwo533mc and use APT flats aid to determine exposure, I use an El panel with white cotton covering and a opaque acrylic sheet over that and my last flats were 3.3sec exposure for a I think a 20,000 adu value using a dslr with the El panel I couldn’t seem to get a long enough exposure and was getting issues from the el panel refresh rate which is only overcome with longer exposure which is recommended for El panels , if funds allow in the future ditch the dslr and move to a cooled set point camera it makes life sooooo much easier .

Regards Dave

Yes, I agree. As soon as I have the cash, I'll happily switch to a cooled camera. No more ice packs strapped on a dslr in an insulated box!