M101 results bad - new to astro

Questions and answers about processing in StarTools and how to accomplish certain tasks.

M101 results bad - new to astro

Postby Mangee » Fri Aug 10, 2018 7:41 pm

Really new to all Astrophotography. I am using a GSO RC 6 inch telescope with a Canon T3i camera, not using filters yet.
The mount is a Bressor exos-2 with AstroEQ go-to. I use APT for tracking and goto and plate solving shows it tracks good.

I captured M101, 20 images 20 seconds each and used DSS for stacking using your quick start guide.
Also followed guide at Youtube " StarTools: M8 in Color with modest data ".
This is the best image so far with StarTools, cropped.
Image

I think my seeing quality is most of my problem. Several sites list it as poor, chart below.

If your seeing is really poor can StarTools really help??

Image
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Re: M101 results bad - new to astro

Postby Rkonrad » Sat Aug 11, 2018 1:04 am

Welcome to StarTools! You're attempt at m101 is actually not bad considering you have only 6.6 minutes of total exposure time. Dark skies are always ideal but you should be able to improve on that greatly with about an hour's worth. I think 20 seconds is a bit short for each shot. If you can extend that to 2 min plus your results should be a lot better. M101 is not a very bright galaxy to image (to get all the details on the spiral arms).

Also feel free to share your stacked tiff or fit with us. We can help you and post a log on who we processed the image.

Cheers

Richard
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Re: M101 results bad - new to astro

Postby Mangee » Sun Aug 12, 2018 8:41 pm

Thanks for the reply.
Tried one minute long no filter and the background around the galaxy was nothing but noise.
Autodev then Wipe was worse.
Ill try 2 minutes 20 shots but with a UHC filter tonight.
I did Darks, Flats "with old style light bulb" and Bias frames.
Traveling to a legal dark area is way to far so my patio is it.
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Re: M101 results bad - new to astro

Postby Mangee » Mon Aug 13, 2018 5:06 pm

Well the UHC filter was a total failure.
APT could not do a plate-solve with it on.
Plus taking it off for plate-solve then back on for capture could not guarantee focus.
So without the filter I captured 20 photos 2 min each. "I" can't get anything worth while in Startools.
Below is link to the tif file from DSS with Lights-Darks-Bias stacked. I didn't like my flats so left them out.
I left the meteor in the stack.

https://drive.google.com/uc?export=download&id=19oiJgAwe_ZIvwcqoayIDUjVK90lE8OSQ

If anyone has time to look at the file and tell me what I am doing wrong would be appreciated.
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Re: M101 results bad - new to astro

Postby admin » Wed Aug 15, 2018 6:25 am

Thank you for uploading.

The data is exceedingly noisy for 20*2m. It almost looks like the stack consists of just a single image rather than 20.
Can you try stacking without any bias or dark frames?

That said, trying to image a low surface brightness galaxy in light pollution is a very hard thing to do. However I would definitely expect a much better quality signal from 20*2m... :think:
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Re: M101 results bad - new to astro

Postby Mangee » Wed Aug 15, 2018 5:44 pm

Well stacked just lights and inside DSS image turned red or pink, Startools same thing all red.
So stacked with just darks and removed two lights with artifacts, meteors.
18 lights 2 min each.

https://drive.google.com/uc?export=download&id=1ItjFY8IUsmWGQ8nrPaGpgNxbZudX120U

I think the skyglow is just to strong. The longer the capture the worse the results.
Ill try the UHC filter one more time. At APT plate-solving is normally 7-8 sec image capture and I went to 30 sec.
With the UHC filter I might have to go to a minute or more.
Thank you for your time.
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Re: M101 results bad - new to astro

Postby admin » Thu Aug 16, 2018 5:53 am

Mangee wrote:I think the skyglow is just to strong.

It's starting to look like it :(
Have you tried other objects though? M101 isn't the easiest to capture, let alone in light pollution.

Perhaps try something bigger in size with a signal that can stand out in the light pollution; M42, M8, maybe M31? The Carina nebula is a great candidate too if you're in the Southern Hemisphere.

For what it's worth, you are already capturing interesting features; a yellow core (older stars, gas depletion), blue/purple outer arms (more gas, star formation going on) and hints of purple HII areas (like M42, M8 in our own galaxy);

M101-LD-emmbeded-2018-08-12--ineger.jpg
M101-LD-emmbeded-2018-08-12--ineger.jpg (32.99 KiB) Viewed 355 times


I can share the workflow, but better data will make the workflow simpler, easier and much more replicable.
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Re: M101 results bad - new to astro

Postby Mangee » Thu Aug 16, 2018 4:56 pm

First I want to thank you for your time and patience with this.
If you could provide me with the workflow I really would appreciate it.

Every thing I capture will have lots of Skyglow. In San Diego California USA all of the true dark sky areas are hours away.
Mt Palomar Observatory has a camp ground outside of it for star gazing but I am not set up for camping.

The RC 6" is recommended for viewing brighter deep sky objects. However I have to view whats above me or at least try.
I look for objects that are high in the sky, less atmosphere plus I am in a box canyon with hills, trees and my house blocking much of the view east and south the worst.
I use CDC to determine what to view and capture. I just now zoomed in and found ngc 7023 Nebula coming up to the East of me, Mag 7.1.
My next viewing time will start on 08/28/2018, Moon rise limiting.

Oh by the way the camera was running at 33C to 35C with outside air temp at 27C. Looking into cooling for the T3i.
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Re: M101 results bad - new to astro

Postby admin » Fri Aug 17, 2018 4:31 am

Mangee wrote:First I want to thank you for your time and patience with this.
If you could provide me with the workflow I really would appreciate it.

No problem - I'm here to help.

I used the 1.4.x version for this.

Type of Data: Linear, was not Bayered, or was Bayered + white balanced
--- Auto Develop
To see what we got.
We can see oversampling/tracking error (eggy stars). We can see a typical light pollution signature and vignetting. We can also see noise already (usually not a great sign for signal quality).
--- Bin
Parameter [Scale] set to [(scale/noise reduction 25.00%)/(1600.00%)/(+4.00 bits)] to improve signal and make use of oversampling (as well as hide tracking error).
Image Size 1284 x 822 pixels
--- Crop
Framing M101 a bit better (and negating a lot of the vignetting in the process).
Parameter [X1] set to [469 pixels]
Parameter [Y1] set to [379 pixels]
Parameter [X2] set to [990 pixels (-294)]
Parameter [Y2] set to [762 pixels (-60)]
--- Wipe
Vignetting preset.
Parameter [Precision] set to [512 x 512 pixels] to improve Wipe's handling of the quickly tapering off gradient (when gradients taper off quickly precision increase may be needed, though it's only needed in severe cases).
Parameter [Dark Anomaly Filter] set to [5 pixels] to make Wipe less sensitive to "dark" noise.
--- Develop
This is one of the very rare cases where I choose to use Develop over AutoDev. AutoDev is focusing too much on the noise and can't detect the detail well enough to come up with a good global stretch.
Parameter [Digital Development] set to [89.22 %]
Parameter [Dark Anomaly Filter] set to [5 pixels] (like in Wipe - for the same reason).

...
When data is this noisy, there is little use to in improving detail with Decon, Contrast, Sharp, HDR, etc. That's why I go straight to color balancing.
...

--- Color
StarTools usually does a decent job with coming up with a plausible color balance. But, due to the noise, not this time. I just had to pull back on the green.
For reasons why (and for methods available to color balance),have a look here. Specifically I used the MaxRGB method, combined with what I know about galaxies and what colors their features are.
Parameter [Dark Saturation] set to [3.10] to introduce a bit more color in the darker regions.
Parameter [Blue Bias Reduce] set to [1.17]
Parameter [Green Bias Reduce] set to [1.31]
Parameter [Red Bias Reduce] set to [1.93]

--- Wavelet De-Noise
This is very much a personal taste thing.
Parameter [Color Detail Loss] set to [14 %]
Parameter [Brightness Detail Loss] set to [14 %]
Parameter [Grain Size] set to [11.8 pixels]
Parameter [Read Noise Compensation] set to [9.04 %]
Parameter [Smoothness] set to [85 %]

And that's it!

Every thing I capture will have lots of Skyglow. In San Diego California USA all of the true dark sky areas are hours away.
Mt Palomar Observatory has a camp ground outside of it for star gazing but I am not set up for camping.

It's definitely not the end of the world. It's just a limitation to be aware of.
Imaging in narrowband would be a perfect solution for you - light pollution doesn't matter then!
The RC 6" is recommended for viewing brighter deep sky objects. However I have to view whats above me or at least try.
I look for objects that are high in the sky, less atmosphere plus I am in a box canyon with hills, trees and my house blocking much of the view east and south the worst.
I use CDC to determine what to view and capture. I just now zoomed in and found ngc 7023 Nebula coming up to the East of me, Mag 7.1.
My next viewing time will start on 08/28/2018, Moon rise limiting.

Really, the most important thing is to enjoy the hobby. Everything flows on from there; decisions on objects/gear/upgrades/travel/etc.
Oh by the way the camera was running at 33C to 35C with outside air temp at 27C. Looking into cooling for the T3i.

Perhaps look into modifying (removing) the IR filter on you T3i, so you can record Ha emissions through a Ha filter; light pollution can't touch you then! :thumbsup:
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Re: M101 results bad - new to astro

Postby Mangee » Fri Aug 17, 2018 10:47 pm

Thanks on the workflow.
I took your flow and followed them on the 2min subs and got the same results.
So then went back to my 1min subs and followed the same flow to the letter.
From the picture below I would say good results.
Next would be to to test changes on the 1min subs and see if I can "learn" to draw out more detail from the light pollution.

Image

Now as to narrow band with H-alpha or O-III filters.
Well T3i IR cut filter removal is priced at $175 to $450 USD. Plus H-alpha filter $70 to $300 USD. Filter wheel $46 USD.
For now ordered the filter wheel because I need to be able to have no filter so as to focus with Bahtinov mask and to do plate-solving with APT.
The wheel also allows me to use my UHC filter for learning on bright objects while I gather money for narrow band.

Read on many astro sites that most Galaxy's don't show up with H-alpha and O-III filters, you get very little data.

We can see oversampling/tracking error (eggy stars).


My RA had a little slop in the belt. Checked the deflection with Dec and added .008in and removed the slop in RA.
Ill look into tracking, I do have a 60MM scope. APT uses dithering code for its tracking????

Again thank you for your time.
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