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First Light with the Uranus-C: getting colours right? (Gassendi)

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#1 Sarciness

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Posted 14 May 2022 - 07:34 AM

Hey all,I got my first dedicated astrocamera and the raw images have come out very green. I know colouration on the moon is not very pronounced, but I'd like to retain realistic looking colour rather than converting to monochrome. Unfortunately, I think I didn't do a very good job with processing this one as the highlights appear yellow. If I increase the blue channel to get the highlights to look whiter, the shadows seem overly blue. Does it mean I need custom curves for each RGB channel? Any tips for colour balancing?

Gassendi 2022.05.13.jpg


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#2 wargrafix

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Posted 14 May 2022 - 09:32 AM

Small color correction in registax.


Also, how is the camera??? I am really thinking of picking one up.


Also, that's a fine image!

#3 Sarciness

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Posted 14 May 2022 - 05:43 PM

Thanks! It's hard for me to judge the camera right now because I'm coming off a mirrorless camera. Firecapture seems to crash unless I delete my preferences before recording, but that could be my laptop or the software at fault? Although at the settings I was using, the camera is capable of 100 FPS, it would work full speed sometimes then drop down to 28 FPS of even as low as 3 FPS at times. The laptop I have has a fast SSD and I need to work out where the issue lies. I haven't worked out how to get metaguide to work and I've never done star collimation. With limited time, I collimated by eye using a sight tube.

#4 wargrafix

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Posted 15 May 2022 - 02:09 AM

How much ram do you have?

#5 Sarciness

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Posted 15 May 2022 - 07:24 AM

How much ram do you have?

16GB



#6 Sarciness

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Posted 15 May 2022 - 07:39 AM

Here are the colours straight out of the camera.

1_stitch.jpg


Edited by Sarciness, 15 May 2022 - 07:40 AM.

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#7 wargrafix

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Posted 15 May 2022 - 09:12 AM

Check your blue red settings in sharpcap

#8 wargrafix

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Posted 15 May 2022 - 09:12 AM

I mean firecapture

#9 Sarciness

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Posted 15 May 2022 - 09:22 AM

Okay, so I just realised I could differentially set gain for each colour channel. I'll try setting up so it appears neutral next time.

In addition, I found a workaround for the firecapture bug. It was caused by the Bin2x setting. If I disable before exiting, the crashes don't occur.

For the slow framerates, I've upped the RAM allocation to 8GB and a dummy run shows that "fixes" the issue but the drive shouldn't be so slow and I will need to wait several minutes between each capture for the buffer to clear.

Next tasks are:
1) Adjusting colour channels in FireCapture
2) Working out collimation on a star, maybe using metaguide to aid
3) Calibrating the ADC in FireCapture.

#10 wargrafix

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Posted 15 May 2022 - 09:48 AM

Wait...why are you binning?

#11 lakeorion

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Posted 15 May 2022 - 01:09 PM

From my testing with frame rates, you need sufficient CPU (and cooling fans) to keep up with the frames.  USB3 has a raw data rate limit, but each individual frame requires CPU overhead.  Preference here is a quad core hyperthreaded CPU, next dual core hyperthreaded, and last an AMD APU or Intel Atom.  Many modern laptops (read thin) have CPU's that boost to almost double their GHz but only for a short time - then they roll back to prevent overheating the CPU.  Gaming or workstation laptops have extra cooling capacity to keep this CPU boost frequency running constantly.

 

Look to the Windows Task Manager - Performance - CPU to see what processor speed you are saturating at.  Optionally download and run Cinebench to load your CPU for extended periods.  You should hear the fans spin up, this is good.  Many gaming laptops have performance profiles you can activate, turn on the loud one.  I have an older workstation class laptop, I use a program called HWINFO64 to get aggressive with the fans.  CPU hits 60°C and the fans go full power.  It's loud but my CPU doesn't slow down and the frame rate stays up.

 

RAM and SSD are the next things to look at.

 

For RAM, look up how much your laptop can take, then fill that cup to the max.  You don't need the fastest bestest expensivest RAM, any is better than none.  Then allocate about half that to the FireCapture RAM buffer.

 

Any SATA SSD should easily outpace the USB3 data speed, NVME are even faster.  The way these work, they don't like to be full - that slows them down.  If you have the ability to add a second drive and keep it empty except just for data that's better.  Mine has a 500GB for (dual) boot + programs and then a 1TB just for acquisition data.  If you only have room for one drive, strip it down to the bare essentials - no cat videos, extra programs or anything not needed.

 

Don't lose heart - you're already doing pretty good.  The pics shown are pretty sharp.



#12 Sarciness

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Posted 15 May 2022 - 05:55 PM

Wait...why are you binning?

Essentially, my mirroless camera has 5.9 micron pixels and my new one has 2.9 micron, so using binning keeps my image scale and optimal sampling without buying a new barlow or powermate. I also see an advantage in gaining higher frame rates and faster processing times for my lunar images, which will use full-chip as I'm processing 4x fewer pixels.

 

I don't really see much downside, but perhaps I'm missing something?

 

Imaging train: 305mm aperture, 1500mm native FL +  5x powermate + ADC + camera gives roughly f / 25 to f  / 30 (I need to measure exact image scale). With 5.8 micron effective pixels, I think Im pretty close to optimal. If not binning, I'm massively oversampling and need to switch to roughly a 2.5x barlow / PM.


Edited by Sarciness, 15 May 2022 - 05:56 PM.


#13 Sarciness

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Posted 15 May 2022 - 06:02 PM

From my testing with frame rates, you need sufficient CPU (and cooling fans) to keep up with the frames.  USB3 has a raw data rate limit, but each individual frame requires CPU overhead.  Preference here is a quad core hyperthreaded CPU, next dual core hyperthreaded, and last an AMD APU or Intel Atom.  Many modern laptops (read thin) have CPU's that boost to almost double their GHz but only for a short time - then they roll back to prevent overheating the CPU.  Gaming or workstation laptops have extra cooling capacity to keep this CPU boost frequency running constantly.

 

Look to the Windows Task Manager - Performance - CPU to see what processor speed you are saturating at.  Optionally download and run Cinebench to load your CPU for extended periods.  You should hear the fans spin up, this is good.  Many gaming laptops have performance profiles you can activate, turn on the loud one.  I have an older workstation class laptop, I use a program called HWINFO64 to get aggressive with the fans.  CPU hits 60°C and the fans go full power.  It's loud but my CPU doesn't slow down and the frame rate stays up.

 

RAM and SSD are the next things to look at.

 

For RAM, look up how much your laptop can take, then fill that cup to the max.  You don't need the fastest bestest expensivest RAM, any is better than none.  Then allocate about half that to the FireCapture RAM buffer.

 

Any SATA SSD should easily outpace the USB3 data speed, NVME are even faster.  The way these work, they don't like to be full - that slows them down.  If you have the ability to add a second drive and keep it empty except just for data that's better.  Mine has a 500GB for (dual) boot + programs and then a 1TB just for acquisition data.  If you only have room for one drive, strip it down to the bare essentials - no cat videos, extra programs or anything not needed.

 

Don't lose heart - you're already doing pretty good.  The pics shown are pretty sharp.

Hi lakeorion, thanks for taking the time to write your post.

 

I have upped the RAM buffer to 8GB which is half and it will do as a workaround for now. My laptop is a gaming one and has a fast octo-core AMD processor (4900HS). I've checked it on Cinebench and it's performing normally at 3900 points. I tried changing the thermal profile from "silent" to "performance" but that didn't help anything.

 

I believe the culprit is most likely:

a) USB port not transferring consistently near specs (I will check with my only other port tonight and see if that fixes it)

b) Drive being overly full (96 GB free of 457)

c) Drive not working to specs (need to replace)

 

I like your idea of adding an additional drive, I'll look into the specs to see if I've a spare slot and work out how to install.


Edited by Sarciness, 15 May 2022 - 06:10 PM.


#14 lakeorion

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Posted 16 May 2022 - 09:11 AM

Yes the drive being 80% full could very well be the issue.  Try a second drive or replace with a larger.  The way SSD's cache and then write is optimized for empty drives so the more filled they are the lower constant throughput they can handle.

 

My Dell Precision 6700 (yes it's old) can only muster 3445 on Cinebench multi core (i7 3740QM + 32GB RAM) but still hits 93 frames/sec on my Neptune IIc.  Smaller chip, so a little pears to apples but it's consistent with no drops.

 

Also, if you can, check the USB Root Hubs in Device Manager - view by Connection.  The camera wants to be on it's own USB Root Hub with no USB2 devices (mouse / mount etc.) sharing.  If you can move any USB2 devices to different USB Root Hubs that can help.


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#15 Sarciness

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Posted 18 May 2022 - 09:33 PM

Bad news is that my laptop only has 1 drive slot. I'll look into replacing with a bigger one.



#16 dcaponeii

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Posted 19 May 2022 - 08:00 AM

If you check Tulloch's FAQ pinned to this forum you'll see that with 2.9 micron pixels you should be imaging at just under f/15.  (5 x pixel size).  This has always proven to be correct for me and as a result I'm wondering why you're trying to work at f/20 +.



#17 Sarciness

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Posted 19 May 2022 - 09:43 AM

I think I explained this above. If I use bin2 I effectively have 5.8 micron pixels which would ask for about f/30. I presume there are some penalties to using BIN2 that I don't know of yet. If you know, please share with me. It seems that it's workable e.g. https://www.cloudyni...m-cam/?hl=+bin2


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