Poor Quality Planetary Images

Discussions of using SharpCap for Planetary Imaging
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sandconp
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Joined: Thu May 31, 2018 7:48 pm

Poor Quality Planetary Images

#1

Post by sandconp »

I have noticed recently that I am not get the quality image of Jupiter and Saturn that I used to get. I went back and compared my SER files and I noticed that the better quality image is (GBRG) and has a very low frame rate of 3 FPS. The poorer quality image is (BGR) and I am getting 130 FPS. This does not make any sense to to me because you would think I would be getting a better quality image which is at a higher frame rate? The only other difference is I was running 3.2 vs 4.0 of Sharpcap Pro and the fact the SER file is showing up as (GBRG) vs (BGR).

Any ideas?

I am using a C8 and a C11 and a ZWO 178MC OSC Planetary Camera.
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admin
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Re: Poor Quality Planetary Images

#2

Post by admin »

Hi,

with the QHY cameras you can get low frame rates if the USB Traffic control is set to high values. Unfortunately on some systems you get no frames at all when this control is set too low, so SharpCap does not start the camera at the fastest (lowest) available value. You should check the value of this and how it affects the frame rate. Personally, I would test things out in daylight by setting RAW8, ~10ms exposure and then tinkering with the USB traffic to optimize frame rate (you should be able to get 50fps from your camera without ROI, more with ROI).

cheers,

Robin
sandconp
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Joined: Thu May 31, 2018 7:48 pm

Re: Poor Quality Planetary Images

#3

Post by sandconp »

Robin,

I assume when you say check the value I am assuming the Turbo USB setting? I have the camera connected right now during the day and I have it set at 40 and I am getting 101 FPS at 640x480 while using RAW8.

Is this is what you wanted me to check?

Shouldn't the highest FPS be the best target?

Is there a place to set the Gamma?
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turfpit
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Re: Poor Quality Planetary Images

#4

Post by turfpit »

Work through this viewtopic.php?f=35&t=2590 to establish best settings to achieve highest fps, tests can be done with just laptop and camera and the camera cap on. 101fps at 640x480 RAW8 SER is plenty to capture decent planetary data.

The only camera settings I use for planetary capture are gain and exposure. For Jupiter, I set gain to 60% of max value, then adjust exposure until right hand side of log histogram is at 60% for luminance. If adding a Barlow, increase gain to 70 or 80%, exposure still 60% saturated histogram. Saturn being dimmer, I use 80 or 90% gain. Figures will vary depending on combinations of equipment used.

Dave
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Re: Poor Quality Planetary Images

#5

Post by admin »

sandconp wrote: Mon Oct 18, 2021 3:32 pm Robin,

I assume when you say check the value I am assuming the Turbo USB setting? I have the camera connected right now during the day and I have it set at 40 and I am getting 101 FPS at 640x480 while using RAW8.

Is this is what you wanted me to check?

Shouldn't the highest FPS be the best target?

Is there a place to set the Gamma?
Sorry, I had a bit of a moment there and gave an answer that was correct for the QHY version of the camera - somehow I misread your first post.

You are right, on the ZWO camera, the setting is 'Turbo USB' and you want it set to 'auto' usually, otherwise start at 80 and adjust from there. Sometimes if you turn it right the way up then the frame rate collapses to very low levels.

cheers,

Robin
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