guide cam not acquiring image

Using SharpCap's Polar Alignment feature
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admin
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Re: guide cam not acquiring image

Post by admin » Wed Aug 01, 2018 3:41 pm

Hi,

if it is the problem that Dave is suggesting then 3.1.5181 should work for you but later versions may not. I have a received a newer version of the SDK software with Altair but I haven't tested whether it fixes the compatibility problem with the older GPCam yet.

cheers,

Robin

Chuck
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Re: guide cam not acquiring image

Post by Chuck » Thu Aug 02, 2018 8:47 pm

Can you give a reason why SC would just decide to stop looping images....it failed to loop again last night. I have been using SC just for fine tuning PA......the exposures don't countdown anymore in the lower right-hand corner after I select the PA tool.

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Re: guide cam not acquiring image

Post by admin » Sat Aug 04, 2018 1:02 pm

Hi,

something has changed since you last had the camera working and we need to try to work out what.

*) Has any hardware changed - are you using a different PC or have you changed your USB cable setup (added an extension or a hub for instance)?

*) Has any software changed - did you update SharpCap to a new version or update windows?

*) Have you changed the settings in SharpCap without realizing - for instance set a very long exposure time or turned up the USB speed setting to a different value? Hold down the 'CTRL' key when selecting the camera from the menu to stop it from re-loading the previous settings (ie set all the camera settings back to their defaults).

*) Has your camera got a problem? Try using it with AltairCapture and see if it shows a picture correctly in that program

Maybe one of these suggestions will help you find out the problem. If not then please do the following to allow us to continue to investigate the problem.

1) Open SharpCap, start the camera, leave it running for a minute or so
2) Make sure the controls on the right hand side are 'expanded' so that the values can be seen
3) Take a screenshot showing the SharpCap window including the control values
4) Get the SharpCap log text (goto Help menu, then Show Log, then press the 'Copy To Clipboard' button
5) Post a reply to this message - include the screenshot and the SharpCap log text.

thanks,

Robin

Chuck
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Re: guide cam not acquiring image

Post by Chuck » Sat Aug 04, 2018 5:27 pm

#1 No

#2 I updated to a new version of SC *after* this issue occurred...in the hopes that would fix the problem.

#3 I think maybe this is possible but IDK...I will check that all camera settings get back to the default settings at my next opportunty.

#4 camera works fine when using PHD2

I will do the 5 step procedure you menion at my next opportunity and post a reply.

Thanks for your assistance, my opportunities are not every day, but I will keep on it.

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turfpit
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Re: guide cam not acquiring image

Post by turfpit » Sat Aug 04, 2018 6:06 pm

Chuck

Have you tried reverting to 3.1.5181?

Dave

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Re: guide cam not acquiring image

Post by Chuck » Mon Aug 13, 2018 2:53 am

I'm glad to report that SC is acquiring images again. I reset everything in the camera control back to defaults and that seemed to do the trick.....thank you for all your help.

Perhaps you can address another thing that I have experienced since using SC. I use SC primarily for fine tuning the PA.....even before this latest issue I had always been able to obtain an "Excellent" PA report, just like I did tonight back on the Veil Nebula. However, when I am in PHD2 and I go to use the Guiding Assistant, the GA always, without fail, tells me that my PA error is significant at 5 arc-min or more. Consequently, I'm not always sure of my PA status as one software is telling me one thing and another software is telling me something else. Having said that, last night I did 360 sec lights on the Veil Nebula with the star "52 Cyg" looking pretty dam round. If you could provide some insight on that apparent discrepancy, that would be great.....thanks.

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Re: guide cam not acquiring image

Post by admin » Tue Aug 14, 2018 3:27 pm

Hi,

something as simple as a loose (hanging) USB cable can cause the SharpCap PA routine to be somewhat off because the weight of the cable can cause the camera to move slightly as you rotate the telescope. See https://www.sharpcap.co.uk/sharpcap/fea ... leshooting for more information on what can cause problems with the polar alignment results.

So far, in every case where we have tracked down the cause of incorrect results it has turned out to be something of the nature of a hanging cable, flexing between the guide scope and the mount or some other physical movement that throws off SharpCap's measurement.

cheers,

Robin

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Re: guide cam not acquiring image

Post by oopfan » Wed Aug 15, 2018 12:44 am

I have a 200mm scope that I use for PA. I hated it from the get go. It has one of those "three point" spring-loaded screw abominations. It is so bad that I can hold the scope in my hand and rotate it 90 degrees -- CLUNK! My advice don't buy such a thing.

As much as I complain I get decent PA out of it. I do get DEC drift but it is well within my tolerance level. Still I despise it.

Brian

Chuck
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Re: guide cam not acquiring image

Post by Chuck » Wed Aug 15, 2018 12:08 pm

admin wrote:
Tue Aug 14, 2018 3:27 pm
Hi,

something as simple as a loose (hanging) USB cable can cause the SharpCap PA routine to be somewhat off because the weight of the cable can cause the camera to move slightly as you rotate the telescope. See https://www.sharpcap.co.uk/sharpcap/fea ... leshooting for more information on what can cause problems with the polar alignment results.

So far, in every case where we have tracked down the cause of incorrect results it has turned out to be something of the nature of a hanging cable, flexing between the guide scope and the mount or some other physical movement that throws off SharpCap's measurement.

cheers,

Robin
Yeah,but which result is incorrect....SC or PHD2? That's the thing. When I achieve an "excellent" in SC the Guiding Assistant in PHD2 says there is a 5 arc-min PA error.........yet, 6 min subs on the Veil Nebula produces nice round stars. That's a good thing, because ultimately, it's the images themselves that tell the story of the mount's and software performance. I just find it puzzling at the reported discrepancy between SC and PHD2.

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morayskies
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Re: guide cam not acquiring image

Post by morayskies » Tue Aug 28, 2018 1:12 pm

Hi
I had a similar problem. Guidescope (Versacope) and GP-CAM would not plate solve in SharpCap but worked fine in PHD2. It turns out that the issue seemed to be with a USB hub I was using. When the GP-CAM was connected to the laptop via a 5m USB lead (yes, I know that's pushing things anyway) and through a USB hub the image seen in SharpCap was relatively dim but this wasn't an issue in PHD2. When I took the USB hub out of the equation and connected the GP-CAM directly to the laptop with the 5m lead it worked fine. I even tried a powered USB hub but this seemed to make little (if any) difference.
Clear Skies

Richard
Celestron 6" SCT, SW ED80, SW 6" f8 "Newt", SW 90mm f10 refractor

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