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  #21  
Old 06-08-2011, 10:49 PM
WingnutR32 (Sam)
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Good to know Robin! Thanks for that information.
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  #22  
Old 07-08-2011, 01:47 AM
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Thanks for that Robin, will have to work out why my mount does not guide whilst the pic is being downloaded. All plotting on the graph stops and starts again after the pic is displayed. If my polar alignment is out the star has clearly moved when guiding resumes so no guide signals seem to reach the mount. The star stays dead center when guiding is in play.

Mark
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  #23  
Old 07-08-2011, 08:18 AM
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Tandum (Robin)
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That's Maxim Mark. If you can find it in the help, they did it because of self guiding cameras having noise in the images from the guider. So they turned off the guider while downloading images.
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  #24  
Old 07-08-2011, 11:34 AM
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Okay Robin I found it.

"When taking exposure sequences with the main camera, the guider must stop during image download. There are several reasons for this. Some cameras use one shutter for the main sensor and guide sensor, so the guider cannot continue during download. Many cameras hog the CPU during image download, preventing the guider from operating properly, or preventing the guider correction pulses from being generated correctly. Other cameras would produce image artifacts if the guider was consuming CPU cycles during download. Filter wheel internal sensors can also flood the sensor array with large amounts infrared light, which can cause image artifacts due to charge traps in the sensor. Although some cameras can happily guide and download at the same time, most cannot. Due to the extremely high likelihood of problems, MaxIm DL simply disables guider calibration during image download for all camera models.
One problem with the autoguider pausing is that some camera models take a very long time to download (sometimes up to a minute), and during this time the tracking can drift. By default, MaxIm DL waits five seconds for the guide star to be reacquired and settled before starting the next image. You can increase this delay time using Expose Tab settings. Alternatively, you can set up a Guider Settling Criteria, so that the next exposure will not happen until the guide star is close enough to center"

No matter what the cause it can be overcome by setting delay exposure X seconds after download. I do not like the "take exposure within X pixels" setting as it can start exposing before the mount fully settles. Still I wonder if there is a way to turn it off? I will stop blaming the ascom driver now .

Mark

Last edited by marki; 07-08-2011 at 11:45 AM.
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  #25  
Old 15-08-2011, 01:00 AM
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OzRob (Rob)
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Quote:
Originally Posted by WingnutR32 View Post
Thanks for that information Mark,

I use PHD for guiding, do you think I should be using MaximDL? I thought that PHD might end up being better because of the 'No USB during download' in Maxim.

That autosave feature is exactly what I was looking for information on!
You should be using Maxim for your guiding. It allows you to dither between images so that any bad pixels are not in the same place allowing them to be rejected easily during stacking.

I have used the feature that Mark posted about recapturing the guide star. I have used the settling criteria to judge when the star is back in the center of the guiding box. It has worked great for me.

Once everything is running you can then walk away and leave it. One of the benefits in this situation with using Maxim for guiding is that it can notify you if something goes wrong. If guiding fails it will run a script that can use Skype to call your phone. Obviously the computer needs to be connected to the internet. I found the script on this forum somewhere (I think). Let me know if you want it.

Edited to add a link to the above mentioned alarm: MaxIm DL Alarm

Last edited by OzRob; 15-08-2011 at 01:18 AM.
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