RA Calibration Failed: Star did not move enough

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David Sliski

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Oct 6, 2019, 9:05:49 AM10/6/19
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Hi Everyone, 

I was wondering if anyone else has received the error,"RA Calibration Failed: Star did not move enough". I can see PhD2 trying to move the mount but they are often in 1" increments. I can't seem to find a setting where PhD2 will bump the mount a larger amount to have the calibration complete. 

Thanks, 

David 
PHD2_GuideLog_2019-10-06_055524.txt

Brian Valente

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Oct 6, 2019, 11:27:47 AM10/6/19
to Open PHD Guiding
Hi David

it looks like your camera setup is kind of messed up. Are you testing different binning levels? if so, you should be creating a new profile (via the wizard) for each binning level. 

you can see your step size is probably too small so it doesn't complete the RA calibration. 
image.png

your exposures are also far too short at 20ms. Ideally you want 3-5 second exposures, but at least 1-2 seconds minimum

To fix this you should use the New Profile Wizard to create a new profile and make sure you enter all the data including your binning correctly into the wizard. 

I would start your exposures at 2-3 seconds and see if that helps

image.png
Brian

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Brian Valente

David Sliski

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Oct 6, 2019, 3:33:28 PM10/6/19
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Hi Brian, 

I have three different binning settings due to the pixel size I was testing, 1x1, 2x2, and 4x4 they each have a profile that I've created under the profile wizard. My goal is to run the telescope with the tip tilt as fast as it can go ~8 Hz which is why I tend to be on brighter targets. Are you saying that I have to pick a portion of the sky and take longer exposures to get the calibration to work? Is there a way to change the step size to complete the RA calibration?

David 


On Sunday, 6 October 2019 08:27:47 UTC-7, Brian Valente wrote:
Hi David

it looks like your camera setup is kind of messed up. Are you testing different binning levels? if so, you should be creating a new profile (via the wizard) for each binning level. 

you can see your step size is probably too small so it doesn't complete the RA calibration. 
image.png

your exposures are also far too short at 20ms. Ideally you want 3-5 second exposures, but at least 1-2 seconds minimum

To fix this you should use the New Profile Wizard to create a new profile and make sure you enter all the data including your binning correctly into the wizard. 

I would start your exposures at 2-3 seconds and see if that helps

image.png
Brian

On Sun, Oct 6, 2019 at 6:05 AM David Sliski <dsl...@sas.upenn.edu> wrote:
Hi Everyone, 

I was wondering if anyone else has received the error,"RA Calibration Failed: Star did not move enough". I can see PhD2 trying to move the mount but they are often in 1" increments. I can't seem to find a setting where PhD2 will bump the mount a larger amount to have the calibration complete. 

Thanks, 

David 

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Brian Valente

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Oct 6, 2019, 5:39:25 PM10/6/19
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Hi David

ah - thanks for the clarification. I have an AO (tip tilt) unit as well so I understand what you are aiming for. 

i didn't see that setup in your profile, So make sure the AO unit is part of your profile (it's also a step in the profile wizard). you should still enter all the information in as you would if it were not present (i.e., focal length, pixel size, etc.) but just add the AO part when it asks. 

when i calibrate the AO unit, I leave it at 1 second - that is just for the calibration portion to ensure it has a solid star for calibration. 


Then when guiding, use auto for exposure length which is designed for AO units. It will automatically adjust the exposure length during guiding to be as fast as possible without dropping the guide star. you can specify the min/max exposure time for the auto exposure. if it drops too much you might disable star mass detection, which tends to help AO

Just make sure you have a different profile for each of these (sounds like you are doing that)


Brian


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