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Feature request: Add field of view for off-axis guider

Please add the option to display field of view for off-axis guider. Stellarium has this feature: Under the Oculars Plug-in, under the Sensors tab in Stellarium, you can specify the parameters for an off-axis guider. See https://photographingspace.com/stellarium-fov/ .

Currently Sky Safari lets you approximate this by displaying the guide camera's field of view along with the imaging camera's field of view, using an x,y offset for the guide camera. But unless I'm missing something, it's trial and error to get the offsets to match the actual field of view of the guide camera.

Thanks!

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9 comments

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    Bill Tschumy

    Robin,

    I don't think I understand.  What is it that makes this harder than setting the FOV for the main camera?  The guide camera's FOV is set the same way.

    Also, What platform are you talking about?  We changed how the FOV is specified in SS6, but it is still fundamentally the same.  You now specify the sensor size in number of pixels and also specify the pixel width and height in microns.

  • 0
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    Robin Clark

    Hi Bill,

    I'm using SSPro 6 on an iPad Pro. What I'm looking for is the ability to precisely specify the FOV of the guide camera that's using an off axis guider.  I'd like to see equipment display settings for the off-axis guider, such as Prism/CCD distance in mm, Prism/CCD height in mm, Prism/CCD width in mm, and position angle in mm. See the link in my original post for a screenshot of how Stellarium provides this.

    Currently in SSPro, you can approximate the position of the guide camera sensor that's using an off-axis guider using the sensor x,y offsets for your guide camera, but it is still trial and error to get the offsets to match the actual FOV of the guide camera/off-axis guider combination. Thanks.

  • 0
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    Robin Clark

    Here is a screenshot showing how an SS user was able to represent an off-axis guider FOV, but I'm not sure how he accomplished it. Perhaps he used two eyepiece FOVs in combination with the sensor x,y offsets? Anyway, it would be great if SS could add this as a feature. https://www.cloudynights.com/topic/509820-avx-mount-and-weight-for-guiding-questions/#entry6755136 

  • 0
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    Bill Tschumy

    Robin,

    The off axis guider is just set up as a second camera and both FOV indicators are turned on.  The only difference is you specify a Sensor x-offset and Sensor y-offset for the off axis "camera".

    Does  that help?

  • 0
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    Robin Clark

    Hi Bill,

    Please see the screenshot I linked to  in my previous comment for what kind of FOV display I'm referring to for an off-axis guider.

    Yes, I understand how to display the FOV's of both cameras and use the offset for the off axis guider camera. But how do you determine the x, y offset values to use? Also, if you need to rotate the off-axis guider camera, how would this be represented in a FOV display? Thanks.

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    Bill Tschumy

    I am not an astrophotographer, but I've been led to believe that specifying the offset in mm was a reasonable thing to do.  It looks like the Stellarium plugin does it that way as well.  How do you want to specify this?

    What we don't handle is the case were the guider frame is rotated relative to the main camera.

  • 0
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    Robin Clark

    OK, then it would be helpful to know what's the best way to determine the x,y offset in mm for the guide camera? For example, are the offsets measured from the center of the optical axis of the telescope to the center of the guide camera sensor? Thanks!

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    Bill Tschumy

    Not being an astrophotographer, I don't know the answer to this.  How do you determine it with the Stelllarium plugin?  We have specified this offset in mm for over 6 years and no one has told me this is a problem.

    Can any astrophotographers help answer this?

  • 0
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    Robin Clark

    I think the offset x,y in mm is measured from the center of the optical axis of the scope (which should also be the center of the imaging camera sensor) to the center of the OAG prism. I think this is how Stellarium specifies it.

    I've asked the question on Cloudy Nights, but no replies so far. Perhaps someone else on this forum can confirm this? Thanks.

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