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  1. #1

    Default Updating the pointing correction model question

    Hi

    Again more on the learning.

    If I start a new pointing correction, the number of entries in the model seems to go up by 10 for the first object, and then by 2 for each further object.

    Why does it go up by 10 for the first object .

    I had assumed that each solve would add one to the count so am missing something here.

    Thanks David

  2. #2
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    Where are you looking at the number of points? It should increase by one per point once it gets past 6 points. Can you post a log of your observing run? It should be inn My DOcuments\ACP Astronomy\Logs. Zip it and attach it to your reply here, don't post the log in the message body, it's too hard to work with.
    -- Bob

  3. #3

    Default

    Hi Bob

    I was looking in the ACP Pointing preferences tab. Am still digging through the old logs. Tonight I reset the model. I did a sync it adds one point. If I acquired an object it plate solves (twice) but the number remains at 1. Did this several times. The log for a succesful plate solve (that doesnt seem to add to the correction model) is attached.

    Cant see why this is not doing this ?

    Thanks, David
    Attached Files Attached Files

  4. #4
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    If the object you're acquiring is "too close" to a location for which you added a point in the past, the point will be replaced instead of added. This is essential to avoid the model getting filled up with points for one area of the sky.

    As you can see from the log, the pointing update does the sync/map. The data image is plate solved for completeness and to measure the pointing error just to make sure (on a long series) it's not drifting out of tolerance (ACP Preferences, PinPoint tab, Max pointing err). If it does, a pointing update will be scheduled for the next target. If the next target is "too far" from the present target (ACP Preferences, PinPoint, Max slew w/o pointing update) that will also trigger a pointing update. The decision process is rather sophisticated, arising from years of ACP astronomers' experience and requests/feedback.

    Looking at your log, your pointing error before and after the pointing update is less than half an arc minute. Perhaps you can get along without the pointing corrector? ACP will center each object via pointing update and sync/reslew.
    -- Bob

  5. #5

    Default

    OK 0 i understand why the same object wont add extra points to the pointing model.

    Is there a defined distance that will create a further point to be updated - reason being is that I was moving around various objects within a fairly small patch of sky (i dont have the distances to hand) but none of these were adding to the model as they plate solved ?

    Thanks

  6. #6
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    The distance depends on the model density and your field of view. I suggest not worrying about the internal workings and just start imaging
    -- Bob

  7. #7

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    Dont worry I have no desire to understand the internal workings! I am merelly trying to learn how to use ACP and wasnt sure if I was doing something wrong as the documentation says a model point is added after every sync.

    For my purpoases I beleive I need the correction model which is why I am trying to see how well it works for me during the evaluation period.

    Thanks
    David

  8. #8
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    OK, well here's hoping it meets your expectations! Just keep in mind that the pointing model is fairly simple and needs only to get the scope close enough for ACP to be able to plate-solve its pointing update exposures. If it does, your targets will always be centered.
    -- Bob

 

 

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