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  1. #1

    Default oops, MaxIm filter changed! Fixing...

    Have finished installing and setting up new computer and made the switch from Maxim v4 to v5. After successful FocusMax Acquirestar focus run, I have had several of the following log entries (see below) in ACP when doing the post slew pointing correction.

    The pointing update is successful, but the subsequent image is out of focus. This happened this evening on every filter change after the first set of images.

    Any Suggestions?

    Thanks....Bill

    02:05:04 Autofocus finished.
    02:05:10 (oops, MaxIm filter changed! Fixing...)
    02:05:15 Start slew to ic405...
    02:05:16 (wait for slew to complete)
    02:05:24 (slew complete)
    02:05:24 (doing post-focus pointing update...)
    02:05:24 Updating pointing...
    02:05:24 Switching from HAlpha to Red filter for pointing exposure
    02:05:24 (taking 18 sec. exposure, Red filter, binning = 3)
    02:05:49 Image finished
    02:05:49 Plate-solve pointing image.
    02:05:49 242 image stars found
    02:05:50 467 catalog stars found
    02:05:50 Solved! 153 stars matched.
    02:05:50 Average residual is 0.4 arcsec.
    02:05:50 Pointing error is 0.324 arcmin @ angle 32.53
    02:05:50 True focal length is 110.3 cm.
    02:05:50 True image center (J2000): 05h 16m 30.2s 34 21' 38.41"
    02:05:50 Imager sky position angle is 205.7 deg.
    02:05:50 [sync] pointing model updated
    02:05:50 Within max error tolerance, no re-slew needed.
    02:05:50 Target is now centered.
    02:05:50 (long exp(s) or requested, no orbital tracking, trying to autoguide)
    02:05:50 Switching from Red to HAlpha filter for imaging

  2. #2
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    Default

    I suspect that you haven't yet set up Focus Offsets in ACP.

    Make sure you have filter names still set up correctly in MaxIm 5. Then you can run the script FocusOffsets.vbs--it runs for about 20 minutes to an hour depending on FocusMax settings and number of filters. (I've also found it's best to run the script when after the scope has cooled well and is roughly temperature equilibrated.)

    Let us know the outcome...
    Last edited by Eric Dose; Nov 15, 2009 at 13:04. Reason: corrected estim. run time for FocusOffsets script
    New Mexico Mira Project, Albuquerque NM

  3. #3

    Default

    Quote Originally Posted by Eric Dose View Post
    I suspect that you haven't yet set up Focus Offsets in ACP.
    You're right about my not having setup the Focus Offsets in ACP. I have never used them in the past, nor have I ever set them up. I have always simply had ACP focus with each filter in the past.

    Any other thoughts? As I am using Astrodons, the filters themselves are actually fairly close to parfocal on my system, but the amount of focus error is more similar to the amount the FMx is moving at the beginning of a focus run.

    Bill

  4. #4
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    Not a lot of other thoughts. FocusOffsets.vbs script is pretty straightforward to use. (Thanks, Bob!)

    If your filters are specified parfocal, and if your script run in fact delivers very low focus-position shifts between them (less than say 0.3 pixels HFD based on the V-curve), then you can manually set their focus offsets to zero. Doesn't sound like that's your case across the board, though.

    Watch out for temperature shifts during FocusOffsets run. Try to run the script when the temperature is more constant than usual, and when the OTA has temperature equilibrated. This minimizes errors due to temp shifts, and keeps convection fuzz out of the defocused star images (helping FocusMax a lot). Note that the script as delivered always runs the filters in the same order, reference filter first, so the later filters in the list will end up with biased offsets if temps have shifted at all in the intervening time. (I've experimented with a script version that alternates the filter order every pass, causing first-order temp shifts to cancel at a small cost in precision.)
    New Mexico Mira Project, Albuquerque NM

  5. #5
    Join Date
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    Montreal, Quebec, Canada
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    Hi Bill,

    Got the same problem last week during a night. All my images with AcquireStar were out of focus. I decided to switch back to the ACP autofocus internal routine and everything worked well.

    I don't know why it was happening during that night but never got such problem before. What is bugging me is that both autofocus routines are using FocusMax so it's very difficult to understand.

    Regards,
    Yves

  6. #6

    Default

    Alright. Ran more tests tonight and again experienced the "oops Maxim" message and out of focus stars.

    As this issue only arose with installing a new machine and the only difference in terms of software was the version of Maxim, I decided I would try a run using Maxim v 4.62. Focus between filters returned as expected.

    Any ideas anyone as the a particular setting in the interaction between ACP/FMx and Maxim v4 vs v5 that may be causing this issue?

    Bill

  7. #7
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    Hi Bill,

    I'm using an old version of MaxIm, so I probably shouldn't say anything, but I think the later versions of MaxIm support focus offsets. ACP expects to manage focus offsets itself, so I suspect you've got both sets of software trying to do the same thing. Disable focus offsets in MaxIm.

    I hope this helps.

    Jim

  8. #8
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    I expect that's exactly right, Jim. MaxIm 5 has filter offsets. In my MaxIm 5, I find that I can do automated focus offsets either directly in MaxIm (for manual astrophotography, handy sometimes), or in ACP, but not in both. Unless I'm mistaken, ACP wants its own offsets and it expects zero offsets in MaxIm 5's filter settings.
    New Mexico Mira Project, Albuquerque NM

  9. #9
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    Eric and Jim, Bill,

    I never got around to "testing" the hypothesis that having offsets in both MaxIm and ACP would result in a double focus shift, but I know you don't want both MaxIm and ACP to shift the focus together. I'm not sure if one would override the other, or what, but I have left zeros in the MaxIm setup just to prevent an unfortunate event like this. Jim and Eric are right on that score.

    Bill, are you saying you do focusing for each filter separately? If so, you really should inplement the offset focusing mechanism - it will save considerable time between exposures. Even if parfocal, build the file by hand, with zeros, using the help file as a guide. The log you provided implies that you focus (and take pointing images) through the Red filter. Is that true?

    If there were a FocusOffset.txt file at work, then the next statement after the last one you provided above would be this (in green):

    02:05:50 (long exp(s) or requested, no orbital tracking, trying to autoguide)
    02:05:50 Switching from Red to HAlpha filter for imaging
    02:05:50 Focus change of xxx steps required ...

    In any case, make sure your MaxIm filter table is right for names and positions, and if your filters are really parfocal, then put zeros in MaxIm's filter offset column.

    If that doesn't fix it, or they're already zero, then something more obscure is going on.
    Dick
    www.VirgilObservatory.us
    Pier-mounted Meade 12-inch SCT "classic"
    w. focal reducer to f/5.3 ~ FL 1630mm
    Optec TCF-S focuser
    SBIG CFW-8A and ST7-XME
    FOV ~ 15' x 10'
    H-alpha, BVRI, RGB & Clear filters
    MaxIm and, of course, ACP!
    AAVSO Code: BRIC

  10. #10
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    Although I haven't tried it, you should be able to keep your focus offsets in either the FilterInfo.txt file (for ACP only) or in MaxIm's focus offsets table. If you want the latter, you should still have a FilterInfo.txt file, but in it, set the focus offsets to 0 for all filters. That way, ACP won't refocus for each filter change, and it will let MaxIm do the focus adjustments.
    -- Bob

 

 

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