Filter Wheel Adjustment

Discussion in 'Aluma Series' started by roger baylon, Dec 3, 2019 at 11:42 AM.

  1. roger baylon

    roger baylon Cyanogen Customer

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    Dear Adam,
    Here is an easy question for you
    What are the three small nobs for on the Aluma 694 filter wheel? There is one on the side and two on the bottom. I have searched all over the internet and can't find an answer.

    I was able to install and test the filter wheel and software, so I am very proud of that. But the three tiny nobs are a mystery.

    Roger
     
  2. Adam Robichaud

    Adam Robichaud Staff Member

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    Ottawa
  3. roger baylon

    roger baylon Cyanogen Customer

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    Adam,l
    Thanks. I read the stt filterwheel manual.

    However, it tells me to adjust the position of the mirror until there is vignetting on the bottom of the Maxim DL display --and then back off by turning clockwise.

    Well, in BOTH of two most extreme positions the degree of vignetting seems 100% identical. Maybe since the 694 sensor is less that 1/4 the area of some other sensors there is no vignetting in any position?

    Therefore, I set the mirror in the middle setting.
    Does this make sense?

    Roger
     
  4. Colin Haig

    Colin Haig Staff Member

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    Roger, Adam may be a bit tied up for a while.
    The geometry of your setup MAY work out so that there is no vignetting on the 694. If it was an Aluma 8300, vignetting would be more obvious due to the chip dimensions.

    You may need to make a bit of an adjustment to get focused stars on both the 694 and the guider's image sensor.
     
  5. roger baylon

    roger baylon Cyanogen Customer

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    Thanks for the quick response
    I guess you mean that, depending on the mirror adjustment, I might get focused stars on the 694 but not the guider, or focused stars on the guider but not on the 694.
    So I would have to make adjustments so that I get focused stars on both the694 and the guider?
    Is that right?
     
  6. Colin Haig

    Colin Haig Staff Member

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    The trick to this is:
    a) get perfectly focused stars on the 694 main image sensor
    b) adjust the pick-off mirror so the guide sensor is reasonably focused. It doesn't have to be perfect.
    We don't need precise focus for the guider or nice round stars, as the guiding software computes the centroid of the stars, and a little blurry is okay.
     
  7. roger baylon

    roger baylon Cyanogen Customer

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    Nov 25, 2019
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    Colin,
    This is very helpful.
    Many thanks.
     

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