SC2 Focus Issue

Discussion in 'Guiding and Adaptive Optics - StarChaser and AO' started by vinifera, Oct 8, 2020.

Tags:
Page 2 of 2
  1. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,316
    I'm looking into this. When it doesn't reach focus, is the focus all the way in (counter-clockwise) or all the way out (clockwise)?
     
    Doug, Oct 19, 2020
    #21
  2. vinifera

    vinifera Cyanogen Customer

    Joined:
    Aug 24, 2017
    Messages:
    45
    its generally in, but really mid range. the image does what you'd expect at both end of travel namely defocuses. through the middle I get the image you see
     
    vinifera, Oct 19, 2020
    #22
  3. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,316
    That's... odd. So you're saying that is the best focus, and it gets worse on either side? That doesn't make a lot of sense, because if it were in focus it would look like a dot, not a semicircle.
     
    Doug, Oct 19, 2020
    #23
  4. vinifera

    vinifera Cyanogen Customer

    Joined:
    Aug 24, 2017
    Messages:
    45
    Got a lot closer last night to real star "dots" on the SC2. Mostly CCW. Had to adjust telescope focus on the SC2, which unfocused the STF8300 images slightly. I'm wondering if there's a little slop in the focusing mechanism for the SC2?
     
    vinifera, Oct 20, 2020
    #24
  5. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,316
    The SC-2 motion is very fine, so there is unlikely to be slop.

    It can be difficult to turn the knob by hand. There's a small hole in the middle of the knob that accepts an Allen key (included), which is faster and easier. (Just don't force it when you do hit the end stop!)
     
    Doug, Oct 20, 2020
    #25
  6. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,316
    Okay looking at this in detail, I think you may have to pull the mirror back slightly in order to achieve focus.

    I think it would be useful to make a new nosepiece assembly available for the AO-8, to make a larger FOV available to the guider. I've worked up a design. I could 3D print an ABS version for you to try out.

    An alternative would be to add a small spacer between the filter wheel and the camera.
     
    Doug, Oct 20, 2020
    #26
  7. vinifera

    vinifera Cyanogen Customer

    Joined:
    Aug 24, 2017
    Messages:
    45
    Didn’t even consider the Allen wrench. Will give that a try. Looks like a week or so of clouds - of course...

    Would be glad to give the abs version a shot - if it works will certainly order a custom piece (although I can’t imagine others don’t have a similar need)

    thank you for all the help.
     
    vinifera, Oct 20, 2020
    #27
  8. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,316
    Yes we'll send you the 3D version, and if it works well for you we'll go ahead and make it a standard aluminum part.
     
    Doug, Oct 20, 2020
    #28
  9. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    10,316
    Okay I've got the prototype part with wider aperture. If you can provide me with your name, address, phone, I'll get that sent to you to try out.

    You can send the details via Private Message.
     
    Doug, Oct 21, 2020
    #29
Page 2 of 2

Share This Page