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ngwillym

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Posts posted by ngwillym

  1. I've found that real limiting factor (in the UK  at least) for imaging quality is seeing. Yes, you may have a scope/camera combination that can do sub arc second resolution, but with average UK seeing in the 2-4 arc sec  range - or even worse early in the evening-  its a matter of finding those very very few nights where the equipment can perform anywhere near its best.

    Alternatively, find a specific area to concentrate on - e.g. planetaries, colliding galaxies or even planetary.

    Clear skies (We can only hope)

    Neil

  2. All,

     

    thanks for the advice.. Secondary was removed and re-seated on its pivot and the collimation screws levelled up. A quick daytime collimation, followed by a star collimation has it looking much better - not perfect, the seeing wasn't really up to it - but I now have a doughnut to work on. There's a forecast for mist/fog over next couple of days, so hopefully the seeing will be much steadier

    Happy days

    Neil

    • Like 2
  3. Thanks Peter - I wasn't sure if it was just collimation error or something preventing the main mirror racking in and out. I did a daylight collimation using thus approach - Daylight Collimation (robincasady.com) and it looked pretty good - hence me suspecting something more that just a dodgy secondary. As it the Hyperstar version, its not too difficult to remove the secondary for a check-out.

    Neil

  4. It spent most of last year stored in a large plastic case in my dome (which has a frost protection heater and dehumdifier) as the planets were too low at my site to do any meaningful observing.

    I decided to re-mount it and do some lunar work. BUT on trying to check the collimation - things didn't look right.

    I've attached 3 pics - one from inside focus, one  at best focus and one outside focus. (images taken on 18th Feb - seeing wasn't brilliant but even so I would have hoped for a much better star profile that what I got)

     

    anyone have any ideas what's causing this - any attempt to adjust only moves the star image around the field (mirror flop) but does not improve the star profile. .

    The C11 has an aftermarket electric focuser attached, (Pegasus Focuscube) but otherwise is unmodded.

     

    Help 🙂

     

     

     

    _ZWO ASI290MM__18_02_2021BInsideFocus.png

    _ZWO ASI290MM__18_02_2021BestFocus.png

    _ZWO ASI290MM__18_02_2021OutsideFocus.png

  5. Agree with Aramcheck - out of focus and well out of collimation.

    What target were you aiming at? If its any sort of nebula it's unlikely you'll see much if anything at all in a live view - especially if the focus is only just slightly off. And the odd stars you're seeing might just be hot pixels. First sort out the ocllimation, then the focus.

    Neil

    • Thanks 1
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