On Sun, 25 Oct 2020 12:09:16 -0400, Dennis Lee Bieber wrote:

> On Sat, 24 Oct 2020 18:41:25 +0200, Björn Lundin 
> declaimed the following:
>
>
>>I did not try the moon yet with the HQ camera (cloudy) , but I did with
>>a rpi camera version 2 which I had before - and well - not so good. But
>>images of closer objects - like a powerline 2 km away are good
>>
>  Have you verified that you still have focus movement available
when
> trying sky objects? The closer an object is, the more the sensor has to
> be "pulled out" of the tube. Objects at infinity should have the sensor
> as far in the tube as possible.
>
>  Second -- how long are the exposures?
>
>  If my math is correct, celestial objects "move" ~15 arcsec per
second,
> even a 1/4sec exposure well encounter nearly 4 arcsec of movement if you
> don't have an equatorial tracking mount on the telescope.

Another factor is diffraction: the PiCam HQ at 38mm square is relatively
large compared with the primary mirror at 11% of total the aperture.
That's not including the mount and with 3D printed support legs, which
will be relatively thick, so at a guess you'll be starting to see
diffraction effects from them as well as reducing light gathering
ability. This combination will tend to soften the focus as well as reduce
light gathering ability.


--
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Martin    | martin at
Gregorie  | gregorie dot org

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