Re: Flexure Measurement - How Much is Too Much ?


Fwiw.. Some time back I moved towards using OAGs. (e.g. ST-8300m + STi on SBIG OAG)  
At most focal lengths (less than 1100mm) I don't have a problem finding stars in the OAG with the STi camera.   
I've also used the Lumicon GEG OAG with a DSI-Pro guide camera.. worked pretty well; rarely had issues finding stars.

With the Mach2, I'm not even bothering with the OAG.   (I hope I no longer need to use guidescopes either, but if i did, i would probably look for an OAG compatible with the imaging camera.)


On Mon, Jun 21, 2021 at 9:48 PM M Hambrick <mhambrick563@...> wrote:
Thanks for the link to your web site Mike. You have some really good information in there. 

I am going to try to get some more flexure measurements over a longer period of time next time we get a clear night here. I noticed in your example of differential flexure that you were getting shifts of multiple pixels. Although I only had one 10 minute subframe, the shift that I measured was much less than one pixel, and the stars in that image looked good.

I am trying to look at everything I can to try to improve my images. Until now I have concentrated all of my efforts on are focusing and guiding. I have not seen anything in my images so far to suggest that I have a problem with flexure, but I want to get an idea of how much there is.


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