SharpCap Forums

First off, I love Sharpcap
made it so easy to start again with astro photography after nearly 20 years - so much changed, particularly the available technology

Using a SVBONY SV106 Guide Scope I'm able to do PA. I'm mounting this guide scope only for that reason and after PA I remove it.

My main equipment is a LX200R 8" with a ZWO ASI585MC, OAG & a 120MM Mini. Would be great to do PA only with that.
With the main gear I'm always able to do a tools -> plate solve, and in PA mode it identifies enough stars. Data acquisition and the possibility to solve the position in general seems not to be the problem, see also two attachments. I understand that as my FOV of 0.32 x 0.18 is much small than the required FOV it's not working.

I was wondering if there is a way to make polar alignment possible for smaller FOVs. Either by adapting the algorithms in sharpcap or by having the possibility to load a more detailed set of stars for polar alignment with a smaller FOV. or would this have a huge impact on the accuracy?

If you introduce this, maybe in experimental mode or a special build, I can offer to try it out

Thanks,
David

Hi David,

it's a good question- the full plate solving support in SharpCap is based on the more limited version that is used for polar alignment, so it might be possible to 'transplant' the more advanced plate solving into polar alignment to allow smaller FOVs.

There are a few things that work against this however... A small FOV increases the likelihood that the north (or south, as appopriate) celestial pole is 'distant' from the field of view being used - ie it is not in view or even close to view, but several fields of view away. That tends to negatively impact the accuracy of the calculations, increasing the effects of any small errors in the plate solving. Additionally, small fields of view tend to require longer exposures to get enough stars to plate solve (I can see 5.3s in your image, which is actually pretty short for that sort of FOV) - this means that the adjustment phase is harder as you have to wait significantly longer for the results of any change to become apparant.

I don't think there's any chance of making a quick change here, but I will keep the idea in mind for future improvements.

cheers,

Robin

Hi Robin,
Appreciate you took your time to explain this to me.
Will keep an eye on future updates in Sharpcap

Best,
David