Dome Rotation Query

[Gina]

As I'm planning a mini dome observatory I have a very basic question.  I could probably work this out myself but asking a question is much quicker  

Is there a simple formula for calculating the amount the dome needs to rotate to keep the slot in line with the object being imaged? 

Thanks in advance

[steppenwolf]

Gina, why not control the dome via ASCOM and use POTH to control your dome driver - POTH does all the necessary calculations for you.

 

P.S. 'Simple' is not a word I'd use in this context!

[steppenwolf]

Just in case you do want to do it yourself, here are the calcs. for you.

[RayD]

2 minutes ago, steppenwolf said:

Just in case you do want to do it yourself, here are the calcs. for you.

ASCOM it is then 

[steppenwolf]

2 minutes ago, RayD said:

ASCOM it is then 

That would be my take on it too!

[Gina]

Thank you Steve 

I am using INDI with RPi and building my own fork mount which I plan to emulate as a standard ASCOM mount such as the NEQ6/EQ8.  There is an INDI driver for this and also an INDI driver for a particular dome so I guess I should be able to emulate that dome in my control electronics.  I just wondered if there was a simpler way.

[Gina]

Had a quick look at those calculations and see it's based on a GEM rather than a fork mount and also that the dome rotation axis may be displaced from the mount axis.  For my widefield imaging rig I can easily arrange that the dome rotation axis lines up with the fork mount RA and Dec axes.  I would have thought this would make the calculations simpler.  I guess I should be able to work this out myself - a matter of converting EQ coordinates to AZ.

[steppenwolf]

Hadn't realised that you were using a fork mount. In that case, you could just slew the dome to match the dome aperture to the telescope and then set it running at sidereal rate?

[Gina]

Yes.  I wondered that - thanks