Re: APPM Questions

Tony Benjamin <tonybenjamin@...>

Think I'm slowly getting a grip on the main issue here. If I'm slewing the scope from within SGP then there is no delay - the scope and dome move together in beautiful harmony. But once an outside party (APPM) is issuing the slew command SGP has to sit idly by until that slew is complete as it doesn't know where the scope/mount is going to end up? Heres the way Jared from SGP put it:

SGP will do “pre-emptive” slews when SGP issues the slew or when the slew comes from the API. If something else is issuing the slew then SGP has to react to it since the slew is done without our notification…what’s worse is that SGP doesn’t know where the slew was commanded to go (we just see RA/Dec changing) so we have to wait until the slew is complete and then we can move the dome accordingly. I’m assuming since APPM talks directly to the mount that it is issuing the slew without SGP’s knowledge.

To enable pre-emptive dome slews without scope slews we’d need to create something on the API side that would allow external applications to send us the coordinates for the slew but not actually do the slew in SGP. Or to allow this now the application could invoke the slew through SGP which would then handle the slaving correctly.


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