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autofocus with OAG guiding ?


glowingturnip

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Hi all,

I'm just starting to think about getting autofocus going on my rig.  My focuser is a Lacerta Octo60 which will accept a focusing motor attachment which I can drive from SGP.

However I'm guiding through an OAG using PHD, and was just wondering if the automatic refocusing interferes with the guiding ?

I assume I can instruct SGP to turn guiding off during refocus and then turn it back on, but does that create any issues with lost guide stars or whatever stopping the session ?

 

Cheers

 

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I certainly find that re-focusing interferes with guiding, so usually turn off guiding during re-focussing.  Otherwise I need at least 2 minutes for the guiding to settle back down.  But I've never had a problem losing the guide star.  I don't use SGP, I use MaxPilote, but I think it does much the same thing.

Chris

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Autofocus does affect the guiding and with an OAG you will need to tell PHD to stop guiding while auto focusing. Make sure that you have 'sticky lock' turned on in phd2 as this will make sure that the same guide star is used. As long as your guiding box is big enough for your combination, you will find that the guide stars get big, then smaller and big again...... but guiding is paused.... then when it switches back on again it will get the original guide star back into the centre of the box. That way you know you're still on the target in the same place ?

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thanks both.  I guess I'll need to be more careful with my polar alignment so that the star doesn't drift off in Dec when the guiding's off.  I'm a set-up and tear-down person at the moment and usually let PHD pick up the slack in my Dec drift.

Good tip on the sticky lock Sara, I'll look into that.

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Just one of the features introduced by the PHD2 team (the spectrograph slit and nudging position were others) to assist us poor guys who persist in carrying out spectroscopy.

I use PHD2 (and AstroArt) for all my guiding - using the Lodestar and reflective slit plate on a C11 @ f10 and NEQ6. No issues, no drama.

 

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