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Old 17-04-2012, 05:34 PM
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gregbradley
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Join Date: Feb 2006
Location: Sydney
Posts: 17,046
As far as I can tell and I have tried several times, library darks for the autoguider only work when it is full frame. Once it does subframing it does not do library darks. Most likely because the frame sizes would no longer match.

If you use autodark which I sometimes do, it works, but because the Lodestar does not have a shutter as Chris mentioned the STi does, it takes a light and subtracts it from the light it took a second ago. I have a STi enroute and I can do a comparison and post the review.

Now funnily enough that actually works in that the guide star must move enough or shift in shape enough that a sizeable portion of the guide stars survives and autoguiding works!

I get perfect round stars at 3 metres and 15 minute subexposures doing just that.

I haven't used PHD and it may be better suited to the Lodestar.

The Lodestar is very convenient with only one cable and also very light and a convenient size fitting in eyepiece holders. But the 2 I have had showed bad artifacts. The first with horizontal lines was cured by using 64 bit driver and the line went. The 2nd I got has a white line down the left. Perhaps that may go with PHD?? I can live with it though. If I get a bright enough guide star it does not interfere. If I do get interference from it (guide errors go to 15 in X and 8 in Y) I simply select autodark and it works.

Greg.
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