Re: Unguided with pointing model


A tracking model that’s good enough for five minute unguided images with your 180 should be possible without losing much imaging time.  That is, you should be able to do it during twilight.  A good polar alignment probably takes about as long as building the model. Maybe an hour total for the two? Depends on the number of points you choose.  If you start as soon as possible after sunset, you may not lose any imaging time at all. If you do lose any, it could easily be less than the accumulated time lost waiting for a guider to settle after dithering twenty or thirty times during the night. Then you could skip the guiding entirely. Assuming you have the AE version of the 1100 you should get results that are equal to or Possibly even marginally better than a well guided image.  Based on testing with my 1100GTO AE the other night (I bought it a year ago but have only been using it for the past couple months), typical star eccentricity at 1,160mm focal length with a 5 minute unguided images is between 0.45 and 0.55. That’s using a model that’s probably better than you would build “in the field”, but still.  It works quite well with a moderate number of points.  When I spoke with Ray G at the last Advanced Imaging Conference he recommended starting with, say, a 70 point model for field use.

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