4/10/2023 0 Comments Above the clouds tiltshift![]() ![]() Polar alignment is very good and there is virtually no drift in DEC - which in turn means that DEC variation in position is mostly due to Seeing - we have in this case error in position measurement introduced by seeing for given exposure time (longer exposure times reduce this error).Īctually, error in DEC can be due to several things - shake of the setup due to wind, or mechanical shake from mount tracking - or seeing. If we look at DEC stats / graph - one thing is obvious. There is quite a bit of seeing introduced error. We don't have accurate RA RMS once this linear trend is removed / model is fixedĢ. ![]() My guess is that the model is somehow flawed (probably because that "moving mirror compensation" - mentioned in the video). This means that mount is not tracking at correct rate. RA has significant drift / downward trend on the graph. Mount tracking is flawed - probably because of poor model. What you see in the video is mount tracking performance as there are no guide corrections made.ġ. Ok, so you need to understand difference between mount tracking performance, mount guiding performance and tracking/guiding measurement precision. ![]() Considering he was using a C11 Hyperstar config, at a forgiven focal length. Since there were no corrections made, everything was running on a model. That is an additional blur of 0.5 " in 1.5" seeing.īut when I reached the 9:55 minute mark, I was kind of disappointed with the numbers reported on 'guiding'. Leave everything as is, except increase the guiding error from 0.35" to 0.75". Submit the default values in the exposure time calculator, then, on the results page go to the Image FWHM tab. I regularly guide at 0.3" with seeing above or at 1.5". Yes you should! Your stars fwhm is determined by a combination of factors like seeing, guiding error, image scale, angle from zenith etc. "No point guiding at 0.3” RMS when your seeing is 1.5”?" That’s my thoughts anyway… Will be interesting to hear comments from mount experts. No point guiding at 0.3” RMS when your seeing is 1.5”? But I suppose what you’re paying for is being able to guide 100kg of payload at that accuracy.Īlso I guess there’s a lower limit on guiding accuracy imposed by your seeing blur. That’s normal according to 10 micron specs…see below. ![]()
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