wow nice work indeed. What's the max exp time you can get on that combo and not leave star trails?
Thanks! Depends on how carefully I can get the mount aligned, (Celestron CGEM) and whether or not I am using guiding. Two or three minutes when not guiding, and basically unlimited if guiding (using Stark Labs "PhD" "push here dummy" guiding software and the Orion Short Tube 80 guidescope setup). My main problem with long exposures isn't usually tracking or guiding accuracy, but rather "skyglow" from all the light pollution hereabouts. And it's worse now that they have changed all the streetlights to LED. I have a photographic filter that cuts sodium and mercury vapor lighting but it doesn't work so well with the new LED light spectra. So ten minutes per exposure is pretty much my practical limit due to light pollution. But if something happens (and it often does) then I lose time, so I generally limit to 5 minutes max and just take a bunch of frames and stack them in DeepSkyStacker (Free software) or Stark Labs Nebulosity (not free but worth the cost). I generally use Nebulosity for controlling the camera and saving the frames. DSLRshutter is another free application from Stark Labs that works well if all you need to do is to control the DSLR exposures and sequencing. A few years ago I installed a concrete pier for the mount so I don't have to use the tripod. It's a lot more stable, but when a truck goes past I still get vibration that can ruin an exposure. It's a tradeoff: Longer exposures mean a given incident of vibration doesn't affect the image as much, but longer exposures also mean more chances for vibration to happen during the exposure. I also have Maxim DL (quite costly, "professional" amateur astrophoto software) but it is so complicated that I never actually use it. So, when seriously imaging, I have the mount connected to the laptop, and I'm running PhD with the Orion guidescope to keep the system on target, and Nebulosity to control the camera and save the exposures. It's a maze of cables. Laptop > USB hub > mount, guidescope camera and imaging camera. This is the result from a stack of ten-minute exposures of the Rosette nebula, taken with the Parsec monochrome cooled CCD camera.
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Topic: Astrophotography (Read 31399 times)
