I see that it’s been over a month since my last post. Weather, time, and health have kept me out of the observatory so there are no new imaging sessions on which to report. Here’s what I know since then:
I mentioned a while back that I seemed to be seeing about 18 arcseconds peak-peak error when unguided in RA. The good folks at Meade wondered about that because their preshipment tests on my mount were better than that so I now have a “loaner” RA assembly to install and try. Fortunately, the mount is very modular so it’ll be an uncomplicated swap once the mount is unloaded and the c/w shaft removed; I’m just waiting for weather and time to get that done. I’ll need to open the roof to remove the OTA so it can’t be raining and I’ll need to see what I’m doing so it can’t be dark. Given the weight of the OTA and the counterweights, it’ll probably require a relative humidity of less than the 80% it has been here (that’s real work for an over-60 guy in hot weather). I’ll report on that project and any performance difference I see afterwards.
note: I relocated the Starlock to the top of the OTA to compensate for tube-ring-related flexure after posting the last image so I haven’t seen what difference that made. If possible, I’ll try to grab one image with that configuration before making the RA change in an attempt to isolate the effects. It shouldn’t affect true PE at all; just RA drift.
For anyone who doesn’t want to bother going through all the earlier posts in search of information: all images posted here were captured using an AT12RC at 2400mm focal length and a QSI683WSG-8 with 5.4 micron pixels. Some of the images are binned to double that size. All were guided with Starlock using the autoset parameters. Polar alignment was done using the mount’s assisted drift alignment routine. Mount control is via TheSky6, using the LX200GPS drivers and the mount’s HPP/Starlock autocentering. Capture and calibration software is Maxim/DL, alignment, noise reduction, and combination are done with CCDStack2, and final processing with Photoshop CS. My last mount was a Takahashi NJP. All images were captured from my red zone location: http://cleardarksky.com/lp/UrbnObOHlp.html?Mn=astronomy .