Koehler Urban Astrophotography

Goal: install, configure & test out the Baader Planetarium Rowe Triplet Coma Corrector - RCC-I on the Orion CN10 (long tube) 10" Newtonian.   This is an attempt at replacing the Teleview Paracorr (type 1) since my example is ancient, hazy (smoky...amber colored...ich) and results in a 15% increase in focal length.  Early testing with my example paracorr suggested similar light throughput as the (deforked) Meade LX10 EMC 8" with a 0.63x focal reducer (which is sad). A key challenge with the RCC-I in this Newtonian is the focuser.  It comes with a T-adapter...and an eyepiece adapter...neither of which work with this 2" coma corrector...because it needs to go _into_ the focuser.  Sadly, the eyepiece adapter for the focuser brings the camera too far out... and the T-adapter provides no mechanism to mount the coma corrector.   This was confirmed on the first night...which resulted in no images... with no mechanism to reach infinity focus.  Had started using local terrain

Collection notes from 05/05.  No moon.  Some breezes. No clouds.  Temps in the low 60's. Seeing described as very poor on meteoblue (40+m/s) and Cleardarksky.com.  Tripod re-positioned over previous location (grass marks from vibration pads).  Initial polar alignment through the polar scope was a bit difficult... lots of branches.  PHD2 drift alignment (with NGC 4438 centered) showed ~2' (3px) error after several minutes of drifting.  Once again, polar scope works on the first attempt.   First collection with the Zwo Asi 120MC-S following firmware upgrade and the Cosmicar 50mm F1.8 lens was refocused (put the line under the 7).  Also readjusted centering using Denebola (also adjusted ST80 focusing w/ the Canon T3I).  Was successful in getting alignment between guide camera and Canon to within 128 arcseconds.   Two jobs scheduled: NGC 4428 until 03:00 then NGC 6888.  Guiding was tough... switch to using ST4 cable and binning (2x). RMS values a bit higher than 5.  NGC 6888 collec