Koehler Urban Astrophotography

Because I found learning calibration challenging during a demo for PixInsight (where horrendous results were obtained initially through simple mistakes), I also started to pay more attention to bias, dark and dark flat calibration frames.  Whereas in Astro Pixel Processor, calibration is so easy that no attention need be paid, in PixInsight the user is down in the weeds looking at data... trying to figure out what's gone pear shaped.  And so, I began to do some searches on the behavior expected for the Canon T3I, whether ISO1600 was (in fact) suitable for lights and darks, whether ISO100 is suitable for flats, etc. This led to an old (2015) page from the  Blackwater Skies Blog  on their PixInsight workflow for the Canon EOS 500D that (similar to other posts) noted that the dark current visible in Canon EOS DSLR cameras is modified before written to the RAW CR2 files to manage the dark current levels.  At one extreme, this may suggest fixed pattern noise is no lo...

Continuing a number of days of collection of M81 + M82 on the Meade LX10 SCT with the Celestron 0.63 focal reducer (1250mm @ F6.3), the Canon T3I with Astronomik CLS EOS clip-in filter. This includes collection with M81 & M82 on 2/20 (15x at 100s), 3/5 (112 at 120s) and 3/6 (52x at 300s). Collection on 3/3 was centered on M81 only (114x at 120s). The Orion C10 Newtonian also collected with M81 centered on 3/7 (92x at 120s). Tonight's collection started off with an initial alignment via polar scope that produce a remarkable result of 0.67" polar alignment error in PHD2's drift alignment tool. After manually focusing on Procyon using the live display, performed at 10s capture in the Ekos/Indi focus tool... just to see what metrics it produced.  Procyon itself measured 24.91 but the 5 other stars with measurements included 2.44, 2.99, 2.47, 2.71 and 2.46.  Started processing in a demo / trail version of PixInsight.  After a week's work...gave up.  No usable results....

Performed some experiments at noon with solar imaging with the venerable Jason Constellation Model 311 and the SVBONY SV305 camera (with solar film clipped into place).  Used AstroDMx Capture as well as Indi/Ekos to grab snapshots as well as SER video files.  Captured flats against the basement LCD tv (white background) and then disassembled the telescope to clean the optics after noting lots of blemishes in the image.  Determined that the dust was actually on the AR coated window on the SV305 itself rather than the telescope.  Attempted to clean this up, but getting all the marks off is likely impossible w/ just a regular glasses cleaning cloth. Afterwards, mounted the giant Orion CN10 Newtonian on the Celestron CGEM and balanced for a second attempted imaging session with Apophis. After getting the system focused (without the Paracorr coma corrector)..which required only one small spacer for the T-mount to the Canon T3I, noted that the skies and this reflector were...

Attempt to collect a series of frames for an animation on the NEA 99942 Apophis.  Magnitude ~15.8.  Yesterday night was closest approach. Example video  from a C8 at F7 (obviously far darker skies than the DC region).  Using the Meade LX10 EMC with a 0.63 Celestron focal reducer (1250mm @ F6.3) on Celestron CGEM DX mount with only the Astrodon CLS EOS clip-in filter.  Canon T3I set with a custom white balance for this filter. Used the polarscope for an initial alignment... PHD2 drift align showed 0.66' after after several minutes drift time in the initial azimuth adjustment position (pointed to the meridian and celestial equator). Two sets of posts... one in the  Indi forum  and one in  Cloudy Nights  provided insights on how to update Stellarium with the latest near Earth asteroid (NEA) ephemoride for Apophis.  Used this RA/DEC to slew the mount in KStars/Indi/Ekos and began guiding and collecting 60 second frames at ISO1600.  Guid...

First significant collection in 2021 started on 2/19 with the venerable ST80 with the generic (non-branded, ebay) dual-band filter, the veteran Canon T3I on our trusted CGEM DX mount. Lots of clouds with alignment not possible until 11pm and real imaging not starting until midnight.  Moon as less than half full, and low in the sky by the time imaging started.  Temperatures were in the upper 20's with little to no breeze noted near midnight. Utilized PHD4 to perform an initial drift alignment following alignment with the polar scope with results at 1.8 arcminutes.  Focus for the ST80 was checked, and remained unchanged from previous session. Set up the Indi/Ekos scheduler to collect against M81 (Bode's galaxy) with 180s light frames at ISO1600.  Utilized the primary telescope for plate solving... which went fast using the remote astrometry driver.  Used the internal guider and found no issues with guiding on the 50mm F1.4 Cosmicar CCTV lens on the Zwo ASI-120mc-s...

Goal:  Patch together collection over 14 total nights (10/2 through 11/20) into a giant mosaic using Astro Pixel Processor.  This all collected from the venerable Orion ST80 with a generic (ebay) dual narrow-band filter, the Canon T3I (astro modded) on the workhorse... Celestron CGEM DX (on franken-tripod). Pre-processing & mosaic creation steps based on the tutorial found here . Started with creation of individual panels composed of the integration of ~100 shots each.  All of these are 180s at ISO1600 with similar weather (temperature) making the selection of darks and bias frames uniform with one master dark and one master bias.   However, camera orientation changes and re-focusing means two sets of flats and flat/darks across these nights (and realistically, perhaps more should have been captured... but with focus being fixed and camera orientation consistent across the two groups of sessions (one with camera in a horizontal orientation when the mount was...

Goal: Capture Mars near the Oct. 13, 2020 date of closest approach (Opposition). Left tripod vibration pads in the lawn from the Mars imaging session on the 15/16th. In the early afternoon of the 17th, brought the tripod back out & set back on vibration pads in the lawn.  Mount was found to be level... no need to re-level (time & effort saved) by keeping the pads in the lawn.   Installed counterweights & the Celestron CN-10.  Rebalanced the mount... determined a working arrangement of counter weights ... and worked out optics configuration  for the CN-10 with the Zwo ASI120MC-S as the primary imaging camera with and without the 3X Barlow.   Was not able to use the M60 -> T-thread adapter with the eyepiece projection cell to the Zwo and reach infinity focus.  Instead, used the 2" eyepiece adapter -> 1.25" eyepiece adapter -> Zwo (with eyepiece adapter installed) for prime focus and inserted the Celestron X-Cel LX 3x Barlow (wit...