Koehler Urban Astrophotography

2/27/26 - No clouds, giant moon (82%).  Because of the size and duration of the moon (all night), narrowband imaging is really necessary... but there are limited targets in view.  Noted M97 is at a favorable position.  Seeing forecast for 02/27-28/2026 from meteoblue showing almost no clouds but large persistent moon. Seeing forecast from clearoutside for 02/27-28/2026 showing favorable conditions overnight. Starting around 20:00, launched a polar drift alignment in PHD2 running on the Odroid C4 desktop over RDC.  Started at ~28' and after two adjustments (to the left, pre-meridian flip) brought this down to 0.26'.  Ran an autofocus in the background with the venerable Meade zero-shift autofocus hanging off the Shoestring Astronomy controller. Reached a minimum HFR of 3.76 after six iterations.  Low temperatures were expected near freezing and so set the SVBony Sv405CC chiller at 0C. After slewing to M97 and starting the focus routine, noted that it's still...

 2/13/2026 -- No moon, no clouds (until 05:00)...clear, cold skies.  Time for some broadband imaging on galaxies in view.  Evening started with relatively poor skies (pseudo sky quality metric of ~9200 at 21:00).  Configuration unchanged with the Celestron CGX DX mount, Meade LX10, Starizona Corrector III (0.63 corrector and reducer), Xagyl filter wheel, Svbony 405cc (chilled to -7C). Seeing forecast for 02/13-14/2026 from meteoblue (top) and clearoutside (bottom) showing clear skies expected until 05:00 and no moon. Initial drift alignment in phd2 running on the Odroid C4 showed an alignment error of ~9'. Not bad, considering it's been sitting for weeks through strong winds, snow, etc. with the cover on.  First adjustment (to the left) over-corrected...with an error of -7'. After several adjustments back & forth...ended up below 1". Set up the scheduler for light frame collection on M106 through 05:35.  Sequence file configured with gain 285, offset 24...

 01/28/2026 -- bad skies, cold temperatures... so far only a few opportunities for imaging in December of '25 and January (so far) in '26... and tonight is not really much better. Giant moon, poor-ish skies... but took the opportunity to finally pull off the covers and test out a new totally dark filter (black) from Svbony that may aid in collecting dark and bias calibration frames at the end of a session. Installed the new black filter in the Xagyl 8-position filter wheel (now with position 1 == UV/IR, position 2 == dual narrow band (Ha/OIII) and finally position 3 == black). The Indi allsky backyard camera pseudo sky quality metric is grim (even in "moon mode") with a value over 37k at 22:31.  Save a copy of the outdoor weather station JSON report at 22:20 and noted lovely conditions (to include light wind): "time": "2026-01-28T22:20:00-0500", "generator": "weewx 5.2.0" "temperature": {"value": 19....

11/16/2025 - One cloud free and moon free night before clouds & rain set in... had cleaned the venerable Meade LX10 8" SCT OTA, corrector, primary and secondary mirror (after a very dark disturbance arrived for two evenings' collection)...and awaiting replacing the steel screws with stainless...so brought up the Orion ST-80 for testing. Worked to attach the Xagyl filter wheel and Svbony Sv405cc camera. Noted the correct back focus for the Hotech SCA flattener is 55mm with 6.5mm between the Sv405cc chip and housing...leaving 48.5mm of back focus distance to work with. Used extension tubes to get as close as practical... and mounted the ST-80 on the CGEM DX with the Cosmicar 25mm F1.8 CCTV lens set up for guiding using the Zwo ASI120-MC.  Focused manually successfully (tested within the focus tab within Ekos).   After focusing, found that the Hotech SCA back focus is not perfect...with coma visible on the extreme edges...extending for nearly 1/5 of the size of the frame...

08/30/2025 - No clouds...some moon early.  Set up the Ekos scheduler for NGC 6960 with dual narrow band filter in place with M 33 scheduled for near the end of the evening (0400) when there's no moon (using the UV / IR filter only). Utilizing the venerable Meade LX10 SCT with the Starizona SCT Corrector III, Svbony SV405cc cooled camera, the Xagyl 1.25" 8-slot filter wheel, the Meade zero-shift focuser on the Celestron CGEM DX mount.  Guiding through the 5x90 RACI guide scope using the Zwo ASI120MC-S camera with built-in ST-4 guide port cable running to the mount .  Double checked polar alignment and tested the internal guider in Ekos and set Ekos up to to use this instead of phd2 (which has a habit of dropping the Indi guide camera...thus ending the imaging session prematurely). In the morning noted 100x NGC 6960 light frames had been collected. Only a few M 33 frames were collected until Ekos shut down the system due to the end of astronomic night time.   Exam...