Koehler Urban Astrophotography

In processing frames for each of six panels making up a 2x3 mosaic of the North American nebula from the venerable Orion CN10, noted rotation across subs and imaging sessions... which is exacerbated by poor guiding with elongation in stars.  Despite efforts at drift alignment to gain good polar alignment, serious issues remain that complicate / frustrate processing to integrate subs into specific panels... with some sessions working out better than others. Wondered if the alignment of the guide scope with the OTA is critical... since these are definitely now far off each other (several degrees at least).  Noted  this link  describing the likelihood of rotation if polar alignment is not perfect for this case.  Fixed this in later collections to ensure nominal alignment between the OTA and the guide scope. Also noted that the camera was not rotated on the OTA to be in line with the collection plan.  This resulted in a failure to co-register all the frames due...

After the Trigertrap  app was abandoned (open sourced, but no clear support on Google Play with any releases), I had few hopes of using my Olympus OMD-EM5 for astrophotography without some other new dongle.  However, on a lark, I tried the original Triggertrap dongle and adapter cable with my current Samsung S10e using the MIOPS Mobile app.  They sell a similar (identical?)  dongle  which is supported by their Android app.  Remarkably, it worked flawlessly. Since this was a vacation to the Outer Banks with a week's weather forecast with clouds and a full moon, I didn't bother transporting a mount and telescope.  However, I did find one clear evening (before the moon rose too high) to test out the old Triggertrap dongle with the OMD-EM5 @ ISO 2500 using the (poor quality) original PEN-1 14-42mm kit lens .  Set the camera on a table pointed at zenith with Cygnus in view overhead.  The OMD-EM5 was set at factory default to collect a dark image o...

With cloudy conditions predicted for the whole week, left the mount and telescope at home for this vacation to the outer banks.  Did find one evening to play with the venerable 500mm F8 Quantaray on the equally venerable Olympus OMD-EM5 with a small telephoto bracket.  Results for nearly handheld were interesting... if only in spotting the four Galilean moons.  Attempted a variety of exposures to try and capture any detail on Jupiter... but even with 3.75um pixels, it wasn't happening.  Astronomy tools shows for that sensor on the 500mm focal length lens, the resolution is 1.55"/pixel... and for a 61.5mm aperture the best possible resolution is 1.89 arc seconds... so not much hope for planetary there. The sky and telescope site showed this for the location of the Galilean moons this evening (Calisto, Europa, Io and Ganymede: Using rawtherapee to process the raw Olympus frames, was able to pull out the following for the planet: And this (for the same frame) for the mo...

08/12/21 -- Crazy idea -- since it's relatively low in the sky early in the evening... attempt a giant mosaic of the North American Nebula (NGC 7000) with the venerable Orion CN10 at F4.7, 1200mm.  It will take a crazy number of panels to complete... but the result should be remarkable. Started on night #1 with no moon, good predictions for seeing... but hot & humid.  Started drift alignment at 8:50pm at ~350'.  After a major over correction, brought the polar alignment to 1.65' after several minutes of drifting. After plate solving with the Canon T3I to establish the current field of view and camera rotation, used the Kstars/Ekos scheduler to generate a 2x3 mosaic with 5% overlap to cover the nebula.  The scheduler launched the first collection at 9:51pm...starting with autofocus (updated to use a 9 second exposure...to differentiate from plate solving which is left at 10s).   Found that the FCUSB light was turning off after the first attempt at moving...

08/08/21 --  Tested the Shoestring Astronomy FCUSB with the Orion Accufocuser in the house in the daylight to confirm smooth operation focusing in and out and to test the connection with Indi/Ekos/KStars. This evening has no moon, but sufficient mid-level clouds to be non-optimal for imaging... but good for testing hardware.  Set up the CN10 on the CGEM DX on the back deck for this basic focusing test.  Started setup at 7:30pm with leveling and basic (compass-based...Polaris buried behind trees) alignment.  Started with Beta Draconis (Rastaban) as an initial location for drift alignment.  After several iterations got the drift error below 3'.  Found phd2 still not connecting to Indi on the Odroid XU4, so used X11 forwarded over ssh (with compression) to run phd2 remotely from the Odroid connected directly to the camera and ST4 guide port. Ultimately, set up a job in the scheduler for NGC 6995 with track, focus, align and guide steps.  This completed au...

First experiment with Shoestring Astronomy FCUSB with the Orion Accufocus under Indi/Ekos/Kstars. The FCUSB device now exceeds the number of USB2 (1x) & USB3 (2x) ports on the Odroid XU4. Used a USB3 unpowered four port hub on the USB2 port to expand as now needed. Oddly, found that with Indi running on the XU4, Kstars connected from the workstation with indi connected remotely, the workstation copy of phd2 was unable to connect (and crashed with a segmentation fault). Ultimately, ran phd2 over X (with compression) via ssh (displaying remotely) with it connecting directly to the onboard ASI ZWO 120MC-S.  Started with a very rough initial polar alignment (measured with phd2 with a drift alignment showing DEC drifting up w/ error over -300'). First adjustment (tighten on the right) got to ~-160'.  Then -90'.  Then -20.  Over correction to +13.  Finally iterated to ~-3.2'. Once polar aligned, finally started trying to work with the FCUSB via Indi to prepare to ...

Installed a 2" Orion  Crayford-Style focuser  to the massive Orion CN10 Newtonian due to wobble and shake with the original rack & pinion.  Additionally, this focuser accepts the Baader RCC I  Rowe Coma Corrector  without needing to be modified and without adapters, custom spacers, etc.   Started setup at 8pm with plenty of light left to level the Celestron CGEM DX mount, stick on the counter weights and the OTA and cameras.  With trees now grown so tall to permanently block polaris, used a best guess approach with the mount in the drive.  After focusing on Epsilon Serpentis, started phd2 to begin a drift alignment.  Remarkably, started at only 15.45' off (without using the polar scope)...just dead reckoning.  After an initial over correction, adjusted to 2.66' after several minutes of drift. Initial frame used for plate solving (before polar alignment) showed strong streaking in the top half of the frame (with long dimensi...