M1 / M 31-- micro-focuser test

 11/24/2024 -- Testing out the new (to me) Meade Zero Image-Shift Microfocuser for the venerable Meade LX10 2000mm F10 SCT... connected to the shoestring astronomy controller on the Odroid XU4....and controlled with Indi/Ekos.  Initial focusing test showed promise using an initial starting movement of 1500ms... this collection against M1 will see how the microfocuser fares with an actual collection.

Meade Zero Image-Shift Microfocuser... into which the Starizona Corrector III is inserted.

Weather started good from 18:00 through mid-night, but clouds are expected and the moon rises (at 28% full) at 01:30... so no real expectations of greatness... but a good night to test equipment.  Using only a 1.25" UV/IR cut filter (broadband color imaging).  After collecting a test image, set exposure to 100s at gain 285 with offset 32 at 0 C.  Spent considerable time re-adjusting the polar alignment (swinging back and forth between -800 to +50". Finally gave up around -11" error...enough to leave notable streaks in a 120s light frame collect without guiding.

Seeing forecast by meteoblue for 11/24-25 suggesting conditions will begin to decline around midnight (just as collection commenced, naturally)

Seeing forecast by cleardarksky also suggests clouds around 01:00 and continuing through morning.

The indi allsky backyard camera noted a pseudo-sky quality metric of ~6000-5000 (not great, not terrible).

Indi/Ekos/KStars focus module from the run launched by the scheduler for M1.

10s light frame (binned 2x2) from the Indi/Ekos focus module following auto-focusing launched from the M1 scheduler.

Internal guider error was ~6" RMS ... nearly all the error in the Dec axis.  Clouds started rolling in visible on the guider view after only 6 light frames collected (~12:16am).  Intermittent wifi network problems were a source of frustration all day.  Ultimately 38 light frames collected over night.

11/26/2024 -- No moon (until after 03:30) but clouds expected to roll in after midnight... set M1 up on the scheduler. Sadly, the focus module did not communicate with the camera driver successfully, and so the scheduled collection did not happen. By the time this was corrected (near 23:30), clouds were hick.

Seeing forecast for 11/26-27 from meteoblue showing clouds expected around 01:00.

Seeing forecast for 11/26-27 from cleardarksky with similar indications of sketchy skies after mid-night.

11/29/2024 - Post-Thanksgiving collection on M1 with no moon and no clouds. Seeing forecast is exceptionally poor, but otherwise a great evening with temps in the upper 20's.   Installed a new EQ6 collar on the franken-mount (Meade Standard Field Tripod...adapted for the Celestron CGEM-DX) to try and improve the setup and polar alignment. The initial installation worked... but left too much slop and movement and will require some more work to fix.  It was not possible to converge to a usable polar alignment...with frequent over & under shoot of the desired position. Tried a see if the internal guider could deal with the polar alignment error and recover some collection for the evening, but no luck - calibration failed repeatedly.

New silver EQ6 collar on the frankenmount.

11/30/2024 - After adding two screws to the new EQ6 adapter on the franken-mount, found some improvement to polar alignment... but it remains sensitive (easy to shift too far one way or the other). Was able to iterate to a polar alignment error <10". Found that the internal guider in Indi/Ekos had no problem with calibration and guiding proceeded successfully with RMS errors < 2".  Set up a mosaic on M31 (2x3 panels) with broadband imaging. Autofocusing with the Meade zero-shift focuser worked out well given a close starting point.  Clouds expected around 22:30-23:00 with poor skies expected by mid-night...so a short set of collections this evening.  Temperatures are low (20's) with the Svbony 405cc reading -5.3(C)... so the cooler remained off for this session.  Indi Allsky backyard camera showed a pseudo skyquality metric of ~6,000 through 21:30.

Seeing forecast by cleardarkskies for Saturday, 11/30 - 12/1/2024 showing an early end to observations with clouds rolling in by mid-night.

Seeing forecast by meteoblue for 11/30/2024 which agrees with cleardarkskies with a gloomy outlook.

Ultimately, 37x100s light frames were collected with the scheduler shutting down collection at 22:30.

Indi Allsky backyard camera for 11/30/2024 indicating worsening skies started appearing at 22:03 with significant clouds at 22:15.

12/01/2024 - Clouds early... still no moon.  Continuing to collect with just the 1.25" UV/IR filter (broad and color) with the SV405cc through the Meade LX10 OTA with the Starizona Corrector III inserted into the Meade zero shift micro-focuser.  Due to the clouds, unable to start until 22:22.  Pseudo sky quality metrics stabilized around 5400 from the Indi Allsky backyard camera.  Had the mount covered with some light snow flakes in the afternoon... but decided to see how well guiding worked without double-checking polar alignment from last evening.

cleardarksky seeing forecast for 12/01-12/02/2024 suggesting clouds early followed by clear skies...but poor seeing.

Seeing forecast from meteoblue with similar predictions with light to very light overcast expected after 21:00.

Indi Allsky backyard camera analysis for the early evening of 12/01/2024 showing impacts from clouds up until 20:35 with pseudo sky quality metric dropping gradually to ~5400 by 23:00.

Scheduler problem/fix:   Reloaded the M31 mosaic from 11/30... but in the scheduler all the jobs are marked 'Complete' (given the scheduler was built for yesterday). Found that the individual mosaic collection jobs in the scheduler can be updated with new parameters and saved into the scheduler with the '+' key (then the original job removed).  This refreshed the scheduler with new jobs.  Given that 37-ish frames were collected for part 6 of the mosaic, removed that job from the list (with sections 1-5 remaining).  Put this in for one run each.

Focus module problem / fix:  Found the OTA out of focus... and in playing with the focus module, found that moving the focuser out produced better focus. However, the main autofocus routine starts by focusing outward... and then moves in from this initial point.  It missed the focus point... and kept moving focus in (further and further out of focus). To fix this, shifted the focus point so that it was out of focus slightly where moving the focuser in would result in correction. This allowed the autofocus routine to work.  So in summary... the OTA needs to be in near perfect focus (or slightly out of focus but at a point where moving the focus inward is correct ... in order for autofocus to work). 

Noted that the mount slewed the OTA to the desired target almost immediately (second try) and that the internal guide routine calibrated successfully and showed excellent guide errors (<1.5" RMS) suggesting that the polar alignment has held from yesterday night. Noted the internal Indi/Ekos guider is set for 2" exposures at gain of 60 with no binning (1:1) through the Celestron 9x50mm RACI finder scope.

Screenshot from Indi/Ekos inside KStars showing the M31 six-panel mosaic

Following the M31 run for panel 5 around 12:30, set up a job in the scheduler to collect against M1 (Crab Nebula). Unfortunately, the focus module did not succeed in finding the focus point until the scheduler ended attempts at 05:02.  :<

12/02/2024 -- Another cloud-free evening with no moon. Indi Allsky backyard camera shows a pseudo sky quality metric of ~5800 (dropping gradually).  Additional broadband collection against the M31 mosaic with 20x100s for each panel 1-4.  Adjusted the focus module to use a different algorithm (Iterative) with an initial step size set to 4500 with a maximum step size of 3000 and maximum travel at 100000.  This appeared to work immediately with M31.  Internal guider calibrated succesfully with a classic L pattern and guided with an error <2" RMS. The guider drift pattern was centered symmetrically on the plot with tight 2" pattern.  This is different from last evening where the guiding looked erratic at times...and significant drifts were visible even during the short 10s focuser collections (wind?).  Similar to last night, the Svbony SV405cc camera was steady at -3.5C without the cooler running.

Seeing forecast from cleardarkskies for 12/02 - 03/2024 showing outstanding conditions..with the usual exception of seeing.

Seeing forecast for 12/02-03 from meteoblue also showing enviable skies for the NCR with the exception of seeing.

12/06/2024 -- Additional session for M31 mosaic.  While near 30%, the moon set at 22:07 freeing the sky for broadband imaging with an additional set of captures for the M31 mosaic.  Sadly, clouds are forecast near 1am which may limit opportunity for collection. Temperatures dip in the 20's, so still no need for a cooler.  Uncovered the scope and checked polar alignment (~40"). Adjusted to below 10" in PHD2 running on the odroid XU4.   Focuser (using the LX10 zero shift microfocus module) succeeded after 11 iterations.  Guider internal calibration was immediately successful. Guider errors started around 1.3" RMS.  Indi Allsky background camera pseudo sky quality values started near 5200 and dropped to 4900 by 24:00.  

Noted that the date and time on the Odroid XU4 is badly off (by 2.5 days in the past).  Attempted to reset the NTP client and sychronize the clock -- but oddly initial attempts with timedatectl and reconfiguring and resetting timesyncd failed.  Similar settings in ubuntu on the Indi Allsky camera raspberry pi produce working NTP synchronization. But FITS files saved by the local indiserver instance have the incorrect time stamp and the DATE-OBS FITS parameter is also unfortunately off.

Seeing forecast for 12/06-07 showing clouds near 1am.

Seeing forecast from meteoblue for 12/06-07 with similar prediction.

12/08/2024  -- Skies started out clear this evening, but the moon is at 40% and is up high in the sky... which is less than optimal for broadband imaging.  However, configured the scheduler to start M31 before clouds move in around 22:00-23:00.  Amazingly, the scheduler did run automatically...and the focuser, alignment (plate solving) and guiding all functioned successfully.  Warmer temperatures did mean setting up the cooler before taking off at 17:00...to have the camera down to 0C by the start of the scheduler jobs (18:24-ish).  

Discovered Indi-Ekos busy collecting light frames when double-checked at 22:00 and four of the six panels in the mosaic had been collected already.  The internal guider showed RMS errors of ~2" with reasonably tight patterns nearly equally distributed in DEC and RA.

Clouds started rolling in around 23:00 and the scheduler was stopped and light frames transferred from the odroid XU4.