Xagyl Filter Wheel Testing

04/01/2025 - Configured a new (to me) 8-position 1.25" Xagyl filter wheel successfully on the venerable LX10.  The Starizona SCT Corrector III is inserted into the Meade zero-shift micro focuser and then there's spacing for proper back focus to the Svbony 405cc (including the 17mm width of the new filter wheel). 

Due to the moon, set up the scheduler to capture a set of light frames of M106 using the dual narrow band (Ha/OIII) filter first followed by a set of light frames using the UV/IR filter.  

The key configuration test was setting up the plate solver and auto focus module to utilize the UV/IR filter during those stages...for collection of light frames with the dual narrow band filter (where these steps are extremely hard through the filter itself.

Conditions started reasonable with no clouds but the moon at 23% and setting at midnight...but clouds expected near 03:00.  Set up the dual narrow band (mislabeled H_Alpha) first with 120s exposures 

Seeing forecast for 04/01 - 02/2025 showing arrival of clouds after 03:00 and the moon phase at 23% with the moon setting just after midnight.

Indi Allsky backyard camera for 04/01-02/2025 showing reasonable skies (pseudo sky quality metric of ~5500) until 03:25 when clouds rolled in.

04/02/2025 - Configured calibration frames for the dual narrow band (mislabeled H_Alpha) and UV/IR light frames. Captured the dual narrow band filter flat and dark flat frames at 20 seconds at gain of 285 and offset 24. Captured UV/IR flat and dark flat frames with 8 second exposure with gain of 185 and offset 24. Finished with bias frames at each gain setting.

M106 with a mix of broadband (UV/IR filter) 56x60s light frames and dual narrow-band (Ha/OIII) 41x120s light frames using the Xagyl filter wheel to enable focusing and plate solving with the UV/IR broadband filter and light frame collection with each, respectively.

4/16/2025 -- Additional collection on M106.  Cleaned the front of the corrector plate...lots of pollen. No clouds, moon rises at 23:47 at 85% (but doesn't rise above 22 degrees...according to Indi Allsky backyard camera metrics)... so starting with wide band (UV/IR) filter and switching to dual narrow band after 00:30.  Initial polar alignment off by 6'... moved from high to low by 1.5 tic marks... slight over correction at -2.6'. Took up backlash and moved from low to high by ~1 tick. Called it good.  

Set up the scheduler to start with 60s UV/IR broad band light frames at 0C, gain 285, offset 24 until 00:30 then switch to 120s with dual narrow band filter (Ha/OIII) which is labeled Ha.  Jobs started at ~22:00.  Wind was mild (1-4 mph via weewx) and the Indi Allsky background camera showed pseudo sky quality value steady at ~5900.

Seeing forecast from meteoblue for 04/16-17 2025 showing the moon rise at 23:47 at 89%, no clouds, poor seeing (as always).

Seeing forecast from cleardarksky with similar metrics for 04/16-17/2025..and confirming results from the Indi Allsky Backyard camera showing the the moon didn't play much of a role until later in the morning of 04/17 with impact to the darkness forecast.

Indi Allsky Backyard camera pseudo sky quality metric and star count (although impacted by a tree branch in the FOV leading to some false star detections). Shows remarkably stable skies throughout the morning from 01:00 to 05:00.

Weewx weather station (sitting beside the mount) showing no significant wind gusts and temperatures above the dew point all night for 04/16-04/17/2025.

Indi Ekos Analysis graphs for collection using UV/IR filter (through 00:30) and the dual narrowband (Ha/OIII) from 00:30 through 04:18. Suggests reduced SNR after 03:20 and poorer guiding after 02:44.

04/17/2025 -- Collected calibration files for the collection on 04/16/2025 because the SCT corrector plate was covered in pollen and was cleaned before collection began.  Set up flats with the LCD panel, added an additional filter onto the stack of neutral density films to bring the ADU count down to ~30,000 (still too high) with the LCD panel on the lowest brightness...and the whole stack covered with a seat cushion (bright sunlight mid day). Set temperature at 8C, gain at 125, offset at 24 with the broadband UV / IR filter for 30x8s flats.  Collected flat frames with the dual narrow band filter (Ha/OIII) with 30x8s using gain of 285 and offset 24. These had much better peak ADU values (~7500). Collected corresponding dark flat and bias calibration files for each gain setting.

04/26/25 -- no clouds...no moon (until after 05:00 in the morning)...but high winds.  Attempting broadband collection on M106, but weewx weather station beside the mount reports wind gusts of 6-8mph.  Started a drift alignment in PHD2 and found significant polar alignment error (8.25'). After on adjustment from high to low by ~1 tick mark, polar alignment error dropped in half to ~4.23'.  A second adjustment from high to low by less than a tick mark. This ground the polar alignment error down to ~0.2'. Noted Indi Allsky backyard camera showed a pseudo sky quality metric of ~5100.  Configured & launched a job in the scheduler for M106 using the UV/IR filter, the Svbony 405cc cooled to 0C, gain set to 285, offset of 24 with 60s light frames.  Sadly, the output directory was not created and Kstars crashed with no frames collected.  :<  Collected several light frames from NGC6888 at 04:25 when skies were remarkably clear with a pseudo sky quality metric of 4130, but winds remained at 2.77mph with 4mph gusts, and guiding performance was exceptionally poor (above 3.5") and so stars were not round. 

Seeing forecast for 04/26-27/2025 by meteoblue showing no moon and no clouds.

Seeing forecast by cleardkarsky for 04/26-27/2025 with no clouds, dark skies, and bad seeing predicted.

04/27/2025 -- no moon, no clouds -- collecting broadband light frames for M106 and NGC6888. Set up the scheduler to collect M106 until 01:30 then switch to NGC 6888...all with the UV/IR cut filter only. The wind is gone...and the initial guiding results look far better with total RMS of ~1.3". Indi allsky backyard camera pseudo sky quality metrics were at 4550 at 23:12...which is a reasonable value for this area.

Seeing forecast for 04/26-28/2025 from meteoblue with minimal clouds and no moon until 06:24.

Seeing forecast for 04/27-28/2025 from cleardarkskies confirming dark skies and no clouds.

Weewx plot of wind and wind gusts from the AcuRite Notos (3-in-1) Weather Sensor installed by the mount showing wind continuing through all of last night (04/26) but tapering off for 04/27.

Ultimately, a large number of M106 light frames were collected (150x60s for M106, 10x60s for NGC6888). 

04/28/2025 -- some clouds, no moon.  Additional collection against M106 and NGC6888.  Set up both jobs in the scheduler and launched it at 21:30.  The scheduler started collection at 21:41.  The indi Allsky backyard camera showed a pseudo sky quality metric of 5800 (steady) which is not great... with the moon at 3% and just below the horizon.  The weewx backyard anemometer, temperature and humidity sensor shows no wind but temperatures higher at 61F.  Camera working harder to get to 0C (41% power on the chiller).  The scheduler cycled through focusing (5 iterations), plate solving (2 collections...nailed it) and guider calibration (beautiful "L" design) quickly... with collection of light frames starting only 6 minutes after the scheduler launched.  Yay!  First M106 light frame had nice, small, round starts with the bright core of the galaxy looking sharp.  Sadly, there are some dust spots on the (mirror? primary? secondary?) visible in the light frames as donuts. Had cleaned the corrector (lots of pollen) yesterday afternoon.

Seeing forecast from meteoblue for 04/28-29/2025 showing high level clouds starting after midnight.

Seeing forecast for 04/28/29/2025 from cleardarkskies showing the European model agrees with meteoblue.

05/09/2025 - no wind and no clouds, but still fairly hopeless with a full moon high in the sky. Attempting some dual narrow band (Ha/OIII) collection against M94 "Cat's Eye Galaxy" just for fun...since the telescope hasn't moved in over a week with rain and clouds.  Suffered a problem with the focus module in Indi / Ekos changing to H_Alpha when the UV/IR filter was initially set in the window. Submitted a question in the Indi forum to see if a default can be saved.  Had not double checked the polar alignment, and found some elevated errors when guiding in the Dec axis. RMS guide errors varied widely with some as low as 1.29".  By 23:51, noted the Indi allsky backyard camera was recording a pseudo sky quality metric (in moon mode at 75% gain) of over 16,500...which is hella bad (with 4000 being good).

Seeing forecast for 05/09-10/2025 from meteoblue showing poor seeing, no clouds, big moon.

Seeing forecast from cleardarksky shows similar trends.

05/31/2025 - No clouds, minimal moon...  Experiencing a (hopefully software) problem with the Shoestring Astronomy FCUSB driver for the Meade zeroshift focuser where the Indi driver crashes once KStars connects due to a mismatched parameter. Submitted a report on the forum.  Set up NGC 6888 (Crescent Nebula) with UV/IR broadband collection near 00:20.  Winds were gusty early in the evening, but appear to have calmed a bit.

Seeing forecast from meteoblue for 05/31/2025 showing few clouds and minimal moon.

Seeing forecast from cleardarksky with similar predictions.

Indi allsky backyard camera pseudo sky quality metric (top plot) near 4200 around 00:20 (very good conditions) with star counts climbing in the lower plot.

06/02/2025 - Poor skies (smoke, moon) so jus testing guiding after re-balancing the mount and performing a polar drift alignment (with PHD2 reporting near 0" alignment error). Sadly, when the job launched from the scheduler, it make repeated attempts to collect against NGC 6888 from 01:00 through 03:00 with each collect aborted with poor RMS guide errors. Only one light frame collected all night. Nothing really lost (due to exceptionally poor skies), but still disappointing. Pseudo sky quality metric started at 23:00 at 39,000 and trended down to 24,000 by 01:17 when the moon set. By 03:00, the sky quality metric had fallen down to 4500 (which is fair).

06/03/2025 - Somewhat better skies (pseudo sky quality metric of ~17,000 at 23:15), but even worse moon.  So tonight just trying to diagnose why guiding is failing.  

Seeing forecast for 06/03-04/2025 from meteoblue showing lots of moon but few clouds.

Seeing forecast from cleardarkskies with a similar prediction.

Set up the scheduler for M106 and guiding immediately failed.  Opened up PHD2 to test guiding...and it complained about RA guide errors...possible ST4 cable issue or cable drag, etc.  Attempted a calibration on PHD2...which succeeded.  Guiding then commenced...and ultimately settled to RMS error of ~0.98" in RA and 0.39" in DEC (an outstanding result).  This suggests a problem in the configuration of the internal guider in Indi/Ekos.  Several severe RA upsets occurred leading to a loss of guiding. PHD2 pulled the guide star back in each time... but these would have had significant impacts on a light frame. This all suggests a cabling problem or possibly intermittent wind gusts.  Examined the mount, found cables caught on one of the feet on the mount...bad strain on motors, etc. Cleared this up and re-bundled the cables to try and make this more straight forward.  Launched the scheduler using the internal guider. Sadly, this did not calibrate and no light frames were recorded overnight. The guide camera was pulled from the 9X50 RACI guide scope.

PHD2 guide plot from 06/03 illustrating good guiding errors in RA and DEC.

06/11/2025 - Guiding test after rewiring...  With the moon at 98%+ and high in the night sky, little hope of clean collection.  However, rewired the Zwo ASI120MC-S, Svbony SV405cc and the Xagyl filter wheel onto a USB3 four-port hub stuck onto the filter wheel (rubber bands) to move from four dangling cables down to two (since the focuser uses its own thin wire that's not USB).  Within PHD2 a recalibration was required due to this change. 

Seeing forecast for 06/11-12/2025 showing high level clouds predicted after 01:00 and massive moon.

Afterwards, polar drift alignment was brought down to 1.5' or so. M57 (the Ring Nebula) is small for this setup (with the Starizona SCT Corrector III at ~0.63x), but to test guiding and imaging performance it's fine. Set up the scheduler for M56 using 100s exposure with the camera cooler set to 5C (given higher ambient temperatures). Guiding errors were huge (12-15") with the internal guider...switched to PHD2...but did not see any immediate improvement.  Weewx showed no wind.  Tried to re-calibrate with PHD2 and try again.  Using PHD2, guide errors stayed below 2" and 80x100s light frames at 5C were collected. Sadly, Indi/Ekos/KStars is still suffering from the bug where the Shoestring Astronomy FCUSB driver is crashing (although additional bug reports are being filed) and so initial focus was good...but clearly off by the end of the collection at 03:02. Scheduler ended due to the twilight constraint at 03:13 and the mount parked successfully and the camera chiller turned off.

Analytical plot from Astro Pixel Processor for the light frames stacked for M57.

A very out of focus result for M57 (due to the Shoestring Astronomy FCUSB focus driver bug in Kstars/Indi/Ekos as the moment).  While disappointing, the guide data showed significant improvement over prior captures using the PHD2 external guider.

06/22/2025 -- While the moon is not an issue, marginal sky conditions for most the the night due to clouds.  Tomorrow predicted to improve, so setting up the scope, aligning and testing on NGC 6888 (Crescent Nebula). Indi All Sky backyard camera pseudo sky quality metric is suggesting modest results with a value of ~5600 at 00:28 (with 4000 being excellent skies). 

Seeing forecast for 06/22-23 from meteoblue suggesting cloud issues through 01:00.

A rosier forecast from clear dark skies suggesting no real issues for 06/22-23.

Overnight 53 light frames were captured successfully.  The analysis tab in Ekos showed intermittent guiding failures (RMS>2") over the period from 01:30 until 03:13.

06/23/25 - Improved skies (maybe) and almost no moon.  Although likely a good night to continue collection on NGC 6888 with the UV/IR filter, stuck with the dual narrowband filter for now given Indi Allsky backyard camera .

Seeing forecast for 06/23-24 from cleardarksky where the European model suggests lots of clouds (but skies at 22:00 are clear outside?)

Seeing forecast for 06/23-24 from meteoblue suggesting some clouds at mid- and high altitude near midnight and again near 02:00. Good seeing is predicted however (high pressure heat dome effect?).

Noted that NGC 6888 comes above the trees a bit later... started the scheduler with M57 - the Ring Nebula. Set up the scheduler to collect M57 through 01:00, then switch to NGC 6888 until 03:30ish.  Ultimately over 50 light frames of each were successfully collected with just a few drop-outs due to exceeding the 2" RMS guide error. Note: did not take the time to recheck focus for this evening (due to similar temperatures at 06/22...which may have been a mistake since the Meade Zero-shift focus driver is still not working on Indi.  :<

KStars/Ekos Analysis tab for the M57 collection (left side early in the evening) and NGC 6888 collection in the early AM illustrating reasonable guiding all night with just a few drop-outs from guide errors.

06/24/25 - High pressure heat dome remains...83F at 22:05... no moon and modest low and mid-level clouds expected. Tested polar alignment error...which remained blissfully low at 1.46' after several minutes of guiding. Examining focus with M5. Initial 100s light frame through the dual narrow band filter looked reasonable...but a little off. Made a very small adjustment with the main mirror focus knob (slight turn counter clockwise) for a noticable but not huge improvement.  Called it good.  For fun, duplicated this with a 60s collect with the UV/IR filter to see if there's a noticeable difference in focus.  Result looked similar...no major difference noted in M 5.  Set up the scheduler to collect M 5 with UV/IR (20x60s) from 22:20-23:30 and then M 57 until 01:30 and then NGC 6888 until 03:45.  At 22:20 the Indi Allsky backyard camera pseudo sky quality metric had dropped to 5822.