NGC 3184 / M94

 3/8/2026 -- Clouds are gradually clearing out and the moon is not set to rise until after midnight...so working to capture light frames from a well-positioned galaxy -- NGC 3184.  Checked polar alignment with PHD2 running on the Odroid C4...drift alignment showed near 0 error (after an extended period of drifting).  Due to sudden heat wave (to 70F), manually adjusted the focus (turned primary mirror focus knob left 1/2 turn, total). 


Seeing forecast for 03/08-09/2026 from meteoblue (top) and cleardarksky (bottom) suggesting clearing skies through midnight...with the moon appearing after 00:49.

Set up the scheduler with NGC 3184 collecting UV/IR light frames through 01:35 and M94 collecting until 05:45.  Set the chiller on the Sv405cc to 0C to match existing calibration frames but also since the temperature is predicted to fall to 45F overnight.

Overnight, 80x80s NGC 3184 light frames and 59x80s M94 light frames were collected.  After a lengthy (30 minute) pause from meridian flip confusion (?), the external (PHD2) guider was not started at the beginning of the M94 collection (started with the second run through 20x80s light frames) and so light frames 001 through 20 are unguided (likely unusable..especially just after a dither). 

Ekos Analyze tab for collection on 03/08-09/2026 for both NGC 3184 (early, on the left) and M 94 (later, on the right).  Illustrates a significant gap in collection from 01:00 to 01:35 where the scheduler / sequence was paused considering a meridian flip (marked completed at 01:35:22).  Additionally, after M 94 started at 01:35;03, the external autoguider (PHD2) was not automatically started...resulting in M 94 light frames from 1 to 20 being unguided.


Overnight measurements from the Indi allsky backyard camera including pseudo sky quality (top) and star count (bottom). The large discontinuing after 01:01:15 in the top plot stems from the start of "moon" mode after the moon rose and camera gain is updated.  Both plots suggest almost no clouds overnight.  Overall pseudo sky quality metrics before moon rise approach excellent skies (~4800 where 4000 is excellent skies over DC suburbs).
Weather conditions overnight (wind, temperature, transparency) were excellent with almost no clouds or wind.  


Weewx outdoor weather station measurements for 03/08-09/2026 showing temperatures above freezing (low ~40F) and no wind overnight.

03/09/2026 - Additional cloud-free evening.  Repeated the scheduler with collection beginning at ~21:00 for NGC 3184.  External PHD2 guide errors remain low (<1.5" RMS).  Surprisingly, the focus was not significantly off ... and little correction in the autofocus tab was made (despite large temperature swings during the day to the evening).   The Indi allsky backyard camera pseudo sky quality metric showed 5814 at 21:30 (not bad for this time of evening).  


Seeing forecast for 03/09-10/2026 for meteoblue (top) and cleardarksky (bottom) suggesting nearly cloud-free collection through 04:00.  Moon rise at 01:50...providing ample no-moon collection opportunity for NGC 3184.

Ultimately, 93x80s NGC 3184 UV/IR light frames were collected from 21:08 through 00:24. In addition, 39x80s M 94 UV/IR light frames were collected between 01:50 and 03:05.  Similar to the collection on 03/08-09, the meridian flip planning between these two jobs took a significant amount of time (an hour).  Unclear why the scheduler / sequence tool in Ekos pauses.   Additionally, collection ended at 03:05 when the scheduler (bizarrely) again switched to "MOUNT_FLIP_PLANNED" status with the scheduler shutting down the mount (and warning the camera via the shutdown script) at 05:27.

The median sky value in the Analyze tab as well as the Indi Allsky backyard camera illustrate clouds went through the scene starting near 03:00.  The Weewx weather station showed no appreciable wind or gusts during collection.

Ekos Analyze tab for collection on NGC 3184 and then M 94 spanning 03/09-10/2026 showing repeated problems where the scheduler / sequence tool was oddly stuck on mount flip planning. Overall external guider (PHD2) errors were relatively consistent < 1.5" RMS.  Clouds are evident towards the end of collection after 02:30 (mirrored in the Indi Allsky results).


Indi Allsky backyard camera measurements for 03/09-10/2026 showing the moon rise after 02:00 and the entrance of clouds starting around 03:00.  Pseudo sky quality metric in red (top) and star count in white (bottom).


Weewx backyard weather station measurements for 03/09-10/2026 showing moderate temperatures well above freezing and no measurable wind or gusts during the collection window.

03/10/2026 - At least a partial night without clouds... repeating the scheduler a third night.  Dinosaur documentary on Netflix intervened and I didn't check on the mount until nearly 22:00.  Sadly, the scheduler was stuck...not launching the job.  Stopped and restarted the scheduler...and it was off.  Odd. The Indi Allsky backyard camera shows a marginal pseudo sky quality metric of ~7000 (dropping down to ~5900 by 23:20).  Clouds expected near 03:00...and rain expected late morning.


Seeing forecast for 03/10-11/2026 from meteoblue (top) and cleardarksky (bottom) suggesting relatively clear skies until midnight...then increasing cloudiness...especially after 03:00.

Overnight, 87x80s light frames for NGC 3184 and 40x80s light frames were M 94 were collected.  These had originally been mistakenly saved in the 20260308 folder and were separated out to 20260310 when transferred.


03/12/2026 - Clear skies (early) and no moon until 04:26... restarted the scheduler once again.  With mid-level clouds expected at 01:00, it will be interesting to see how accurate the prediction from meteoblue is for Maryland weather is overnight. The revived cleardarknight site shows no clouds on either model.

Seeing forecast from meteoblue (top) and cleardarksky (bottom) for 03/12-13/2026 with mixed messages about mid-level clouds.
Ultimately, overnight 60x80s light frames for NGC 3184 and 124x80s light frames from M 94 were collected.  The Analyze tab highlights an hour block of time in the middle of the NGC 3184 collection where the outdoor temperature dropped below 0C...and the sequencer was waiting until the Sv405cc chiller brought the temperature (nominally down) to 0C.  Turned off the temperature requirement, which means light frames were collected with the temperature slightly below 0C overnight. 

Note an extended time at the start of M 94 collection (shown in the Analyze tab) where the external PHD2 guider was not running (right around 01:40 for nearly 30 minutes).  An additional block of time was unguided for M 94 near the middle of the collection (~02:40?).  These light frames should be double checked for large elliptical stars.

Ekos Analyze tab for collection over 03/12-13/2026 for NGC 3184 (from ~21:40 to midnight) and then M 94 (from ~01:35 until ~05:20).



Weewx outdoor weather station readings for 03/12-13/2026 showing a few instances of light wind until midnight with outdoor temperatures dipping below 30F overnight.


Indi Allsky backyard sky camera measurements for 03/12-13/2026. Star count (top, white) and pseudo sky quality metric (bottom, red) suggesting several cloud belts went over between ~04:00 and 05:00.

03/13/2026 -- marginal skies expected...with some low and mid-level clouds predicted by meteoblue... but no moon until after 05:00... and so set off the scheduler once again with hopes of getting some light frames between clouds.  The Indi Allsky backyard camera shows reasonable (but not great) pseudo sky quality metric values of ~7200 at 20:30 dropping to ~6100 at 22:30.  Intermittent winds continued, causing problems for focusing and guiding.


Seeing forecast for 03/13-14/2026 from meteoblue (top) and cleardarksky (bottom) suggesting potentially poorer skies due to some low to mid-level clouds.

03/17/2026 - Cold temps, no moon (at all...0%) and relatively clear skies. 


Seeing forecast for 03/17-18/2026 from meteoblue (top) and cleardarkskies (bottom) showing no moon and no clouds until ~04:00.

Encountered a serious problem with the Celestron CGEM DX mount... the hand controller backlight turned on when the mount was switched on...but no text.  Tried adjusting hand controller cable (and extension cable connectors) and briefly saw 'initializing'... then the backlight...everything on the hand controller went dark.  :<  After bringing the hand controller and extension cable inside, immediately noted corrosion in the extension female-to-female connector / adapter.  An entire conductor was broken off (copper oxidation).  Replaced this temporarily with an ethernet female-to-female adapter (which, remarkably, worked...since it actually has additional conductors inside compared to the RJ12 6P6C on the hand controller cable).  Ordered a compatible extension cable from Amazon (3m...which means the coupler can stay inside the telescope enclosure case with the Odroid, Shoestring Astronomy controller, etc. so no future issues). Finally restarted the mount at ~23:00.  

Slewed to alpha Sextantis for a polar alignment check.  Immediately found the alignment tab showed a completely dark image.  Cycled through the filters...selecting the dual narrow band (slot 2) then the UV/IR (slot 1). This fixed the problem.  Then manually focused using the Meade zeroshift focuser since it was a bit far out for auto focusing.   Noted variability in star shape during the focusing...and the Weewx outdoor weather station indeed reported steady 2-3 mph wind with frequent / regular 4-5 mph gusts.

After several minutes of drifting in PHD2, found a polar alignment error of ~-7' (turned to the left). Brought this to ~2.5'.  Started the scheduler for NGC 3184 and M 94.  The sequence tab was configured without the cooler running.  This will result in frames collected with a temperature below 0C and somewhat variable (low temp expected at 22F)...but prefer this than setting the camera to a really low temperature where fresh calibration frames would be needed.

At this point, the Indi Allsky backyard camera showed a pseudo sky quality metric of 5320...which is ok...not great.  This is a bit high for 23:38 and no moon.  The Weewx outdoor weather station reported:

        "time": "2026-03-17T23:35:00-0400",
        "generator": "weewx 5.2.0"
        "temperature": {"value": 29.44444444444444, "units": "°F"},
        "dewpoint": {"value": 10.45854685781084, "units": "°F"},
        "humidity": {"value": 44.407407407407405, "units": "%"},
        "heat index": {"value": 29.44444444444444, "units": "°F"},
        "wind speed": {"value": 2.2962962962962963, "units": "mph"},
        "wind gust": {"value": 6.0, "units": "mph"},
        "wind chill": {"value": 28.34172050255745, "units": "°F"},

Ultimately, only 15x80s light frames were collected from NGC 3184 and only 18x80s light frames were collected from M 94.  Collection was interrupted by a demand for a meridian flip (MERIDIAN_FLIP_WAITING) that lasted nearly 3 hours ... from 02:35 until the scheduler shutdown the system at 05:14.  Despite the fact that MERIDIAN_FLIP_COMPLETED was noted at 02:33.  This process had already played out starting with the first MERIDIAN_FLIP_COMPLETED at 01:16...which was followed by a 40+ minute pause (from 00:02 until 00:44) for MERIDIAN_FLIP_WAITING.  Very odd behavior from either the scheduler, the hand controller or a combination of both.

Ekos Analyze tab for collection over 03/17-18/2026 illustrating 15x80s NGC 3184 light frames and 18x80s M 94 light frames followed by meridian flip for the rest of the night. :<


Indi Allsky backyard camera measurements for 03/17-18/2026 with pseudo sky quality (red, top) and star count (white, bottom) shown. Suggests no clouds until after 04:30 and moderately transparent skies (where a pseudo sky quality value of ~4000 would be very clear for the DMV).


Weewx backyard weather station measurements for 03/17-18/2026 showing temperatures below freezing and some light winds (2-4 mph) persisting most of the night.



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