David's Astronomy - Notes 2025-11-30 (S1381)

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Notes - Session 1381 (2025-11-30)

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	Session Aims & Highlights
	- Observing Result - Night Summary Plot - Session Event Log

	Operational Issues
	- Critical Issues (0), Major Issues (0), Minor Issues (2), Small Defects (1), Continuous Improvement (3)
	- Figures (1)

	Images from 2025-11-30 >>

Session Aims & Highlights (2025-11-30)

Main aims

Targets. Acquire images of a selection of variable stars, nearby stars, comets & deep sky targets as allowed by sky conditions.
AstroMain - Check fixes added to AstroMain 3.78.9 for fixing issue with failed telescope slews and Dome Reconnection after a Dome Restart.

Equipment & Software

12" LX200 and ST-10XME
80mm APO and ZWO ASI 178MC
TheSky6 6.0.0.65, CCDSoft 5.00.201, DeviceHub 7.1.0.4707, MeadeGeneric 1.3.12.522, UPB 3, Pulsar Dome Firmware 1.51 & Driver 6.3.10
Pegasus-UI 2.10, Peg-Focuser 2.10, Peg-Switch 2.10, TCF-LSI 3.3.5
SharpCap 3.2, PHD2 2.6.13, Siril 1.0.6, deCONZ 1.18.2, ASCOM 7.1.0.4707
[ DomeLink 1.0 / 1.1 - not used ]
AstroMain 3.78.11 / 3.78.12, AstroPlan 1.44, AstroShCap 1.3.16, AstroGuard 1.12 (1.12.1 ?) (any new items or versions in bold)
AstroMag 1.5.12, AstroVOE 1.15.1, AstroSN 1.14, AstroProtect 1.10.6, AstroMove 1.17.1
AstroWeather 1.29.2, AstroAllSky 3.26.2, AstroObsCam 1.12.2, AstroNorthCam 1.7.4, AstroLaunch 1.14.3

Highlights

Targets. 12/48 planned targets were completed, with a further 2 targets partially completed. Other planned targets failed due to cloud / session suspension or cancellation due to early finish of the session (due to forecast rain).
CCD Camera. There were no isues with the CCD Camera
Dome. No issues open/closing shutter. Dome was successfully parked at the end of the session

NotesNotes

Summary Plots & Logs

Observing Plan

Observing Result

Dome & Scope Slewing Performance

Slew/Centering Performance

Guiding Performance

Sky Conditions (Locate Frames)

Night Sky Summary Plot
Top axis: Sky Brightness at Zenith (in ADU/s)
Lefthand axis: Local Time (hh LT). Righthand axis: Sun Altitude (degs)
Note: The NorthCam Star Count line is unreliable and should be ignored
(The AstroNorthCam 'Find' Star method is producing many false positives from clouds)

Actual Weather vs Pre-Session Weather Forecast

Session Event Log

Time	Event	Detail
16:12:35	Session Monitoring	AutoStart monitoring for Live Session opportunity between 16:20 & 06:23
16:12:39	AutoStart Waiting	AutoStart waiting till earliest start time at 16:20
16:21:00	AutoStart Delayed	Session delayed due to too few stars
16:50:48	Session AutoStarting	Session autostarting (16:50)
16:51:00	CCDSoft Restarting	CCDSoft being restarted (to set AutoSave No.)
16:51:15	Session Created	Session Created (Live, 2025-11-30 S01381, ImageSaveNum: 1381001)
16:51:23	Scope Switched On	Telescope Power has been switched on via UPB Switch
16:53:06	Services Started	Observatory Services started
16:53:17	Observatory (Auto)	Observatory placed in Fully-Automated Mode
16:53:19	AutoStart Delayed	Session delayed due to too few stars
16:53:21	Session Pending	Session pending (2025-11-30)
16:53:23	Session Initiating	Session initiating (2025-11-30)
16:53:39	Camera1 Connected	SBIG Camera connected (Set point -25°C)
16:53:47	Plan Requested	Observing Plan requested from AstroPlan (1.44.1)
16:54:39	Plan Loaded	Observing Plan loaded to queue (Plan ID: 1168)
16:55:19	Telescope Connected	Telescope connected (TheSky6)
16:55:43	Session Equilibration	Session ready to Open Dome
16:56:48	Wait On Weather	Waiting for acceptable conditions
16:56:50	Session Suspending	Session suspending
16:56:52	Dome Closed	Dome already closed
16:56:54	Session Suspended	Session suspended
16:57:20	Queue Started	Observing Queue started (48 targets selected)
17:03:59	Session Resuming	Session resuming
17:04:44	Dome Opened	Dome opened (Opening time 45s, Zigbee 41s)
17:04:45	Session Running	Session running
17:04:48	Queue Resumed	Observing Queue resumed
17:04:49	Target Started (1/48)	Target started (1/48, GCVS BL Lac)
17:05:05	Dome Unparked	Dome unparked
17:07:21	Focusing Started-Foc2	Foc2 Focusing Started (Secondary Scope, using ShCap)
17:09:24	Focusing Completed	Foc2 AutoFocus Completed (Profile No 1, wide)
17:11:11	Focusing Completed	Foc2 AutoFocus Completed (Profile No 1)
17:13:02	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
17:16:01	Focusing Completed	Foc1 AutoFocus Completed (Profile No 2, wide)
17:18:15	Focusing Completed	Foc1 AutoFocus Completed (Profile No 2)
17:22:06	Target Completed	Target completed (1/48, GCVS BL Lac)
17:22:10	Target Started (2/48)	Target started (2/48, Nova Ser 2025)
17:26:13	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
17:28:57	Focusing Completed	Foc1 AutoFocus Completed (Profile No 3)
17:36:07	Target Completed	Target completed (2/48, Nova Ser 2025)
17:36:10	Focuser1	Focuser1 (TCF-LSI) not accessible (Last valid data at 17:35:47)
17:36:11	Target Started (3/48)	Target started (3/48, CGCG 250-013 w/SN2023jf)
17:39:49	Focusing Skipped	Foc1 focusing skipped - star is too dim (TCF-LSI)
17:55:56	Target Completed	Target completed (3/48, CGCG 250-013 w/SN2023jf)
17:56:00	Target Started (4/48)	Target started (4/48, LEDA 68428 w/SN2025acqv)
17:59:54	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
18:02:40	Focusing Completed	Foc1 AutoFocus Completed (Profile No 4)
18:19:20	Target Completed	Target completed (4/48, LEDA 68428 w/SN2025acqv)
18:19:25	Target Started (5/48)	Target started (5/48, GCVS CY Lyr)
18:22:42	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
18:24:55	Focusing Completed	Foc1 AutoFocus Completed (Profile No 5)
18:28:45	Target Completed	Target completed (5/48, GCVS CY Lyr)
18:28:49	Target Started (6/48)	Target started (6/48, (2) Pallas)
18:32:46	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
18:35:25	Focusing Completed	Foc1 AutoFocus Completed (Profile No 6)
18:38:06	Target Completed	Target completed (6/48, (2) Pallas)
18:38:10	Target Started (7/48)	Target started (7/48, C/2025 T1 (ATLAS))
18:41:20	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
18:43:42	Focusing Completed	Foc1 AutoFocus Completed (Profile No 7)
18:52:54	Target Completed	Target completed (7/48, C/2025 T1 (ATLAS))
18:52:58	Target Started (8/48)	Target started (8/48, AT2024eh (CV))
18:56:06	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
18:58:41	Focusing Completed	Foc1 AutoFocus Completed (Profile No 8)
19:04:45	Target Completed	Target completed (8/48, AT2024eh (CV))
19:04:49	Target Started (9/48)	Target started (9/48, M31 w/Nova M31 2025-11c?)
19:08:29	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
19:11:16	Focusing Completed	Foc1 AutoFocus Completed (Profile No 9)
19:27:52	Target Completed	Target completed (9/48, M31 w/Nova M31 2025-11c?)
19:27:56	Target Started (10/48)	Target started (10/48, GCVS RX And)
19:31:43	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
19:33:59	Focusing Completed	Foc1 AutoFocus Completed (Profile No 10)
19:37:05	Target Completed	Target completed (10/48, GCVS RX And)
19:37:09	Target Started (11/48)	Target started (11/48, GCVS SS Cyg)
19:40:52	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
19:43:14	Focusing Completed	Foc1 AutoFocus Completed (Profile No 11)
19:45:58	SoftSuspend Called	Soft Suspend called due to Deteriorating Conditions (too few stars)
19:46:31	Target Completed	Target completed (11/48, GCVS SS Cyg)
19:46:33	Queue Paused	Queue paused for Session Suspension
19:46:35	Session Suspending	Session suspending
19:47:23	Dome Closed	Dome closed (Closing time 50s, Zigbee 44s)
19:47:24	Session Suspended	Session suspended
19:48:55	User Intervention	User Intervention to abort job queue & switch back to Manual Mode
19:48:57	Queue Aborted	Job Queue aborted
19:48:59	Observatory (Manual)	Observatory placed in Manual Mode
19:49:33	Services Stopped	Observatory Services stopped
19:49:52	Session Closed	Session closed by User
19:49:55	Program Closed	Program closed by User
19:50:35	Program Opened	Program Opened (AstroMain 3.78.12)
19:50:37	Session Resumed	Session Resumed (Live, 2025-11-30 S01381, ImageSaveNum: 1381084)
19:50:41	Obs.Overseer Started	Obs.Overseer started
19:51:13	Obs.Manager Started	Obs.Manager started
19:51:18	Services Started	Observatory Services started
19:51:56	Session Monitoring	AutoStart monitoring for Live Session opportunity between 19:51 & 06:23
19:51:58	Observatory (AutoStart)	Observatory placed in Auto-Start Mode
19:52:01	AutoStart Delayed	Session delayed due to cloud
20:04:20	Session AutoStarting	Session autostarting (20:04)
20:05:08	Services Started	Observatory Services started
20:05:18	Observatory (Auto)	Observatory placed in Fully-Automated Mode
20:05:20	Session Pending	Session pending (2025-11-30)
20:05:22	Session Initiating	Session initiating (2025-11-30)
20:05:32	Camera1 Connected	SBIG Camera connected (Set point -25°C)
20:05:43	Plan Loaded	Observing Plan loaded to queue (Plan ID: 1168)
20:06:25	Telescope Connected	Telescope connected (TheSky6)
20:06:50	Session Equilibration	Session ready to Open Dome
20:07:36	Dome Opened	Dome opened (Opening time 45s, Zigbee 41s)
20:07:37	Session Running	Session running
20:07:40	Queue Started	Observing Queue started (36 targets selected)
20:07:46	Target Started (13/48)	Target started (13/48, AT2025absq)
20:27:41	Target Completed	Target completed (13/48, AT2025absq)
20:27:45	Target Started (14/48)	Target started (14/48, AT2025adhw)
20:32:44	Critical Cloud Alert	Critical Cloud Alert (Obs.Manager will close the Dome)
20:32:46	HardSuspend Called	Hard Suspend called due to Critical Conditions (cloud)
20:32:48	Target Aborted (14/48)	Target aborted (14/48, AT2025adhw) due to cloud
20:32:50	Queue Paused	Queue paused for Session Suspension
20:32:52	Session Suspending	Session suspending
20:33:40	Dome Closed	Dome closed (Closing time 50s, Zigbee 44s)
20:33:41	Session Suspended	Session suspended
20:42:30	Target Cancelled	Target cancelled (14/48, AT2025adhw) due to cloud
21:01:42	Session Resuming	Session resuming
21:02:27	Dome Opened	Dome opened (Opening time 45s, Zigbee 41s)
21:02:29	Session Running	Session running
21:02:31	Queue Resumed	Observing Queue resumed
21:02:33	Target Started (15/48)	Target started (15/48, AT2022xao)
21:07:18	SoftSuspend Called	Soft Suspend called due to Deteriorating Conditions (too few stars)
21:12:16	Target Completed	Target partially completed (15/48, AT2022xao)
21:12:18	Queue Paused	Queue paused for Session Suspension
21:12:20	Session Suspending	Session suspending
21:13:09	Dome Closed	Dome closed (Closing time 50s, Zigbee 43s)
21:13:10	Session Suspended	Session suspended
21:15:13	Session Resuming	Session resuming
21:15:59	Dome Opened	Dome opened (Opening time 45s, Zigbee 41s)
21:16:00	Session Running	Session running
21:16:02	Queue Resumed	Observing Queue resumed
21:16:04	Target Started (16/48)	Target started (16/48, AT2025adxl)
21:20:24	SoftSuspend Called	Soft Suspend called due to Deteriorating Conditions (too few stars)
21:23:34	Critical Cloud Alert	Critical Cloud Alert (Obs.Manager will close the Dome)
21:23:36	HardSuspend Called	Hard Suspend called due to Critical Conditions (cloud)
21:23:38	Target Aborted (16/48)	Target aborted (16/48, AT2025adxl) due to cloud
21:23:40	Queue Paused	Queue paused for Session Suspension
21:23:42	Session Suspending	Session suspending
21:24:29	Dome Closed	Dome closed (Closing time 50s, Zigbee 43s)
21:24:31	Session Suspended	Session suspended
21:26:50	Target Cancelled	Target cancelled (16/48, AT2025adxl) due to cloud
21:39:00	Target Cancelled	Target cancelled (17/48, GCVS FU Ori) due to cloud
21:48:02	Target Cancelled	Target cancelled (18/48, GCVS EV Lac) due to cloud
21:55:38	Target Cancelled	Target cancelled (19/48, Vega) due to cloud
22:09:37	Target Cancelled	Target cancelled (20/48, GCVS RR Lyr) due to cloud
22:17:48	Target Cancelled	Target cancelled (21/48, Vega) due to cloud
22:27:06	Target Cancelled	Target cancelled (22/48, KIC 8462852) due to cloud
22:31:23	Focuser1	Focuser1 (TCF-LSI) not accessible (Last valid data at 22:30:59)
22:47:06	Target Cancelled	Target cancelled (23/48, AT2025abul) due to cloud
23:09:06	Target Cancelled	Target cancelled (24/48, SN 2025aedz) due to cloud
23:20:50	Target Cancelled	Target cancelled (25/48, GCVS TV Cas) due to cloud
23:39:53	Target Cancelled	Target cancelled (26/48, AT2025adxd) due to cloud
00:01:53	Target Cancelled	Target cancelled (27/48, AT2025aefi (CV)) due to cloud
00:15:01	Target Cancelled	Target cancelled (28/48, GCVS RZ LMi) due to cloud
00:31:09	Target Cancelled	Target cancelled (29/48, 24P/Schaumasse) due to cloud
00:46:47	Target Cancelled	Target cancelled (30/48, C/2025 R2 (SWAN)) due to rain
01:06:47	Target Cancelled	Target cancelled (31/48, NGC 5448 w/AT2025aesq) due to cloud
01:29:07	Target Cancelled	Target cancelled (32/48, AT2025acvr (CV)) due to cloud
01:51:07	Target Cancelled	Target cancelled (33/48, SN 2025zry) due to cloud
02:11:30	User Intervention	User request to close and finish session
02:11:32	Queue Aborted	Job Queue aborted
02:11:35	Session Closing	Session closing
02:11:40	Dome Closed	Dome already closed (closed at 21:24, closing time 50s, zigbee 43s)
02:12:15	Dome Parked	Dome parked (parking time 26s), Az: 90.0 deg
02:13:04	Telescope Parked	Telescope parked (parking time 44s total)
02:13:34	Telescope State	Handbox reads 'Scope parked Turn scope off.'
02:13:56	Telescope Switched Off	Telescope Power has been switched off via UPB Switch.
02:13:59	Telescope	Telescope Power has turned on (external to AstroMain
02:15:22	Services Stopped	Night Services stopped
02:15:25	Session Finishing	Session Finishing started (Create Fits Summary, Transfer Files)
02:15:47	Dome (Find Park)	Find Park started (Search Az 88.0 to 92.0°, Step 0.2°, Narrow)
02:16:29	Dome	Find Park found (Best Park Az 90.7°)
02:16:34	Dome	Dome has been synced at park position (Az 90.0°, Adjustment: -0.7°)
02:16:36	Dome Parked	Dome parked
02:16:40	Dome Charging	Dome is parked and re-charging Ok (3mA)
02:16:42	Session Finished	Session Finished

Session Alerts & Alarms

Time	Type		Name	Detail
17:36:10	Red	Alert	Focuser1	Focuser1 (TCF-LSI) not accessible (Last valid data at 17:35:47)
17:36:26	Green	Clear	Focuser1	Focuser1 (TCF-LSI) is accessible again. Outage was 39s
22:31:23	Red	Alert	Focuser1	Focuser1 (TCF-LSI) not accessible (Last valid data at 22:30:59)
22:31:38	Green	Clear	Focuser1	Focuser1 (TCF-LSI) is accessible again. Outage was 39s
02:16:40	Green	Clear	Dome Charging	Dome is parked and re-charging Ok (3mA)

Operational Issues (2025-11-30 S1381)

Critical Issues (0)
Major Issues (0)
Minor Issues (2)
Small Defects (1)
Continuous Improvement (3)
Figures (1)

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Critical Issues

None

Major Issues

None

Minor Issues

RA Rate of Motion reported by 'Get Motion' and 'Title2' button operation in AstroPlan/AstroMain using TheSky6 are incorrect. AstroPlan 1.45 and AstroMain 3.79 and earlier versions report RA rate directly from the TheSky ObjectInfo.Property(skObjInfoProp_RA_RATE_ASPERSEC), using
RaRate = ObjectInfo.Property(skObjInfoProp_RA_RATE_ASPERSEC) * 60 * 60 ' (x 3600 to get arcsec/hr )
From comparison with JPL's Horizon system with expicitly reports RaRate as d(RA)/dt * Cos(Dec), the 'skObjInfoProp_RA_RATE_ASPERSEC' value from TheSky is d(RA)/dt. For C/2025 K1 (ATLAS) at Dec 71.7 Horizon system reports RaRate as -6.8 arcmin/hr, whilst the GetNonSiderealMotion() routine using TheSky6 information was reporting RaRate at -22.1 arc min/hour. Angular displacement of comet over a one hour period measured in virtual sky confirm Ra movement of -6.8 arc min. To calculate Ra Rate in the plane of the sky, TheSky6's RA_RATE_ASPERSEC value needs to be mutiplied by cos(dec). Reporting issue fixed in AstroPlan 1.45.1, AstroMain 3.79.1.
The implication of this historic issue is that all Comet Motion Rates published on Observatory Website have been incorrect to some extent (a smaller or larger extent dependant on Declination of the comet at the time). A retrospective correction to motion rates reported on comet and image web pages will be the subject of a Continuous Improvement ticket. A separate Continuous Improvement to ticket will examine the handling of Rates of Motion for initiating PHD2 LockShifts during guiding for comet and asteroid targets.
To do 2025-12-02 (AstroPlan 1.45.1, AstroMain 3.79.1)
RA Rate of Motion reported after changing target or using 'Title2' button operation in AstroPlan/AstroMain Analysis Tab may be incorrectly reported. AstroMain Image Set workflow will normally 'Image Link' an image within the ImageSet, which sets TheSky6's date/time, and the subsequent use of Title2 when documenting Rate of Motion for a non-sidereal target (such as a comet) will be applicable for the Date/Time of the Imageset. However currently in AstroMain 3.79 and earlier versions if the target is changed (after going to a new session or after changing the active imageset) the initially reported Rate of Motion data is likely to not be valid for the date/time that the image set was acquired. This issue surfaced when starting a COntinuous Improvement ticket to go back and retrospective get corrected RA rate values (due to issue with interpretation of the TheSky6's RA_RATE_ASPERSEC value). Fixed in AstroMain 3.79.1. When an imageset is changed the GetObjectTargetDetails() routine has been modified to update TheSky's Date/Time when the Image.JulianDay is read from the first image in the ImageSet's Reduced folder, using the following call
SetWhenWhere(Image.JulianDay)
To do 2025-12-02 (AstroMain 3.79.1)

Small Defects

AstroAllSky kept crashing with an unhandled 'generic error occurred in GDI+' exception (2025-12-02 00:38 - 01:28) . Multiple AstroAllSky crashes occured during during an hour long period with the same 'System.Runtime.InteropServices.ExternalException - A generic error occurred in GDI+.' exception, all from globals.vb:line 16181. In each case AstroAllSky performed an auto-restart and continued. Investigating showed that code line in AllSkyTakeFrames() routine was a call to frmImage.DrawAllSkyImage_FLIP() routine which writes a 'AllSky.LatestImageFlip.jpg' file. The exceptions coincided with testing of new AstroPlan code on the Development Computer which was using the 'AllSky.LatestImageFlip.jpg' in a plot image routine on the SubmitToO Form. A Try..Catch..End Try block was added around the call to DrawAllSkyImage_FLIP() in AstroAllSky (for future Build) and the routine in AstroMain 3.79.1 was modified to take a copy of the 'AllSky.LatestImageFlip.jpg' before trying to use it.
To do 2025-12-02 (AstroPlan 3.26.3 TBA, AstroPlan 1.45.1)

Continuous Improvement

Modify AstroPlan's Submit ToO Form to optionally show an underlay of the E-W flipped image from AllSky Camera on the virtual AzAlt plot.
Currently in AstroPlan 1.45 and earlier version the AzAlt Plot on the Submit ToO Form is used for illustrating the current and future (2h, 4h) of the target, and the moon (if risen) along with annotated altitude circles, no-go Dec region, and the local horizon. The background is plain white. It is proposed to add an option whereby duirng night time hours the latest E-W flipped image from the AllSky Camera is drawn as an underlay providing an immediatel visual indicator of cloud or clear sky at the potential ToO target location. Implemented in AstroPlan 1.45.1 (see Fig 1). A further enhancement was made on 2025-12-14 (AstroPlan 1.45.5) which rotates the E-W Flipped anticlockwise to make it precisely align with the orthogonal axis used by AzAlt Chart.
Done 2025-12-02 (AstroPlan 1.45.1)

Query: Review how Rate of Motion information from non-sidereal targets is applied in guiding. Autoguiding in AstroMain 3.79 and earlier versions utilises PHD2 LockShift for non-sidereal targets such as comets. Due to an incorrect interpretation of the RA_RATE_ASPERSEC value obtained from TheSky6, the RA Rate of motion used for setting PHD2 lock shift may or may not be correct. It is established (2025-12-02) that the RA_RATE_ASPERSEC from TheSky6 is a 'd(RA)/dt' value. The rate of motion in plane of sky needed for PHD2 Lock Shift needs to be a 'd(RA)/dt * cos(dec)' value. Is a cos(d) factor applied prior to guiding ?, Also, is it applied in the correct direction ? A positive RaRate indicates motion in an Eastward direction ' whilst a negative RaRate indicates motion in a Westward direction. AstroMain setups up and enables PHD2 Lock Shift for comets using from the PHD2.SetShiftLock(RaRate As Double, DecRate As Double) routine which is called by Guider.UsePhd2ShiftLock(T.RaRate, T.DecRate)

  ' Call "Set 
	set_lock_shift_params" method using parameters 
	{"rate":[XRATE,YRATE],"units":UNITS,"axes":AXES} 
  ' 
	-----------------------------------------------------------------------------------------------------------
  
	Params = " ""params"": [{""rate"": [" + CStr(RaRate) + ", " + CStr(DecRate) 
	+ "] ""units"": ""arcsec/hr"", ""axes"": ""RA/Dec""}]"
  
	SendRequest("{""method"": ""set_lock_shift_params"", " + Params + ", ""id"": 
	#ID}", Response, "result", Result)

  ' Set Lock Shift Params
  
	' ----------------------
  SendRequest("{""method"": 
	""set_lock_shift_enabled"", ""params"": [true], ""id"": #ID}", Response, 
	"result", Result)

Fixed in AstroMain 3.79.1. RaRate changed to a 'd(RA)/dt * cos(Dec)' value in LookupRaAndDecRates() and LookupKeyTargetInfo() routines.
Done 2025-12-02 (AstroMain 3.79.1)

Rate of Motion Information posted against non-sidereal object observations on Observatory WebSite need to be corrected. Due to an incorrect interpretation of the RA_RATE_ASPERSEC value obtained from TheSky6, the RA Rate of motion (and therefore also the Overall Rate of motion) of non-sidereal targets reported on the Observatory Website are incorrect to some extent (this is a smaller or larger extent dependant on the Declination of the target object at the time). It is established (2025-12-02) that the RA_RATE_ASPERSEC is a 'd(RA)/dt' value. The rate of motion in plane of sky used in reporting needs to be a 'd(RA)/dt * cos(dec)'. Whilst corrected point-forward, the rates of motion stated on historic web pages, principally Comet and Session Image pages need to be retrospectively calculated and the web pages updated with correct values.This is long task, and will begin with recent 2025 pages, and then work back in time.
Update 2025-12-02 - Completed RA rate correction on sessions back to S1370 (2025-10-27) - lots to go !
To do 2025-12-30 (WebPages)

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Fig 1. New AllSky Underlay Option on AstroPlan's Submit ToO Form

AzAlt Plan plot for C/2025 T1 (ATLAS) - normal view (left), and with AllSky underlay (right)

An enhancement was ladded later to rotate the AllSky E-W Flipped image by -1.07° to align it precisely with the axis used by the AzAlt Chart. Despite this differences between the local horizon used on the AzAlt Chart and that shown in the AllSky image are apparent particular the gable ends of the house in east diretcion, however this is explained by the offset between the Telescope Viewpoint and the AllSky Camera View point which are separted by around 2.5m.

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This Web Page:	Notes - Session 1381 (2025-11-30)
Last Updated :	2025-12-14
Site Owner :	David Richards
Home Page :	David's Astronomy Web Site

David's Astronomy Pages Notes - Session 1381 (2025-11-30)

Session Aims & Highlights (2025-11-30)

Operational Issues (2025-11-30 S1381)

David's Astronomy Pages
Notes - Session 1381 (2025-11-30)