David's Astronomy - Notes 2021-12-05 (S939)

David's Astronomy Pages
Notes - Session 939 (2021-12-05)

Notes
(S938)

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Notes
(S940)

	Pre-Session

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

	Operational Issues
	- Critical Issues (1), Major Issues (4), Minor Issues (8), Small Defects (1), Continuous Improvement (8)

	Images from 2021-12-05 >> [ Local Files >> ]

	Telescope Maintainance
	Observatory Maintainance
	Attempted remediation of bulge in observatory roof panel

	Session
	Anomalies Opening & Closing Observatory Dome
	Detached Rubber Strip and Dome Not Fully Closing

	2021-12-06
	Observatory Computer Replacement
	New Observatory Computer - Setup & Migration

Session Aims & Highlights (2021-12-05)

Main aims

Targets. Acquire images of a selection of variable stars, nearby stars, comets & deep sky targets as allowed by time & conditions.
Guiding Performance. Review Guiding Performance following rebalancing of scope in Dec.
Wind Exclusion Zone. Test new procedures that create and use a Azimuthal Exclusion Zone to avoid facing telescope into moderate/strong wind.
Shutter Operations. Test new code for managing shutter operations (AstroMain 3.48)
AstroMain 3.48. Test new feature and bug fixes in AstroMain 3.48

Equipment & Software

12" LX200 and ST-10XME
80mm APO and ZWO ASI 178MC
CCDApp2, TheSky6, CCDSoft5, DeviceHub 6.5.1.7, MeadeGeneric 1.3.2.367, UPB 1.5, ASCOM 6.5 SP1
Pegasus UPB & Motor Focus, TCF-S
SharpCap 3.2, PHD2 2.6.10
AstroMain 3.48 / 3.48.1, AstroPlan 1.29, AstroShCap 1.3.12, AstroGuard 1.6.2, AstroVOE 1.9, AstroSN 1.7.1, AstroProtect 1.6
(AstroWeather 1.15, AstroAllSky 3.14, AstroObsCam 1.7.2 AstroLaunch 1.7.2)

Highlights

Targets. x Targets acquired in first part of the night
Wind Exclusion Zone. As per design hourly wind forecast data was used for defining exclusion zones for building the night's observing plan . The effect unfortunately couldn't be tested due to failure of the dome rotation/shutter system and due cloud in the second half of the night
Centering Performance. Guiding performance was fairly poor
Guiding Performance. Guiding performance was mixed.
Shutter Operations. Dome opening / closing operations were anomalous and in one case left the shutter the still partially open when it was meant to have closed.
Rubber Strip. Rubber strip around the inside roof flange became detached and blocked movement of the Dome, causing upset to dome rotation/shutter operations
Observatory Computer. Observatory Computer screen turned completely black before/during session. Computer couldn't be rebooted the following day. Computer is deemed to be dead and requires replacement (Observatory operations will be down for at least the next 5-6 days).

Notes:

Balancing. Telescope was rebalanced in Dec/Altitude before the start of the session.
Short Mapping Job. Although telescope pointing of 'snap' images at commencement of session seemed very good following the necessary release of Dec Clutch during Tube Rebalaning, the Scope was resynced on a starfield and a short mapping run conducted. After which the scope was parked, powered off and then restarted.
Backlash. Dec Anti-Backlash setting in Scope at 85% for first 5 targets but then changed to 75% during Target 6 (M31 w/Transient).
Centering performance was poor and suggests and suggests that an anti-backlash setting of 90-95% would be better

(Whilst a lower value is potentially helpful to fix Dec jumps when changing Dec Guide Mode in PHD2, the lower values definately seem to lead to poorer centering.)

Summary Plots & Logs

Observing Plan

Observing Result

Dome & Scope Slewing Performance

Slew/Centering Performance
Poor centering performance in Dec. One rogue jog.

Guiding Performance
Reasons for poor Dec guiding :

Black point (2)		- cloud/lost star in frames 4 to 7, Black point (15) - dome roof occluding the sky from guidescope
Red points (3 & 4)		- Dec Guide Mode selection & excessive Dec Jumps when changing Dec Guide Mode
Red point (16)		- cloud/lost star in last 3 frames. Orange point (9) - still taking off Dec Backlash during first 2 frames
Yellow point (11)		- excessive Dec jump put star on wrong side for the chosen Guide Mode.
Yellow point (1)		- Scope position not responding well to 'N' guide pulses in first 3 frames
Green points (5, 6, 7, 8, 10, 12, 13, 14)		- guiding good (typical better than RA)

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)

Actual Weather vs Pre-Session Weather Forecast

Session Event Log

Time	Event	Detail
17:05:04	Camera1 Connected	SBIG Camera Connected (set point -25°C)
17:05:06	Session Created	Live Session Created (2021-12-05 S00939, ImageSaveNum: 939001)
17:05:29	Scope Switched On	Telescope Power has been switched on via UPB Powerbox.
17:06:54	Services Started	Observatory Services started
17:07:19	Telescope Connected	Telescope Connected (TheSky6)
17:08:18	Dome Opened	Dome opened (opening time 44s)
17:10:12	Camera1 Connected	SBIG Camera Connected (set point -25°C)
17:12:55	Services Started	Observatory Services started
17:14:59	Automapping Started	Automapping started (12 points planned)
17:27:16	Automapping Completed	Automapping completed (12 points mapped out of 12 points)
17:31:12	Telescope Parked	Telescope parked (parking time 70s)
17:31:27	Telescope State	Scope parked Turn scope off. (Handbox)
17:31:47	Telescope Switched Off	Telescope Power has been switched off via UPB Switch.
17:34:45	Scope Switched On	Telescope Power has been switched on via UPB Powerbox.
17:36:33	Telescope Connected	Telescope Connected (TheSky6)
17:38:54	Observatory (Auto)	Observatory placed in Fully-Automated Mode
17:38:56	Session Pending	Session pending (2021-12-05)
17:38:58	Session Initiating	Session initiating (2021-12-05)
17:39:00	Plan Requested	Observing Plan requested from AstroPlan (1.29)
17:40:14	Plan Loaded	Observing Plan loaded to queue (, Plan ID: 692)
17:40:27	Camera1 Connected	SBIG Camera Connected (set point -25°C)
17:40:33	Telescope Connected	Telescope Connected (TheSky6)
17:41:02	Session Equilibration	Session ready for dome & camera equilibration
17:41:04	Session Running	Session running
17:41:06	Queue Started	Observing Queue started (42 targets selected)
17:41:09	Target Started (NrZen)	Target started (Focus Field 22, HIP 108888)
17:42:53	Focusing Skipped	Foc1 focusing skipped - star is too dim (TCF-S)
17:42:58	Focusing Started-Foc2	Foc2 Focusing Started (Secondary Scope, using ShCap)
17:45:23	Focusing Completed	Foc2 AutoFocus Completed (Profile No 1, wide)
17:47:26	Focusing Completed	Foc2 AutoFocus Completed (Profile No 1)
17:47:47	Target Completed	Target completed (Focus Field 22, HIP 108888)
17:53:04	Target Started (1/42)	Target started (1/42, C/2017 K2 (PANSTARRS))
17:58:04	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
18:00:56	Focusing Completed	Foc1 AutoFocus Completed (Profile No 2, wide)
18:03:10	Focusing Completed	Foc1 AutoFocus Completed (Profile No 2)
18:12:12	Target Completed	Target completed (1/42, C/2017 K2 (PANSTARRS))
18:12:16	Target Started (2/42)	Target started (2/42, UGCA 1)
18:35:36	SoftSuspend Called	Soft Suspend is called due to Deteriorating Conditions (too few stars)
18:40:11	Target Completed	Target completed (2/42, UGCA 1)
18:40:13	Queue Paused	Queue paused for Session Suspension
18:40:15	Session Suspended	Session suspended
18:40:36	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
18:41:36	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
18:43:12	Session Resuming	Session resuming
18:43:27	Dome Opened	Dome opened (opening time 10s)
18:43:29	Session Running	Session running
18:43:31	Queue Resumed	Observing Queue resumed
18:43:32	Target Started (3/42)	Target started (3/42, NGC 7436)
19:00:40	Target Completed	Target partially completed (3/42, NGC 7436)
19:00:44	Target Started (4/42)	Target started (4/42, VV 305)
19:03:10	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
19:04:58	Focusing Completed	Foc1 AutoFocus Completed (Profile No 3)
19:23:11	Target Completed	Target completed (4/42, VV 305)
19:23:16	Target Started (5/42)	Target started (5/42, GCVS BL Lac)
19:28:43	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
19:30:56	Focusing Completed	Foc1 AutoFocus Completed (Profile No 4)
19:35:28	Target Completed	Target completed (5/42, GCVS BL Lac)
19:35:33	Target Started (6/42)	Target started (6/42, M31 w/Nova2021aceg)
19:38:55	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
19:40:42	Focusing Completed	Foc1 AutoFocus Completed (Profile No 5)
19:54:43	Target Completed	Target partially completed (6/42, M31 w/Nova2021aceg)
19:54:48	Target Started (7/42)	Target started (7/42, SN 2021win)
20:00:03	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
20:01:53	Focusing Completed	Foc1 AutoFocus Completed (Profile No 6)
20:18:47	Target Completed	Target completed (7/42, SN 2021win)
20:18:51	Target Started (8/42)	Target started (8/42, GCVS SU Tau)
20:21:45	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
20:24:07	Focusing Completed	Foc1 AutoFocus Completed (Profile No 7)
20:29:12	Target Completed	Target completed (8/42, GCVS SU Tau)
20:29:16	Target Started (9/42)	Target started (9/42, C/2019 L3 (ATLAS))
20:42:49	Target Completed	Target completed (9/42, C/2019 L3 (ATLAS))
20:42:51	Queue Aborted	Job Queue aborted
20:43:01	Services Stopped	Observatory Services stopped
20:43:02	Program Closed	Program closed by User
20:43:56	Session Resumed	Live Session Resumed (2021-12-05 S00939, ImageSaveNum: 939092)
20:44:10	Obs.Manager Started	Obs.Manager started
20:44:12	Obs.Overseer Started	Obs.Overseer started
20:44:16	Services Started	Observatory Services started
20:45:35	Services Started	Observatory Services started
20:47:58	Telescope Connected	Telescope Connected (TheSky6)
20:48:19	Camera1 Connected	SBIG Camera Connected (set point -25°C)
20:48:28	Observatory (Auto)	Observatory placed in Fully-Automated Mode
20:48:30	Session Pending	Session pending (2021-12-05)
20:48:32	Session Initiating	Session initiating (2021-12-05)
20:48:52	Plan Loaded	Observing Plan loaded to queue (, Plan ID: 692)
20:49:07	Camera1 Connected	SBIG Camera Connected (set point -25°C)
20:49:13	Telescope Connected	Telescope Connected (TheSky6)
20:49:36	Session Equilibration	Session ready for dome & camera equilibration
20:49:38	Session Running	Session running
20:49:41	Queue Started	Observing Queue started (33 targets selected)
20:49:46	Target Started (10/42)	Target started (10/42, UGC 2505 w/SN2021bge)
21:05:34	Target Completed	Target partially completed (10/42, UGC 2505 w/SN2021bge)
21:05:39	Target Started (11/42)	Target started (11/42, 132P/Helin-Roman-Alu)
21:19:18	Target Completed	Target partially completed (11/42, 132P/Helin-Roman-Alu)
21:19:23	Target Started (12/42)	Target started (12/42, UGCA 38)
21:42:09	Target Completed	Target completed (12/42, UGCA 38)
21:42:13	Target Started (13/42)	Target started (13/42, 10P/Tempel)
21:45:24	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
21:47:32	Focusing Completed	Foc1 AutoFocus Completed (Profile No 11)
21:57:55	Target Completed	Target completed (13/42, 10P/Tempel)
21:57:59	Target Started (14/42)	Target started (14/42, M110 w/AT2021yul)
22:01:58	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
22:03:48	Focusing Completed	Foc1 AutoFocus Completed (Profile No 12)
22:17:34	Target Completed	Target partially completed (14/42, M110 w/AT2021yul)
22:17:38	Target Started (15/42)	Target started (15/42, Nova Cas 2021)
22:22:54	Focusing Started-Foc1	Foc1 Focusing Started (TCF-S)
22:25:35	Focusing Completed	Foc1 AutoFocus Completed (Profile No 13)
22:33:05	Target Completed	Target completed (15/42, Nova Cas 2021)
22:33:10	Target Started (16/42)	Target started (16/42, AT2021vqu)
22:47:22	SoftSuspend Called	Soft Suspend is called due to Deteriorating Conditions (too few stars)
22:52:05	Target Completed	Target partially completed (16/42, AT2021vqu)
22:52:07	Queue Paused	Queue paused for Session Suspension
22:52:08	Session Suspended	Session suspended
22:52:13	Dome Closing	Dome closure failed after 5s (ShutterState=4)
22:52:38	Job Queue Frozen	Job Queue appears to have frozen at around 22:52 - 22:52
22:53:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:54:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:55:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:56:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:57:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:58:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:59:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
23:01:23	Dome Closing	Dome closure failed after 10s (ShutterState=4)
23:09:04	Dome Closed	Dome closed (closing time 55s)
23:09:26	Target Cancelled	Target cancelled (17/42, ARP 228) due to cloud
23:31:48	Target Cancelled	Target cancelled (18/42, UGC 1977 w/AT2021irz) due to cloud
23:48:10	Target Cancelled	Target cancelled (19/42, Nova Per 2020) due to cloud
23:48:13	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
23:49:23	Dome Closed	Dome closed (closing time 50s)
23:50:43	Dome Closed	Dome closed (closing time 5s)
23:54:34	Telescope Parked	Telescope parked (parking time 72s)
23:54:49	Telescope State	Scope parked Turn scope off. (Handbox)
00:00:12	Target Cancelled	Target cancelled (20/42, GSC 1224:29) due to cloud
00:15:20	User Intervention	User request to close and finish session
00:15:23	Queue Aborted	Job Queue aborted
00:15:25	Session Closing	Session closing
00:16:42	Services Stopped	Night Services stopped
00:16:44	Session Housekeeping	Housekeeping Started (Cleanup FITS, Create Fits Summary, Transfer Files)
00:16:56	Session Finished	Session Finished

Session Alerts

Time	Alert	Detail
18:40:36	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
18:41:36	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
18:43:17	Unexpected Dome Opening	Dome is unexpectedly opening (Good Conditions)
22:18:49	Dome	Dome didn't appear to move during the last telescope slew.
22:18:51	Dome Discrepency	Difference between Telescope Az and Dome Az is > 8 deg (Nova Cas 2021)
22:18:53	Dome	Dome position has been static for more than 5 mins
22:34:20	Dome	Dome didn't appear to move during the last telescope slew.
22:34:22	Dome Discrepency	Difference between Telescope Az and Dome Az is > 8 deg (AT2021vqu)
22:34:24	Dome	Dome position has been static for more than 10 mins
22:48:42	Dome	Dome has been stationary for more than 15 mins
22:52:13	Dome Closing	Dome closure failed after 5s (ShutterState=4)
22:53:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:54:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:55:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:56:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:57:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:58:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
22:59:33	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
23:01:24	Dome Closing	Dome closure failed after 10s (ShutterState=4)
23:02:43	Job Queue	Job Queue appears to be frozen (last IamAlive message at 22:52:05)
23:46:53	Unexpected Dome Opening	Dome is unexpectedly opening (Good Conditions)
23:48:13	Dome Closing	Dome closure hasn't begun with 20s (ShutterState is 'open')
23:57:54	Dome Alert	DomeRecords have stopped updating
23:58:09	Dome Alert	DomeRecords have resumed updating

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Critical Issues

Rubbber trim came off roof rim and caused the dome rotation system to stall and possibly prevented requests to close the shutter from being enacted. See Details - Detached Rubber Trim & Dome Not Fully Closing
Fixed in-session (Pulsar Dome)

Major Issues

Shutter not closed when requested (softsuspend) (18:40). Shutter still closed after 20s message/alarm. Issue with Shutter, or more likely, with new Shutter Control routines. Pulsar Log shows CloseShutter command at 18:40:12 (from Open State (ShutterState 0). but no reaction, with followup command at 18:41:17 from Open State (ShutterState 0), which again produced no reaction. A manually initiated call to Close Shutter made on DeviceHub Dome Tab was received at 18:42:04. Dome Closing at 18:42:05 (Shutter State 3), becoming closed at 18:42:16 (Shutter State 1, ie Dome Closing time of 12s, compared to normal time of 45-50s. Logs show that CloseShutter command being sent at 18:40:11. After ShutterStatus momentarily changed to 'Closing' the ShutterStatus fell back to 'Open' with 1.5s. A second attempt to send CloseShutter command was cancelled as an 'Open Shutter request is more recent'. A follow-up attempt to close shutter was made at 18:41:16, and again the 1st call to CloseShutter fell back to 'Open' after 1.6s, and 2nd call was again cancelled as an 'Open Shutter request is more recent'. Code reveals a bug in the new code added in AstroMain 3.48 which was setting LastShutterCommand = "Open" after 1st attempt instead of LastShutterCommand = "Close".
Fixed (AstroMain 3.48.1)
Shutter didn't completely close when session suspended (22:52), 15cm gap left). After the session suspended, the dome was commanded to close at 22:52:08 but first attempt failed with message 'Dome closure has stopped (Dome closure failed (5s, ShutterState=4))' . 1.5s after commanding dome closure ASCOM dome was reporting ShutterStatus: Error. CloseShutterTask didn't appear to make a 2nd attempt to connect (not sure why, but presumably because ShutterStatus had changed from its initial state (Open). As Dome had reported Closed state after 60s, a new attempt was made to Close Shutter. Initial State (Open). Around 25 attempts where made to close the shutter but in case the Immediate 'Closing' status was quickly overturned by the dome which reported 'Open'. Finally an attempt to close dome at 23:08:17 seemed to work, and Dome was reported to be closed at 23:09:04 (Dome is Closed (55s) ). When Observatory was checked the Shutter wasn't fully closed but had a gap off around 15cm. There was no indication that shutter had hung up on the lower lip of the aperture (unless the shutter had 'backed-off' after stalling on the lip and had then pulled back up 10-15cm). Pulsar Log confirms the CloseShutter command being made at 22:52:08 and return of Shutter State 4 at 22:52:09, which continued until it dropped back to return Shutter State 0 (Open) at 22:52:37. Next attempt to close shutter was recieved at 22:53:13 but immediate shutterstatus=3 (closing) quickly reverted back to shutterstatus=0 (open). Finally a CloseShutter command at either 23:08:09 or 23:08:18 was finally responsible for dome reporting ShutterStatus = 3 (Closing) at 23:08:18. which changed to ShutterStatus = 1 (Closed) at 23:09:01, ie a closing time of 43s. Dome rotating at 22:11 following a SlewToAzimuth to 246.1 (from 245.0, so assumed to be either slaved response to telescope tracking). Dome gets to 245.9 but doesn't stop 'rotating' and is still 'rotating' when the close command is made at 22:52:08, and is still 'rotating' (1) when the final attempt to close the shutter was made at 23:08:18. So maybe the mutiple commands to close dome weren't acted upon because the main Dome Control Unit was preoccupied with dome rotation or had stalled in some way. Pulsar Log shows that no 'OpenShutter' commands that might explain why the dome might have partially opened after being apparently finishing closing and reaching closed state at 23:09:01. A SlewToAzimuth 239.7 was recieved at 23:24:51and the dome began rotating the other way (2), several movements after that. See description and details. Shutter control seemed ok the following day and it would seem that the Main Dome Unit software might have hung or stopped normal functionality during the incident where rotation drive probably stalled due to the rubber trim that self-detached itself during the session.
Probably answered/undestood (Pulsar Dome).
Calibrate Dome not working ('Home' not found). Pulsar Dome kept rotating unable to find its home position during attempted re-calibration. This may or may not have something to do with the home magnet having begun to corrode again, or issue whereby the rubber strip around dome flange came off during the S939 Session. Dome magnet was put back in position before the calibration was attempted, but the home sensor has previously shown itself to be quite sensitive to the precise position of the magnet. Calibration was aborted after the dome had rotated round 4 times. After this the dome was manually rotated around to it's Park Position (=90 deg), at position where the two parts of induction charger align, and Device Hub's Sync Azimuth (90) facility (listed under Dome/Other Actions) then used to reset the Dome Az which had was out by some 150 degs by this point. Daytime test on 2021-12-07 indicates that dome is able to move accurately to different azimuth and a recalibration isn't necessary. However it would good to understand why the home magnet isn't been found by the Dome Unit during a 'Home' operation, as this is vital should a recalibration eventually become critical,
Fixed, dome recalibrated 2021-12-14 (Pulsar Dome)
Display on Observatory Computer has gone totally black (and later the computer totally failed) . Display on this old laptop computer was previously only working over 80% of display area, but was enough to get by with when needed. Since the main use of computer is via VNC remote connection its broken hinge, dodgy keypad have not been an issue for its role as an 'outdoor' observatory computer. Laptop screen still not working the following day. Computer was restarted but screen remainsl black and it was not possible to get a working VNC connection. The computer was brought inside for more detailed examination but it wasn't possible to boot the computer at all. Light on mouse wouldn't light and no display would come through to a connected external monitor. There was little/no activity from Hard Drive light. It was concluded that the computer is dead, and a replacement is needed. This has been ordered 2012-12-06 (see Observatory Computer Replacement, 2021-12-06) delivery 2021-12-09, configured over the next 24 hours (see setup & migrate to the new computer) and used in first session on 2021 (see first session with new observatory computer, 2021-12-10).
Resolved with new computer 2021-12-10 (Observatory Computer)

Minor Issues

'Shutter unexpectedly opening' message reported when session resumed (18:43). This is almost certainly due to OpenShutter commanding the shutter to open, and the Obs.Manager saw this opening movement and interpreted it as an unexpected opened when it was entirely expected. Log file shows call to OpenShutter being made at 18:43:12.09, following by message 'Dome is unexpectedly opening (Good Conditions)' around 5s later at 18:43:17.07, with message 'Dome is Open (opening time 10s)' at 18:43:27 which is just 19s after command to close !. Pulsar Log shows ''Open Shutter at 18:43:12 , when Shutter was closed (ShutterState 1). opening at 18:43:13 (ShutterState 2), becoming open at 18:43:23 (ShutterState 0). This is an impossibly short time of 11s, compared to normal closing time of 45-50s. When Shutter was first opened at 17:07 the opening time was a normal 44s. Code reveals a bug in new code added in AstroMain 3.48 which was checking MonitorShutterClosure = False instead of MonitorShutterOpening = False.
Fixed (AstroMain 3.48.1)
Park Telescope routine producing message 'Telescope power can not be switched off at this time' after waiting 20s after scope had finished parking (confirmed with Handbox message. This message was produced because SessionState was 'Suspended' at the time, which is appropriate according to current design.
Closed after review (AstroMain)
Trying to start Device Manager from AstroLaunch is causing AstroLaunch to crash on Windows 10. Issue is happening on both the Development Computer and the new Observatory Computer., but AllSky/Weather Computer is unaffected by issue and Device Manager launches ok.
Fixed (AstroLaunch 1.7.2)
General issues centering targets, difficulty jogging southwards / strong northward bias in final centering error. Propose to set AntiBacklash setting back to 95%
Fixed 2021-12-16 (AstroMain 3.48.4)
Home Magnet corroding again. Magnet cleaned off and reinserted in roof flange (2021-12-06) . Battery condition looked ok when visually checked on 2022-05-12, and functioned ok, in view of successful recalibration of dome (also on 2022-05-12). A backup magnet should be acquired in due course.
Close 2022-05-12 (Pulsar Dome)
Issue centering Target 1/42 (C/2017 K2 (PANSTARRS) ) first Jog to N overcorrected, and following jogs to south undercorrected. Guide Star jumped 8+ arc secs to north when guiding started. It then drifted south and crossed the zero line. It is proposed to address this issue by forthcoming changes to guide manager algorithum. Fixed my making an initial jog in the N/S required direction before starting to guide (AstroMain 3.48.19).
Fixed 2022-01-14 (AstroMain 3.48.19)
Guide Pulses after changing Dec Guide Mode are overcorrecting - the Autostar II DecAntiBacklash setting of 85% seems too high. Guide Run 3 (NGC 7436) guide star position is overcorrected by 3-4" from a single 'S' guide pulse, then overcorrects 3-4" from a single N guide pulse. The overcorrections seems symmetrical and therefore a bias due to an OTA balance is less likely to be the reason (especially given the improvement in telescope balance made before the session). It therefore seems that this is overcompensation from telescope's backlash compensation. There was a similar 3-4" overcorrection from a single S guide pulse when Dec Guid Mode changed during Guide Run 4 (VV 305) between frames 4 and 5. Anti-backlash setting changed from 85% to 75% to help alleviate this issue (change made during Target 6), however either of these value is too low to achieve the required level of centering accuracy. Its a 'no-win' situation. It is proposed to address this issue by forthcoming changes to guide manager algorithum which will eliminate or strongly reduce Dec Guide Mode changes for a given target, and utitlise adjustments in Star Lock position instead. Fixed my making an initial jog in the N/S required direction before starting to guide (AstroMain 3.48.19).
Fixed 2022-01-14 (AstroMain 3.48.19)
For Guide Run 3 (NGC 7436) at Az 196/Alt 58 a Dec Mode North was auto-selected but a South mode would have been more suited. Unclear if this point is representative for this sky area. It seems to be an outlier. Closed after review on 2022-06-09. Item is no longer percieved as being a current issue.
Closed 2022-06-09 (Session)

Small Defects

SkyConditionsTab01.png is null (blank) file and doesn't show the first Sky Conditions tab from the session. Unclear if this is an issue of AstroMain, AstroPlan or session circumstances. Issue occurred again in session S972 (2022-02-15). AstroMain code modified so that the MoveSkyConditionsTabFiles() routine is no longer called. This prevents a blank SkyConditions picture (without data) from overwriting a previous picture (with data). AstroPlan / WebSite updated to upload/display up to 4 SkyCondition pictures (previously only 3 pictures were uploaded).
Fixed 2022-02-16 (AstroMain 3.49.6, AstroPlan 1.29.10, Website) .

Continuous Improvement

Improve Current Weather web page by placing thin black border around weather/environments charts and data boxes.
Done (Website)
Reduce height of DPP Charts produced by AstroWeather. Charts vwsGraph38 and vwsGraph37. Change Y Height (cf Chart16), Change XAxis Major from 1 to 2
Done 2021-12-05 (AstroWeather 1.15.1)
Make a number of improvement to 60 min precipitation chart. Put 'summary' line into header (Move Source to bottom right) and Colour code in Green, Orange, Red. Increase Y max from 2.0 to 3.0, change grid to 0.50 major, 0.25 minor
Done 2021-12-05 (AstroWeather 1.15.1)
Query: An semi-linear object unexpectedly appeared on ObsCam Image frames during Target 10P/Tempel (21:42:40) where it was present in 4 successive frames and stayed for at least 5 minutes moving slightly between frame. It disappeared before the frames from the next Target (M110) at 21:58:26. It looks to very close to the camera lens, a thread of spider silk ? Investigate in morning. As it turned out a visit to the observatory to see why shutter was having a problem closing, revealed the object to be the long circumferential rubber strip which had coming down from the inside roof flange, which caused a subsequent dome rotatation issue. It would have been useful to have determined that the object was the rubber strip from the ObsCam images allowing an interventation to be made before the observatory slewed or tried to slew to the next target but it wasn't possible to identify the object as the rubber strip in the ObsCams' b/w images. It would have been useful to have been able to remotely turn on a light in the observatory in order to obtain a colour image of the object. This is raised as a separate improvement ticket.
Object identified 2021-12-06 (ObsCam, Pulsar Dome / Observatory)
Auto-extract astro image from a screen capture that includes a FITS image shown in FV program. The FV program places a lime green border (#00FF00) around the image and therefore it seems feasible to automatically find a lime green rectangle within a larger image and to crop the larger image down to the inside dimensions of the lime green rectangle. This would be a very helpful, time saving facility for capturing and saving square root scaled / log scaled / false coloured images that have been set up in FV for viewing but can't be saved directly as a disk file image. A working prototype has been developed in AstroMain 3.48.2 (2021-12-08), but it needs to be made more robust, as it finds the first and last lime coloured pixel along row 500 and along colum 500, so if image doesn't lie in this region or their are other lime coloured pixels in the screen grab then a false detection results. In both case the image should still lie within the image area placed into PaintShopPro, which will require manually cropping, but that isn't any worse than current situation.
Prototype built for trial 2021-12-08 (AstroMain 3.48.2)
Change all AstroSuite program references to the old Observatory Computer name (Laptop9_Chill) to the new Observatory Computer name (Laptop9). Modifications made to AstroMain, AstroMove, AstroLaunch, AstroPlan, AstroAllSky, AstroWeather programs. Other programs (AstroShCap, AstroGuard , AstroSN, AstroVOE, AstroObsCam) checked but don't have refer to 'Laptop9' and therefor don't require any modification.
Done 2021-12-07 (AstroMain 3.48.2, AstroMove 1.8, AstroLaunch 1.8, AstroPlan 1.29.1, AstroAllSky 3.14.1, AstroWeather 1.15.2)
Add a remotely controllable light to observatory to allow the interior to be viewed in colour using ObsCam when required instead of b/w. Bring old USB powered light into service, by plugging it into the vacant 6th USB port on the Pegasus UCH Usb hub. Update AstroObsCam to be able to switch the USB light on/off as required via ASCOm Switch. Whilst the new 'Toggle Aux. Light' feature worked in AstroObsCam, the illumination from the USB light was too dim to trigger the camera into 'daylight' (colour) mode, and it remained in b/w night mode. A new bright light is required. Research has been unable to find a USB light that would seem to be particularly bright (they mostly seem to be targetted towards the reading-light market). Not sure if USB light strips/light ropes will be sufficiently bright. All the 'bright' lights found via a online search aren't USB powered, they are simply USB chargeable and therefore the light itself can't be turned off/on via USB control. Have decided for time being to go down the route of using a 240V powered light and use a Philips Hue Smart Plug (similar to one used with the SBIG camera power) which can be used to turn plug off/on from an IPad inside the house. Smart Plug arrived 2021-12-08 and paired with IPad. It was installed in the observatory today (2021-12-09) and tested. A different light is needed as the existing one is too tall and heat generated from bulb is too close to fibreglass surface at top of bay. At the moment the light is turned on/off from an IPad in the house but this needs to be close to the back door/window to get a signal with the Smart Plug (same as for the SBIG Power Plug). Alternate ways of operating both lights via Conbee II dongle will be explore under a separate ticket.
Done 2021-12-09 (Observatory, Conbee, Zigbee Network, deConz, AstroMain)
Explore Programming Control of Smart Devices like Hue Smart Plugs (used for operating power switch for SBIG Camera and Observatory Aux. Light). Have decided for time being to go down the route of using a 240V powered light and use a Philips Hue Smart Plug (similar to one used with the SBIG camera power) which can be used to turn plug off/on from an IPad inside the house. Control of Light from Windows PC would notionally require Hue Bridge (expensive & restricted to Hue devices) & WinHue ( https://github.com/Hyrules/WinHue , no longer supported ) , or using a Conbee II dongle https://phoscon.de/en/conbee2 (https://www.amazon.co.uk/dp/B07PZ7ZHG5, £31) ), with control from either Home Assistant https://www.home-assistant.io/ (requires Virtual Machine) , RedNode or most probably using ZigbeeNet ( https://github.com/Mr-Markus/ZigbeeNet ). Implemented in Oct 2022 using Conbee2 and Zigbee network accessed via deConz.
Done 2022-Oct (Observatory, Conbee, Zigbee Network, deConz, AstroMain)

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Telescope Maintainance (2021-12-05)

Several maintainance tasks carried out today (2021-12-05) including

Rebalanced telescope in Dec
- Tube was found to be too tail heavy when OTA was horizontal which might explain the poor guiding that has been experienced in the south (down) direction
- OTA is balanced up to about 80 deg in altitude at which point it want's to pull over the zenith point (pull towards 90 -> 100 deg)
- Difficult to get perfect balance when the OTA is pointing vertical without affecting the balance when horizontal.
  
  However satisified that the scope is now very well balanced in the altitude range 0 to 75 deg.
Dec Motor Adjustments
- Tightened 2 bolts holding the Dec Motor Unit to the Fork
  
  Both bolts were found be be slightly loose, or at least not as tight as they should be, which might have been causing the occasional retrograde movements seen when centering and starting to guide in Dec
- Examined the tension on the Dec Motor carriage
  
  Decided that the existing tension was ok and didn't need adjustment at this point
- Also checked bolts holding the Dec Mounting/Axle to OTA and confirmed they were tight with no sign of any play.

Observatory Maintainance (2021-12-05)

Several maintainance tasks carried out today (2021-12-05) including

Washed outside of observatory from blown-on debries/leaves following Storm Arwen last week and green algae that has developed in the damp conditions over last few months
Cleaned observatory floor from dust, debris/small leaves blown in by Storm Arwen and otherwise brought in on footwear.

Attempted remediation of bulge in observatory roof panel (2021-12-05)

Opportunity was also taken to look at the issue with the bulge in the panel that lies below the lower lip of the shutter aperture. This bulge caused the shutter to hold up when closing during an earlier session S932 (2021-11-09) and may have potentially caused an issue with shutter opening during session S938 (2021-11-28).

An attempt was made to see if the panel could be 're-trained' to stay in its correct 'non-bulged' state, by employing a bungee cord to pull the panel inwards whilst heat was applied to the panel with a hair-dryer and then left to cool down. The tie was left in place for about one hour. It may or may not have made a slight improvement. The cord was removed after an hour since an observing session will probably proceed this evening, and the tie cannot be left in place whilst the dome rotates in azimuth. Although it is doubtful that the 'training' will work, further and longer attempts to 'train' the panel will be made over the next few weeks.

Photo showing bulge in roof paneling below lower aperture This is with shutter in its fully closed position		Photo showing roof paneling with it pulled in by bungee cord (bulge is pulled in but returns again when elastic cord is removed)


Photo showing bungee cord being used to pull-in the bulge in the roof panel (this is in an attempt to retrain the panel to remove the buldge that caused the shutter to hang up)		Photo showing bungee cord connecting roof panel and telescope pier/wedge (obviously the tie can't be left in place whilst the Observatory is operational since the dome needs to rotate)

Anomalies Opening & Closing Observatory Dome (S939 Session)

Anomalies during closing / opening shutter :

- Two close commands ignored by the dome

- Closing (from Open to Closed states) took only 12s, compared to normal 44-50s
- Opening (from Closed to Open states) took only 11s, compared to normal 44-50s

-------------------------------------------------- Normal Opening at 17:07:3417:07:33.602 ShutterStatus 1 (closed) 17:07:34.601 OpenShutter Call to Open Shutter 17:07:34.601 ShutterStatus 2 (opening) immediate status set to opening 17:07:34.991 Volatile 90.2 0 0.000000 0.0 0 1 volatile line shows shutterstate 1 (closed) 17:07:35.615 ShutterStatus 1 (closed) the immediate opening status is overturned by the Dome 17:07:35.958 Volatile 90.2 0 0.000000 0.0 0 2 volatile line shows shutterstate 2 (opening), taken 1.4s for dome to catchup and respond 17:07:40.622 ShutterStatus 2 (opening) Shutter is Opening to Shutter is Opening 17:08:16.716 ShutterStatus 2 (opening) Shutter is Opening 17:08:17.403 Volatile 90.2 0 0.000000 0.0 0 0 volatile line shows shutterstate 0 (open) 17:08:17.715 ShutterStatus 0 (open) Shutter is Open, opening time 43s (Normal) -------------------------------------------------- Anomalies Start from 18:40:12 18:40:09.981 ShutterStatus 0 (open) Shutter is Open 18:40:12.024 CloseShutter 1st call to Close Shutter 18:40:12.024 ShutterStatus 3 (closing) immediate status set to closing 18:40:12.524 Volatile 169.4 0 0.000000 169.4 0 0 volatile line shows shutterstate 0 (open) 18:40:13.038 ShutterStatus 0 (open) the immediate closing status is overturned by the Dome Shutter is still Open (CloseShutter command was ignored !) to 18:41:13.067 ShutterStatus 0 (open) Shutter is Open 18:41:17.061 CloseShutter 2nd attempt to close shutter after 1st attempt failed 18:41:17.061 ShutterStatus 3 (closing) immediate status set to closing 18:41:17.591 Volatile 169.4 0 0.000000 169.4 0 0 volatile lines shows shutterstate 0 (open) 18:41:18.075 ShutterStatus 0 (open) the immediate closing status is overturned by the Dome Shutter is still Open (CloseShutter command was ignored !) to 18:42:03.134 ShutterStatus 0 (open) Shutter is Open 18:42:04.273 CloseShutter 3rd attempt to close shutter (made directly in DeviceHub) 18:42:04.273 ShutterStatus 3 (closing) immediate status set to closing 18:42:05.256 Volatile 170.5 0 0.000000 170.5 0 3 volatile line shows shutterstate 3 (closing) 18:42:05.287 ShutterStatus 3 (closing) Shutter is Closing to Shutter is Closing 18:42:15.275 ShutterStatus 3 (closing) Shutter is Closing 18:42:16.274 ShutterStatus 1 (closed) status goes to open before reporting of first Volatile line with closed state 18:42:16.383 Volatile 170.5 0 0.000000 170.5 0 1 volatile line shows shutterstate 1 (closed) 18:42:21.281 ShutterStatus 1 (closed) Shutter is Closed, closing time only 12s (This is too quick based on CloseShutter at 18:42:04 !) (If we assume actual time of 44s, then CloseShutter would have been at 18:41:32) 18:43:11.303 ShutterStatus 1 (closed) Shutter is Closed 18:43:12.176 OpenShutter Call to Re-Open Shutter 18:43:12.176 ShutterStatus 2 (opening) immediate status set to opening 18:43:13.143 Volatile 170.5 0 0.000000 170.5 0 2 volatile line shows shutterstate 2 (opening) 18:43:13.190 ShutterStatus 2 (opening) Shutter is Opening to Shutter is Opening 18:43:22.223 ShutterStatus 2 (opening) Shutter is Opening 18:43:23.221 ShutterStatus 0 (open) status goes to open before the first Volatile line with closed state ! 18:43:23.315 Volatile 170.5 0 0.000000 170.5 0 0 volatile goes shows shutterstate 1 (open) 18:43:28.229 ShutterStatus 0 (open) Shutter is Open, opening time only 11s 18:43:33.221 ShutterStatus 0 (open) (This is too quick based on OpenShutter at 18:43:12 !)

Detached Rubber Trim & Dome Not Fully Closing

Observatory was visited as the Observatory Control program was reported repeated failures to close the Dome when cloud developed.

Whilst shutter was found to be partially open, the immediate thing that was noticed was the Rubber Trim that normally runs around the inner flange of the observatory roof had became detached and was drooping on to the floor in some section and suspended from dome clamps in others. Investigating showed that the small colied spring that holds the Dome Rotation encoder arm in tension against the roof flange had snapped and the elastic band backup was loose.

Either because of the encoding not reading the movement of the dome or because the rubber strip stalled the movement of the dome passing through the dome rotation motor or through the 4 dome clamps, the dome rotation stopped responding to automated dome azimuth requests (Dome Slaved to Telescope in DeviceHub) and probably blocked the commands to close the domes shutter (some 25 automated requests to close the shutter failed).

This is the second time that the rubber strip has self detached itself during an observing session since the observatory was commissioned in 2018 (the last time was 2 years ago in session S714, 2019-10-24)

Earlier a mystery object that appeared in 4 frames from the ObsCam but disappeared after 5 minutes turned out to be the rubber trim falling down. This was seen at the time, but the object was not recognised as the rubber trim in dim black/white nighttime images which is unfortunate as the subsequent problems might possibly have been avoided if the session was suspended and the observatory visited in person. I was putting on shoes to go see what it the mystery object was when it was noticed that the object had disappeared in the refreshed images, and trip out to observatory wasn't made. This proved to be a costly error.

Mystery Object seen on ObsCam Images at the time turned out to be the rubber trim falling down		Photo showing detached rubber trim section seen on ObsCam picture


Photo showing detached rubber trim		Photo showing partially open shutter when Observatory was visited.

The rubber trim was reattached and pressed tight with pliers all the way around. After fixing the decode arm tension issue with an elastic band backup the dome then began rotating. Each time the Abort button was pressed on the Dome Rotation Unit, the rotation would stop but then start again a few moments later. It isn't clear if this was dome was still being commanded to move, the Driver still had a locked in target azimuth which it was still trying to deliver or the Dome Unit was busy trying to find home or do a self calibration.

The dome's home magnet fell out from its position during the incident. The dome magnet was found but noted to be corroded badly on one side with outer casing fragmented. This was a surprise, but not a total surprise since the magnet was a new replacement magnet installed 12 months in Dec 2020 (a replacement because the original 2018 magnet had almost completely corroded away). Although corroded the magnet seems still having good magnetic strength and it was repositioned into its slot in the roof flange.

Photo showing new magnet (Dec 2020)		Photo showing the new magnet just 12 months later (Dec 2021)

Update 2022-05-31. A batch of 10 new magnets (10mm x 3 mm) were purchased and delivered from Amazon on 2022-05-31. They will provide ample backup in case of further deterioration of the home magnet.

2021-12-06

Observatory Computer Replacement

The Observatory Computer (an old Chilblast laptop with broken hinge, partially failed display) has completely failed and cannot be restarted. It's screen went comletely dead before or during S939 session and although it lasted to the end of session working across a VNC remote connection, the following day it was found that screen was still dead and the computer could not be restarted after several attempt to reboot it. Little/no activity on hard disk light, no output to external monitor. Possible factors in its failure were : basic old age, cold temperature (-3 degC), recent power cuts/fluctuations/spikes associated with Storm Arwen

Some quick research identified a suitable replacement (ASUS ExpertBook Core i7-10510U 8GB 512GB 14 Inch Windows 10 Pro Laptop P2451FA-EB1438R) which was ordered today (2021-12-06).

Key features of new computer i7 cpu, were 8GB, 512GB SSD drive, Lan Port, USB Ports, Screen Resolution 1920 x 1080, Robustness, Business Style, Windows 10 Pro

ASUS ExpertBook, P2451FA-EB1438R
at laptopsdirect : https://www.laptopsdirect.co.uk/asus-expertbook-core-i7-10510u-8gb-512gb-14-inch-windows-10-pro-laptop-p2451fa-eb1438r/version.asp

(The possibility of getting a Toshiba Dynabook Satellite Pro C50-E-102 which is the computer model used for the current AllSky/Weather Computer was looked into, but it wasn't available )

Once the new computer arrives (hopefully in the next 3 days) it will require a few days to set up and test.:

Update: The replacement computer is due to arrive Thursday (2021-12-09)

New Observatory Computer - Setup & Migration

Steps for the setup and migration to the new observatory computer

Windows
- Admin and User Account
- Computer Name, HomeGroup
- Desktop Picture, Desktop DPI, Icons Sizes
- Taskbar Toolbars: Astro, Comp, Apps
- Control Panel
- Device Manager
- Internet Explorer & MS Edge, Google Search Provider.

Core / General Software
- Kaspersky Internet Security (for firewall & antivirus)
- UltraVNC Server (for remote control access)
- TextPad 4 (for file editing)
- ACDSee Classic (for general non-Fits image viewing)
- 7 Zip (for file/folder Zip access)
- PaintShopPro 5 (for image capture)
- Dimension 4 (for time synchronisation)
- Net Framework (for ASCOM & other programs)
- Visual Studio 2019 (for program debugging)

Drivers
- MeadeGeneric Driver (from ASCOM site)
- Pegasus Astro
- USB / Serial Drivers
- SBIG Camera drivers
- Pierro-Astro USB-RS232 LX200 Cable

Observatory Software
- CCDSoft5
- TheSky6
- ASCOM 6.5.SP2 (incl DeviceHub)

- OptecTCF-S Installer (6.0.6), TCF Commander and ASCOM Driver/Local Server
- Pulsar Dome Software / Driver
- Pegasus UPB 1.6
- Pegasus UPB Ascom Drivers (Switch, Focuser, Observing Conditions)
- PHD2 (autoguiding)
- SharpCap 3.2
- PHD2
- ASTAP
- ImageMagicK

- AstroLaunch
- AstroMain
- AstroPlan
- AstroVOE
- AstroSN

Data
- Session Data (including the latest S939 Session) has already been taken off the Observatory data
- Other key data / program files is available on the Development/Analysis Computer indoors, or can be reconstructed or remade.
- The mSata SSD drive has been removed from old Computer and an attempt will be made to read the mSata SSD drive once
   a 'mSata to USB enclosure' is recieved from Amazon.     https://www.amazon.co.uk/dp/B08W1W3SVK/ref=pe_27063361_485629781_TE_item
   This arrived today (2021-12-08) and with mSata drive installed, access to the old computer's C Drive was obtained
   Windows complaining that Ihad no permission to files in folders, but offered a Continue dialog which then allowed permission but took around one hour to process.
- A 2.5" HDD (Secondary Drive) has also been removed and has been shown to be readable via an existing 2.5" Sata to USB Enclosure.
This drive contained mainly old back up data, but will be pressed into service as a future external hard drive.

New Settings
Once new programs have been installed a number of program/data settings will have to be input. These include:

   UltraVNC
   DeviceHub. Dome
   Meade Generic
   PHD2
   SharpCap
   Pegasus UPB
   PHD2 will need also need a new calibration.
   PemPro
   AstroMain (need COM Ports associated with Telescope, Dome, TCF-S focuser)

Key Tests:
   AstroMain access to TheSky/CCDSoft objects
   CCDSoft access to SBIG ST10 camera & filter wheel
   AstroMain access to TCP/IP datafeeds from AllSky/Weather Computer
   AstroPlan access to Targets Database
   AstroMain access to TCF-S focuser

   DeviceHub Working (with Access to Pulsar Dome & LX200)
   AstroMain access to Pegasus UPB PowerBox, Pulsar Dome & LX200 Telescope

   PHD2 access to LX200 Mount and ZWO ASI 178MC camera
   SharpCap access to ZWO ASI 178MC camera
   AstroMain access to PHD2 & SharpCap.
   AstroMain access to ASTAP.

Other Programs
- PemPro
- RSpec
- SigmaBeta 11

Computer Name
- Old Computer was called 'LAPTOP9_CHILL'
- New Computer will be called 'LAPTOP9'

The proposed change in name requires Program links to be changed :

- AstroMain 3.48.2 - Done, 2021-12-08
- AstroMove 1.8 - Done
- AstroLaunch 1.8 - Done
- AstroWeather 1.15.2 - Done
- AstroAllSky 3.14.1 - Done
- AstroPlan 1.29.1 - Done

- AstroShCap 1.3.12 - No change required
- AstroGuard - No change required
- AstroSN 1.7.1 - No change required
- AstroVOE 1.9 - No change required
- AstroObsCam 1.8 - No change required

Requires shortcut links to Laptop9 to be changed (changes can only be made once the new computer is networked connected)

IP Addresses
- Laptop9 VNC Links (changes to IP Address as required)

PHD2
Equipment Profiles
TS80/178MC - Camera: Simulator (later ASI 178MC), Mount: Device Hub Telescope (ASCOM)
LX200/ST10 - Camera: Simulator (later SBIG), Mount: Device Hub Telescope (ASCOM)

Revised Guiding Algorithum

A revised guiding algorithum is being developed to better manage recent issues with positioning and guiding in Dec which are partly due to variability in Dec backlash, overcorrection of Dec position from a initial single guide pulse, problems caused for changing Dec Guide Mode during a guide run, intermittant poor response from telescope to Dec Guide corrections.

Guiding performace is heavily influenced by the behaviour of the telescope mount. The observatory's fork mounted LX200 GPS telescope has a significant backlash as telescope's go but is similar to that of other LX200 scopes.

In order to achieve accurate centering it is necessary to use a backlash compensation setting in the scope that is 95% or close to the scope's Dec Backlash value, and use Uni-Directional Dec Guiding, where the direction of Dec Guiding (Dec Guide Mode) is either determined from the direction of star drift during an initial extended settling period with Dec Guiding turned off or selected based on the telescope position and previously determined star drift information as that position. With a reasonable good Polar Alignment in Azimuth (the more easily determined alignement of the two), it then becomes a matter of using a particular Dec Mode (north or south) on one side of the Meridian and using the opposite Dec Mode on the other side of the Meridian.

PrincipalDecMode = the Dec GUide Mode that is selected as the appropriate Mode for the current telescope position.

Update 2022-02-11
The overall combination of telescope rebalancing, adjusted/improved Polar alignment and a revised Guiding control algorithum have largely resolved the earlier guiding performance issues (note added 2022-02-11)

This Web Page:	Notes - Session 939 (2021-12-05)
Last Updated :	2024-09-28
Site Owner :	David Richards
Home Page :	David's Astronomy Web Site

David's Astronomy Pages Notes - Session 939 (2021-12-05)