David's Astronomy Pages Notes - Session 1155 (2023-10-05)

Notes (S1154)

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Notes (S1156A)

	Session Aims & Highlights
	- Observing Result  - Night Summary Plot  - Session Event Log
	Operational Issues
	- Critical Issues (0),  Major Issues (1),  Minor Issues (0),  Small Defects (2),  Continuous Improvement (15)
	Images from 2023-10-05 >>
	2023-10-08
	LX200 - Mirror Lock Fix

Session Aims & Highlights (2023-10-05)

Main aims

1. Targets.  Acquire images of a selection of variable stars, nearby stars, comets & deep sky targets as allowed by sky conditions.
2. AstroMain. Check new AstroMain version (3.62.16) for recent fixes and improvements.

 Equipment & Software

• 12" LX200 and ST-10XME
• 80mm APO and ZWO ASI 178MC
• CCDApp2, TheSky6, CCDSoft5, DeviceHub 6.6.1.1,  MeadeGeneric 1.3.5.414, UPB 1.5, ASCOM 6.6
• Pegasus UPB & Motor Focus, TCF-S
• SharpCap 3.2, PHD2  2.6.11dev4, Siril 1.0.6, deCONZ 1.18.2, ASCOM 6.6 SP1
   
• AstroMain 3.62.16, AstroPlan 1.38.5,   AstroShCap 1.3.15, AstroGuard 1.10.2
  AstroVOE 1.13  AstroSN 1.10,  AstroProtect 1.7,  AstroMove 1.12.6
  (AstroWeather 1.21.2, AstroAllSky 3.19.4,  AstroObsCam 1.11.4, AstroLaunch 1.11.1

Highlights

• Targets. 16/22 planned targets were completed. However images from 6 of the last 7 target were later rejected due to effects of cloud/poor sky transparency. Other targets failed due to cloud/session suspension. Dew/Condensation inside the AllSky Camera Hemisphere meant that session was running without reliable a AllSky Star Count, and meant the session was still running when it should have really been suspended for entire second half of the night.
• AstroMain. No issues with new AstroMain version (3.62.16)
•  Dome Slews. There were significant issues with dome slewing during the session and during dome parking.  8 dome slews (42% of all slews) were affected by significant hold-ups, with individual hold-ups of up to 170s (Hold Up Stats: 8/19 slews affected, 42%, 9.5 minutes total hold-up time).  Dome parked ok.
•  AllSky Camera. AllSky Camera was again affected by significant condensation/dewing.

Notes:

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)

Actual Weather vs Pre-Session Weather Forecast

Session Event Log

Time     Event Detail 22:53:16 Session Monitoring AutoStart monitoring for Live Session opportunity between 22:53 & 05:18 22:53:17 Session AutoStarting Session autostarting (22:53) 22:53:37   CCDSoft Restarting CCDSoft being restarted (to set AutoSave No.) 22:53:50 Session Created Session Created (Live, 2023-10-05 S01155, ImageSaveNum: 1155001) 22:54:17   Scope Switched On Telescope Power has been switched on via UPB Powerbox. 22:56:02   Services Started Observatory Services started 22:56:08 Observatory (Auto) Observatory placed in Fully-Automated Mode 22:56:12 Session Pending Session pending (2023-10-05) 22:56:14 Session Initiating Session initiating (2023-10-05) 22:56:16   Plan Requested Observing Plan requested from AstroPlan (1.38.5) 22:57:11   Plan Loaded Observing Plan loaded to queue (Plan ID: 929) 22:57:32   Camera1 Connected SBIG Camera connected (set point -10°C) 22:58:09   Telescope Connected Telescope connected (TheSky6) 22:58:33 Session Equilibration Session ready to Open Dome 22:59:18   Dome Opened Dome opened (opening time 45s) 22:59:20 Session Running Session running 22:59:22   Queue Started Observing Queue started (22 targets selected) 22:59:24     Target Started (NrZen) Target started (Focus Field 1, HIP 4911) 22:59:38       Dome Unparked Dome unparked 23:04:12       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 23:06:55       Focusing Completed Foc1 AutoFocus Completed (Profile No 1, wide) 23:08:52       Focusing Completed Foc1 AutoFocus Completed (Profile No 1) 23:08:55       Focusing Started-Foc2 Foc2 Focusing Started (Secondary Scope, using ShCap) 23:10:43       Focusing Completed Foc2 AutoFocus Completed (Profile No 2, wide) 23:12:25       Focusing Completed Foc2 AutoFocus Completed (Profile No 2) 23:12:42     Target Completed (NrZen) Target completed (Focus Field 1, HIP 4911) 23:12:47     Target Started (1/22) Target started (1/22, M31 w/Nova M31 AT2023trk) 23:15:30       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 23:17:42       Focusing Completed Foc1 AutoFocus Completed (Profile No 3) 23:33:41     Target Completed Target completed (1/22, M31 w/Nova M31 AT2023trk) 23:35:04     Target Started (2/22) Target started (2/22, M33 w/AT2023nou) 23:36:23     Dome Slew Dome slew held up at Az. 132.6° (Delay 56s) 23:38:11       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 23:40:40       Focusing Completed Foc1 AutoFocus Completed (Profile No 4) 23:56:40     Target Completed Target completed (2/22, M33 w/AT2023nou) 23:57:24     Target Started (3/22) Target started (3/22, AT2023txn (CV)) 00:01:30     Dome Slew Dome slew held up at Az. 154.2, 156.6, 175.5, 217.5° (Total delay 170s) 00:03:36       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 00:05:48       Focusing Completed Foc1 AutoFocus Completed (Profile No 5) 00:11:48     Target Completed Target completed (3/22, AT2023txn (CV)) 00:11:52     Target Started (4/22) Target started (4/22, NGC 6745 w/AT2023ucy) 00:12:55     Dome Slew Dome slew held up at Az. 264.7, 265.3° (Total delay 34s) 00:15:17       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 00:17:30       Focusing Completed Foc1 AutoFocus Completed (Profile No 6) 00:33:45     Target Completed Target completed (4/22, NGC 6745 w/AT2023ucy) 00:33:49     Target Started (5/22) Target started (5/22, AT2022wyp) 00:37:07       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 00:39:16       Focusing Completed Foc1 AutoFocus Completed (Profile No 7) 00:44:48       SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars) 00:45:43       SoftSuspend Cancelled Soft Suspend is cancelled due to improved conditions 00:55:27     Target Completed Target completed (5/22, AT2022wyp) 00:55:31     Target Started (6/22) Target started (6/22, AT2023tvi (CV)) 00:58:07       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 01:00:22       Focusing Completed Foc1 AutoFocus Completed (Profile No 8) 01:06:09     Target Completed Target completed (6/22, AT2023tvi (CV)) 01:06:13     Target Started (7/22) Target started (7/22, GCVS BL Lac) 01:07:00       SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars) 01:07:59     Dome Slew Dome slew held up at Az. 268.6, 267.6, 266.4, 259.4° (Total delay 83s) 01:10:01       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 01:12:15       Focusing Completed Foc1 AutoFocus Completed (Profile No 9) 01:13:05       SoftSuspend Cancelled Soft Suspend is cancelled due to improved conditions 01:16:08     Target Completed Target completed (7/22, GCVS BL Lac) 01:16:22     Target Started (8/22) Target started (8/22, AT2023rfq) 01:17:21       SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars) 01:17:24     Dome Slew Dome slew held up at Az. 259.5, 264.2, 265.5° (Total delay 33s) 01:19:40       Focusing Skipped Foc1 focusing skipped - star is too dim (TCF-S) 01:27:07       SoftSuspend Cancelled Soft Suspend is cancelled due to improved conditions 01:29:42       SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars) 01:32:52       SoftSuspend Cancelled Soft Suspend is cancelled due to improved conditions 01:35:39     Target Completed Target completed (8/22, AT2023rfq) 01:38:42     Target Started (9/22) Target started (9/22, GCVS SS Cyg) 01:38:58       SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars) 01:41:26       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 01:43:30       Focusing Completed Foc1 AutoFocus Completed (Profile No 10) 01:46:13       SoftSuspend Cancelled Soft Suspend is cancelled due to improved conditions 01:47:40     Target Completed Target completed (9/22, GCVS SS Cyg) 01:48:54       SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars) 01:48:56   Queue Paused Observing Queue pausing for Session Suspension 01:48:59 Session Suspending Session suspending 01:49:49   Dome Closed Dome closed (closing time 50s) 01:49:51 Session Suspended Session suspended 02:14:19     Target Cancelled Target cancelled (10/22, 29P/Schwassmann-Wachmann) due to cloud 02:34:39     Target Cancelled Target cancelled (11/22, AT2023tdi) due to cloud 02:56:59     Target Cancelled Target cancelled (12/22, LEDA 1488100 w/SN2023olz) due to too few stars 03:07:31 Session Resuming Session resuming 03:08:16   Dome Opened Dome opened (opening time 45s) 03:08:18 Session Running Session running 03:08:20   Queue Resumed Observing Queue resumed 03:08:23     Target Started (13/22) Target started (13/22, UGC 4992 w/AT2023rpu) 03:11:15     Dome Slew Dome slew held up at Az. 308.8, 309.3° (Total delay 62s) 03:12:56       SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars) 03:14:01     Target Failed (13/22) Target failed due to cloud (13/22, UGC 4992 w/AT2023rpu) 03:14:03   Queue Paused Queue paused for Session Suspension 03:14:05 Session Suspending Session suspending 03:14:51   Dome Closed Dome closed (closing time 50s) 03:14:54 Session Suspended Session suspended 03:19:00     Target Cancelled Target cancelled (13/22, UGC 4992 w/AT2023rpu) due to cloud 03:40:59     Target Cancelled Target cancelled (14/22, UGC 5313 w/AT2023tmr) due to cloud 04:03:19     Target Cancelled Target cancelled (15/22, M101 w/SN2023ixf) due to too few stars 04:07:52 Session Resuming Session resuming 04:08:37   Dome Opened Dome opened (opening time 45s) 04:08:39 Session Running Session running 04:08:41   Queue Resumed Observing Queue resumed 04:08:43     Target Started (16/22) Target started (16/22, Nova Cas 2021) 04:11:37     Dome Slew Dome slew held up at Az. 60.8, 308.6° (Total delay 68s) 04:27:20     Target Completed Target completed (16/22, Nova Cas 2021) 04:27:24     Target Started (17/22) Target started (17/22, M31 w/Nova M31 2023-10a?) 04:28:35     Dome Slew Dome slew held up at Az. 300.6, 267.5° (Total delay 33s) 04:49:07     Target Completed Target completed (17/22, M31 w/Nova M31 2023-10a?) 04:49:11     Target Started (18/22) Target started (18/22, GCVS RR Tau) 04:53:46       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 04:56:03       Focusing Completed Foc1 AutoFocus Completed (Profile No 11) 05:02:38     Target Completed Target completed (18/22, GCVS RR Tau) 05:02:43     Target Started (19/22) Target started (19/22, C/2017 K2 (PANSTARRS)) 05:15:39     Target Completed Target completed (19/22, C/2017 K2 (PANSTARRS)) 05:15:43     Target Started (20/22) Target started (20/22, AT2023cub (CV)) 05:20:32       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S) 05:26:41     Target Completed Target completed (20/22, AT2023cub (CV)) 05:26:45     Target Started (21/22) Target started (21/22, GCVS DX Cnc) 05:32:15       Focusing Skipped Foc1 focusing skipped - star is lost (TCF-S) 05:36:53     Target Completed Target completed (21/22, GCVS DX Cnc) 05:37:16     Target Started (22/22) Target started (22/22, NGC 2708 w/SN2023bee) 05:42:23       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S) 05:58:28     Target Completed Target completed (22/22, NGC 2708 w/SN2023bee) 05:58:31   Queue Completed Job Queue completed 05:58:32 Session Closing Session closing 05:59:27   Dome Closed Dome closed (closing time 50s) 06:00:13   Dome Parked Dome parked (parking time 39s), Az: 90.0 deg 06:01:30   Telescope Parked Telescope parked (parking time 71s) 06:01:45   Telescope State Handbox reads 'Scope parked Turn scope off.' 06:02:08   Telescope Switched Off Telescope Power has been switched off via UPB Switch. 06:03:35   Services Stopped Night Services stopped 06:03:37 Session Housekeeping Session Housekeeping started (Create Fits Summary, Transfer Files) 06:03:58 Session Finished Session Finished

Session Alerts & Alarms

Time     Type       Name Detail 22:56:12 Yellow Alert Disk Space Free Space on C:\ Drive (36.07 GB) is less than 50 GB 23:12:54 Yellow Alert Anomalous Dome Slew Dome slew resumed at Az 112.9° (T+2.2s) 23:36:23 Yellow Alert Dome Slew Dome slew held up at Az. 132.6° (Delay 56s) 00:01:30 Red Alert Dome Slew Dome slew held up at Az. 154.2, 156.6, 175.5, 217.5° (Total delay 170s) 00:01:38 Yellow Alert Dome Discrepency Difference between Dome Az and Telescope Az is > 8 deg (AT2023txn) 00:01:40 Yellow Alert Dome Discrepency Difference between Dome Az and Slave Az is > 1 deg (AT2023txn) 00:12:55 Yellow Alert Dome Slew Dome slew held up at Az. 264.7, 265.3° (Total delay 34s) 01:07:59 Yellow Alert Dome Slew Dome slew held up at Az. 268.6, 267.6, 266.4, 259.4° (Total delay 83s) 01:17:24 Yellow Alert Dome Slew Dome slew held up at Az. 259.5, 264.2, 265.5° (Total delay 33s) 03:11:15 Yellow Alert Dome Slew Dome slew held up at Az. 308.8, 309.3° (Total delay 62s) 04:11:37 Yellow Alert Dome Slew Dome slew held up at Az. 60.8, 308.6° (Total delay 68s) 04:28:35 Yellow Alert Dome Slew Dome slew held up at Az. 300.6, 267.5° (Total delay 33s) 06:03:55 Yellow Alert Disk Space Free Space on C:\ Drive (35.18 GB) is less than 50 GB

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Operational Issues (2023-10-05, S1155)

• Critical Issues (0)
• Major Issues (1)
• Minor Issues (0)
• Small Defects (2)
• Continuous Improvement (7)
  

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Critical Issues

• None

Major Issues

• 'AllSky Camera Pictures showing signs of very bad condensation/dew. This is a continuation of the problem that affected the previous S1154 session (2023-10-04). Condensation/dew inside the AllSky Camera's hemisphere is an occasional issue and when it occurs it introduces visual artefacts and effects image quality over parts of the sky and reduces the AllSky Star Count.  These have impacts on Aurora Imaging (northern panorama) and Observatory Operations using 'Too Few Stars' option as one criteria for opening/closing the observatory. The issue follows heavy rain earlier in the day.  Camera hemisphere needs to be opened in daylight and dried out, ideally replacing air inside with lower humidity air if possible.  In Session S1155 images from 6 of the last 7 targets were acquired but had to be later rejected due to the effects of cloud/poor sky transparency.  Dew/Condensation inside the AllSky Camera Hemisphere meant that session was running without reliable a AllSky Star Count, and meant the session was still running when it should have really been suspended for entire second half of the night.  Daylight hours prior to the S1155 session were too wet and/or too humid to open the AllSky Camera's hemisphere to fix issue. 2023-10-06 is forecast to be drier with lower humidity which should provide opportunity to dry out the AllSky Camera. AllSky Camera checked on 2023-10-06, the hemisphere had also completely cleared of condensation (just a trace left), but hemisphere was opened anyway to dry the condensation traces and to allow internal air to be replaced by outside air that was likely at lower humidity to prevent the issue from reappearing during the next cold night.  Result appeared good on night 2023-10-06, but issue of dew appeared again straight away from dusk on 2023-10-07 after 24 hours of rain & high humidity. 
  Fixed 2023-10-06 (AllSky Camera)
  
  Update 2023-10-07.
  Although the result of opening and replacing the air in the AllSky Camera seemed to have resolved the issue based on images from night 2023-10-06, the issue of dew appeared again on 2023-10-07 with dew visible in images  from dusk onwards. This was after 24 hours of rain & high humidity. Looking back on images from the previous night (2023-10-06) shows presence of some diffuse condensation,  but the condensation has clumped together into distinct droplets of water by evening of 2023-10-07.  Does the Dew Heater 'pull in water' .  Theory is that heating air in the Camera by the dew heater allows the air to hold more water vapour volume (this extra water in notionally 'pulled' in from the outside ambient air ?), this extra water then drops out when the air circulates by convection into the cooler conditions at the top of the hemisphere.  If the dew heater wasn't on perhaps the condensation problem would be less frequent / less intense, that's a theory and a possible test/mitigation.
  
  Update 2023-10-09
  AllSky Camera's hemisphere opened and interior wiped dry of consensation & water droplets

Minor Issues

• None

Small Defects

• 'Copy ./_Reduced Files'  facility wasn't used during Reduction Workflow, making it difficult to go back after using Group Reduced File in Excel to correct Object Name from 'M31' to 'M31_Nova_2023-10a' (post-session).  It is awkward to go back without manually changing file names. Normal practice is to change the Object Name in Excel, copy the relevant 'unnamed' reduced files from '_Copy of Reduced' folder to the '_Reduced' Folder before running the 'A5_Group_Reduced_FITS_direct' macro and then deleting the 'incorrectly named' ImageSet .   Closed after review 2023-10-07. Two Continuous Improvement' tickets have been raised to try to prevent a situation where Group Reduced FITS is run without having a '_Copy of Reduced' files as a backup.
  Closed 2023-10-08 (Session Reduction, Excel Fits Summary.xls, AstroMain)
   
• When connecting TheSky6 Telescope to DeviceHub/Ascom.Simulator.Telescope, AstroMain reports Side of Pier 'East' (Dev Computer). This is different to the telescope connection on Observatory Computer where DeviceHub Telescope is connected to Meade Generic/LX200 and 'Side of Pier' is reported as Unknown  Properties of Ascom.Simulator.Telescope changed to untick the 'Side of Pier' behaviour.
  Fixed 2023-10-08 (Ascom.Simulator.Telescope, AstroMain)

Continuous Improvement

• Query. When monitoring the start of a new Observatory Session why is there an unnatural 20s delay between 'Restart CCDSoft (to set AutoSave No.) and the reporting AutoSave Starting Number and AutoSave Folder ?.  Examine code - are there any unnecessary calls to Thread.Sleep(). Examining AssignObservatorySession() shows that after the code section that calls RestartCCDSoftByThread (with RestartMode = RestartCCDSoftMode.SetAutosaveNo), there is section that calls StoreSessionEvent("Session Created"...) and then performs a 20s wait (using Thread.Sleep(20 * 1000) ). A note indicates this is a trial pause to allow session event to reach Observatory Alarms web page ' added 2022-11-06 (CI).  It is reasonable to have this significant  'green' Alarm to reach Observatory Alarms Web Page.  However the Alarms Web Page is typically not used in practice.  And it would be better in most cases to not have the delay.  To review and decide course of action. One immediate action seems to be the need to inform user about the delay with the addition of a ReportComment to say there is a 20s delay in progress which is to allow Information to reach the Observatory Alarms/Events Web Page.  Improvement made in AstroMain 3.62.17  : an 'Add Delays for Events/Alarms Page' checkbox has been added to More/Obs. tab with default value 'Unchecked' which allows 20s delay to be completely by-passed, reporting added to signal the start/end of the delay with reason.
  Improvements made 2023-10-07 (AstroMain 3.62.17)  
   
• Query. When Running AutoStart why is there a 20s delay after the ReportComment "Create Live Session" ?  Code for ObservatoryManager.AutoStartSession() routine outputs the report message "Create Live Session.." and then calls WriteLiveLogs() which sets ObservatoryManager.bWriteLiveLogs = True. There is then a Thread.Sleep(20 * 1000) before objConsole.AutoCreateSession() is called.  Why is there a wait delay and why does it need to be as long as 20s ?  Setting bWriteLiveLogs triggers the OverSeerLoop (cycling every 5s) to call WriteLatestLiveLogs() which generates 'Session.LatestReport.htm' and 'Session.LatestLog.log'.  Changes made in AstroMain 3.62.17  :  wait delay decreased from 20s to 10s, reporting added to signal the start/end of the delay with reason.
  Improvements made 2023-10-07 (AstroMain 3.62.17)
   
• Put up a user confirmation dialog in order to 'Analyse Reduced Folder' if  '_COPY OF REDUCED' folder doesn't exist. This is try to prevent situation in reduction of files from Session S1155 where Reduced Files from the session were grouped by session's Excel Fits Summary macros without there being a '_Copy of Reduced' folder containing 'unnamed' Reduced Files, leaving no easy way to go back and correct an incorrectly named Image Set.
  Done 2023-10-07 (AstroMain 3.62.17)
   
• Record QC Focus Result on Focus Profile Charts. Best Focus text (e.g. Best Focus 3442) should be suffixed with the QC Result  (e.g (QC: Passed)  or (QC: Rejected). This is intended to make it easier to quickly go through the session's Focusing results.
  Done  2023-10-07 (AstroMain 3.62.17)
   
• Check floor of Observatory for water following 48 hours of rainfall (2023-10-06 20:00 to 2023-10-08 20:00). Check floor (above & below rubber floor tiles) for water encroachment under observatory walls or up various bolt holes in the concrete base, and from drops through known minor leak path between a couple of roof quadrants (need for a repair was previously raised as a Minor Issue ticket in Session S1048 (2022-10-22) has still to be completed).  Floor checked 2023-10-10 and slightly damp there was no evidence of any significant incursion of water into the observatory.
  Done 2023-10-10 (Observatory)
   
• Move Session folders from old Development Computer onto new Archive Drive.  A new 4 TB External Drive (Toshiba * , exFAT formatted, renamed as CCDArchive) that is intended specifically for archiving CCD Sessions has arrived today (2023-10-08). Sessions that currently only reside on old Development Computer should be moved to the new Archive Drive. This is in order to make them more readily accessible and perform the analysis on a backlog of sessions from Apr-Oct 2021.  There was difficulty logging onto Old Development Computer with problems initially find boot device. Eventually got in but had to re-setup account.  Operating via a VNC Connection for convenience, review of CCD Imaging/Analysis folder showed presence of session folders for sessions 2020-08-29 S00800 through to 2023-03-02 S01103.  The new (current) Developement Computer has folders for sessions 2022-09-01 S01035 through to 2023-10-05 S01155.  Copies of Session 2020-08-29 S00800 through to 2022-08-31 S01034 were copied from old Computer to the CCDArchive Drive.  (S800 to S899 - 345,430 files / 66 GB, S900 to S999 - 312,410 files / 65 GB,  S1000 to S1034 - 71,550 files / 13 GB). Later on copies of 2022-09-01 S01035 through to 2023-10-05 S01155 were copied from new computer to CCDArchive Drive to provide backup. (S1035 to S1099 - x GB, S1100 to S1155 - GB). It should be noted that not all these session folders have been fully analysed. As and when sessions from the backlog of un-analysed sessions are analysed the updated session folders will need to replace the folders that are archived now, alternatively backlog analyses needs to operate on session folders/files in their archive location.
  Done 2023-10-09 (Dev. Computer / CCDArchive )
   
  *Toshiba Canvio Partner 4TB Portable 2.5" External HDD, USB 3.2 Gen 1, Mac and Windows Compatible, USB Powered (£92.99)
   
• Look for back-up copies of Session folders prior to 2020-08-29 S00800. Old Development Computer (laptop10) contains session folder for sessions 2020-08-29 S00800 through to 2023-03-02 S01103 of which S800 to S1034 session folders will be copied to new 4 TB CCDArchive Drive,  S1035 to S1155+ will be archived or at least backed-up based on files from new Development Computer (Laptop11). Sessions prior to S800 are most probably backed up on some other portable hard drive, CD-R or DVD-R. These need to be gone through in order to move them to the new CCDArchive drive.  All Sessions found and copied to the 'CCDArchive' Disk .
  Done 2023-11-25 (CCD Archive)
   
• Put up a user confirmation dialog in order to use 'Group Reduced Files if '_COPY OF REDUCED' folder doesn't exist.  This is try to prevent situation in reduction of files from Session S1155 where Reduced Files from the session were grouped by session's Excel Fits Summary macros without there being a '_Copy of Reduced' folder containing 'unnamed' Reduced Files, leaving no easy way to go back and correct an incorrectly named Image Set.
  To do 2023-10-08 (Excel Fits Summary.xls)  

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2023-10-08

LX200 - Mirror Lock Fix (2023-10-08)

The Focus Position on the LX200 has been noted to be drifting on a number of occasions during the last 2-3 years (eg S1057 (2022-11-01), see Focusing - Temperature and Primary Mirror Slippage Effects (2022-11-01), and S1151 (2023-09-29), see Investigation - Drift in Best Focus Position (Primary Mirror Focus Slipping / Mirror Lock Not Working (2023-09-30) Whilst occassional adjustments of the LX200 Primary Mirror position buys time by taking telescope's focus back to a position corresponding to rough half-way on the TCF-S focuser range (ie 3500 in 1-7000 range), the root cause to the issue is that the mirror lock on the 12" LX200R Main Scope isn't working.

Research suggest that the Mirror Lock can be fixed and is something that I can do myself based on reading the web page Meade Mirror Lock Fix on the Peterson Engineering web site  (https://petersonengineering.com/meade-upgrades/meade-mirror-lock-fix )

Steps in fixing the mirror lock are as follows.  These are lifted from the Pete Peterson's page on the Peterson Engineering site - see link above (the steps which are themselves lifted from old LX200GPS user group postings and to a procedure attributed to Buck Harley and Doc Clay, and extended to include an addendum added by Phi Westeir in Dec 2017).

The steps are those to fix the issue that the locking knob spins freely in either direction and does not lock, but it hoped that they will also apply to my issue where the locking knob can't be turned and can't lock the primary mirror.

1. First, turn the knob all the way clockwise to the unlock position stop.
   
   On my scope the mirror lock knob can no longer be turned but it is evident from the observed focus drift and the ability of the focus knob to change the scope's focus that the mirror lock is in an unlocked position)
    
2.  Then remove the 3 cap screws that hold the locking knob assembly from the backplate of the OTA. The locking knob assembly will now be free. You may have to tilt the knob assembly slightly as you removed it from the telescope.
    
   Viewing through the backplate locking knob hole you will be able to see the 8" steel gear that serves to lock the collar around the mirror sled. About 1-inch of the rim of the gear has no teeth on it. This is the “stop”. (For those of you familiar with machinery, the mirror lock is simply a very large collet)
    
3. Insert your right index finger into the hole and push down, rotating the gear clockwise ONLY until the part with no teeth on the gear has just passed the hole where the mirror locking knob fits.  DO NOT ROTATE THE LARGE GEARED LOCKING DISK COUNTERCLOCKWISE as you will be unscrewing it from a very short thread, and if it comes free you’re faced with a major disassembly of the telescope or a return to Meade for major repair.
    
4. Once you have rotated the locking section of the gear past the open hole, reinstall the locking knob assembly.
    
   The knob has teeth on the back of it, well those teeth are spring to slide back and forward. If you simply reinsert the knob, the teeth do not reach far enough into the scope to engage with the scope gear teeth. What you have to do is use a thin screwdriver to push the knob teeth out (i.e. extend them) as you are inserting the knob. This makes them long enough to reach the scope teeth. Hold the knob with a small bit of sideways pressure to keep the two sets of teeth together, then withdraw the screwdriver and keep holding the knob while you reinstall the three capscrews.
   
   The spring on the knob teeth pulls the teeth back and the bottom plate of the knob teeth then sits behind the scope gear teeth.
    
   It all sounds tricky but it’s very easy and is an essential step to ensure the knob teeth are properly engaged in the scope teeth.
    
   Once inserted correctly the mirror lock should now lock and unlock properly. Don’t worry about how many turns you have from end stop to where you start to feel locking resistance. All that matters is that you have some free movement in the full clockwise position and when the knob is turned counter-clockwise you’re able to snug up the mirror.
   
   (Pete Westeir noted that once re-installed the clockwise (unlock) stop worked perfectly, then it was 8.5 turns counterclockwise to the mirror lock position.

The steps above will be adjusted in due course based on my own experience of attempting a mirror lock  fix, an attempt was made to remote the gear clockwise until the part with no teeth has just passed the hole where the mirror locking knob fits.

Update 2023-11-11

An attempt to fix the Mirror Lock was made today (2023-11-11).

1. The Mirror lock knob was already as far clockwise as it could go (in fact the knob couldn't be turned in either direction)
    
2. The 3 cap screws that hold the locking knob assembly from the backplate of the OTA were removed, and the locking knob assembly was then taken out (this was easily achieved) .
   
    
   
    Viewing through the back plate locking knob hole the 8" steel gear that serves to lock the collar around the mirror sled was visible.
    The short section of gear with no teeth (the "stop") was just visible on the anti-clockwise side.
   
   
   
3.  Right index finger was inserted into hole and pushed down.
    It was assumed this meant pushing down on the gear rim. When this was done there was no noticable 'give'  (the feel was 'solid').
    
   An attempt was made to rotate the gear clockwise, but it wouldn't budge / wouldn't rotate.
    
4.  After making several unsuccessful attempts to manually rotate the gear, gave up and reinserted mirror lock assembly and refitted the 3 cap screws.
   
   The steps on Peterson Engineering web site talk about the teeth on the back of the knob being spring loaded and needing to push them out with a small screwdriver for them to engage but I couldn't see what he was talking about.
   
   

I may try again to fix the mirror lock on a later occasion.

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