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 Notes - Session 946 (2021-12-29)

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Bullet Session Aims & Highlights
 - Observing Result
 - Night Summary Plot
 - Session Event Log
 
Bullet Operational Issues
  - Critical Issues (0),  Major Issues (0),  Minor Issues (2),  Small Defects (2),  Continuous Improvement (8)
 
Bullet Images from 2021-12-29 >>         [ Local Files >> ]
2021-12-31
Bullet Guiding Review - Lock Position Adjustments

Session Aims & Highlights (2021-12-29)

Main aims

  1. Guiding Manager. Test out new method for limiting impact of Dec Backlash
  2. Targets.  Acquire images of a selection of variable stars, nearby stars, comets & deep sky targets as allowed by time & conditions.

Equipment & Software

Highlights

Notes:

  Summary Plots & Logs

Observing Plan
Image
  
Observing Result
Image
   
  
Dome & Scope Slewing Performance
Image
  
Slew/Centering Performance
Image
  
Guiding Performance
Reasons for poor Dec guiding :
Black points (12, 19, 20,
21,22, 23)		   - Cloud
Black points (9)   - Dec Guide anomalies
Purple point (10)   - Ineffective Dec Guiding (Near Zenith)
Red points (6)   - Ineffective Dec Guiding.    In addition point 6 (black point on RA plot) had
poor RA guiding due to either a bad RA gear section or cable hang.
Orange points (1)   - Ineffective RA guiding (Near Zenith)
Yellow points  (14)    - Wrong side of Zero Line for the chosen DecGuideMode
Yellow points (5, 7, 14,15)   - 14
Image
Image
  
Sky Conditions (Locate Frames)
Sky Brightness measurements are invalid due to a SBIG camera bias level issue (eventually fixed 2022-01-02)
Image
 
Night Sky Summary Plot
Top axis: Sky Brightness at Zenith (in ADU/s)
Lefthand axis: Local Time (hh LT). Righthand axis: Sun Altitude (degs)
Image   
  
Actual Weather vs Pre-Session Weather Forecast
Image
Image   
  
Session Event Log
Time     Event Detail
20:14:55 Session Monitoring AutoStart monitoring for Live Session opportunity between 20:14 & 06:27
20:15:00 Session AutoStarting Session autostarting (20:15)
20:15:40   Camera1 Connected SBIG Camera Connected (set point -15°C)
20:15:42 Session Created Live Session Created (2021-12-29 S00946, ImageSaveNum: 946001)
20:15:44   Scope Switched On Telescope Power has been switched on via UPB Powerbox.
20:17:24   Services Started Observatory Services started
20:17:30 Observatory (Auto) Observatory placed in Fully-Automated Mode
20:17:35 Session Pending Session pending (2021-12-29)
20:17:37 Session Initiating Session initiating (2021-12-29)
20:17:39   Plan Requested Observing Plan requested from AstroPlan (1.29.2)
20:18:10   Plan Loaded Observing Plan loaded to queue (, Plan ID: 700)
20:18:26   Camera1 Connected SBIG Camera Connected (set point -15°C)
20:18:32   Telescope Connected Telescope Connected (TheSky6)
20:18:56 Session Equilibration Session ready for dome & camera equilibration
20:19:41   Dome Opened Dome opened (opening time 45s)
20:20:41 Session Running Session running
20:20:43   Queue Started Observing Queue started (32 targets selected)
20:20:46     Target Started (NrZen) Target started (Focus Field 3, HIP 14181)
20:22:34       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
20:25:45       Focusing Completed Foc1 AutoFocus Completed (Profile No 1, wide)
20:28:09       Focusing Completed Foc1 AutoFocus Completed (Profile No 1)
20:28:33       Focusing Started-Foc2 Foc2 Focusing Started (Secondary Scope, using ShCap)
20:30:41       Focusing Completed Foc2 AutoFocus Completed (Profile No 2, wide)
20:32:28       Focusing Completed Foc2 AutoFocus Completed (Profile No 2)
20:32:46     Target Completed Target completed (Focus Field 3, HIP 14181)
20:32:50     Target Started (1/32) Target started (1/32, NGC 1569 w/AT2021aczn)
20:38:16       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
20:40:16       Focusing Completed Foc1 AutoFocus Completed (Profile No 3)
20:57:05     Target Completed Target completed (1/32, NGC 1569 w/AT2021aczn)
20:57:10     Target Started (2/33) Target started (2/33, 61 Cyg, ToO)
21:01:05       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
21:03:06       Focusing Completed Foc1 AutoFocus Completed (Profile No 4)
21:06:27     Target Completed Target completed (2/33, 61 Cyg, ToO)
21:06:31     Target Started (3/33) Target started (3/33, AT2021xrf)
21:18:39     Target Completed Target partially completed (3/33, AT2021xrf)
21:18:43     Target Started (4/33) Target started (4/33, SN 2021win)
21:21:24       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
21:23:12       Focusing Completed Foc1 AutoFocus Completed (Profile No 5)
21:39:43     Target Completed Target completed (4/33, SN 2021win)
21:39:47     Target Started (5/33) Target started (5/33, NGC 7446 w/SN2021agdd)
21:43:11       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
21:45:16       Focusing Completed Foc1 AutoFocus Completed (Profile No 6)
22:01:47     Target Completed Target completed (5/33, NGC 7446 w/SN2021agdd)
22:01:51     Target Started (6/33) Target started (6/33, GCVS BL Lac)
22:04:33       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
22:06:47       Focusing Completed Foc1 AutoFocus Completed (Profile No 7)
22:10:47     Target Completed Target completed (6/33, GCVS BL Lac)
22:10:51     Target Started (7/33) Target started (7/33, Nova Cas 2021)
22:13:52       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
22:15:40       Focusing Completed Foc1 AutoFocus Completed (Profile No 8)
22:23:06     Target Completed Target completed (7/33, Nova Cas 2021)
22:23:10     Target Started (8/33) Target started (8/33, 132P/Helin-Roman-Alu)
22:27:20       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
22:29:38       Focusing Completed Foc1 AutoFocus Completed (Profile No 9)
22:38:54     Target Completed Target completed (8/33, 132P/Helin-Roman-Alu)
22:38:58     Target Started (9/33) Target started (9/33, UGC 1971 w/SN2021afkk)
22:42:08       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
22:44:27       Focusing Completed Foc1 AutoFocus Completed (Profile No 10)
23:01:29     Target Completed Target completed (9/33, UGC 1971 w/SN2021afkk)
23:01:33     Target Started (10/33) Target started (10/33, UGC 3855 w/SN2021agco)
23:05:30       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
23:07:30       Focusing Completed Foc1 AutoFocus Completed (Profile No 11)
23:24:05     Target Completed Target completed (10/33, UGC 3855 w/SN2021agco)
23:24:09     Target Started (11/33) Target started (11/33, Scholz's Star)
23:27:49       Focusing Skipped Foc1 focusing skipped - star is lost (TCF-S)
23:43:03     Target Completed Target completed (11/33, Scholz's Star)
23:43:07     Target Started (12/33) Target started (12/33, AT2021agjs)
23:47:26       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S)
23:55:11   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
00:04:31     Target Completed Target completed (12/33, AT2021agjs)
00:04:33   Queue Paused Queue paused for Session Suspension
00:04:35 Session Suspended Session suspended
00:05:22   Dome Closed Dome closed (closing time 50s)
00:23:29     Target Cancelled Target cancelled (13/33, NGC 2761 w/SN2021aggu) due to cloud
00:45:21     Target Cancelled Target cancelled (14/33, AT2021aagc) due to cloud
01:01:51     Target Cancelled Target cancelled (15/33, C/2019 L3 (ATLAS)) due to wind
01:15:00 Session Resuming Session resuming
01:15:45   Dome Opened Dome opened (opening time 45s)
01:15:47 Session Running Session running
01:15:49   Queue Resumed Observing Queue resumed
01:15:52     Target Started (16/33) Target started (16/33, 67P/Churyumov-Gerasimenko)
01:25:53     Target Completed Target partially completed (16/33, 67P/Churyumov-Gerasimenko)
01:25:57     Target Started (17/33) Target started (17/33, AT2021agdv (CV))
01:30:32       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
01:32:33       Focusing Completed Foc1 AutoFocus Completed (Profile No 12)
01:37:59     Target Completed Target partially completed (17/33, AT2021agdv (CV))
01:38:03     Target Started (18/33) Target started (18/33, AT2021afkg)
01:41:06       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
01:43:02       Focusing Failed Foc1 focusing failed - star lost
01:59:35     Target Completed Target completed (18/33, AT2021afkg)
01:59:40     Target Started (19/33) Target started (19/33, UGC 5341)
02:02:56       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S)
02:19:01     Target Completed Target completed (19/33, UGC 5341)
02:19:05     Target Started (20/33) Target started (20/33, NGC 3254)
02:21:48       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
02:23:49       Focusing Completed Foc1 AutoFocus Completed (Profile No 14)
02:40:22     Target Completed Target completed (20/33, NGC 3254)
02:40:26     Target Started (21/33) Target started (21/33, NGC 3310 w/SN2021gmj)
02:43:41       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
02:45:53       Focusing Completed Foc1 AutoFocus Completed (Profile No 15)
02:57:23   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
03:03:33     Target Completed Target completed (21/33, NGC 3310 w/SN2021gmj)
03:03:35   Queue Paused Queue paused for Session Suspension
03:03:37 Session Suspended Session suspended
03:04:19   Dome Closed Dome closed (closing time 45s)
03:21:15     Target Cancelled Target cancelled (22/33, PGC 38265) due to cloud
03:43:07     Target Cancelled Target cancelled (23/33, UGC 8975 w/AT2021adpe) due to cloud
03:51:34 Session Resuming Session resuming
03:52:19   Dome Opened Dome opened (opening time 45s)
03:52:22 Session Running Session running
03:52:24   Queue Resumed Observing Queue resumed
03:52:26     Target Started (24/33) Target started (24/33, NGC 3389 w/AT2021hkw)
04:10:16     Target Completed Target partially completed (24/33, NGC 3389 w/AT2021hkw)
04:10:20     Target Started (25/33) Target started (25/33, NGC 3836 w/SN2021aefs)
04:15:45       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S)
04:26:53   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
04:30:09 Critical Cloud Alert Critical Cloud Alert (Obs.Manager will close the Dome)
04:30:11   HardSuspend Called Hard Suspend is called due to Critical Conditions (cloud)
04:30:13     Target Aborted (25/33) Target aborted (25/33, NGC 3836 w/SN2021aefs) due to cloud
04:30:15   Queue Paused Queue paused for Session Suspension
04:30:17 Session Suspended Session suspended
04:31:04   Dome Closed Dome closed (closing time 50s)
04:40:43     Target Cancelled Target cancelled (26/33, AT2021aena (CV)) due to cloud
05:13:31     Target Cancelled Target cancelled (27/33, NGC 2371) due to cloud
05:35:23     Target Cancelled Target cancelled (28/33, UGC 4671 w/SN2021afsj) due to cloud
05:57:45     Target Cancelled Target cancelled (29/33, NGC 4921) due to other condition
06:11:37     Target Cancelled Target cancelled (30/33, AT2021agpw (CV)) due to other condition
06:13:37 Session Resuming Session resuming
06:14:22   Dome Opened Dome opened (opening time 45s)
06:14:24 Session Running Session running
06:14:26   Queue Resumed Observing Queue resumed
06:14:29     Target Started (31/33) Target started (31/33, Hickson 81)
06:17:54       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S)
06:34:17     Target Completed Target completed (31/33, Hickson 81)
06:35:03     Target Started (32/33) Target started (32/33, GCVS U Her)
06:35:20   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
06:37:45       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
06:39:58       Focusing Completed Foc1 AutoFocus Completed (Profile No 16)
06:44:56   SoftSuspend Cancelled Soft Suspend is cancelled due to improved conditions
06:49:03     Target Completed Target completed (32/33, GCVS U Her)
06:49:07     Target Started (33/33) Target started (33/33, C/2017 K2 (PANSTARRS))
06:53:43       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S)
07:00:58   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
07:02:13     Target Completed Target completed (33/33, C/2017 K2 (PANSTARRS))
07:02:15   Queue Paused Queue paused for Session Suspension
07:02:18 Session Suspended Session suspended
07:03:08   Dome Closed Dome closed (closing time 50s)
07:09:55     Target Cancelled Target cancelled (33/33, C/2017 K2 (PANSTARRS)) due to cloud
07:10:00   Queue Completed Job Queue completed
07:10:04 Session Closing Session closing
07:10:09   Dome Closed Dome already closed (closed at 07:03, closing time 50s)
07:10:27   Dome Parked Dome parked (parking time 10s), Az: 90.0 deg
07:12:12   Telescope Parked Telescope parked (parking time 102s)
07:12:32   Telescope State Scope parked Turn scope off. (Handbox)
07:12:55   Telescope Switched Off Telescope Power has been switched off via UPB Switch.
07:13:51   Services Stopped Night Services stopped
07:13:53 Session Housekeeping Housekeeping Started (Cleanup FITS, Create Fits Summary, Transfer Files)
07:14:14 Session Finished Session Finished
 
Session Alerts
Time     Alert Detail
-- No Alerts                --                              

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2021-12-31

Guiding Review - Lock Position Adjustments

Lock Position Adjustments
Lock Position adjustments are being tried during guide settling in order to overcome issues with Dec backlash & backlash overcompensation.  In situation where guide star starts out on the wrong side of zero line for planned uni-directional guiding or where first guide pulse pushes the guide star onto the wrong side of the zero line, a simple adjustment of lock position can be used to quickly bring the guide star 'back' to the zero line without any of the side effects of swamping the Dec Guide Mode only to swap it back later on, with the extra uncertainty that brings to Dec position.

The technique has been usefully applied during sessions S945 & S946 to adjust guide star position during settling/focusing stage, prior to acquiring main frames.

There is opportunity to extend the technique to make adjustments between main frames to help reduce guide error in two particular situations.

1) where Dec Guiding is proving to be ineffective in bringing the guide star back to the zero line
 (this can happen particularly where the target is lying close to zenith)

2) where guide position has moved to the wrong side of the zero line where principal Dec guide mode can not appply guide pulses to bring the guide star back to the zero line.

Examples of these two situations from session S945 & S946 are shown below.

1a) Non-Effective Dec Guiding - Guide Run 1 (Near Zenith)

At the end of Frame 2 and certainly at the end of Frame 3 & 4, an adjustment in Lock Position would have been helpful in bringing the guide star back to zero position.  Doing this in this case particular case would have reduced the average guide error over the entire guide run, but wiuld probably not have changed the quality of an image made up of the 5 aligned and stacked frames.

Image

1b) Non-Effective Dec Guiding - Guide Run 5

In this example a lock shift adjustment at end of Frame 1 would have arguably reduced the guide errors during Frame 2.  Resetting the Dec Guide error back to zero,  would have reduced the likelihood of seeing the 3-4 arc sec movement in position at 21:51 when the Dec Pulse guides finally returned the guide star back to zero line part way through Frame 2 exposure. .

Image

2) Guide Star on Wrong Side of Zero Line  - Guide Run 22 (close to Meridian)

In this example lying close to Meridian there is no strong direction of star drift and there is every chance that the Principal Dec Guide Mode may be inappropriate or not optimised for the precise target position.  Possibly related to cloud/atmosphere change at 02:51:30 the Guide Star has become positioned on the wrong side of the zero line where unidirectional Dec Guiding is inactive. Adjustment in Lock Position at end of Frame 1, 2 and 3 could have limited the drift in position which eventually reached 4" during Frame 4.  Eventually a change in DecGuideMode was triggered at end of Frame 4,  but a single guide pulse saw telescope position move from +3 to  -4.  which again left the guide star on the wrong side of the zero line for the fifth and final frame. 

A change in lock position should have been employed to bring the reset the zero position, which might have prevented the overshoot in position caused by the change in Dec Guide Mode.  A purple line around the time of the Dec Guide Mode change shows that a lock position chnage was made,  but being coincident with the Dec Guide Pulse might have been a factor in the overshoot (from two changes being made at same time)

Image

Logs associated with change in DecGuide Mode and Lock Position just before Starting Frame 5 :

03:03:42.63 | TakeImage       | Image 5/5
03:03:42.98 | GuideMonitor    | Starting GuidingStats (Frame)
03:03:43.00 | RecentDecPoints | 1) T 03:03:25 gY 3.92"
03:03:43.00 | RecentDecPoints | 2) T 03:03:28 gY 3.89"
03:03:43.00 | RecentDecPoints | 3) T 03:03:31 gY 4.26"
03:03:43.00 | RecentDecPoints | 4) T 03:03:35 gY 4.52"
03:03:43.00 | RecentDecPoints | 5) T 03:03:38 gY 3.39"
03:03:43.00 | RecentDecPoints | 6) T 03:03:41 gY 3.07"
03:03:43.00 | RecentDecPoints | N 6, Av gY 3.8", Min gY 3.1", Last gY 3.1"
03:03:43.12 | DecMode         | Changing Dec Guide Mode to South (Star needs to be moved back to lock position)
03:03:43.12 | ImagingHold     | Starting a 30s delay after changing Dec Mode (Guide Monitor)
03:03:43.12 | PHD2 Event      | PHD2 event during guiding :GuideParamChange
03:03:44.47 | GuideMonitor    | Y Adjustment Required: PrincipalDecMode=North, G.dy=3.48", yAdj=3.37 px
03:03:45.22 | LockPosition    | New Lock Position x: 1,941.57, y: 1,579.56, y_adj: 3.37
03:03:45.22 | PHD2 Event      | PHD2 event during guiding :LockPositionSet
03:03:47.14 | WaitOnGuider    | Waiting for Guider to set bReadyForImage=True
03:04:13.21 | ImagingHold     | Ending hold on imaging (Guide Monitor)
03:04:13.42 | WaitOnGuider    | Guider has set bReadyForImage=True (30s)
03:04:13.42 | Start           | [ TakeImage() Start ]
03:04:13.75 | Camera.TakeImage| [ TakeImage() TakeImage ]
03:05:03.68 | PHD2 Event      | PHD2 event during guiding :GuideParamChange
03:05:14.99 | PHD2 Event      | PHD2 event during guiding :GuideParamChange

Actions

Image  Lock Position Adjustments. Use Lock Position adjustments to correct Dec Guide Errors before starting a new image instead of changing Dec GuideMode.   This is to minimize overall Dec Guide Errors and prevent overshoots due to Dec Backlash/Overcompensation. Lock Position adjustment to be made where Dec error is <-1.0 or >+1.0 (Dec Guide mode is only changed when crossing Meridian).

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