David's Astronomy Pages
Notes - Session 848 (2021-01-11)

 
Bullet Session Aims & Highlights
 - Observing Result
 - Night Summary Plot
 - Session Event Log
 
Bullet Operational Issues
  - Critical Issues (0),  Major Issues (0),  Minor Issues (6),  Continuous Improvement (12)
Bullet Images from 2021-01-11 >>
Bullet Aurora Images/Video from 2021-01-11 >>
Bullet Investigation - Autoguiding Issues (Uncorrected Dec drift during Guide Run 4)
Bullet Analysis: Protection from approaching showers

Session Aims & Highlights (2021-01-11)

Main aims

  1. Software. Check out new versions of AstroPlan and AstroMain which have received notable changes since last session
  2. Targets. Acquire images of a selection of variable stars, nearby stars, comets and deep sky targets as allowed by conditions.

Equipment & Software

Highlights

Summary Plots & Logs

Observing Plan
Image
  
Observing Result
Image
   
Dome & Scope Slewing Performance
Image
  
Slew/Centering Performance
Image
  
Guiding Performance
Black Points correspond to Guide Runs 26 to 36 , where guding failed due to a closed observatory dome issue.
Apart from that the Guiding was relatively good.
Image
Image
  
Sky Conditions (Locate Frames)
Data for second part of night is erronous as Observatory shutter was unknowingly closed
Image
Chart unavailable for this session
  
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   
  
Pre-Session Weather Forecast (API data from darksky.net)
Pre-Session Weather forecast showed initial snow showers followed by slight clearing (85-91% cloud cover),
followed by overcast skies,  with possible sleet/snow showers moving to later to rain showers
as temperatures rose from -2 degC at dusk to 4 degC at dawn
Wind calm/light in first part of night, but strengthening later reached 17-19 mph by dawn.

In the event skies were very clear from dusk to 22:30 before clouding over for the remainder of the night with
prolonged rain shower at rain shower at 02:30-03:15.
Minumum Temperature of -4 degC at 22:00 before warming later in night under cloud.
Winds relatively light in first half of night, but strengthening towards dawn.
Image
Image   
  
Session Event Log
Time     Event Detail
19:53:20   Camera1 Connected SBIG Camera Connected (set point -30°C)
19:53:22 Session Created Live Session Created (2021-01-11 S00848, ImageSaveNum: 848001)
19:53:24   Scope Switched On Telescope Power has been switched on via UPB Powerbox.
19:54:36   Services Started Observatory Services started
19:54:37 Observatory (Manual) Observatory placed in Manual Mode
20:05:59   Services Stopped Observatory Services stopped
20:06:09 Program Closed Program closed by User
20:06:11 Program Closed Program closed by User
20:20:50 Session Resumed Live Session Resumed (2021-01-11 S00848, ImageSaveNum: 848001)
20:21:30   Obs.Manager Started Obs.Manager started
20:21:32   Obs.Overseer Started Obs.Overseer started
20:21:35   Services Started Observatory Services started
20:22:40   Services Started Observatory Services started
20:23:37   Telescope Connected Telescope Connected (TheSky6)
20:23:53   Camera1 Connected SBIG Camera Connected (set point -25°C)
20:24:17   Services Started Observatory Services started
20:24:30 Observatory (Auto) Observatory placed in Fully-Automated Mode
20:24:32 Session Pending Session pending (2021-01-11)
20:24:34 Session Initiating Session initiating (2021-01-11)
20:24:36   Plan Requested Observing Plan requested from AstroPlan (1.19)
20:25:05   Plan Loaded Observing Plan loaded to queue (2021-01-11 V1 BEST PLAN, Plan ID: 583)
20:25:09   Camera1 Connected SBIG Camera Connected (set point -25°C)
20:25:13   Telescope Connected Telescope Connected (TheSky6)
20:25:25 Session Equilibration Session ready for dome & camera equilibration
20:26:10   Dome Opened Dome opened (opening time 45s)
20:26:12 Session Running Session running
20:26:14   Queue Started Observing Queue started (34 targets selected)
20:27:30       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
20:30:10       Focusing Completed Foc1 AutoFocus Completed (Profile No 1)
20:31:55       Focusing Completed Foc1 AutoFocus Completed (Profile No 1)
20:31:58       Focusing Started-Foc2 Foc2 Focusing Started (Secondary Scope, using ShCap)
20:34:13       Focusing Completed Foc2 AutoFocus Completed (Profile No 2, wide)
20:36:04       Focusing Completed Foc2 AutoFocus Completed (Profile No 2)
20:36:20       Focusing Checked Foc2 Focusing Check Succeeded
20:36:26     Target Started (1/34) Target started (1/34, Nova Per 2020 w/AT2020abap)
20:47:52     Target Completed Target partially completed (1/34, Nova Per 2020 w/AT2020abap)
20:47:54     Target Started (2/34) Target started (2/34, C/2020 M3 (Atlas))
20:50:21       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
20:52:11       Focusing Completed Foc1 AutoFocus Completed (Profile No 3)
20:57:29     Target Completed Target completed (2/34, C/2020 M3 (Atlas))
20:57:31     Target Started (3/34) Target started (3/34, GSC 1224:29)
21:00:13       Focusing Skipped Foc1 focusing skipped - star is too dim (TCF-S)
21:06:53     Target Completed Target completed (3/34, GSC 1224:29)
21:06:55     Target Started (4/34) Target started (4/34, UGC 784 w/SN2021pc)
21:10:03       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
21:12:13       Focusing Completed Foc1 AutoFocus Completed (Profile No 4)
21:28:16   Camera1 Connected SBIG Camera Connected (set point -25°C)
21:28:21     Target Completed Target completed (4/34, UGC 784 w/SN2021pc)
21:28:23     Target Started (5/34) Target started (5/34, UGC 1436 w/SN2021nv)
21:31:14       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
21:33:17       Focusing Completed Foc1 AutoFocus Completed (Profile No 5)
21:49:05     Target Completed Target completed (5/34, UGC 1436 w/SN2021nv)
21:49:45     Target Started (6/34) Target started (6/34, UGC 2528 w/AT2020adnx)
21:52:14       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
21:54:16       Focusing Completed Foc1 AutoFocus Completed (Profile No 6)
22:09:51     Target Completed Target completed (6/34, UGC 2528 w/AT2020adnx)
22:09:53     Target Started (7/35) Target started (7/35, NGC 1555, ToO)
22:11:58       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
22:13:48       Focusing Completed Foc1 AutoFocus Completed (Profile No 7)
22:22:26     Target Completed Target completed (7/35, NGC 1555, ToO)
22:22:28     Target Started (8/35) Target started (8/35, GCVS CM Tau)
22:35:38     Target Completed Target partially completed (8/35, GCVS CM Tau)
22:35:40     Target Started (9/35) Target started (9/35, UGCA 114)
22:38:19       Focusing Skipped Foc1 focusing skipped - star is too dim (TCF-S)
22:53:04 Critical Cloud Alert Critical Cloud Alert (Obs.Manager will close the Shutter)
22:53:06   HardSuspend Called Hard Suspend is called due to Critical Conditions (cloud)
22:53:08     Target Aborted (9/35) Target aborted (9/35, UGCA 114) due to cloud
22:53:10   Queue Paused Queue paused for Session Suspension
22:53:12 Session Suspended Session suspended
22:53:59   Dome Closed Dome closed (closing time 49s)
22:58:59     Target Cancelled Target cancelled (10/36, NGC 4414 w/SN2021J, ToO) due to cloud
23:03:57     Target Cancelled Target cancelled (11/36, GCVS U Mon) due to cloud
23:24:06 Session Resuming Session resuming
23:24:08     Target Cancelled Target cancelled (12/36, Scholz's Star) due to wind
23:24:52   Dome Opened Dome opened (opening time 45s)
23:24:54 Session Running Session running
23:24:56   Queue Resumed Observing Queue resumed
23:26:09     Target Started (13/36) Target started (13/36, UGCA 164)
23:28:17       Focusing Skipped Foc1 focusing skipped - star is too dim (TCF-S)
23:29:02   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
23:29:07   SoftSuspend Cancelled Soft Suspend is cancelled due to Improved Conditions
23:34:37   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
23:34:47   SoftSuspend Cancelled Soft Suspend is cancelled due to Improved Conditions
23:39:18   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
23:42:58   SoftSuspend Cancelled Soft Suspend is cancelled due to Improved Conditions
23:45:38     Target Completed Target completed (13/36, UGCA 164)
23:48:30     Target Started (14/36) Target started (14/36, GCVS RZ LMi)
23:52:01       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
23:53:49       Focusing Completed Foc1 AutoFocus Completed (Profile No 8)
23:59:04     Target Completed Target completed (14/36, GCVS RZ LMi)
00:00:18     Target Started (15/36) Target started (15/36, M85)
00:04:39       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
00:06:42       Focusing Completed Foc1 AutoFocus Completed (Profile No 9)
00:13:31   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
00:14:21   SoftSuspend Cancelled Soft Suspend is cancelled due to Improved Conditions
00:15:11     Target Completed Target completed (15/36, M85)
00:15:20     Target Started (16/36) Target started (16/36, GCVS RR Tau)
00:18:28       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
00:20:23       Focusing Completed Foc1 AutoFocus Completed (Profile No 10)
00:26:18     Target Completed Target completed (16/36, GCVS RR Tau)
00:26:20     Target Started (17/36) Target started (17/36, UGC 3879)
00:28:21       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
00:30:20       Focusing Completed Foc1 AutoFocus Completed (Profile No 11)
00:46:11     Target Completed Target completed (17/36, UGC 3879)
00:48:46     Target Started (18/36) Target started (18/36, GCVS ER UMa)
00:51:07       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S)
00:52:49 Critical Cloud Alert Critical Cloud Alert (Obs.Manager will close the Shutter)
00:52:52   HardSuspend Called Hard Suspend is called due to Critical Conditions (cloud)
00:52:54     Target Aborted (18/36) Target aborted (18/36, GCVS ER UMa) due to cloud
00:52:56   Queue Paused Queue paused for Session Suspension
00:52:58   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
00:53:00 Session Suspended Session suspended
00:53:40   Dome Closed Dome closed (closing time 45s)
00:58:04     Target Cancelled Target cancelled (18/36, GCVS ER UMa) due to cloud
00:58:55 Session Resuming Session resuming
00:59:40   Dome Opened Dome opened (opening time 45s)
00:59:42 Session Running Session running
00:59:44   Queue Resumed Observing Queue resumed
00:59:46     Target Started (19/36) Target started (19/36, UGCA 184)
01:01:38       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
01:03:39       Focusing Completed Foc1 AutoFocus Completed (Profile No 12)
01:04:31   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
01:17:02 Critical Cloud Alert Critical Cloud Alert (Obs.Manager will close the Shutter)
01:17:04   HardSuspend Called Hard Suspend is called due to Critical Conditions (cloud)
01:17:06     Target Aborted (19/36) Target aborted (19/36, UGCA 184) due to cloud
01:17:08   Queue Paused Queue paused for Session Suspension
01:17:10 Session Suspended Session suspended
01:17:57   Dome Closed Dome closed (closing time 50s)
01:18:26     Target Cancelled Target cancelled (19/36, UGCA 184) due to wind
01:40:48     Target Cancelled Target cancelled (20/36, NGC 2377) due to wind
01:45:39 Session Resuming Session resuming
01:46:24   Dome Opened Dome opened (opening time 45s)
01:46:26 Session Running Session running
01:46:28     Target Started (21/36) Target started (21/36, GCVS SY Cnc)
01:46:30   Queue Resumed Observing Queue resumed
01:48:32       Focusing Skipped Foc1 focusing skipped - star is too dim (TCF-S)
01:53:22     Target Completed Target completed (21/36, GCVS SY Cnc)
01:53:24     Target Started (22/36) Target started (22/36, NGC 2782 w/SN2020scc)
01:55:10       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S)
02:12:56     Target Completed Target completed (22/36, NGC 2782 w/SN2020scc)
02:15:50     Target Started (23/36) Target started (23/36, UGCA 201)
02:17:56       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
02:19:49       Focusing Completed Foc1 AutoFocus Completed (Profile No 13)
02:35:52     Target Completed Target completed (23/36, UGCA 201)
02:38:11     Target Started (24/36) Target started (24/36, NGC 3277)
02:40:04   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
02:40:07       Focusing Skipped Foc1 focusing skipped - star is too dim (TCF-S)
02:41:10 Critical RainThreat Alert Critical Rain Threat Alert (Obs.Manager will close the Shutter)
02:41:12   HardSuspend Called Hard Suspend is called due to Critical Conditions (threat of rain)
02:41:14     Target Aborted (24/36) Target aborted (24/36, NGC 3277) due to threat of rain
02:41:16   Queue Paused Queue paused for Session Suspension
02:41:18 Session Suspended Session suspended
02:42:05   Dome Closed Dome closed (closing time 49s)
02:57:33     Target Cancelled Target cancelled (24/36, NGC 3277) due to wind
02:57:51 Session Resuming Session resuming
02:58:36   Dome Opened Dome opened (opening time 45s)
02:58:38 Session Running Session running
02:58:40   Queue Resumed Observing Queue resumed
03:00:33     Target Started (25/36) Target started (25/36, NGC 3321)
03:03:42       Focusing Skipped Foc1 focusing skipped - star is too dim (TCF-S)
03:19:43     Target Completed Target completed (25/36, NGC 3321)
03:22:55     Target Started (26/36) Target started (26/36, UGCA 217)
03:25:37       Focusing Skipped Foc1 focusing skipped - star is too dim (TCF-S)
03:32:44   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
03:33:29 Critical RainThreat Alert Critical Rain Threat Alert (Obs.Manager will close the Shutter)
03:33:31   HardSuspend Called Hard Suspend is called due to Critical Conditions (threat of rain)
03:33:34     Target Aborted (26/36) Target aborted (26/36, UGCA 217) due to threat of rain
03:33:37   Queue Paused Queue paused for Session Suspension
03:33:40 Session Suspended Session suspended
03:34:29   Dome Closed Dome closed (closing time 50s)
03:42:17     Target Cancelled Target cancelled (26/36, UGCA 217) due to rain
03:43:40   Camera1 SetPoint -20°C SBIG Camera Set Point Temperature Updated (new set point -20°C)
04:04:39     Target Cancelled Target cancelled (27/36, NGC 4454 w/SN2020abgq) due to other condition
04:27:01     Target Cancelled Target cancelled (28/36, IC 3558) due to cloud
04:32:35 Session Resuming Session resuming
04:33:20   Dome Opened Dome opened (opening time 45s)
04:33:22 Session Running Session running
04:33:24     Target Started (29/36) Target started (29/36, UGC 7321)
04:33:26   Queue Resumed Observing Queue resumed
04:35:05       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S)
04:37:30   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
04:38:15   SoftSuspend Cancelled Soft Suspend is cancelled due to Improved Conditions
04:51:26   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
04:52:32   SoftSuspend Cancelled Soft Suspend is cancelled due to Improved Conditions
04:53:18     Target Completed Target completed (29/36, UGC 7321)
04:53:21     Target Started (30/36) Target started (30/36, NGC 4290)
04:59:56       Focusing Skipped Foc1 focusing skipped - star is too dim (TCF-S)
05:17:20     Target Completed Target completed (30/36, NGC 4290)
05:17:22     Target Started (31/36) Target started (31/36, NGC 4414 w/SN2021J)
05:19:28       Focusing Skipped Foc1 focusing skipped - star is too dim (TCF-S)
05:37:20     Target Completed Target completed (31/36, NGC 4414 w/SN2021J)
05:37:22     Target Started (32/36) Target started (32/36, UGCA 314)
05:40:16       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S)
05:58:07     Target Completed Target completed (32/36, UGCA 314)
05:59:29     Target Started (33/36) Target started (33/36, NGC 5331 w/AT2020abir)
06:01:35       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
06:03:37       Focusing Completed Foc1 AutoFocus Completed (Profile No 14)
06:11:54   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
06:11:56 Critical Cloud Alert Critical Cloud Alert (Obs.Manager will close the Shutter)
06:11:58   HardSuspend Called Hard Suspend is called due to Critical Conditions (cloud)
06:11:59     Target Aborted (33/36) Target aborted (33/36, NGC 5331 w/AT2020abir) due to cloud
06:12:01   Queue Paused Queue paused for Session Suspension
06:12:04 Session Suspended Session suspended
06:12:54   Dome Closed Dome closed (closing time 50s)
06:18:21     Target Cancelled Target cancelled (33/36, NGC 5331 w/AT2020abir) due to cloud
06:25:20 Session Resuming Session resuming
06:26:05   Dome Opened Dome opened (opening time 45s)
06:26:07 Session Running Session running
06:26:09   Queue Resumed Observing Queue resumed
06:26:11     Target Started (34/36) Target started (34/36, GCVS R CrB)
06:27:49       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
06:29:28       Focusing Completed Foc1 AutoFocus Completed (Profile No 15)
06:32:27     Target Completed Target completed (34/36, GCVS R CrB)
06:32:29     Target Started (35/36) Target started (35/36, GCVS U Her)
06:32:36   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
06:35:11   SoftSuspend Cancelled Soft Suspend is cancelled due to Improved Conditions
06:36:49       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
06:38:29       Focusing Completed Foc1 AutoFocus Completed (Profile No 16)
06:41:26   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
06:41:51   SoftSuspend Cancelled Soft Suspend is cancelled due to Improved Conditions
06:44:32   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
06:45:17   SoftSuspend Cancelled Soft Suspend is cancelled due to Improved Conditions
06:45:41     Target Completed Target completed (35/36, GCVS U Her)
06:45:43     Target Started (36/36) Target started (36/36, UGC 6930 w/SN2020rcq)
06:48:51       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
06:50:57       Focusing Completed Foc1 AutoFocus Completed (Profile No 17)
07:02:00     Target Completed Target completed (36/36, UGC 6930 w/SN2020rcq)
07:02:03   Queue Completed Job Queue completed
07:02:05 Session Closing Session closing
07:02:58   Dome Closed Dome closed (closing time 50s)
07:04:26   Dome Parked Dome parked (parking time 81s), Az: 90.0 deg
07:05:10   Telescope Parked Telescope parked (parking time 38s)
07:05:40   Telescope Switched Off Telescope Power has been switched off via UPB Switch.
07:06:30   Services Stopped Night Services stopped
07:06:32 Session Housekeeping Housekeeping Started (Cleanup FITS, Create Fits Summary, Transfer Files)
07:06:44 Session Finished Session Finished
 
Session Alerts
Time     Alert Detail
19:54:37 Telescope Alert ASCOM Telescope not connnected
21:50:57 Dome Dome position has been static for more than 5 mins
01:00:38 Dome Discrepency Difference between Telescope Az and Dome Az is > 8 deg (UGCA 184)
04:55:04 Dome Discrepency Difference between Telescope Az and Dome Az is > 8 deg (NGC 4290)

Back to Top


Operational Issues (2021-01-11 S848)

[ Prev | Next ]

Critical Issues

Major Issues

Minor Issues

Continuous Improvement

[ Prev | Next ]

Back to Top


Investigation - Autoguiding Issues (Uncorrected Dec drift during Guide Run 4)

Issue.  Guide Run 4 showed particular anomalous 6 arc sec Dec Drift in Frame 5 .  

Description.  After acquiring  4 x 180s with more or less acceptable guiding, the guide star drifted 6" away from Lock Position either though Dec Guide corrections where being made.  Target observation lay west of Meridian (Az 232°/Alt 19.5°) where autoguiding issues seem to be more common/worse.

Guiding Results for Guide Run 4
Declination drift ( to north) corrected over some intervals, but during Frame 5 Dec guide corrections have no effect (Dec) ,
 some residual periodic error & random mechanical movement  (RA),  plus normal seeing variations ( RA & Dec)
Image   
  
 

Impact on Imaging.  The small picture inserts on the guiding chart above show expected (simulated) star shapes based on the guide error seen.
Looking at the simulated star shape for Frame 5 It would be expected that Frame 5 would have been deemed unusable and would have been thrown away to make a 4 x 180s stack of the first 4 frames only.  In fact the effect on Frame 5 was minimal and the frame was included in the original 5 x 180s final stack (with alignment of frames). See image below.

UGC 784 with SN 2021pc - 2021-01-11 (T+4.7d)
UGC 784 / PGC 4443 (catalog mag + 16.0)
Other galaxies in same FOV: PGC 1110475 (catalog mag + 16.8)
Image
Annotated CCD Image  (50% size, square root scale)
5 x 180s exposure (average combine), 3x3 binning, C Filter
2021-01-11 21:21 UT (#848043-47)
12" LX200R (at f/10.4) + ST-10XME
Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

Re-examining the individual image frames shows that there is a minimal visual difference between frames. The original inclusion of frame 5 in stacking was surprisingly justified. Measured Av. Star Elongation in frames 1 to 5 is 1.15, 1.11, 1.13, 1.12 & 1.16. Frame 5 (1.16) is marginally worse that the other frames and visually its star elongation is perceived to be very slightly higher, but the impact on star elongation is no where as bad as would be suggested by the guiding results and the simulated star shape.

Frame 2 and 5 Compared
Frame 5 had very slightly more elongation than Frames 2 but it is significantly less than is
suggested by the frame's guiding result and the simulated star shape (see guiding chart above)
Image    Image
180s exposures, 150% size, cropped areas from 
Frame2 #848044 (left),  Frame 5 #848047 (right)
  

The full frame Y pixel position of the centroid associated with star at the centre of above image has the following value in Frames 1 to 5  :
275.6, 275.2, 276.2, 276.4, 274.2 .  The largest Y position difference is between Frame 4 and Frame 5 where the 2.2 px difference corresponds to a distance of 3.1".    Comparing the Stacked Composite of Frames 4 and 5 with and without alignment of the frames shows the impact of this difference on overal star shape.
 
Frames 4 and 5 Stacked
With Alignment (Left), Without Alignment (Right)
Whilst alignment (left) has nullified the effect of guiding anomaly in Frame 5,
 the difference in Y Position of the two frames (central star 276.4 (left) and 274.2 (right)
shows that guiding anomaly seen in guidescope camera has affected the main scope.
Image    Image
2 x 180s exposures, 150% size, cropped areas from 
Frames 4 &5,  #848046-47
  

Discussion.

Action: The effect of cable dragging & weight distribution on guiding needs to be viewed in person in the observatory during a live session. Alternatively a daytime  telescope slews, telescope tracking to series of prior night sky positions needs to be run and considered in light of guide run results from each sky position. 

Guiding problems were reviewed 2021-01-21 (see Investigation -  Guiding Issues (West of Meridian)

Back to Top


Analysis: Protection from approaching showers

Although night of 2020-01-11 was mostly relatively clear three fast moving light showers came through between 01:30 and 4:00. These are shown on the Night Sky Summary Plot below.

Although the Observatory System & Shutter worked perfectly to protect the observatory, an analysis was made to understand exactly how much notice there was for each shower and how quickly the Observatory System & Shutter responded.  What was the margin for error and how does this impact on the level of risk to the Observatory

  
Night Sky Summary Plot , S848
Top axis: Sky Brightness at Zenith (in ADU/s)
Lefthand axis: Local Time (hh LT). Righthand axis: Sun Altitude (degs)
Image   
  
 

Back to Top