David's Astronomy Pages Notes - Session 786 (2020-05-29)

Notes (S785)

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Notes (S787)

	Session Aims & Highlights
	- Observing Result  - Night Summary Plot  - Session Event Log
	Operational Issues
	- Critical Issues (0),  Major Issues (0),  Minor Issues (2),  Continuous Improvement (1)
	Problems imaging C/2020 F8 (SWAN)
	Images from 2020-05-29 >>

Session Aims & Highlights (2020-05-29)

Main aims

1. Software Testing: Test 3.24.1 version of AstroMain ( CanOpen(), MustClose() handling & Bug Fixes)
2. GRB 200529A: Make followup images of starfield around GRB 200529A to help identify any candidate for GBR afterglow in images
   collected the previous night
3. Targets: Acquire images of a number of targets if conditions allowed.  

Equipment & Software

• 12" LX200 and ST-10XME
• 80mm APO and ZWO ASI 178MC
• CCDApp2, TheSky6, CCDSoft5, PHD2,  POTH Hub
• Pegasus UPB & Motor Focus, TCF-S
• SharpCap 3.2, PHD2  2.6.8
   
• AstroMain 3.24.1,  AstroGuard 1.3,   AstroPlan 1.15.1,  AstroShCap 1.2.22, AstroVOE 1.3.6, UPB 1.5 
  (AstroWeather 1.10, AstroAllSky 3.5.1)
  

Highlights

Lowlights

• None. 

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)

Pre-Session Weather Forecast (API data from darksky.net) Pre-Session Weather forecast showed variable skies range from 5 to 50% cloud cover,  light winds (wind 7mph) and a minimum temperature of 6°C. In the event conditions were clear and calm through the whole night, with a minimum temperature of around 4°C

Session Event Log

Time     Event Detail 22:59:48 Session Created Live Session Created (2020-05-29 S00786, ImageSaveNum: 786001) 23:00:12   Scope Switched On Telescope Power has been switched on via UPB Powerbox. 23:02:03   Services Started Observatory Services started 23:02:50 Observatory (Auto) Observatory placed in Fully-Automated Mode 23:02:54 Session Pending Session pending (2020-05-29) 23:02:56 Session Initiating Session initiating (2020-05-29) 23:02:58   Plan Requested Observing Plan requested from AstroPlan (1.15.2) 23:03:30   Plan Loaded Observing Plan loaded to queue (2020-05-29 V1 BEST PLAN, Plan ID: 515) 23:03:43   Camera1 Connected SBIG Camera Connected (set point -10°C) 23:03:48   Telescope Connected Telescope Connected (TheSky6) 23:04:04 Session Equilibration Session ready for dome & camera equilibration 23:23:16   Shutter Opened Shutter opened (opening time 44s) 23:23:19   Equilibration Started Dome Equilibration started 23:36:32   Equilibration Ended Dome Equilibration ended (13.3 mins total) 23:36:34 Session Running Session running 23:36:36   Queue Started Observing Queue started (11 targets selected) 23:37:40       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 23:40:24       Focusing Completed Foc1 AutoFocus Completed (Profile No 1) 23:40:27     Target Started (1/11) Target started (1/11, HIP 87937) 23:50:12     Target Completed Target completed (1/11, HIP 87937) 23:50:14     Target Started (2/11) Target started (2/11, NGC 3643) 00:12:34     Target Completed Target completed (2/11, NGC 3643) 00:12:36     Target Started (3/11) Target started (3/11, M61) 00:34:23     Target Completed Target completed (3/11, M61) 00:34:26     Target Started (4/11) Target started (4/11, UGCA 309) 00:57:06     Target Completed Target completed (4/11, UGCA 309) 00:57:08     Target Started (5/11) Target started (5/11, GRB 200529A) 01:24:04     Target Completed Target partially completed (5/11, GRB 200529A) 01:24:06     Target Started (6/11) Target started (6/11, GCVS U Her) 01:28:46       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 01:31:35       Focusing Completed Foc1 AutoFocus Completed (Profile No 2) 01:38:03     Target Completed Target partially completed (6/11, GCVS U Her) 01:38:05     Target Started (7/11) Target started (7/11, GCVS SS Her) 01:47:01     Target Completed Target completed (7/11, GCVS SS Her) 01:47:04     Target Started (8/11) Target started (8/11, GCVS AM Her) 01:49:43       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 01:52:35       Focusing Completed Foc1 AutoFocus Completed (Profile No 3) 01:57:26     Target Completed Target completed (8/11, GCVS AM Her) 01:57:28     Target Started (9/11) Target started (9/11, GCVS CI Cyg) 02:00:05       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 02:02:50       Focusing Completed Foc1 AutoFocus Completed (Profile No 4) 02:06:31     Target Completed Target completed (9/11, GCVS CI Cyg) 02:06:33     Target Started (10/11) Target started (10/11, 61 Cyg) 02:13:14     Target Completed Target completed (10/11, 61 Cyg) 02:13:16     Target Started (11/11) Target started (11/11, C/2020 F8 (SWAN)) 02:16:22       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S) 02:17:10       Focusing Failed Foc1 Focusing Failed - star lost 02:31:21     Target Completed Target completed (11/11, C/2020 F8 (SWAN)) 02:31:24   Queue Completed Job Queue completed 02:31:26 Session Closing Session closing 02:32:14   Shutter Closed Shutter closed (closing time 45s) 02:32:57   Dome Parked Dome parked (parking time 42s) 02:34:14   Telescope Parked Telescope parked (parking time 73s) 02:34:45   Scope Switched Off Telescope Power has been switched off via UPB Powerbox. 02:35:31   Services Stopped Night Services stopped 02:35:33 Session Housekeeping Housekeeping Started (Cleanup FITS, Create Fits Summary, Transfer Files) 02:35:44 Session Finished Session Finished

Session Alerts

Time     Alert Detail -- No Alerts                --

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Operational Issues (2020-05-29, S786)

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

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Critical Issues

• None

Major Issues

• None

Minor Issues

• Problem with annotation on second locate picture for M61 .  Second locate picture for M61 (M61 Locate 2 (0.4') ) has a correctly coloured target cross (green for pointing error < 1.0') but it is plotted in the wrong place, it seems to have retained the x,y location associated with target in the first  locate picture (5.4' pointing error).     (There was a not dissimilar problem with the third locate frame for NGC 3643 (NGC 3643 - Locate 3 (0.5')) which didn't show a green cross when it should have. This was probably because the pointing error for the second locate frame (7.3') lay outside the field of view) Other targets have locate pictures that are correct, suggesting the bug is quite subtle. Examining the code for ConvertFitsToJpg() routine shows that position of the Target cross is determined from the variable LocateInfo (type TLocateInfo with 3 fields: x, y & pointingerror) .  LocateInfo.x & LocateInfo.y are set in the routine CalculatePointingError() following executiion of statement XY= Image.RADecToXY, LocateInfo.pointingerror is set a little later in the routine.  It seems that only two situations could have led to 2nd locate frame have target positioning at same XY location as the first. This would be i) there was an exception in Image.RADecToXY such that LocateInfo.x & .y weren't set to new values or ii) Image object was still pointing at the locate frame 1 image and wasn't pointing at the new locate frame image.  Code modified to write trace statements to logfile to try to sort out what might be happening. 
  
  Issue replicated when re-playing back images against AstroMain 3.35.9 (2021-02-01).   Logs appear to show that 786029 image has linked with Stars 6, Scale 1.404, Angle 179.57, and has got a correct point error (0.43 arc mins),  that the Active Star count is 0/0 and failure to show newly introduced Report Line 'Checking WCS... ' suggests some issue during Link process.  Debugging show that teh Link is made through FailSafeLinkProcess whereby Link is made through TheSky without InsertWCS being possible. In this situation the Image does allow Image.RaDecToXY to work and it isn't possible to produce an XY location for target. The current code plots the target XY it had from the first successful link.   Correct thing  to do is to not plot the XY location.   This is implemented in beta vsersions of AstroMain 3.36 . 
  Fixed 2021-02-09 (AstroMain 3.36)
  
  A future improvement is to independently calculate the XY location from RaDec by using a) CentreRaDec from FailSafe Link and b) ImageScale & Rotation from current or previous Locate. This option was implemented on 2021-02-10 in final version of AstroMain 3.36.
   
• Image frames for Target 11/11 (C/2020 F8 (SWAN)) are blank with no stars.  None of the 15 x 45s C image frames for C/2020 F8 (SWAN) have an indication of any stars, image pictures seem entirely black with no indication of stars & strong vignetting that effect the two locate frames.  Investigating the FITS images show that the 45s exposures are strongly overexposed (peak 63250 ADU) as the target lay in NNE sky at altitude of only 14deg which would have placed it the dawn light in the NNE sky. The 2 locate frames with 10s exposure are themselves very bright but not overexposed (peak 27300 ADU).   The raw .jpg pictures appeared blank (solid black) due to the particular way that  IV.Background and IV.Range are produced for a highly saturated image.  In this case nearly all values are at ~ 64741, and with black at 64740 amd white at 65035 , the image comes out solid black.   Issue resolved by including extra code in ConvertFitsToJpg() routine to set black (background) to white - 3000 where White > 65000 and IV.Range < 3000. This produces a relatively solid grey background colour to at least show there is a saturation issue.
  Fixed 2020-06-04  (AstroMain 3.24.5)

Continuous Improvement

• Create 5 day temperature plot comparing outside temperature with base unit temperature. Plot is required for helping to understand the diurnal rhythm seen in pressure (barometer) data. Is it a temperature effect ? New plot reuses Graph 2. Graph shows that diurnal pressure rhythm is indeed due to a strong diurnal late afternoon rise in base unit temperature due to late afternoon sunshine & associated heating.
  Done (AstroWeather 1.10.1)

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Problems imaging C/2020 F8 (SWAN)

C/2020 F8 (SWAN) has recently become visible from northern hemisphere, but imaging this comet from northern Scotland is partiicularly challenging. At the the end of May the night hours are very short and with the comet positioned low down on the northern horizon it sits in very bright twiliight sky where it is simply too bright for taking 30s or 45s exposures that I normally use for cometary imaging.  

Maximum solar depression at this time of year from my latitude is only 10.9°. At point of greatest solar depression the comet lies just west of north which in an azimuthal region that is blocked for automated operation of the observatory  (this is to reduce the risk of cables getting wrapped around the pier in event that scope continues tracking beyond the north position).  After passing through due the due north position the comet became available for imaging but at this time the solar depression had reduced to just 9.5° and twilight was starting to rapidly brighten

Proposal is to try imaging C/2020 F8 (SWAN) again but using multiple (say 50) frames of 10s exposure each and see if the comet will be visible in the stacked image.

All Sky Image of northern horizon at time of imaging C/2020 F8 (SWAN) (Sun Altitude -9.5°)

Update: 2020-12-30
Unfortunately there were no more opportunites to image C/2020 F8 (SWAN) in 2020

Update:  2021-05-09

AstroPlan's Schedule Builder was modified in AstroPlan 1.22 (2021-05-09) to reject targets that are lying too close to rising or setting sun. 

This is to avoid taking images of targets that end up having very high (potentially semi-saturated or saturated) background light levels.   This enhancement will help make the most of summer time observations where the best images will come from sky positions furthest from the sun.  Note:  Comet targets should have slightly more relaxed limits as they are naturally often located closer to the sun position and it is a requirement to try to observe them whatever their position.  There will still be some situations where the sky is simply too bright.   Therefore Comet and All Other Targets will need separate Sky Brightness cutoffs.  First implementation added in AstroPlan 1.22.  Uses Equations defined in  Kastner, S. O. (1976).  Calculation of the twilight visibility function of near-sun objects. Journal of the Royal Astronomical Society of Canada, vol. 70, Aug. 1976, p. 153-168. http://adsabs.harvard.edu/full/1976JRASC..70..153K . At the moment the code doesn't identify comets as a separate group even though a LogLCutoff_Comet is defined, and Sky Brightness calculations are based on Sun and Target Positions at Mid Observation (a later implementation should make Sky Brightness checks at both the start and end of observation).  The revised Schedule Builder was used for the first time in session S897 (2021-05-10).

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