David's Astronomy Pages
Notes - Session 870 (2021-03-14)

 
Bullet Session Aims & Highlights
 - Observing Result
 - Night Summary Plot
 - Session Event Log
 
Bullet Operational Issues
  - Critical Issues (0),  Major Issues (0),  Minor Issues (4),  Continuous Improvement (2)
Bullet Images from 2021-03-14 >>     [ Local Files >> ]
Bullet Camera Cable Rerouting
Bullet ASTAP - Plate Solving Software

Session Aims & Highlights (2021-03-14)

Main aims

  1. Resync Scope.   Resync scope and perform short mapping job at start of session. This was necessary as scope pointing had been compromised during earlier daytime testing of new cable routing (Dec Gears was overdriven by 4 degs)
  2. New Cable Routing.  Perform nighttime test of new cable routing for SBIG power cable and ZWO USB 3 cable. Instead of passing from the back of the imaging train to the right hand fork & ground which might be affecting autoguiding performance (see Investigation - Guiding Issues (West of Meridian), 2021-01-16) , the cables are now taken back up to the OTA and then down to the right hand fork & ground.  Test ran the risk of SBIG camera disconnections due to movements of the cable adapter in the SBIG camera, despite being tied off.
  3. Targets. Acquire images of a selection of variable stars, nearby stars, comets & 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
Image
Image
  
Sky Conditions (Locate Frames)
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   
  
Pre-Session Weather Forecast (API data from darksky.net)
Image
Image   
  
Session Event Log
Time     Event Detail
19:20:49 Session Created Live Session Created (2021-03-14 S00870, ImageSaveNum: 870001)
19:21:13   Obs.Manager Started Obs.Manager started
19:21:15   Obs.Overseer Started Obs.Overseer started
19:21:19   Services Started Observatory Services started
19:21:29   Camera1 Connected SBIG Camera Connected (set point -20°C)
19:21:47   Scope Switched On Telescope Power has been switched on via UPB Powerbox.
19:23:36   Services Started Observatory Services started
19:27:11   Telescope Connected Telescope Connected (TheSky6)
19:29:48   Dome Opened Dome opened (opening time 44s)
20:05:02 Observatory (Auto) Observatory placed in Fully-Automated Mode
20:05:03 Session Pending Session pending (2021-03-14)
20:05:05 Session Initiating Session initiating (2021-03-14)
20:05:07   Plan Requested Observing Plan requested from AstroPlan (1.21.3)
20:06:38   Plan Loaded Observing Plan loaded to queue (, Plan ID: 608)
20:06:41   Camera1 Connected SBIG Camera Connected (set point -20°C)
20:06:47   Telescope Connected Telescope Connected (TheSky6)
20:06:58 Session Equilibration Session ready for dome & camera equilibration
20:07:03 Session Running Session running
20:07:04   Queue Started Observing Queue started (30 targets selected)
20:08:01       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
20:09:58       Focusing Completed Foc1 AutoFocus Completed (Profile No 1)
20:10:01     Target Started (1/30) Target started (1/30, UGC 1436 w/SN2021nv)
20:13:24       Focusing Started-Foc2 Foc2 Focusing Started (Secondary Scope, using ShCap)
20:18:45       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S)
20:18:48 Critical Cloud Alert Critical Cloud Alert (Obs.Manager will close the Shutter)
20:18:50   HardSuspend Called Hard Suspend is called due to Critical Conditions (cloud)
20:18:52     Target Aborted (1/30) Target aborted (1/30, UGC 1436 w/SN2021nv) due to cloud
20:18:54   Queue Paused Queue paused for Session Suspension
20:18:56 Session Suspended Session suspended
20:19:43   Dome Closed Dome closed (closing time 49s)
20:27:25     Target Cancelled Target cancelled (1/30, UGC 1436 w/SN2021nv) due to wind
20:43:47     Target Cancelled Target cancelled (2/30, Nova Per 2020 (CV)) due to wind
20:56:09     Target Cancelled Target cancelled (3/30, AT2021dbp (CV)) due to wind
21:16:01     Target Cancelled Target cancelled (4/30, AT2021ckv) due to wind
21:37:53     Target Cancelled Target cancelled (5/30, M31 w/Nova2021fbz) due to wind
22:00:15     Target Cancelled Target cancelled (6/30, SN 2021xn) due to cloud
22:01:08 Session Resuming Session resuming
22:01:53   Dome Opened Dome opened (opening time 45s)
22:01:55 Session Running Session running
22:01:57   Queue Resumed Observing Queue resumed
22:04:17       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
22:06:24       Focusing Completed Foc1 AutoFocus Completed (Profile No 2)
22:06:27     Target Started (7/30) Target started (7/30, NGC 4631 w/AT2021biy)
22:11:05       Focusing Skipped Foc1 focusing skipped - star is too dim (TCF-S)
22:27:03     Target Completed Target completed (7/30, NGC 4631 w/AT2021biy)
22:27:05     Target Started (8/30) Target started (8/30, NGC 3515 w/AT2021fmd)
22:30:07       Focusing Skipped Foc1 focusing skipped - unable to find a star (TCF-S)
22:33:54   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
22:35:59   SoftSuspend Cancelled Soft Suspend is cancelled due to Improved Conditions
22:37:09 Critical Cloud Alert Critical Cloud Alert (Obs.Manager will close the Shutter)
22:37:11   HardSuspend Called Hard Suspend is called due to Critical Conditions (cloud)
22:37:15     Target Aborted (8/30) Target aborted (8/30, NGC 3515 w/AT2021fmd) due to cloud
22:37:17   Queue Paused Queue paused for Session Suspension
22:37:19 Session Suspended Session suspended
22:38:09   Dome Closed Dome closed (closing time 50s)
22:40:39 Session Resuming Session resuming
22:41:24   Dome Opened Dome opened (opening time 45s)
22:41:26 Session Running Session running
22:41:28   Queue Resumed Observing Queue resumed
22:42:18       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
22:44:08       Focusing Completed Foc1 AutoFocus Completed (Profile No 3)
22:44:11     Target Started (8/30) Target started (8/30, NGC 3515 w/AT2021fmd)
22:44:13     Target Failed Target failed due to missed start time (8/30, NGC 3515 w/AT2021fmd)
22:46:59     Target Started (9/30) Target started (9/30, NGC 4227 w/SN2021biz)
22:52:09       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
22:54:13       Focusing Completed Foc1 AutoFocus Completed (Profile No 4)
23:10:18     Target Completed Target completed (9/30, NGC 4227 w/SN2021biz)
23:10:20     Target Started (10/30) Target started (10/30, AT2021bxp (CV))
23:14:51     Target Failed Target failed due to aborted (10/30, AT2021bxp (CV))
23:14:53   Queue Aborted Job Queue aborted
23:16:58       Focusing Started-Foc2 Foc2 Focusing Started (Secondary Scope, using ShCap)
23:19:48       Focusing Completed Foc2 AutoFocus Completed (Profile No 5, wide)
23:21:54       Focusing Completed Foc2 AutoFocus Completed (Profile No 5)
23:22:10       Focusing Checked Foc2 Focusing Check Succeeded
23:22:34 Observatory (Auto) Observatory placed in Fully-Automated Mode
23:22:36 Session Pending Session pending (2021-03-14)
23:22:38 Session Initiating Session initiating (2021-03-14)
23:22:43   Plan Loaded Observing Plan loaded to queue (, Plan ID: 608)
23:22:48   Camera1 Connected SBIG Camera Connected (set point -20°C)
23:22:53   Telescope Connected Telescope Connected (TheSky6)
23:23:04 Session Equilibration Session ready for dome & camera equilibration
23:23:06 Session Running Session running
23:23:08   Queue Started Observing Queue started (20 targets selected)
23:23:10     Target Started (11/30) Target started (11/30, UGC 5760 w/SN2020zoq)
23:26:48       Focusing Skipped Foc1 focusing skipped - star is lost (TCF-S)
23:29:34   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (too few stars)
23:37:14 Critical Cloud Alert Critical Cloud Alert (Obs.Manager will close the Shutter)
23:37:16   HardSuspend Called Hard Suspend is called due to Critical Conditions (cloud)
23:37:20     Target Aborted (11/30) Target aborted (11/30, UGC 5760 w/SN2020zoq) due to cloud
23:37:22   Queue Paused Queue paused for Session Suspension
23:37:25 Session Suspended Session suspended
23:38:14   Dome Closed Dome closed (closing time 50s)
23:40:05     Target Cancelled Target cancelled (11/30, UGC 5760 w/SN2020zoq) due to wind
00:02:27     Target Cancelled Target cancelled (12/30, UGCA 241) due to wind
00:17:49 Session Resuming Session resuming
00:18:34   Dome Opened Dome opened (opening time 45s)
00:18:36 Session Running Session running
00:18:38     Target Started (13/30) Target started (13/30, UGCA 245)
00:18:40   Queue Resumed Observing Queue resumed
00:26:50 Critical Cloud Alert Critical Cloud Alert (Obs.Manager will close the Shutter)
00:26:52   HardSuspend Called Hard Suspend is called due to Critical Conditions (cloud)
00:26:54   CCDSoft Issue CCDSoft has encountered an image save issue [0000]
00:26:56   CCDSoft Restarting CCDSoft restarting in attempt to fix image save issue [0000]
00:27:10   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (reducing clarity)
00:27:14   Camera1 Connected SBIG Camera Connected (set point -20°C)
00:27:25   SoftSuspend Cancelled Soft Suspend is cancelled due to Improved Conditions
00:27:30   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (reducing clarity)
00:28:53 Session Suspended Session suspended
00:29:40   Dome Closed Dome closed (closing time 47s)
00:30:30     Target Aborted (13/30) Target aborted (13/30, UGCA 245) due to cloud
00:30:32   Queue Paused Queue paused for Session Suspension
00:47:11     Target Cancelled Target cancelled (14/30, UGCA 256) due to wind
01:22:35     Target Cancelled Target cancelled (15/30, UGCA 271) due to wind
01:46:27     Target Cancelled Target cancelled (16/30, UGC 3502 w/AT2021cwc) due to wind
02:08:19     Target Cancelled Target cancelled (17/30, IC 992 w/SN2021dwg) due to wind
02:30:11     Target Cancelled Target cancelled (18/30, MCG +11-22-33 w/SN2021eay) due to wind
02:42:29     Target Cancelled Target cancelled (19/30, KIC 8462852) due to wind
03:02:21     Target Cancelled Target cancelled (20/30, AT2021dtd) due to wind
03:23:33     Target Cancelled Target cancelled (21/30, 7P/Pons-Winnecke) due to wind
03:32:08     Target Cancelled Target cancelled (22/30, HIP 87937) due to wind
03:37:10 Session Resuming Session resuming
03:37:55   Dome Opened Dome opened (opening time 45s)
03:37:57 Session Running Session running
03:37:59     Target Started (23/30) Target started (23/30, GCVS AM Her)
03:38:01   Queue Resumed Observing Queue resumed
03:40:51       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
03:42:52       Focusing Completed Foc1 AutoFocus Completed (Profile No 6)
03:47:48     Target Completed Target completed (23/30, GCVS AM Her)
03:47:50     Target Started (24/30) Target started (24/30, GCVS CY Lyr)
03:49:59       Focusing Started-Foc1 Foc1 Focusing Started (TCF-S)
03:51:49       Focusing Completed Foc1 AutoFocus Completed (Profile No 7)
03:54:20 Critical Cloud Alert Critical Cloud Alert (Obs.Manager will close the Shutter)
03:54:22   HardSuspend Called Hard Suspend is called due to Critical Conditions (cloud)
03:55:20   SoftSuspend Called Soft Suspend is called due to Deteriorating Conditions (reducing clarity)
03:55:31     Target Aborted (24/30) Target aborted (24/30, GCVS CY Lyr) due to cloud
03:55:33   Queue Paused Queue paused for Session Suspension
03:55:36 Session Suspended Session suspended
03:56:25   Dome Closed Dome closed (closing time 50s)
04:01:37     Target Cancelled Target cancelled (25/30, GCVS CI Cyg) due to wind
04:14:41     Target Cancelled Target cancelled (26/30, GCVS S Cyg) due to wind
04:23:43     Target Cancelled Target cancelled (27/30, 61 Cyg) due to wind
04:33:03     Target Cancelled Target cancelled (28/30, GCVS BL Lac) due to wind
04:44:44     Target Cancelled Target cancelled (29/30, GCVS U Her) due to wind
05:04:05     Target Cancelled Target cancelled (30/30, GCVS SS Her) due to rain
05:04:11   Queue Completed Job Queue completed
05:04:15 Session Closing Session closing
05:04:20   Dome Closed Dome already closed (closed at 03:56, closing time 50s)
05:04:41   Dome Parked Dome parked (parking time 13s), Az: 90.0 deg
05:05:23   Telescope Parked Telescope parked (parking time 35s)
05:05:53   Telescope Switched Off Telescope Power has been switched off via UPB Switch.
05:06:42   Services Stopped Night Services stopped
05:06:44 Session Housekeeping Housekeeping Started (Cleanup FITS, Create Fits Summary, Transfer Files)
05:06:56 Session Finished Session Finished
 
Session Alerts
Time     Alert Detail
00:26:50 CCDSoft Image file [0000] hasn't been saved to disk, possible CCDSoft issue
03:38:53 CCDSoft Image file has been saved to disk following CCDSoft Restart

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Operational Issues (2021-03-14 S870)

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Critical Issues

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Minor Issues

Continuous Improvement

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Camera Cable Re-Routing

As part of an attempt to better understand and improve autoguiding performance issues (see Investigation - Guiding Issues (West of Meridian), 2021-01-16) the SBIG power cable and the ZWO 178MC USB 3 cable were rerouted during the daytime ahead of session S870 (2021-03-14) . Instead of passing from the back of the imaging train to the right hand fork & then indirectly to floor  the cables were rerouted to take them back up to the OTA and then down to the right hand fork & then indirectly to the floor. 

A daytime test was performed to ensure that cables positions would cause any holdups or other issue slewing to various parts of the sky.  

The cables have to have enough slack between camera and their respective tieoff points on either side of the Dovetail for the Secondary Scope's to allow Focusers to move the cameras in/out of focus.   The cables then have to have another slack or easy movement to allow the OTA to be move 90 deg in Declination/Altitude  without straining the cables, and then have another slack to allow the telelescope +/-180 deg in azimuth without the cables straining.     

The cables also have to allow minimal impact on small declination movements made during autoguiding, or at least less impact that the previous routing.   In theory the scope shouldn't feel a force from the cables bending , but may feels a greater force from the weight of the cables hanging off the scope.   Any force in the new set up will lie closer to the decination axis and therefore should be smaller.  (maximum force on the Dec Gears is hypothesized to occur when cables hang at the large distance from the Dec Axis which they would do in the original routing.

Although the power cable is tied off at the / close to the camera and there should be minimal movement in the cable section between SBIG camera and the tieoff point on the OTA, there is a risk of  SBIG camera power disconnections due to movement of the power adapter pins in the SBIG Camera's power port.

Pictures illustrating the cable routing before/after the change are shown below:

S870 was the first night time test of the new cable arrangement but it the benefits or otherwise of the rerouting could not be established because  poor weather (wind/cloud) severely limited the observing opportunities during the session.   No data collected on clear sky guiding a target west of Meridian, so unclear if the rerouting helps resolve guiding issues, but at leasy no adverse impact was seen on 2 targets guided east of the Meridian.  Importantly there were no hang-ups or serious issues with the new cable arrangement during the session. 

( It is uncertain whether the one instance of 'CCD Image [0000] has not saved to disk"  during the session was caused by a power/communication glitch with the SBIG camera (and a side-effect of new cable routing) or not)

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ASTAP - Plate Solving Software

Downloaded and installed ASTAP 64 bit version beta 0.9.512a (dated 2021-03-09)  today (2021-03-08), along with H18 star database and demonstrated that it could plate solve  a FITS image from SBIG camera, with starting coordinates lying 3 degrees from its true position.

Found that Flip Vertical needed to show image with same orientation as orginal (N Down)

Found that

- Take CCD Image in CCDSoft of starfield containing reasonable number of round stars, and save to disk.
- Load FITS image into ASTAP
- Solve image asstrometric (plate solve)
- Copy Ra and Dec fields into Ra/Dec fields on AstroMain's Observing/TheSky Tab & click on 'Centre in TheSky' button
- Go to Centre


Live Trial (Session S870)

- 5s exposure (3x3) taken with the scope believed to a few degrees off it's true position (this was due to a
- Tried to Image Link using CCDSoft/TheSky6,  but failed
- Opened image in ASTAP, Image showing RA 06 44 02.655, Dec +13 13 55.49
- Plate Solved. Solution took 7.7s and reported RA 06 43 26.900, Dec +17 13 50.00 (ie an offset 4 deg)
- Copy Ra and Dec fields into Ra/Dec fields on AstroMain's Observing/TheSky Tab & click on 'Centre in TheSky' button
- Checked that stars in TheSky matched those in image.
- Clicked on TheSky's Virtual Field Centre and synced scope
- Began a short mapping job.
- Saved TheSky Document & commenced live session

Conclusion :  Process worked and was fairly quick.

Streamlined Method
An alternate method where tried out whereby after platesolving in ASTAP the ime was saved with new header, then opened in CCDSoft and an image link performed hoping that it would then successfully link in TheSky without having to go through process of copying and pasting  RA/Dec values, however this didn't work. Although an WCS is inserted in the FITs file header,  OBJCTRA & OBJCTDEC keywords are left with their original values, and as these are the values used by CCDSoft Image Link, the linking doesn't work any better than the originally acquired file.

A routine could easily be written that would read the FITS file saved by ASTAP, and write in new values for OBJCTRA & OBJCTDEC based on CRVAL1 (RA deg) & CRVAL2 (Dec deg).    The routie could help by saving the FITS file with a specific name/specific location to aid the location of the image in ASTAP.

Command Line Method
ASTAP has a command line intereface, documented at  www.hnsky.org/astap.htm#astap_command_line
 So it is feasible to have button routine in AstroMain for aligning the scope when its position is only roughly known.

- Button
- Take 10s image   'Snap.1933.52.FIT
- Run Shell  
    astap.exe -f   "C:\Data\CCD Imaging\New\2021-03-14 S00870\_FOCUS\Snap.1933.52.FIT"    -r 5
- Read WCS data.

Note:  The -update option will update the Image's fits header with the found solution.  However when this was tried the resulting .FIT file couldn't be opened in CCDSoft (CCDSoft produces a dialog "Undescribed error. Error code = 701" ).  Fortunately the original file is saved with a .bak extension.

Ra/Dec Position
Getting image's RA/Dec from WCS. We need to read CRVAL1 & CRVAL2

CRVAL1 = 2.444617601865E+001 / RA of reference pixel (deg)
CRVAL2 = 5.366454564370E+001 / DEC of reference pixel (deg)

RA = CRVAL1 / 15   (RA in hours)
Dec = CRVAL2         (Dec in degs)

RA = 1.629745
Dec = 53.664

Image Scale
Getting image's pixel scale from WCS or INI file. We need to read CDELT1 & CDELT2.

CDELT1 = 3.882527481525E-004 / X pixel size (in deg)
CDELT2 = 3.885837446741E-004 / Y pixel size (in deg)

Image Scale  (in arcsec / px) = ( CDELT1 * 60 * 60 + CDELT2 * 60 * 60) /2
Image Scale =  1.398 arcsec/px

[ Number of stars in object http://www.xparallax.com/  ]

Image Rotation
Getting image's rotation from WCS or INI file. We need to read CROTA2.

CROTA2 = -7.529744000419E-001 / Image twist of Y axis (deg)

Image Rotation  = CROTA2 + 180
Image Rotation  = 179.2 deg

For a more precise (better) value  then could implement   (CROTA1 + CROTA2) / 2 + 180

180 is added to CROTA2 in order to get rotation to the numbe equivalent to that consistent with how TheSky6 measures Image Rotation.  It seems reasonable given that the Camera Orientation is North Down. 

Update 2021-03-16
Following the successful use of ASTAP in session S870 (2021-03-14), a new button routine bas been built in AstroMain 3.38.5 to streamline the process of checking and resetting telescope pointing.  This new routine was successfully operated during session S871 (2021-03-16).  See AstroMain - New Button Routine to Check/Reset Telescope Pointing

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