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Observing Plan (2019-02-13, S663) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Observing Result (2019-02-13, S663) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Night Sky Summary Plot -
2019-02-13, S663 Top axis: Sky Brightness at Zenith (in ADU/s) Lefthand axis: Local Time (hh LT). Righthand axis: Sun Altitude (degs) |
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Session Event Log (2019-02-13, S663) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Under automated operation the Shutter was commanded to open at 18:18:37 (this
was some 10 minutes before the starting time for the nights Observing Plan).
The process of opening the shutter normally takes 45-50s. However upon checking
the session over a remote connection at around 19:00 it was noted that the plan
session hadn't started the observing plan. Checking showed that the session
hadn't progressed through the dome equilibration phase and was seemingly still
waiting for the shutter to finish opening. Shutter status field in
AstroMain and POTH.HUb showed the shutter was still 'Opening'. The
shutter was manually commanded to close which it duly did in a normal time of
45s.
The observatory was visited and the the shutter system observed
whilst it was opened. On reaching the Open Limit Switch there seemed to be
a bit of hiccup and the motor stopped (I think, but I might have intervened).
Checking the wires to the Shutter Drive Unit showed them to be somewhat
disturbed and the plug that comes from the upper relay switch was partially
pulled out from it's port. The plug was reinserted and the wires tidied
up. The observatory dome was then operated ok for the remainder of the
session include a further close / open operation and a final close operation at
the end of the session.
It would seem that the wires to shutter unit became pulled loose when passing one of the dome clamps during the last session which had pulled the relay plug from its port.
As per a previous incident involving a probable short circuit in wires going to the lower relay switch, the shutter drive motors continue turning as the relay failed to tell the system that the open/close operation has completed. Examining the shutter units battery level records showed that it dropped from 97% down to 85% and voltage dropped from 15.0v down to 14.6v. Temperature Sensor reading jumped from 10° C to 20° C during the incident. 16 hours later the battery has still not started to recharge itself.
It then became clear why there was no recharging ... Upon checking
the observatory the following afternoon it was discovered the two- wire charging
cable for the shutter drive unit was wrapped around one of the dome clamps,
one end had been ripped from its metal male plug (which was still inserted in
the shutter drive unit) whilst the other end had been ripped out of the upper
induction charging box. There seems to have been no damage to
the shutter drive unit or induction charger themselves. It is presumed
that the damage was done during the previous session and at the same time that
the plug from the upper relay switch was pulled loose. (whilst relay wire &
plugs were looked just after the Shutter Opening Issue, it was dark and this
probably explains why the broken cable was noticed). After contacting Pulsar
Observatories the induction charger box was removed and it and the cable sent to
them by mail for repair.
Actions :
Dome Shutter Health Charts showing impact of the
incident (incident time 2018-02-13 18:18 to 19:00) |
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Selected Focus Profiles from Session |
FWHM and HFD V Slope Focusing Compared a) Case with well performing HFD Method (11 steps different) Focusing prior to Target 7, GCVS TZ Cas Focus Star Mag +7.2, Focus Frame Exp. 1s, 1x1 binning, Temp 7.1 C Best Focus 1491 (FWHM), Total Time 2.7 mins (Profile 1) Best Focus 1480 (HFD), Total Time 1.6 mins (Focus No 1) |
FWHM and HFD V Slope Focusing Compared b) Case with poorly performing HFD Method (189 steps different) Focusing prior to Target 9, GCVS Z And Tau Focus Star Mag +xx Focus Frame Exp. 1.5s, 2x2 binning, Temp. 6.6 C Best Focus 1557 (FWHM) , Total Time 3.0 mins (Profile 2) Best Focus 1368 (HFD), Total Time 1.9 mins (Focus No 2) |
FWHM and HFD V Slope Focusing Compared c) Case with very poorly performing HFD Method (189 - 872 steps different !) Focusing prior to Target 9, XO-2 Focus Star Mag +xx Focus Frame Exp. 2s, 2x2 binning, Temp. 6.8 C Best Focus 1531 (FWHM) , Total Time 3.1 mins (Profile 3) Best Focus 659 (HFD), Total Time 2.0 mins (Focus No 4) - target before Best Focus 1102 (HFD), Total Time 1.9 mins (Focus No 5) - target before |
FWHM and HFD V Slope Focusing Compared d) Case with poorly performing HFD Method (183 steps different !) Focusing prior to Target 16, GCVS SU Tau Focus Star Mag +xx Focus Frame Exp. 1.5s, 2x2 binning, Temp. 6.6 C Best Focus 1426 (FWHM) , Total Time 2.8 mins (Profile 4) Best Focus 1243 (HFD), Total Time 2.0 mins (Focus No 6) |
FWHM and HFD V Slope Focusing Compared e) Case with moderately performing HFD Method (155 steps different !) Focusing prior to Target 18, GCVS RR Tau Focus Star Mag +xx Focus Frame Exp. 1s, 2x2 binning, Temp. 7.1 C Best Focus 1385 (FWHM) , Total Time 2.6 mins (Profile 5) Best Focus 1230 (HFD), Total Time 1.7 mins (Focus No 7) |
FWHM and HFD V Slope Focusing Compared f) Case with poorly performing HFD Method (202 steps different !) Focusing prior to Target 23, GCVS FO Ori Focus Star Mag +xx Focus Frame Exp. 1s, 2x2 binning, Temp. 7.1 C Best Focus 1219 (FWHM) , Total Time 2.6 mins (Profile 6) Best Focus 1017 (HFD), Total Time 1.7 mins (Focus No 11) |
Focus Offsets for FWHM Profile and HFD- VSlope Methods
compared FWHM measurement are much more consistent and known to be of better quality. |
Issues
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This Web Page: | Notes - Session 663 (2019-02-13) |
Last Updated : | 2024-10-09 |
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