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ENR CTIO Blanco 4-m 2019-11-07

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Date: 
Thursday, November 7, 2019
Telescope: 
CTIO Blanco 4-m
Submitter: 
Points
Submitter Email: 
Observer Support: 
Hernan Tirado
Night Assistant: 
Claudio Aguilera
Also Present: 
Omar and Rolando from La Serena
Problems: 

We had severe failure around 5am local when we moved to the last field (eng01.48323.fits).  About 1/2 of the detector was obscured.  Our first though was that the guide probe was in the way, blocking the light.  We homed the guider, but this did not help.  The subsequent images looked l;ike bias frames.  We then decided to try and take some lamp spectra, but the problem continued.  Given the time, we decided to close.  After we closed, Claudio and I went to the C-floor, moved the telescope to zenith so we could enter the Cass cage.  We checked to make sure that the connector that controls the shutter was in place.  We the took some 5-10sec exposures to see if we could hear the shutter opening and closing.  We did not hear the normal shutter opening noise, but there were other noises in the dome that may have prevented us from hearing it.

As it stands, we do not see any light on the detector.  It is likely that something is blocking the light, but Claudio and I were not equipped to perform more diagnostics.  For tomorrow/today/Friday, the day crew (Hernan, Humberto, etc) should check the shutter cable to make sure that it is properly seated, and look for any other things that could be blocking the light path (i.e., check the rotator and guider so that M4 and the guide probe are properly stowed.  Tests should be made by trying to take arc lamo exposures to see if any light reaches the detector  If no light is on the detector, we may need to check the shutter cable to make sure it is not damaged.  Any other recovery ideas are welcome. I can be reached in my room (x511) if necessary.

Comments: 

We started the night working with Rolo and Omar to test the guiding.   We wanted to perform these tests because during the last COSMOS run the observer was sometimes spending up to 30min trying to perform an acquisition.  In this case the star would be ~1" N of slit, we would perform an offset and the star would be 1" S of the slit and this would continue without the star ever being properly centered on the slit.  We went through the acquisition sequence for objects ranging in hour angle of +03:00 to -03:30 and with Decs between -10 and -60deg.  We discussed the proper proceedure for the operators to work with the guider when desired offsets were on the order of 3 pixels.  This was very successful and documentation will be placed in the COSMOS operator's notes.  I would also mention at this stage that the pointing for the night remained excellent where the object was always in the center of the FOV when we slewed, even when we covered large distances in RA and Dec.  The work that Rolo and Omar did in the Oct engineering run seems to have paid off.

After performing these tests, I started on a program to obtain spectra of stars covering a 5-6Vmag range and spectral types from DA to G5 with the blue and red grisms.  These will be used in a webpage for visiting astronomers to calculate exposure times. 

Conditions: 
General Conditions
Comment: 
None.
1st Quarter
Clouds: 
Clear
Seeing Value: 
1.00
Seeing Variability: 
0.2
Seeing Source: 
CTIO Seeing monitor
Sky : 
0
2nd Quarter
Clouds: 
Clear
Seeing Value: 
1.00
Seeing Variability: 
0.2
Seeing Source: 
CTIO Seeing monitor
Sky: 
0
3rd Quarter
Clouds: 
Clear
Seeing Value: 
1.00
Seeing Variability: 
0.2
Seeing Source: 
CTIO Seeing monitor
Sky: 
0
4th Quarter
Clouds: 
Clear
Seeing Value: 
1.00
Seeing Variability: 
0.2
Seeing Source: 
CTIO Seeing monitor
Sky: 
0
Program: 
Proposal: 
COSMOS Engineering
Target of Oportunity: 
No
Time Observed: 
0.0
Time Engineering: 
8.0
Time lost technical: 
0.0
Time lost weather: 
0.0
Time lost other: 
0.0
Primary Investigator: 
Points
Institution: 
CTIO
Instrument: 
CTIO 4m COSMOS
Total Program Time: 
8
Total Times Time Observed Time Engineering Time lost technical Time lost weather Time lost other Total Program Time
2019-11-07 0.0 8.0 0.0 0.0 0.0 8