Observing Log – 25 Dec, 2011 UT

Richard Green, Weihao Bian, Fuyan Bian

Summary of the Night:  Initial struggle to point and collimate after more than a week of being closed.  Photometric conditions, with very poor 
seeing and strong NE wind all night, requiring pointing only to the west.  We resorted to bright object programs, where we could open 
up the slit and double the exposure time to get close to S/N requirements.  After midnight, the seeing settled down to 1.5-2”.  We did 
run a full sequence of wide-slit observations of GD71, to add it to the regular standards list.

Clear at sunset, winds ~15 m/s from NE.  Telescope has been closed for more than a week, and the mirror is ~4 deg warmer than ambient.  
Right shutter door will not open; substantial ice on the rail.  

Initial difficulties in pointing and collimation; start on sky ~18:15 local time.

Spent 2.5 hours with help from Dave T and Andrew establishing collimation.  Seeing is ~3 arcseconds FWHM.  Mirror is 5 deg warmer than ambient.

Acquired and centered G191-B2B and started exposure at 21:10.

21:50  Fe II Qs   J0256-08   changed script to use 1.2” slit, double exposure time to 800 sec.

22:00 stopping observing to diagnose air leak in mirror support.  This was a stuck pop-off valve.  A good smack got it working again.

22:26 presetting to next object.  Fe II J0300-08 -  start exposure at 22:34.

22:54 preset to Fe II J0332+01 after OSA check for wind speed by rotating dome.  Seeing 1.8”.  (Collimation 150 nm)

23:39 preset to GD 71.  Seeing improving to ~1.5”.  Ran full script of dual, red, and blue for grating and prism.

00:56 preset to J0736+32;  shell rip’ed once because looking into wind.  Preset re-sent.  Seeing 1.6”.  Shell rip’ed again, 
 stopping exposure after 300 seconds.  Preset re-sent.  Giving up when shell ripped the third time.

01:27  Going to 0908+49; straight into NE wind.  Completed successfully.

01:54  Back to J0736+32; now just west, so enclosure has back to the wind.  Note two very low-z emission-line galaxies in the slit as 
well as the quasar.

02:25  preset sent to J0757+15.  We need to keep pointing west to keep back to the wind, since it’s creeping up toward the limit.  
That may preclude the only other partner targets that can tolerate bad seeing, because they are rising in the east.  Seeing still ~1.5”.  

02:51 preset to J0757+23.  

03:22 preset to J0905+10.  Seeing 1.5”, wind > 15 m/s from NE.  We realize that working west makes previous assumptions about parallactic angle at low dec 
 incorrect.  New parallactic angle tweaked slightly to retrieve previous guide star.

03:52 preset to J0920+03.  We stop briefly after this exposure to rotate and get a more valid wind speed sample.  Seeing getting as bad as 1.9”.  

04:19 preset to J0946+01.  Wind increasing toward 20 m/s.  Turn in azimuth to check before slew to next object.

04:47 preset to J0949+10.

05:13 preset to J0935+35.  Will check for wind at that azimuth.

05:35 preset to J0955+28.  Seeing still ~1.5”.  Wind still 15 m/s out of NE, so we still must face west.  
    [Weihao’s program was the only one meeting the criteria.]

05:55 preset to F 34.  Sky cam consistent with photometric conditions all night.