PartnerObserving Log for 2007 Mar 10/11

Observer: John Hill
Telescope Operator: Ed Lundin

Some more SDT-related observing during engineering time. Note that I'm not paying any attention to the SDT queue. I'm only using convenient SDT targets to test various aspects of the telescope. (i.e. focus offset for SDT_Uspec wide UV filter, field-dependent astigmatism, apparent jumps in WCS coordinates for dithered exposures)

Note that filters have been cleaned and rearranged in the LBC-Blue filter wheel during the installation of SDT_Uspec and the balancing rings. Other than the filters, the baffling and vignetting should be the same as during the February SDT run. The undersized L2 baffle is responsible for the vignetting around the edge of the field.

Opened after sunset: Sky mostly clear, but not photometric. There are occasional chunks of broken cirrus drifting by. Seeing uninspiring at ~1.2 arcsec.

10 bias frames

SDT_Uspec (a.k.a. Wide-UV) sky flats (first ever taken) -- unsaturated flats start at 014833

r-SLOAN sky flats

02:07- 02:20 Bfastextra WF 020708 thru 022327

02:20 - 03:00 Engineering focus frames for SDT_Uspec (Note that hselect only likes 7 characters in the filter name)

03:09 Bfastextra WF at M67

03:12 WDs_M67_SCI_B1 Dithers show apparent jumps in WCS coordinates (not actual jumps in tracking). PCS shows corresponding errors in achieved pointing when the dither offset is non-zero.

04:12-04:15 Bfastextra WF at grb070125; elevation 86 degrees

04:19 grb070125 shows some field-dependent astigmatism, but no sign of rotator errors.

04:45 Bfastextra then another Sfinefoc for SDT_Uspec

05:04 Bfastextra for LeoII

05:07 LeoII_1_U through clouds, couldn't see the guide stars

05:45 Run 3-step dither on pointing star to demonstrate that the remaining achieved pointing issue (#487) is a cos(dec) effect.

07:02 Bfastextra for COSMOS 070406

07:06 cosmos_SDT_Uspec_1a -- Taking these with the non-optimized focus offset of 0.40 mm (compare 0.46 to 0.48 below). This may be a contributor to the already poor seeing.

07:43 Bfastextra for COSMOS

07:46 cosmos_SDT_Uspec_1b -- Clear, but 2 arcsec seeing. Moonrise during the 5th dither of the OB

08:22 Bfastextra for COSMOS

08:25 cosmos_SDT_Uspec_1c -- Clear, last quarter moon in east. Guiding failed on first dither, even with an apparently good star on Tracker #1. Guiding failed on second and third dithers for lack of guide stars.

09:05-09-12 Bfastextra for Fan Quasar field

09:13 sdt_fan1_1 -- Seeing 1.2 arcsec, but background getting hammered by the moon. Think of these as U sky flats.

09:50-11:10 Test observations of next week's Pluto occultation (I wasn't able to rediscover Pluto in the last 2 nights -- makes you appreciate Clyde Tombaugh.)

11:15-11:22 Bfastextra for Fan Quasar field

11:33-11:38 Engineering focus frames for SDT_Uspec from Sfinefoc ---> 0.46 mm in 1.2 arcsec seeing (Adopted this value as a useful, but not optimized value for the focus offset.)

11:40 sdt_fan1_2

11:57-12:05 Bfastextra for Fan Quasar field

12:08-12:12 Engineering focus frames for SDT_Uspec from Sfinefoc ---> 0.48 mm in 1.2 arcsec seeing

12:17 Bfastextra, but no pupils

Close 12:22 UT T=-0.7degC Wind 8 m/sec from NW D=-12degC

-- JohnHill - 11 Mar 2007
Topic revision: r7 - 21 Jul 2009, NormCushing
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