HET End-Trimester Report
First Period of 2003
December 1 - March 31

In this section we will discuss the status of each instrument and any limitation to configurations that occurred during the period.

• LRS: G3 was successfully run during December, February and March. G3 can now be installed with 24 hour lead time but due to the delicate nature of the optics this should be minimized. The LRS was offline for 2 nights due to a failure of the CCD electronics power supply.

• SAMS and MARS: Some MARS engineering and software improvements were made during this period. SAMS became unreliable for 4 nights because of failure of several sensors.

• HRS: During four nights in this period the HRS cryotiger lost the vacuum. But two of these occurred during an engineering night and a new moon night so no time was lost for science. In three cases the HRS cryotiger was re-pumped and ready for science the next night.

• Instrument Commissioning: During this period there were 8 nights scheduled for MRS IC, of which 4 were used. During this period there were 0 nights scheduled for HRS IC and LRS IC.

• Engineering: During this period there were 8 nights of engineering scheduled: 2 night of IQ assessment, 5 nights of optical characterization, and 2 nights to test HEFI. On a number of nights during this period small engineering tests were conducted along side science observations or during cloudy weather.

The following image quality statistics were taken from the statistics recorded for science operations in the night report.

For comparison here is the image quality for the same period of 2002

Here are the DIMM values reported in the night report. NOTE: There are a large number of nights when the DIMM was not operated; there is also times when the DIMM failed due to wind shake or extremely bad seeing.

Month by Month Summary

The following table gives the observing statistics for each month. The second column gives the fraction of the month that was spent attempting science (as opposed to engineering or instrument commissioning). Science time is defined to begin at 18 degree twilight or the first science target. Science time is defined to end at 18 degree twilight or the last science target. The fourth column gives the fraction of the possible science time (A) lost due to weather. The fifth through seventh columns give the amount of remaining science time (after removing weather losses) not spent attempting science targets. Please note that the first stack of the night often occurs before 18 degree twilight.

Month	A:Fraction of the Time that was Possible Science	B:Average Night Length	C:Fraction of Total Science Time Lost due to Weather	D:Fraction of Actual Science Time Lost due to Alignment	E:Fraction of Actual Science Time Lost due to Calibrations	F:Fraction of Actual Science Time Lost due to Problems
December	0.625	10.94	0.43	0.06	0.06	0.06
January	0.920	10.77	0.27	0.12	0.06	0.07
February	0.777	10.19	0.47	0.14	0.08	0.04
March	0.877	9.33	0.40	0.08	0.07	0.11

Details on Nightly cloud cover based on the TO's observations of the sky reported 3 times a night in the night report.:

Month	Fraction of the Nights that were Clear	Fraction of the Nights that were Mostly Clear	Fraction of the Nights that were Partly Cloudy	Fraction of the Nights that were Mostly Cloudy	Fraction of the Nights that were Cloudy
December	0.23	0.19	0.26	0.10	0.19
January	0.64	0.10	0.03	0.13	0.10
February	0.29	0.11	0.11	0.18	0.32
March	0.32	0.16	0.19	0.10	0.23

Please note that the HET could be closed due to humidity, smoke or high dust count and still have a "Clear" statistic in the night report.

The total number of 1421 acceptable shutter open science exposures during this period for a total of 168.0 hours. There were a number of rejected spectra obtained during this period as well the following table give the total number of rejected spectra and the category that each falls into.

Number of Times	Time Lost (Hours)	Type
17	4.0	E - Rejected by RA for Equipment Failure
12	1.3	H - Rejected by RA for Human failure
69	12.8	W - Rejected by RA for Weather
6	0.9	P - Rejected by PI and confirmed by RA
1	0.2	Q - Rejected due to error in the queue
1	0.2	C - Acceptable by RA but PI rejects
14	2.8	N - Acceptable but NOT charged due to weather or hole in queue
66	11.8	B - Acceptable but Border line conditions

So this is a total of 19.4 hours of rejected spectra with an additional possible 11.8 hours of spectra that may be rejected.

The following overhead statistics include slew, setup, readout and refocus between exposures (if there are multiple exposures per visit). In the summary page for each program the average setup time is calculated. The table below gives the average setup time for each instrument PER VISIT and the average and maximum COMPLETED science exposures and visits.

The "Exposure" is defined by when the CCD opens and closes. A "Visit" is the requested total CCD shutter open time during a track and might be made up of several "Exposures". "Visit" as defined here contains no overhead. To calculate one type of observing efficiency metric one might divide the "Visit" by the sum of "Visit" + "Overhead".

Instrument	Avg Overhead (min)	Median Overhead (min)	Avg Exposure (sec)	Median Exposure (sec)	Max Exposure (sec)	Avg Visit (sec)	Median Visit (sec)	Max Visit (sec)
LRS	16.98	16.0	709.2	600	1500	1261.6	900	4100
HRS	12.78	12.93	949.4	980	1800	1259.8	1200	4320

The overhead statistics can be shortened by multiple setups (each one counted as a separate visit) while on the same target as is the case for planet search programs. The overhead statistics can be lengthened by having multiple tracks that add up to a single htopx visit as can happen for very long tracks where each attempt might only yield a half visit.

The following is a summary of the Acceptable CCD shutter time for each institution based on our htopx data base. It does not include any overhead.

Time Usage by Institution (hours)
-TOTAL-	Used	% of All
PSU	39.977	20.4
UT	125.057	63.8
Stanford	16.833	8.6
Munich	6.729	3.4
Goetting	7.500	3.8
NOAO	36.830	--
SALT	0.000	--
DDT	0.000	--

This is how each institution has allocated its time by priority.

Time Allocation by Institution (hours)
Institution	Priority 0	Priority 1	Priority 2	Priority 3	Priority 4
PSU	11.500 (10%)	25.200 (23%)	37.700 (34%)	36.500 (33%)	0.000
UT	15.500 (6%)	52.900 (21%)	61.400 (25%)	59.600 (24%)	60.000 (24%)
Stanford	0.000	5.000 (26%)	4.500 (23%)	5.000 (26%)	5.000(26%)
Munich	0.000	0.000	0.000	0.000	0.000
Goetting	0.000	0.000	0.000	0.000	0.000
NOAO	10.000 (6%)	83.700 (52%)	62.600 (37%)	6.000(4%)	0.000
SALT	0.000	0.000	0.000	0.000	0.000
DDT	0.000	0.000	0.000	0.000	0.000