HET Mid-Trimester Report
First Period of 2003
December 1 - January 16

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.

• 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 one night in this period the HRS cryotiger lost the vacuum but this occurred during an engineering night so no time was lost for science. The HRS cryotiger was re-pumped and ready for science the next night.

• Instrument Commissioning: During this period there were 5 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 6 nights of engineering scheduled: 1 night of IQ assessment, and 5 nights of optical characterization. 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	0.590	10.94	0.43	0.06	0.06	0.06

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

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 506 acceptable shutter open science exposures during this period for a total of 65.3 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
5	0.8	E - Rejected by RA for Equipment Failure
5	0.2	H - Rejected by RA for Human failure
27	3.9	W - Rejected by RA for Weather
0	0.0	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
5	1.4	N - Acceptable but NOT charged due to weather or hole in queue
36	5.7	B - Acceptable but Border line conditions

So this is a total of 6.7 hours of rejected spectra with an additional possible 5.7 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 science exposures (ie. the CRSPLIT NOT the VISIT length).

Instrument	Avg Overhead (min)	Median Overhead (min)	Avg Exposure (sec)	Median Exposure (sec)	Max Exposure (sec)
LRS	15.4	14.8	759.0	600	1500
HRS	10.7	9.3	944.4	900	1800

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	22.769	29.7
UT	42.239	55.0
Stanford	7.167	9.3
Munich	2.069	2.7
Goetting	2.500	3.3
NOAO	8.492	--
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	13.500 (6%)	49.900 (20%)	61.400 (25%)	59.600 (24%)	60.000 (25%)
Stanford	0.000	7.000 (34%)	6.000 (29%)	7.500 (37%)	0.000
Munich	0.000	0.000	0.000	0.000	0.000
Goetting	0.000	0.000	0.000	0.000	0.000
NOAO	0.000	53.700 (56%)	42.600 (44%)	0.000	0.000
SALT	0.000	0.000	0.000	0.000	0.000
DDT	0.000	0.000	0.000	0.000	0.000