HET Mid-Trimester Report
Second Period of 2003
April 1 - May 22

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

• LRS: LRS was run with G3 for the first seven days of the period after which G2 has been on for all science nights. There were three nights of LRS instrument commissioning from May 2-4.

• SAMS and MARS: Some MARS engineering and software improvements were made during this period. SAMS problem reports have become more frequent than in previous periods.

• HRS: During four science nights in this period the HRS cryotiger lost its vacuum and only LRS was available.

• Instrument Commissioning: During this period there have been 8 nights scheduled for IC, of which 5 were for MCS and 3 were for LRS. During this period there were 0 nights scheduled for HRS.

• Engineering: During this period there were 22 nights of engineering scheduled: 1 guider software, 8 optical characterization, 2 SPS, 2 DIMM, 3 MARS/HEFI, 4 rho encoder replacement (PR-818) and 2 to align the SAC and PM. The rho encoder replacement and restarting science has taken longer than expected and at the creation of this report we are still not ready for science.

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.

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	Fraction of Actual Science Time Not accounted for or Lost
April	0.601	8.27	0.26	0.07	0.05	0.10	0.03

The last column is new and acounts for all of the lost or not used minutes. Some of this time is accounting errors and some is time not charged to any program due to operations inefficiency.

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
April	0.37	0.27	0.23	0.03	0.10

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 481 acceptable shutter open science exposures during this period for a total of 47.0 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
2	0.9	E - Rejected by RA for Equipment Failure
6	1.9	H - Rejected by RA for Human failure
62	6.3	W - Rejected by RA for Weather
3	0.8	P - Rejected by PI and confirmed by RA
1	0.2	Q - Rejected due to error in the queue
0	0.0	C - Acceptable by RA but PI rejects
2	0.4	N - Acceptable but NOT charged due to weather or hole in queue
8	1.3	B - Acceptable but Border line conditions

So this is a total of 10.4 hours of rejected spectra with an additional possible 1.3 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	15.4	14.8	722.2	600	2700	1031.5	600	4200
HRS	10.7	9.3	674.6	1200	1800	1190.3	1200	3900

The overhead statistics can be shortened by multiple setups (each one counted as a seperate 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.

CCD shutter Open by Institution (hours)
-TOTAL-	Used	% of All
PSU	16.217	32.5
UT	13.889	27.9
Stanford	7.083	14.2
Munich	10.417	20.9
Goetting	2.250	4.5
NOAO	15.594	--
SALT	0.000	--
DDT	0.000	--

The following is a summary of the total charged time for each institution based on our htopx data base (for shutter open) and night reports (for overhead). It includes shutter open time and overhead.

Time Charged by Institution (hours)
-TOTAL-	Used	% of All
PSU	29.53	37.3
UT	21.41	27.0
Stanford	11.91	15.0
Munich	13.49	17.0
Goetting	2.93	4.1
NOAO	N/A	--
SALT	0.00	--
DDT	0.00	--

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	6.000 (5%)	26.800 (21%)	26.700 (21%)	27.000 (21%)	42.830 (33%)
UT	21.160 (13%)	29.500 (18%)	44.800 (27%)	41.000 (25%)	29.000 (18%)
Stanford	0.000	7.000 (32%)	7.000 (32%)	4.000 (18%)	4.000 (18%)
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	31.220 (56%)	18.360 (33%)	6.000 (11%)	0.000
SALT	0.000	0.000	0.000	0.000	0.000
DDT	0.000	0.000	0.000	0.000	0.000