HET Mid-Trimester Report
Third Period of 2003
August 1 - Oct 31

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 month of the period we plan to switch to G2 in the first few days of November. During engineering the LRS became non-functional for 3 days.

• SAMS and MARS: SAMS and MARS were run during the entire period.

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

• Instrument Commissioning: During this period there has been no nights dedicated to IC but a few hours during bright time and during clouds were spent with MRS IC.

• Engineering: The re-coating of the SAC mirrors, installing the rho ring, and recreating the mount model was was completed on Oct 5th. Since then much of bright time has been used for image quality engineering work.

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
August	0.063	7.87	0.40	0.00	0.02	0.14	0.05
September	0.004	8.94	0.00	0.00	0.17	0.00	0.00
October	0.591	9.89	0.24	0.07	0.06	0.09	0.09

The last column is new and accounts 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
August	0.19	0.00	0.63	0.19	0.00
September	0.43	0.00	0.13	0.00	0.10
October	0.48	0.07	0.19	0.07	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 following tables give a break down of all attempted visits as well as the category that each falls into.

Charged exposures
Number of Times	Shutter Open (Hours)	Type
237	52.8	A - Acceptable
23	5.2	B - Acceptable but Border line conditions
1	0.1	4 - Priority 4 visits (does not include 1/2 charge)
0	0.0	Q - charged but PI error
0	0.0	C - Acceptable by RA but PI rejects

Uncharged exposures
Number of Times	Shutter Open (Hours)	Type
3	0.9	I - Targets observed under otherwise idle conditions
8	1.3	E - Rejected by RA for Equipment Failure
13	1.0	H - Rejected for Human failure
21	4.7	W - Rejected by RA for Weather
5	1.4	P - Rejected by PI and confirmed by RA
0	0.0	N - Rejected due to unknown cause

So this is a total of 58.1 hours of uncharged spectra with an additional possible 5.2 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	17.4	15.9	947.8	1200	1800	1719.1	1200	3600
HRS	13.3	11.5	593.5	780	1320	888.5	900	4800

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 overheads for this period are larger than the previous for the following reasons:

• For the current trimester we have a new guide field on the LRS with a smaller field of view to which the RAs and PIs need to adapt.
• We are training a new TO during this period.
• We are trying to standardize the setup methodology on the HRS.

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 (9%)	15.520 (23%)	20.570 (31%)	16.460 (24%)	8.800 (13%)
UT	11.500 (6%)	35.000 (19%)	47.000 (26%)	41.500 (23%)	45.000 (25%)
Stanford	0.000	4.000 (33%)	4.000 (33%)	2.000 (17%)	2.000 (17%)
Munich	0.000	13.700 (100%)	0.000	0.000	0.000
Goetting	0.000	4.700 (100%)	0.000	0.000	0.000
NOAO	0.000	41.370 (54%)	29.510 (38%)	6.000 (8%)	0.000
SALT	0.000	0.000	0.000	0.000	0.000
DDT	0.000	0.000	0.000	0.000	0.000

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. And does not weight based on any priority scheme (ie. priority 4 are counted at full cost).

CCD shutter Open by Institution (hours)
-TOTAL-	Used	% of All
PSU	13.197	29.4
UT	26.982	60.0
Stanford	1.750	3.9
Munich	3.033	6.7
Goetting	0.000	0.0
NOAO	15.228	--
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 (weighting priority four by half) and overhead.

Time Charged by Institution (hours)
-INST-	Used THIS PERIOD	% of All THIS PERIOD	-TOTAL TO DATE-	-% TO DATE-
PSU	21.40	29.8	708.7	29.3
UT	42.73	59.6	1374.5	56.7
Stanford	3.05	4.3	183.6	7.6
Munich	4.53	6.3	64.5	2.7
Goetting	0.00	0.0	90.9	3.8
NOAO	N/A	--	--	--
SALT	0.00	--	--	--
DDT	0.00	--	--	--

The original "TOTAL TO DATE" was found to be in error on Dec. 11 2003; it did not include the overhead time. The values given here in red are the corrected totals.
Total to Date starting from Oct 1999. Priority weighting began in the 2003-2 period.