HET End-Trimester Report
Second Period of 2003
April 1 - August 3

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

• LRS: The G3 and G2 grisms were swapped several times during the period. The LRS was offline for 25 nights: 2 for guider failures, 23 for cyro failures.

• 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, but seemed to be fixed at the end of the period with new software and a fresh piston of the primary.

• HRS: During four science nights in this period the HRS cryotiger lost its vacuum and only LRS was available. The apogee fiber offset setup method was commissioned and all the TOs were trained. This method can now be use for all targets.

• Instrument Commissioning: During this period there have been 11 nights scheduled for IC, of which 8 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. At the end of the period roughly an hour a night was given to John Good for Dome Seeing work during bright time or during holes in the queue.

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
May	0.688	7.24	0.30	0.07	0.03	0.59	0.05
June	0.926	6.66	0.46	0.13	0.04	0.28	0.10
July	0.823	6.94	0.27	0.12	0.05	0.08	0.08

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
April	0.37	0.27	0.23	0.03	0.10
May	0.26	0.10	0.26	0.16	0.23
June	0.10	0.17	0.37	0.20	0.17
July	0.42	0.20	0.16	0.10	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 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
770	98.1	A - Acceptable
39	8.8	B - Acceptable but Border line conditions
145	26.0	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
100	8.3	I - Targets observed under otherwise idle conditions
54	3.2	E - Rejected by RA for Equipment Failure
20	4.0	H - Rejected for Human failure
86	14.8	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 32.7 hours of uncharged spectra with an additional possible 8.8 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	15.9	l5.0	379.7	600	2700	1036.2	600	4800
HRS	14.3	10.9	613.9	1200	3000	1017.5	1200	5720

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 histogram of the final HET queue visits. The last days of the period there were significant holes.

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	22.500	0.000	0.000	0.000

The DDT time was given out to encourage candidates to come to the HET and fill in as an RA during June when we unexpectedly short an RA.

The following is a summary of the Acceptable CCD shutter time for each institution based on our night report data base. It does not include any overhead. Priority 4 time is charge at 0.5 of the visits completed.

CCD shutter Open by Institution (hours)
-TOTAL-	Used	% of All
PSU	27.07	26.5
UT	50.67	49.6
Stanford	10.49	10.3
Munich	11.67	11.4
Goetting	2.27	2.2
NOAO	15.93	--
SALT	0.00	--
DDT	8.80	--

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. Priority 4 time is charged at half its normal rate.

Time Charged by Institution (hours)
-INST-	Used	% of All	-TOTAL TO DATE-	-% TO DATE-
PSU	44.52	28.8	687.3	29.2
UT	73.30	47.5	1331.8	56.7
Stanford	17.41	11.3	180.5	7.7
Munich	15.38	10.0	60.0	2.6
Goetting	3.81	2.5	90.9	3.9
NOAO	N/A	--	--	--
SALT	0.00	--	--	--
DDT	11.16	--	--	--

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.