HET End-Trimester Report
Second Period of 2021
April 1 - July 31

• Facility Status
• Observing Statistics
• Observing Programs Status
• Institution Status
• TAC Response

• Facility:
• Significant operational adjustments remain in place for COVID-19 procedures, returning gradually to fully in-person observations by July.
  

The following tables give a break down of all attempted science visits as well as the category that each falls into.

Charged exposures
Number of Times	Shutter Open (Hours)	Type
2233	319.78	A - Acceptable
83	18.67	B - Acceptable but Border line conditions
181	41.92	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 caught by RA
Number of Times	Shutter Open (Hours)	Type
0	0.00	N - Rejected due to unknown cause
10	1.97	E - Rejected for Equipment Failure
189	44.60	W - Rejected for Weather
6	1.63	H - Rejected for Human failure

Uncharged exposures caught by PI
Number of Times	Shutter Open (Hours)	Type
0	0.00	P - Rejected for weather
0	0.00	F - Rejected for Equipment Failure
3	1.80	T - Rejected for poor track choice
0	0.00	X - Rejected for Human failure

Acceptable but Uncharged exposures
Number of Times	Shutter Open (Hours)	Type
4	0.0	I - Targets observed under otherwise idle conditions

The following setup statistics include slew, acquisition, and starting data collection script. The table below gives the average setup time for each instrument PER ACTUAL VISIT and the average and maximum COMPLETED charged science exposures and visits.

The "Exposure" is defined by when the (CCD) shutter 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".

The average setup per visit is calculated from acceptable priority 0-3 (not borderline) science targets. This number reflects how quickly we can move from object to object on average for each instrument, however, this statistic tends to weight the setup for programs with large number of targets.

The average overhead percentage is calculated for each instrument and shows how much of that instrument's total time on sky (overhead+exposure) was overhead. NB: LRS2 has the smallest overhead %, but typical LRS2 observations use much longer exposures than VIRUS, even though VIRUS has a faster average setup time.

Instrument	Avg Setup per Visit (min)	Total time exposed (hrs)	Overhead %
VIRUS	4.73	124.52	24.48%
LRS2	5.96	48.57	31.35%
HPF	6.61	94.15	33.98%

The setup statistics can be shortened by multiple setups (each one counted as a separate visit) while on the same target such as moving from LRS2-B to LRS2-R.

Within the times when HETDEX shots were available on-sky for >20 minutes, the following percentages summarize how the time was used:

• 22.9% HETDEX (18.0% exposures, 4.86% overhead)
• 50.5% weather losses
  
• 22.8% sci/GTO/eng/comm (3.08% engineering/commissioning, 13.9% science/GTO exposures, 5.86% science/GTO overheads)
• 75.2% at P0 (70.1h)
• 5.7% at P1 (5.3h)
• 10.6% at P2 (9.9h)
• 6.3% at P3 (5.9h)
• 2.1% at P4 (2.0h)
  
• 1.9% mirror alignment
• 1.9% problems

Overall time charged: 193.5 (eng/comm/GTO) + 184.17h (sci) = 377.67h
Total estimated science time available (in TAC time determinations): 493.80h
   Conclusion: weather in 21-2 was significantly worse than average, giving us only 76% of expected/average time available.

Observing Programs Status

In the table below we show the breakdown of the charged time for each program submitted. The "Total %" is the completion of the entire TAC time including P4 time. The last four columns show the completion rate for targets submitted in each priority bin. This completion rate is the greater of the targets completed percentage and the TAC allocation completed percentage in each priority bin.

Program Completion Rates (sci only, removing NT/HC/TD)
Priority	Average Completion	Median Completion
P0	100.0%	100%
P1	76.5%	100%
P2	94.6%	100%
P3	88.3%	100%

NB poor weather at the start of the trimester resulted in a low P1 completion rate for targets which became inaccessible to observations later on.

Institution Status

Below we show how the TAC allocations were determined.

This is how each institution had allocated its time by priority:

Time Allocation by Institution (hours)
Institution	Priority 0	Priority 1	Priority 2	Priority 3	Priority 4	Total P0-P3	Frac. of allowed
Goettingen	0.00	0.60	0.60	0.60	-	1.80	99.4%
Munich	1.10	3.10	4.20	4.20	-	12.60	99.9%
PSU	3.50	12.00	17.00	17.00	30.29	49.50	98.7%
UT	10.80	31.80	43.30	43.30	102.00	129.20	100.0%
Other allocations
GTO	201.00	13.00	8.00	3.00	5.00	225.00	100.0%

Notes:
1) Allocations in joint programs are reported separately for each partner

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 (no overhead for priority 4 observations). Recently this calculation was re-derived using a deficit/surplus model. For each financial year the share paid is compared with the time charged - any discrepancy between the two is tracked and carried forward as a deficit. A negative deficit means more time was observed for that partner than their financial share; a positive deficit means less time was observed. These deficits are calculated in each previous financial year; the table below also includes a preliminary total for the current financial year so far.

Below are the summaries of the Guaranteed Time Observations (GTO) programs granted by the Board:

GTO and Special Time Charged by Project (hours)
Project	Allocated in 21-2	Allocated total to date including 21-2	Charged in 21-2	Charged total to date including 21-2
HETDEX (HETYY-P-100)	155.0	2191.0	111.78	1550.79
LRS2 GTO (HETYY-P-2XX)	10.0	175.94	10.46	101.15
HPF GTO (HETYY-P-3XX)	20.0	180.40	19.71	181.08
GW (HETYY-P-400)	0.00	70.00	0.00	12.37

(Totals to date start from the 11-2 period)

SJ, Aug 4 2021