HET End-Trimester Report
First Period of 2023
December 1 - March 31

This report is composed of five sections:
Facility Status

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

                       








Probe and instrument availability statistics:
There were a total of 122 nights in the trimester:
LRS2-B
 LRS2-R
 VIRUS
 HPF
 HPF
LFC
 HPF
high-prec.
 Guider 1
 Guider 2
 WFS 1
 WFS 2
 DIMM
122
 122
 122
 122
 122
 121
 122
 122
 122
 122
 122
100%
 100% 100% 100%
 100%
 99%
 100% 100% 100%
 100% 100%




Observing Statistics

Commissioning, Engineering, and Guaranteed Time Report There were 224 hours granted in the 23-1 period:

There were 132.6 hours of eng/comm/GTO used (charged) in the 23-1 period, in the following categories:





Month by Month Summary

The following table gives the observing statistics for each month. Column A 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 evening twilight and end at 18 degree morning twilight. Column B gives the fraction of the possible science time (A) lost due to weather. The other 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:
Fraction of Total Time Lost due to Weather 		C:
Fraction of Actual Science Time Spent with Shutter Open 		D:
Fraction of Actual Science Time Lost due to Overhead 		E:
Fraction of Actual Science Time Lost due to Alignment		 F:
Fraction of Actual Science Time Lost due to Problems		 G:
Fraction of Actual Science Time Not accounted for or Lost
Dec
 0.987
 0.497
 0.618
 0.270
 0.0706
 0.0418
 0.0000
Jan
 0.990
 0.452
 0.654
 0.259
 0.0653
 0.0214
 0.0000
Feb 0.982
 0.589
 0.607
 0.261
 0.0630
 0.0688
 0.0000
Mar
 0.985
 0.512
 0.612
 0.249
 0.0423
 0.0973
 0.0000

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
3145
 410.73
 A - Acceptable
198
 44.45
 B - Acceptable but Border line conditions
362
 83.10
 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
19
 5.77
 E - Rejected for Equipment Failure
587
 123.62
 W - Rejected for Weather
9
 1.43
 H - Rejected for Human Errors

Uncharged exposures caught by PI
Number of Times Shutter Open (Hours) Type
20
 6.55
 P - Rejected for weather
0
 0.00
 F - Rejected for Equipment Failure
0
 0.00 T - Rejected for poor track choice
0
 0.00 X - Rejected for Human Errors

Acceptable but Uncharged exposures
Number of Times Shutter Open (Hours) Type
0
 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 4.81
 103.00
 24.56%
LRS2 6.30
 72.63
 31.74%
HPF 6.98
 197.87
 31.18%

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.



HETDEX time interruptions:

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




Overall time charged: 17.25h (eng/comm) + 518.28h (sci/GTO) = 535.53h
Total estimated science time available (in TAC time determinations): 651.6h
   Conclusion: weather in 23-1 was much worse than expectations...
      The past two 1st trimesters charged times were 657.72h and 628.34h so this one had exceptionally poor weather



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.

Institution Tot exp
 Tot OH
Tot Chrg Tot TAC Total % P0 Completion
 P1 Completion P2 Completion P3 Completion










G23-1-001 0.43
 0.23
 0.67
 0.67
 100%

100%
G23-1-002 9.50
 2.60
 12.01
 15.54
 78%
 100%
 91%
 100% 50%
G23-1-003 J*
 J* J* J* J* J* J* J* J*










M23-1-001 2.45
 0.37 2.82
 6.00
 47%
100%
 24%
M23-1-002 1.83
 0.50
 2.33
 4.00
 58%
 88%
 48%

M23-1-003 J*
 J* J* J* J*
 J* J* J* J*
M23-1-004 8.88
 4.47
 13.34
 19.75
 68%(P4)
100%
 100%
 100%
M23-1-005 4.00
 0.87
 4.87
 8.00
 61%
60% (DT)
 93%
 48%










PSU23-1-001 J*
 J*
 J* J* J* J* J* J* J*
PSU23-1-002 3.33
 0.50
 3.83
 4.11
 93%
 100%
 100%

PSU23-1-003 0.13 0.00
 0.13 6.23 2%(P4)



PSU23-1-004 1.00
 0.00
 1.00
 1.75
 57%(P4)



PSU23-1-005 0.36
 0.00
 0.36
 6.33
 5%(P4)



PSU23-1-006 6.83
 1.53
 8.35
 16.92
 49%(P4)


69%
PSU23-1-007 0.05
 0.00 0.05 0.26
 17%(P4)



PSU23-1-008 0.33
 0.17 0.50 1.38 36%


36%(TD)
PSU23-1-009 3.68
 1.58 5.25 9.03
 58%(P4)
100%
 89%
 90%
PSU23-1-010 8.17
 0.00
 8.17
 10.92
 75%(P4)



PSU23-1-011 0.25
 0.00
 0.25
 2.67
 9%(P4)



PSU23-1-012 1.50
 0.75
 2.25
 2.53
 89%
 100%


PSU23-1-013 1.54
 0.56
 2.10
 4.10
 51%(P4)

100%
PSU23-1-014 J*
 J* J* J* J* J* J* J* J*
PSU23-1-015 2.52
 0.61
 3.13
 4.33
 72%
 100%

35%
PSU23-1-016 J* J* J* J* J* J* J* J* J*
PSU23-1-017 0.69
 0.14
 0.83
 1.00
 83%
100%

PSU23-1-018 2.50
 0.64
 3.14
 3.33
 94%
 100%
 100%











UT23-1-001 6.50
 1.62
 8.12
 18.00
 45%
 100%
 100%
 0% (NT)
UT23-1-002 5.00
 1.12
 6.12
 8.70
 70%(P4)

100%
 100%
UT23-1-003 --
 --
 --
 --
 --



UT23-1-004 J* J* J* J* J* J* J* J* J*
UT23-1-005 18.29
 9.45
 27.74
 39.10
 71%(P4)
100%
 74%
 92%
UT23-1-006 J* J* J* J* J* J* J* J* J*
UT23-1-007 5.75
 3.08
 8.83
 22.30
 40%(P4)

90%
 		19%
UT23-1-008 8.50
 2.07  10.57 22.00 48% 57% (DT)
 37% (DT)

UT23-1-009 5.30
 1.63
 6.93
 6.65
 104%
 100%


UT23-1-010 3.38
 1.64
 5.01
 23.70
 21%(P4)

71%
 17%
UT23-1-011 14.20
 5.29
 19.49
 47.80
 41%(P4)

100%
 42%
UT23-1-012 J*
 J* J* J* J*
 J* J* J* J*
UT23-1-013 13.55
 9.49
 23.03
 35.00
 66%(P4)

100%
 		100%
UT23-1-014 11.17
 3.25
 14.42
 20.00
 72%

72%
UT23-1-015 6.00
 1.58 7.58
 8.50
 89%
 100%
 77%











HET23-1-100 71.90
 20.75
 92.65
 195.00 48%
 48%


HET23-1-203 1.64
 0.54
 2.18
 2.00
 109%
 100%
 100%

HET23-1-300 15.23
 4.42
 19.65
 20.00
 98%
 100%
 100%
 96%




















UT23-1-004
+PSU23-1-014
 35.59
 8.07
 43.66
 58.00
 75%(P4)
93%
 87%
 39%










PSU23-1-001
+UT23-1-012
 70.37
 18.41
 88.77
 100.02
 89%(P4)
 100%
 100%
 100%
 85%










UT23-1-006
+PSU23-1-016
+M23-1-003
+G23-1-003
 10.60
 1.97
 12.57
 11.86
 106%
 100%
 100%





















J* = joint program between multiple partners - see summary at bottom of table
NT = no (or very late-in-trimester) targets submitted at this priority (even though time was allocated)
HC = HETDEX conflict (targets submitted were in direct competition with HETDEX; PI was aware of issue)
SI = Seasonally inappropriate or narrowly distributed target list
TD = Time Domain targets (either none submitted or submitted targets unreachable due to weather)
DT = Dark Time targets (or grey time; often need high priority and good sky distribution to be successful)
P4 = Program's overall completion fraction is significantly impacted by the utilization of P4 time


Program Completion Rates
(sci only, removing NT/HC/SI/TD)
Priority Average Completion Median Completion
P0 92.9% 100%
P1 89.2% 100%
P2 88.0% 93%
P3 63.3% 60%

Special note for 23-1: (similar to 22-3, unfortunately)
  While these percentages are lower than most trimesters, they were driven down by two main factors:
1) a number of programs (many dark time or single-target programs) achieving low completion rates at a given priority.
2) a number of HPF programs submitting the same targets at Pr1, Pr2, and Pr3, which reduces our chances to complete the program.
The table below shows the numbers of hours allocated and charged at each priority, to give a different perspective:
(UT+PSU+G+M; not including HET GTO programs)

 hours allocated
(allowed)
 hours charged
P0
 55.50
 52.65 (94.9%)
P1
 83.40
 73.27 (87.9%)
P2
 138.60
 123.26 (88.9%)
P3
 138.60
 84.24 (60.8%)




Completion trends by priority









Institution Status

Below we show how the TAC allocations were determined.

quantity
 Dec
(hrs)
 Jan
(hrs)
 Feb
(hrs)
 Mar
(hrs)
 Total
(hrs)
18deg-18deg
 339.17
 334.00
 285.43
 289.23
 1247.83
Weather loss frac. 0.44
 0.44
 0.46
 0.47
Efficiency loss frac.
(align+PRs)
 0.05
 0.06
 0.06
 0.06
"Clear science" time
 183.66
 178.96
 144.89
 144.10
 651.60
Com/Eng/GTO time
(estimated)



235.50
"Allowed" hours
given to TACs
for science



416.10




Partner
 Share
 Time deficit correction
 Notes
 Total hours
allowed
Goettingen
 0.03860
 +1.14
17.20
Munich
 0.05724
 +4.05
28.40
PSU
 0.24897
 -5.70
98.11
UT
 0.65518
 +0.51

276.75

Corrections were applied using 20% of the cumulative deficits in time balance between the partners. As of August 1st 2022, those time deficits were:
  UT:   1.7h deficit
  PSU: 19.0h surplus
  M:    13.5h deficit
  G:     3.8h deficit
Actual time usage is carefully monitored to ensure equitable balance between the partners; these corrected allocations should help improve this balance over the long-term.

Note that effective 1-Dec 2022, TACs may allocate up to 13.3% at P0*, 20% at P1*, 33.3% at P2 and 33.3% at P3; P4 allocations are not restricted. Priorities of Com/Eng/GTO time are assigned by the HET Board.

*In September 2022 the HET Board approved a proposal (available here) from the Users Committee to temporarily change the fractional time allocations at each priority. After the HETDEX guaranteed time observations are completed, the priority breakdowns will return to the previously adopted fractions.


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 2.30
 3.50
 5.71
 5.70
 -
 17.21
 100.0%
Munich 2.40
 9.00
 9.50
 9.50
 9.50
 30.40
 107.0%
PSU 14.59
 21.58
 32.63
 32.64
 38.17
 101.44
 103.4%
UT 37.15
 55.81
 95.70
 88.10
 77.00
 276.76
 100.0%
Other allocations
GTO 217.50 9.00 8.00 0.00
 -
 234.50
 100.0%

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





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.

Accumulated deficits
for each partner
UT
 PSU
 M
 G
 total sci
hours
FY2015-2016
+4.6
 -6.9
 +1.1
 +1.2
 40.49
FY2016-2017
+22.7
 -22.8
 +0.8
 -0.8
 439.56
FY2017-2018
+37.7
 -21.9
 -14.7
 -1.2
 887.71
FY2018-2019
+43.0
 -32.0
 -10.8
 -0.2
 1401.17
FY2019-2020
+48.9
 -48.4
 +0.6
 -1.1
 2101.82
FY2020-2021
+25.1
 		-37.6
 		+13.8
 -1.3
 3095.70
FY2021-2022
+1.7
 -19.0
 +13.5
 +3.8
 4140.40
FY2022-2023 (as of 1-Apr)
+23.4
 -33.4
 +5.7
 +4.2
 4854.40
percent of deficit:
+0.48%
 -0.69%
 +0.12%
 +0.09%
  In summary, all partner deficits are <0.7% of total science hours since the WFU; continued effort is underway to actively balance these percentages.
NB: a more comprehensive annual partner fractional time charging analysis is produced separately from these trimester reports; a current copy can be provided upon request.



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 23-1		 Allocated total
to date
including 23-1 		Charged
in 22-3		 Charged total
to date
including 22-3
HETDEX (HETYY-P-100) 195.0 2899.0 92.7
 2277.0
LRS2 GTO (HETYY-P-2XX) 2.0 207.9 2.2
 129.6
HPF GTO (HETYY-P-3XX) 20.0 280.4 19.7
 280.8
GW (HETYY-P-400) 17.5 87.5
 0.0
 12.4

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














SJ, 4 Apr 2023