HET Beginning-Trimester Report
  Second Period of 2022
April 1 - July 31

This report is primarily to give updates to PIs on recent changes/improvements and to summarize the determination of time allocations for the 22-2 trimester.



Updates on recent changes/improvements:

Updates to documentation

   Further information has been added to the "Observing Status" page on Hydra, and continues to be updated with new details!
        https://hydra.as.utexas.edu/?a=help&h=7

   Acknowledgements for the HET and for each instrument are available here:
        https://hydra.as.utexas.edu/?a=help&h=61


Updates to TSL
    We no longer accept PMEPOCH or EQUINOX keywords in TSL. It was recently realized that our system has been tacitly ignoring anything the users submit for these quantities in  TSL files and is always hard-coding values of PMEPOCH=2000 and EQUINOX=2000. Until we are able to support other values, we will not accept these keywords in TSL Phase II files to prevent confusion and misunderstandings.


Planned HPF downtime
    Details are still converging, but the likely plan is:
    May ~20th, HPF goes offline for detector engineering work and some troubleshooting
    June ~10th, HPF comes back for low-precision science observations, but not fully stable for high-precision work
    July ~31st, HPF is fully stabilized and able to make high-precision observations again








Commissioning, Engineering, and Guaranteed Time allocations


The HET Board granted the following allocations for the 22-2 period:



 





Breakdown of how science hours for TACs at each partner were determined:



quantity
 Apr
(hrs)
 May
(hrs)
 Jun
(hrs)
 Jul
(hrs)
 Total
(hrs)
18deg-18deg times
 248.20
 224.58
 199.88
 215.15
 887.82
Weather loss frac. 0.396
 0.384
 0.435
 0.487
Efficiency loss frac.
(align+PRs)
 0.06
 0.07
 0.07
 0.04
"Clear science" time
 140.92
 128.66
 105.03
 105.96
 480.56
Com/Eng/GTO time
 *calculated based on
  statistical averages of
  time actually used in
  previous ~3 years



235.00
"Allowed" hours
given to TACs
for science



245.56




 

Hours allowed for each TAC as determined Feb 2, 2022:


Partner
 Share
 Time deficit
correction
 Total hours
allowed
Allocated
as of Apr 1
(excl. Pr4)
Goettingen
 0.03860
 -0.26
 9.22
 9.20
Munich
 0.05724
 +2.76
 16.82
 14.80
PSU
 0.24897
 -7.52
 53.62
 52.09
UT
 0.65518
 +5.02
 *145.91
 151.80
*includes 20h removed for TESLA

Corrections were applied using 20% of the cumulative deficits in time balance between the partners. As of August 1st 2021, those time deficits were:
  UT:   25.1h deficit
  PSU: 37.6h surplus
  M:    13.8h deficit
  G:     1.3h surplus
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 TACs may allocate up to 8.3% at P0, 25% 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.



Special note for planned HPF downtime this trimester:

As of 2-Feb, the planned HPF downtime timeline is expected to be roughly:
~May 20th, HPF goes offline for warm-up pumping
~3 weeks without HPF available
~6-8 weeks of low-precision HPF observations as it cools

In practice that means the following percentages of time available this trimester:
   45%: 1-Apr to ~20-May: full/normal HPF observations
   15%: ~20-May to ~10-Jun: no HPF observations
   40%: ~10-Jun to ~31-Jul: low-precision HPF only (chemistry/abundances)

For planning purposes, I have broken down the partner time allocations into these fractions as well, to discourage over-allocations of HPF programs which cannot be executed in the limited time available.











SJ, 2 Apr 2022