1. Telescope Access Metrics
Presentation to NOAO Users Committee
October 12, 2004

2. Ground rules Categorize telescopes as
Large: 6.5m or greater
Gemini, others with TSIP (FIP) access
Medium: 3-4.2m
Mayall, Blanco, WIYN, SOAR
Small: m
KP 2.1m, WIYN 0.9m, SMARTS
Count nights available for science for past semesters
Extrapolate for future semesters
Gemini ramps up to 60 U.S. nights/telescope/semester
Currently averages ~50
SOAR begins science observations in 2005B and ramps up over 1 year

3. Precommitments-Surveys
Note that surveys are subject to the same peer review as regular proposals
20% cap
Proposals only taken once per year
Program started in 1999; none solicited in 2003 or 2004
Surveys can run up to 5 years
Actual nights committed run 10-20% for both medium and small telescopes
No surveys have been granted on large telescopes

4. Precommitments - NASA Agreements with HST, Chandra, Spitzer
Up to 5% of NOAO time available for complementary (not follow-up) ground-based observations connected with successful proposals
Proposals go through NASA peer review and NOAO technical review
Actual nights committed typically are 5-15 per semester on all telescopes << 15% maximum

5. Precommitments – instrument partnerships
Aimed at providing new instrumental capabilities on NOAO telescopes for guaranteed time
U Maryland agreement: 20% of Mayall time
Exchangable for WIYN or 2.1m
U. Md contribution (cash plus manpower) for NEWFIRM
Flamingos: base (4m: 3n, 2.1m: 5n) plus 4-6n for every 14 nights (after first 14) allocated to community
GSFC IRMOS: draft MOU – 4-5 n per semester on 4m, 8-10 n per semester on 2.1m,
Ge Exoplanet Tracker: draft MOU – 21 n per semester on 2.1m
All “guaranteed time proposals” go through TAC
If they do not succeed (which is rare), they are deferred to a later semester so the proposal can be improved

6. Current tally
2002
2003
2004
2005
2006
2007
Large-total
Precommit
remaining
146
201
253
265
263
278
Medium-total
739
207
532
698
166
654
168
486
714
132
582
774 47
727
786
Small-total
1071
186
885
633
141
492
653
119
534
640 29
611 12
628

7. Reasonable predictions
TSIP will continue to add large telescope-nights per year
TSIP will also add medium telescope-nights per year
The survey program will resume in 2005, leading to a future level of precommitment about the same as the past
The NASA precommitments will continue at a level of a few nights per semester
PREST will add approximately 200 nights of small telescope time per year

8. Tally with reasonable predictions
2002
2003
2004
2005
2006
2007
Large-total
Precommit
remaining
146
201
253
277
290
305
Medium-total
739
207
532
698
166
654
168
486
744
170
574
834
664
846
676
Small-total
1071
186
885
633
141
492
653
119
534
690
140
550
740
600
840
700

9. Nights remaining with predictions

10. Oversubscription rates
Nights requested divided by nights available after precommitment
Even with devolution of small telescopes, access is reasonable
Survey proposals (not included in graph) run for medium telescopes; for small telescopes

11. Conclusions
All oversubscription rates are in healthy range – and increase with increasing aperture
Status quo results in reasonable access
TSIP and PREST are expected to improve the situation – particularly for medium and small telescopes
Large telescope access is limited by willingness of independent observatories to give up more nights (TSIP) and by our fraction of Gemini.