Computation of the Cost of a Night of Keck Telescope Observing

The cost of one night of observing with one of the Keck 10-meter telescopes is derived from two numbers; total annual cost of the Keck facility divided by the number of nights the telescopes are used for observations by the Keck Observatory partners.

Cost per night = (Annual cost) / (Number of nights telescopes used by partners)

The annual cost is a combination of three cost areas:

• Amortized telescope development
• Amortized instrument development
• Annual operations cost

The earliest that the Keck Observatory can provide observing nights to the TSIP is in calendar year 2003, so the computation of cost per night is computed for FY03 (the Keck fiscal year matches the federal fiscal year). The annual cost is computed using the following rules:

• Telescope development costs are linearly amortized over 20 years.
• Instrumentation costs are linearly amortized over 10 years.
• The costs are in actual year dollars (no inflation factor used).
• Only the costs for instruments that have been commissioned by the start of FY03 are included. Costs for instruments in development or not in use have not been included.
• The annual operation cost is the amount of funds provided annually by the Keck Observatory partners.
• The Keck Interferometer project is not included in the cost. The TSIP computation is for the two single apertures and associated instrumentation.

The total development cost for the Keck telescopes was $183.1 million, which is a combination of two phases: Phase I ($101.4 million) and Phase II ($81.7 million). The total development cost for the instruments is $47.8 million.

Keck I instrumentation:  HIRES, LRIS, LWS, NIRC
Keck II instrumentation: Adaptive Optics, DEIMOS, ESI, NIRC2, NIRSPEC

The annual operations funds come from contributions by the University of California and NASA. In FY03, these funds are projected to be $11.9 million. Combining these figures, the total annual cost for FY03 is computed (figures are in millions of dollars).

Cost area	Total Cost	Annual Cost
Telescope development	183.1	9.1
Instrumentation	47.8	4.8
Annual Operations		11.9
Keck Observatory - total annual cost		25.8

The number of observing nights available to the Keck Observatory partners is the time remaining after subtraction of engineering time and U.Hawaii observing time. Over the past 2 years, the average allocation of nights is as shown in the table below.

Total number of nights / both telescopes	730
Telescope engineering time	-57
Christmas Eve shutdown	-2
U.Hawaii observing time	-84
Instrument engineering time	-43
Number of nights available for allocation to the three observatory partners	544

With an annual cost of $25.8 million and 544 nights available for observing, the cost of one observing night on a Keck telescope is $47.4 thousand dollars.