Hyper Suprime-Cam (HSC)

Information for S24A applicants

  HSC operation

There will be at most three (3) or four (4) HSC observing runs in the S24A semester, depending on the number of PFS commissioning runs as well as the timing of the facility maintenance works.

  Requested time for queue-mode proposals

Applicants for HSC queue-mode observation must include various overheads to the requested time. Total requested time for observing plan should be calculated using the Overhead and Required Time Calculator. Please clearly indicate at "Observing Method and Technical Details" in your proposal how it is calculated, for example:

  • -------------------------------------------------------------------
  • HSC-g:    240 sec × 20 shots
  • HSC-i2:   200 sec × 40 shots + 30 sec × 4 shots
  • Total on-source time:   3.59 hours
  • Total required time:     4.89 hours
  • -------------------------------------------------------------------

Note that, if no quantitative justification is explicitly shown for the time request, a low evaluation value will be given in the technical assesment process.

According to the decision of Subaru Advisory Committee (SAC), 30% bad weather factor will be considered for time allocation of the HSC queue-mode programs in order to increase the observation completion rate by ensuring sufficient observation time. To keep the limitation of the maximum nights, the requested time in the HSC queue mode should not exceed 3.5 nights for each Normal program and 28 nights for each Intensive program.

  Filter set

Applicants wishing to use the NB872 filter must obtain an approval from the filter developer team in advance of the proposal submission. All applicants must explicitly describe the filters they intend to use in the "Instrument Requirements" section of the application form, where the desired set as well as the minimum acceptable set should be clearly specified.

  Default observation mode

Queue mode is the default observing mode for the Normal, Intensive, and Filler programs (see the detail information at the "HSC Queue Mode Webpage"). Applicants wishing a classical mode observation with HSC have to describe why the classical mode is preferred to the queue mode in "Scheduling Requirements" section of the application form. Without any convincing reason, the observation mode may be changed from classical to queue. Note that a proposal requesting the NB387, NB391, or NB395 filter must be submitted as a classical mode program.

  "No-Additional-Target" policy

Requesting additional targets for filling dead time (a.k.a. "Sukima time"), when there is no planned target on the night sky, is not allowed for any HSC observations. "Sukima time" will be exploited as effective as possible depending on the situation (observing priority: (1) observations of standard stars, (2) queue-mode observations for Grade A/B programs, (3) observing applicant's back-up targets, and (4) queue-mode observations for Grade C and F [Filler] programs).

  No service programs

Service observations are not available for HSC.

Last update: July 24, 2023



The Hyper Suprime-Cam (HSC) is a gigantic mosaic CCD camera, which is attached at the prime focus of Subaru Telescope. The HSC uses 104 main science CCDs which cover 1.5-deg field-of-view in diameter with a pixel scale of 0.17 arcseconds, as well as 4 CCDs for auto guider and 8 CCDs for focus monitoring.

It takes about 30 min for changing filters (including a focus check). Before starting a filter exchange, it is necessary to move the telescope to the zenith and rotate the instrument rotator to the appropriate angle. We also have to close the cover of the primary mirror for safety operation.

When you cosider to develop a new HSC filter, please be sure to read the filter policy carefully and contact the Subaru Telescope (contact person: T. Terai [terai_at_naoj.org] ) well before applying for funds. Also, please refer the procedure to determine filters for each HSC run.

We ask for your understanding in advance that the obtained data of which proprietary period (18 months) has not yet expired may be used by Subaru staff without PI's permission for engineering purposes.



Data Analysis and Archive


Image Quality

Investigation Reports

Problem Reports


Questions regarding HSC should be directed to Satoshi Miyazaki (satoshi_at_naoj.org) and Tsuyoshi Terai (terai_at_naoj.org).

Please note that all numbers on these pages are subject to change as the performance of HSC is better determined.

Last update: August 11, 2023

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