Requirements and Recommendations for HSC observers

When we proceed your HSC observation, we would like to ask you some requirements and recommendations listed below, which may take some observation time from you. We really appreciate your understanding and cooperation.


  1. Take 10 or more dome flats in each band at least once per HSC observing run
    1. Use the same configuration for each filter (lamp voltage and instrument rotator angle = 0)
    2. Keep the dome flat lamp on for 10 min before starting exposures for warm up
    3. To avoid light leak from outside, dome flats should be taken 30 min after the sunset/before the sunrise
  2. Take a shot of 30s exposure for photometric calibration (1)
    1. Every time after filter change
    2. At least three times per night: at the beginning, middle, and end of the night (can be shared with 2-i.)
    3. When you take only long exposures (>=2min/shot), take a 30sec exposure on at least one of the fields according to 2-i. and 2-ii.
  3. If you take short exposures with Texp<=60sec continuously more than 20 shots, we may stop the on-site analysis system to avoid the stall of the system. You may continue observation but information from the on-site analysis sytem will not be available. When you restart the long exposure with Texp>60sec, we will restart it.


      (1) As the Pan-STARRS1 catalog is available in HSC pipeline from 2017/2, we do not need to choose the 'SDSS' fields for photometric calibration.


  1. Take 5 or more bias frames at the beginning and end of each night
  2. In small dither, use dither steps of r>~120 arcsec for the IMAG_N mode, and r>~60 arcsec for the IMAG5 mode.
  3. Continuous short exposures (Texp < 3 sec) more than 20 shots should be strongly discouraged because it would cause a data transfer stall

Copyright © 2000-2020 Subaru Telescope, NAOJ. All rights reserved.