Observing with MuSCAT

Submitting Proposals

MuSCAT is now open to any researchers under the shared-risk policy in the open use program of the 188cm telescope at Okayama Astrophysical Observatory. Please contact the PI of the instrument (Norio Narita, norio.narita <at> nao.ac.jp) prior to submitting your proposal to confirm if your observation can be conducted with MuSCAT. The following pages provide the information on how to submit proposals.
  • call for proposal (Japanese)
  • call for proposal (English)
  • Specifications

    Parameter ch.1 ch.2 ch.3
    Camera name PIXIS 2014B_eXelon PIXIS 2014B PIXIS 2014B_eXelon
    CCD format 1024 x 1024 pixels
    Pixel scale 0.358 arcsec/pixel
    Field of view 6.1 x 6.1 arcmin2
    Filter *1 g'2 r'2 z's2
    Gain 1.00 e-/ADU 1.02 e-/ADU 1.00 e-/ADU
    Dark current < 0.0015 e-/ADU at -70 °C
    Shutter speed 8 ms
    Readout mode (Readout time) high (0.58 s) or low (10 s)
    Readout noise (high) 11 e- 12 e- 12 e-
    Readout noise (low) 3.9 e- 3.8 e- 4.2 e-
    Full well ~70,000 e-/pixel
    Linearlity range < 50,000 ADU for < 1% non-linearlity
    Total throughput *2 ~20% ~28% ~13%
    Limiting magnitude *3 21.7 21.7 19.8
    *1 Filters are fixed and not chanbeable.
    *2 Measured by observing stars, which means that it includes the reflactance of the telescope mirrors and the atmospheric transmittance.
    *3 For 10 sigma detections, calculated from 10 x 60s exposure images obtained with the high readout mode on a dark night (the sky grightness was 19.9, 19.5 and 18.7 mag arcsec-2 in g, r, and z bands, respectively). Note that the readout noise of ch.3 was 24-27 e- at the time of the observation due to an electronic glitch, which has been fixed.


    MuSCAT uses the PIXIS series CCD cameras manufactured by Princeton Instrumetns; PIXIS1024B for ch.2 and PIXIS1024B_exelon for ch.1 and ch.3. Both types of cameras are equipped with a back-illuminated 1k x 1k CCD chip, while the latter one (PIXIS1024B_exelon) is processed to suppress the etaloning effect in the NIR region and improve the sensitivity in the shorter and longer wavelengths. More information on the CCD cameras can be found here.

    Total Efficiency

    MuSCAT uses the Astrodon Photometrics Genelation-2 Sloan g', r', and zs filters (see here for the details). The expected total efficiencies including the reflectances/transmittances of dichroic mirrors, broadband anti-reflection coating on the CCD windows, filters, and quantum efficienies of the CCDs are available here and are shown in Figure 1.

    total efficiency
    Figure 1. Expected total efficiency of MuSCAT, which includes the reflectances/transmittances of dichroic mirrors, broadband anti-reflection coating on the CCD windows, filters, and quantum efficienies of the CCDs.

    Observing Mode

    MuSCAT offers only an imaging mode. The three CCD cameras can be operated either synchronously or independently. Even in the synchronous mode, the exposure time for each camera can be set independently. Please see the observing manual for more details.

    Forbidden Sky Area

    Because of the interference with the south pier, the 188-cm telescope equipped with MuSCAT cannot be directed to the following regions:
    Dec >= 75°
    Dec >= 70° && Dec < 75° && HA > 2.16 hours
    Dec >= 62° && Dec < 70° && HA > 1.76 hours
    Dec >= 56° && Dec < 62° && HA > 1.96 hours
    Dec >= 54° && Dec < 56° && HA > 3.28 hours
    Dec >= 52° && Dec < 54° && HA > 5.31 hours

    Observing Manual

  • MuSCAT Observing Manual (Japanese)
  • MuSCAT Observing Manual (English) (Under construction)
  • More Information

    For more information about the instrument, please refer to the following paper.
    Narita, N., 2016, JATIS, 1(4), 045001

    If you have any technical questions about the instrument, please contact the MuSCAT development team via email:
    muscat_core <at> abc-nins.jp
    MuSCAT photo

    MuSCAT logo