The filter exchange unit of the HSC can hold up to 6 filters in one observing run. Their list for given semester and given run, including QM runs, is published together with the CfP. See the following links for the availability and characteristics of HSC filters:
QM proposals requesting filters which are not scheduled for the given semester will be rejected. Please note that the r and i-band filters have been replaced with new ones - r2 and i2. Please use only the new names in the proposal. The specifications of the old filters are still given, for comparison. They will still be stored, but will no longer be available, with the exception of special cases. Such cases should be properly justified. Please contact Dr. Tsuyoshi Terai (terai [at] before submitting a proposal using the old r and i filters.

Overall, there are 5 broad band filters (BBF) and a number of narrow band filters (NBF). Note, however, that NBFs are user-owned filters, and to use them in your program you must first get the approval. For this reason the usage of NBFs is subject to slightly different policies, regarding calibrations or carry-over, for example (see further Sections).

Note also that to change the filter during the night, the telescope has to be pointed to the zenith and the dome has to be closed. The whole filter changing procedure takes approximately 0.5 h, and in general we try to minimize the number of such operations. If your program requires observations of the same field in several filters, very likely they will not be performed in the same night.

Starting from S19B, a proposal using narrow-band filters with their central wavelength shorter than 400 nm should only be submitted to classical mode, and will not be accepted in queue mode. Currently, this applies to filters NB387, NB391, and NB395.