I think you mean the high-resolution mode of the ACS instrument (https://www.spacetelescope.org/about/general/instruments/acs...) but that is broken and it was not repaired during the last HST service mission.
I think you mean the high-resolution mode of the ACS instrument (https://www.spacetelescope.org/about/general/instruments/acs...) but that is broken and it was not repaired during the last HST service mission.