In Cycle 6, NIRSpec is offering the new ‘multistripe’ readout capability for BOTS Prism observations. This method dramatically reduces frame time and increases the bright-source limit, allowing observations of brighter sources over a broad (0.6-5 microns) wavelength range. BOTS multistripe subarrays can only be used with the PRISM/CLEAR disperser-filter combination. For the smallest multistripe subarray, the new 2-group bright limit is J ~ 8 and the frame times are ~15x shorter compared to the nominal Prism SUB512 subarray. These gains come at the expense of reduced exposure efficiency, as only a portion of the subarray is read out at any given time. Instead of reading a single subarray region, the multistripe subarrays split the subarray into multiple regions (or “stripes”) that are read out individually, with the stripe moving to a different location in the subarray after the integration for the previous stripe is completed (Figure 1).

On August 20^th, JWebbinar 52 – Developments in Instrument Modes and Capabilities for JWST Cycle 6 will cover the details of this new capability. Observers are encouraged to attend the JWebbinar and to contact the NIRSpec team through the JWST Help Desk with any questions.