Data acquired before 19 July 2024 UT:
A bug in the QHY instrument agent caused the FITS header keywords UTSTART and UTSTOP to be populated with incorrect values. Those values should not be used.
Data acquired before 19 July 2024 UT:
A bug in the instrument agent caused a change in the executed exposure time for images taken 1. in a sequence, 2. with self-guiding enabled (which is the default setting), and 3. with requested exposure times <0.1s. All images in the sequence after the first were made with an exposure time of 0.1 s, regardless of what the user requested. On July 19, this bug was fixed. The minimum exposure time is now 1 ms.
Data acquired before 9 July 2024 UT:
A bug in the QHY instrument agent caused the value for the EXPTIME keyword to be wrongly reported for short exposures. (The REQTIME was correctly recorded.) The EXPTIME had a minimum value of 0.1 seconds, regardless of an image's actual exposure time! For QHY600 data acquired before July 9 UTC, if there's a discrepancy between the EXPTIME and the REQTIME values, the REQTIME value should be used.