Bright horizontal strip near the middle of the field

[lwymarie]

On 2021 May 3 and 4, I observed two redshift two quasars with the Hn5 filter and the 0.05" plate scale. In some of their reduced frames a bright horizontal strip shows up, and all at these same spaxels in the field. Quicklook2 display of one such frame is attached below. Comparing the spectrum of this strip and the blank region seems to indicate that the brightness is contributed by continuum wavelengths. Here's a link to the reduced frame:
https://www.dropbox.com/s/7zan0jlh6sapl1x/s210504_a020002_Hn5_050.fits