Hello,
I downloaded recent Rubin alerts via Fink and checked them also in Lasair, and I have a question to clarify midpointMjdTai conversion to UTC.
For example the alert with diaObjectId 170389126969294877 (see the screenshot), the packet field is: midpointMjdTai = 61172.00230775271
When I interpret this as MJD in TAI and convert it to UTC with Astropy, I get:
2026-05-12 00:02:42 UTC
However, both Fink and Lasair display the same alert time as:
2026-05-12 00:03:19 UTC
So it looks like the ~37 second TAI→UTC offset is not being applied in the broker-displayed UTC time.
For visual alert inspection and cutout review this may not matter much, but for MPC/SkyBoT matching with known asteroids and comets, 37 seconds can be a significant offset.
Could someone clarify whether midpointMjdTai should be converted from TAI to UTC with 37 sec adjustment before querying MPC/SkyBoT, or whether the broker-displayed UTC time is the intended time to use?
Thank you!
