This breakout session will cover what we've learned from early commissioning with ComCam and LSSTCam and the potential impacts on early science. Focus topics would include early FGCM results, the photometric calibration of standard sources like white dwarfs and calspec, throughput measurements with the Collimated Beam Projector, and studies of atmospheric transmission with AuxTel.

Contributed talks:

• S05: Christopher Stubbs - What we've learned about variability of atmospheric transmission above Cerro Pachon. 
• S16: Michael Wood-Vasey - Measuring Precipitable Water Vapor with dual-band GPS at the Rubin Observatory

Go to the list of all contributed abstracts.

Agenda:

• Introduction to the session (5 min): Jeff Carlin
• Photometric Calibration Status and Preliminary Results (25 min): Eli Rykoff
• Flatfield System and Collimated Beam Projector Status (15 min): Elana Urbach
• What we've learned about variability of atmospheric transmission above Cerro Pachon (15 min): Chris Stubbs
• Discussion (30 minutes)