2025-07-11 On-sky Commissioning Update

News
#1

Week 12 of the on-sky commissioning campaign with LSSTCam. The team has transitioned to sustained wide-area survey-mode observations, running the Science Validation surveys with the Feature Based Scheduler (FBS) for nearly full nights all this week. The team continues to accumulate experience during this full rehearsal of operational procedures, and to streamline operational workflows.

New highlights this week:

  • During the month of July, excluding one night of closed dome testing due to high winds, an average of >570 science program visits have been acquired per night. The current single-night record is >750 science program visits, comparable to steady-state LSST operations.
  • Sustained survey-mode observations have enabled preliminary trending analyses and comparisons to independent measures of the atmosphere contribution to the delivered image quality, including with the permanent DIMM located on Calibration Hill beside the Auxiliary Telescope (AuxTel). The team has also begun testing with a portable DIMM located inside the Simonyi Survey Telescope dome. While the delivered image quality has varied between nights, within a given night, and across the focal plane for individual visits, the Observatory has achieved a few near-contiguous hours of sub-arcsecond delivered image quality across the full focal plane in wide-area survey-mode observations. The team continues analyses of the Active Optics System (AOS) performance, thermal controls, and dome environment to improve the consistency of delivered image quality.
  • AuxTel has begun routine survey-mode operations in parallel with observations on the Simonyi Survey Telescope.
  • The FBS is now receiving cloud maps from the DREAM instrument, allowing for the option to consider variable atmosphere transparency across the sky when selecting targets.
  • Using a simulated Target of Opportunity (ToO) event, the team successfully tested some aspects of the response that is planned for operations.
  • Sequencer updates for LSSTCam were deployed that reoptimize focal plane performance, based on on-sky operating experience. Calibrations data products will be updated accordingly.
  • The currently loaded filter set is grizy with a filter swap of y for u planned for next week.
4 Likes
#2

In these observations, is there one of the Saturn Neptune conjunction with the discovery of many new moons of both?
#CaptureTheCosmos

1 Like
#3

That’s exciting!

A question from a layman (myself):

Finally, the SV Survey Comissioning is running (as planned, from July to September-October).

With calibrations throughout, the quality of the images will therefore improve.

Can you confirm that I have understood correctly: the sky map covered by the SV will be +/- 10 degrees around the plane of the ecliptic, from Scorpio to Aries.

Will the protocol be the same as that of the standard survey ? Exposure time: 2x15“ or 1x30”, each sector being shot twice to produce tracklets (with a time interval between 15 and 60 minutes) which will be analyzed by mobile object tracking software in search of solar system objects (NEOs, asteroids, TNOs, dwarf planets, Planet 9?, etc.).

For example, if there were a dwarf planet in the shot sector, would we already find it with the SV Survey Commissioning LSSTCam DP2 ? (Before the start of the standard survey in November)

https://sitcomtn-005.lsst.io/

This link shows the map of the coverage (Figures 4, 6, and 10)

image
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But we also see in Figure 7 a graph showing the cumulative coverage of the SV Survey over time (survey nights: up to 100 nights = more than 3 months)

image
image909Ă—782 86.3 KB

And I note that it continues to increase over time. I therefore deduce that we will explore the 6 sectors of the ecliptic plane (Scorpio, Sagittarius, Capricorn, Aquarius, Pisces, Aries) every 15 days each, when that sector is ideally positioned at the zenith of the sky. July = Sco-Sag, August = Cap-Aqu, and September = Pis-Ari.

(Except for bands u and y that will stop before at Aquarius and the northern hemisphere will not be shot)

(So September will benefit from better image quality thanks to the calibrations carried out throughout July and August? )

(With a good chance of discovering new large TNOs as early as this SV survey, especially in September with a better quality image, even before the standard survey scheduled for November :thinking: ? )

Am I all right?

Thank you in advance for your confirmation or your corrections !

Cool Raoul :sparkles: :ringer_planet: :telescope: :star_struck:

#4

Imagining footage of Betelgeuse going supernova in “real time”!!:sweat_smile::rofl: Wow