Is there a document that defines the conditions for Rubin operations as to average hours available each night for observation, historical weather patterns, etc?
Hi @sdcorle1 , https://pstn-051.lsst.io/ Section 2.1 gives the model of observing conditions based on historical data. Figure 1 shows the cloudiness (~70% time cloud level below 3/10 and the observatory would open). Figure 2 shows the average time (~6hr available). Perhaps @ljones can provide more details.
Shenming Yes, PSTN-051 is a good resource for this information. There have been some updates in the range of weather conditions we consider – we extended our cloud and seeing records to cover a much wider range of years, and now consider simulations with a variety of start time to sample a wider range of historical weather. The average time per night is approximately the same, although we have also updated the downtime estimates for the first year of observing to account for a ramp-up in observing efficiency.
Another way to look at the expected conditions is to look at the simulated pointing histories, such as those released with the Phase 3 survey strategy recommendations, announced here - SCOC Phase 3 recommendation. These pointing histories include the expected conditions for a theoretical Rubin survey, with details for every simulated observation.
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Thanks, this is very helpful. I believe that what I would like to have is buried in Figure 14 of the SCOC recommendation. My search is for the average onsky time over the 10 year mission with the impacts that are plotted vertically removed. Would I find something like that somewhere in the opsim documentation? That is, the details that went into making Figure 14?
Hi @sdcorle1 - I just wanted to check in to see if you found the information you were looking for. Another place to look is at the links provided by @ljones at the bottom of the SCOC Phase 3 recommendation page that Lynne pointed you to above. If you scroll down on that page, you’ll find links to the simulations that were used in the Phase 3 recommendation, which should include those used to make Figure 14.
@sgreenstreet Thanks for following up on this. Before the holidays, I had a brief look. The collection is pretty intimidating and my answer may well be buried in there. Is there a place that you could suggest that I start?
Sorry - missed this over the holidays, thanks @sgreenstreet for picking this up.
I’m not entirely certain what you’re looking for, if you want the on-sky time with the additional impacts of slewtime, clouds, or other downtime removed, so that it’s really only the on-sky exposure time without any overheads? Or if it’s something else.
Here is the Downtime notebook that was used to generate that figure, however - including a small update to account for some changes in rubin_scheduler and also to add what I think you might possibly be looking for (after cell 55).
As an explanation of that output - the mean length of the night available from -12 to -12 twilight is about 10 hours, however the mean of the “actively used” hours is only 6.5 – this does include slewtime, but does not include downtime due to clouds or scheduled maintenance or unscheduled engineering issues. With our typical slew times and overhead per exposure (shutter time and readout), this then translates to a mean of 4.7 hours of on-sky exposure time per night, for the 3651 nights that the survey runs in the simulation.
