2023-07-31 DM-SST Agenda and Meeting Notes

Short : ls.st/dmsst 

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• Updated measurements of the the reflectance of the protected aluminium and silver coatings; now believe we can move forwards with triple silver coatings for M1M3. This is a big gain for throughput with only a small effect in the u band

Follow on from discussion at  2023-06-05 DM-SST Agenda and Meeting Notes

The first five slides of this deck.

Survey scheduling does not use the term "Special Programs" - this is a DM term for processing.  Terminology in DMTN-065 is important. WFD should be clearly defined?

Survey 

• At least 1 micro survey in year 1 - twilight survey for NEOs and a northern strip up to +30 deg. 
• KB: From a technical capability standpoint, we might need this in place for commissioning given the variety of different programs being run in commissioning
• KB: How does this discussion interface with the question of rolling cadence. From a user perspective managing releases with different depths is relevant
• JB: Assumed that the definition of a program was not depth but what program it was taken as part of. 
• ER: DESC just want the WFD coadd with the WFD survey strategy with nothing else in it 
• CTS: What is WFD? DDF is easy to define, few sq. degrees, the who contention is, is the GP WFD - this is 100s of sq. degs and this blows up the size. 
• ER: It has a particular dither strategy . GP has a different cadence and the scheduler need to know this.
• ER Are we doing regular coadds into the GP? 
• CTS: yes - the whole area
• JB: yes, planning to do it but no promise of quality. See no reason to make separate - can just flag. 
• KB: Do we need to think about distinctions where we want to use a different pipeline configuration 
• JB: For everything except FGCM, every tract is independent.
• CTS: main differences are: 1) are there differences the output schema and 2) are the regions with multiple coadds hat ext for a single tract. Each all-sky coadd is a 1PB, all bands
• MLG: is it problematic if a tract spans 2 regions 
• JB: Might loose some area. Tract is probably about the size of the FoV. Early proposals were 12 tracts over the whole sky bt have moved to smaller tracts. This mitigates any concerns with the jagged edges. 
• YAS: Could give people the inner and outer tract list. Ad we do plan to use WFD images in the DDF processing. 
• Move forward with scenario A. The deep coadd is all of the regions with a second DDP coadd. 

Twilight images and PP 

• JB: How bright is bright? Key question is .. will there be enough stars to do PSF modelling. 
• CTS: How big is the window and how many stars that will can calibrate on will we get? 
• JB: Possibly can run a slower version of AP that uses some components of DRP
• MLG : talk to Eric and get some DECam images   
• JB: Will we need to wait for templates from the main survey, we are not going to make twilight templates? DCR not too bad in r. 
• MLG: Evening twilights are more likely to have templates. 
• KB: What and how much data would be useful to gather during commissioning (even if we don't have the cycles to process it in commissioning)

Naming 

• region label  and a program label is needed. 
• labels driven by the use case .. what do users want to do with this data
• rename Special Programs to Special Processing for the DM processing of data