6/6/2014 (Simulations Telecon):
- Sky brightness, single value for sky at zenith as a function of time (to go into evolution of sky model)
- B, G from all-sky channel, R, Y, and Z from photo-diode- B, G are not well-calibrated, but can give sky-cover. photo-diode well calibrated.
- Cloud model
- Check that the cloud model is appropriate
- Hard to fill-in the structure function scale (up to 1 degree) -> all-sky camera scale (5-10 degrees)
- Format for sky brightness time-series
- OpSim: Altitude and azimuth, not really high resolution, break sky into quadrants
- Healpix! (email Peter)
- Break up data into eighths and classify nights into eighths
- Compare our camera cloud cover to the telescope operator values
- Stick it in a database that we can query (few week time-frame)
- Night timestamp, observation timestamp, B/G/R/Y/Z (at zenith)
- Michael needs to remember that each pixel maps out the same solid angle
- CTIO water vapor absorption vs. time (no spatial dependency), up for several months
6/3/2014:
September: paper titled "Dynamic real-time scheduling of optical systems"
- Write down merit functions Field FOM x SSM x DSM = IFM
Field FOM is a function of time
SSM is static airmass associated term (everything computable in advance)
DSM is sky brightness and clouds and like
Issues: - Photometric scatter
- Photometric transfer equations
- Transform from our R,G,B to G,R,I,Z,Y (stars on Wiki can be used to generate )
- Internal Reference Catalog - Convert FITs files to healpix
- To observatories in real time (web server with FITs image and contour map with RA/Dec lines laid on top)
- LSST simulation guys
- Tier in to IR All Sky Camera - Sky flat
- Making Reference catalog
- Correction to LSST sky
- Stelar density dependent correction to sky brightness because LSST can resolve many of the stars that we cannot
- Pixel and time dependent
- Sky brightness model
- Jacobians
- Check assumption that the solid angle subtended per pixel is same across entire image
- Take white teflon sheet behind point source and rotate lens and ask if the number of counts per pixel insensitive to rotation info of lens
Opport:- DES tie-in
Michael to-do for scatter:
Excess noise (non-Gaussian)
- take darks in lab
bad pixels - m vs. t
- dm vs. m
- m_i vs m_j,
- m_R vs m_G
- residuals vs. dx, dy
- resid vs dm
- resid vs chi/N
- compare short exposures
05/30/2014:
- Talk with Andy to figure out what output they want
- Convert pixels to RA, Dec for each image and then add it all together. Use to make a template and search for transients.
- Things to fix / look at: secant, stars that have magnitude issues (look constant)
- Make the deltax, deltay plots
05/29/2014:
Attendees: Michael and Chuck
1. Create a public fits files directory
2. [coughlin@lsst-dev ~]$ pwd
/lsst/home/coughlin
# User specific environment and startup programs
PATH=$PATH:$HOME/bin
PATH=$PATH:$HOME/allsky/bin
PATH=$PATH:$HOME/wcstools-3.8.7/bin
PATH=$PATH:$HOME/fisheye
PATH=$PATH:$HOME/sextractor-2.19.5/bin
PATH=$PATH:$HOME/tphot
PATH=$PATH:$HOME/tonrytools
PATH=$PATH:$HOME/ffmpeg
PATH=$PATH:$HOME/ImageMagick-6.8.9-0/bin
PATH=$PATH:$HOME/cfitsio
https://github.com/mcoughlin/fisheye.git
3. Create master catalog for all stars by looking at photometry over all the nights2. [coughlin@lsst-dev ~]$ pwd
/lsst/home/coughlin
# User specific environment and startup programs
PATH=$PATH:$HOME/bin
PATH=$PATH:$HOME/allsky/bin
PATH=$PATH:$HOME/wcstools-3.8.7/bin
PATH=$PATH:$HOME/fisheye
PATH=$PATH:$HOME/sextractor-2.19.5/bin
PATH=$PATH:$HOME/tphot
PATH=$PATH:$HOME/tonrytools
PATH=$PATH:$HOME/ffmpeg
PATH=$PATH:$HOME/ImageMagick-6.8.9-0/bin
PATH=$PATH:$HOME/cfitsio
https://github.com/mcoughlin/fisheye.git
- CS: There are existing catalogs of stars, for example the paper I sent you with bright stars and their griz-band magnitudes. It's better to get an external catalog
with excellent astrometry than to make our own, I think.
4. Abi (dophot) can fit individual images to extract magnitudes (compare with tphot/source extractor)
5. Search for transients with image subtraction (pixel by pixel image difference)
-> Convert (x,y) to RA/Dec (w/ fisheye)
- CS: Converting to RA, DEC is not enough. We'd have to rotate the images about the celestial pole, match PSF and sky, and then subtract.
Sounds hard.
6. For a given star, plot the magnitude differences vs fractional pixel remainder of the centroid (1024.35 -> 0.35) -> probably worst for R/B due to 1 pixel, different for x and y
7. Can see milky way in cloud plots -> problem with sky brightness in photometry. Fix!