====== Telecon 20170926 ======

Attending: Julian, Brian, Kris, Shaul, Qi, Karl, ... \\

__Agenda:__ 

  * optical system (Qi) {{::crossdragone_with_fold_mirror.pdf|}}
  * {{::compare_scans.pdf|Scan angles}} (Gorski, Delabrouille)
  * {{::pico_fdm_noise_model_status_20170926.pdf|noise model and focal plane options (Young)}}

__Notes:__

Attending: Brian, Jeff, Julian, Kris, Shaul, Qi

Scanning rates

  * Brian will look into scanning speeds, possible limits etc. (**AI**)
  * With reaction wheels, there is not much coupling between precession and spin; If increase spin, precession may be slower.
  * WMAP used reaction wheels

Scan angles (Kris)
  * mitigation of polarization systematics
  * alpha: angle between boresight and spin axis; beta: angle between sun-satellite and spin axis (swapped definitions)
  * Plots are one-year average on single pixel; at least 4 hits per pixel
  * Large precession angle helps mix pixels
  * Kris is going to calculate at different spin and precession rates. (**AI**)

Cross Dragone (Qi)
  * Requirements: no direct view of sky, no significant sidelobes, and can fit into the envelope
  * With a third flat mirror, two designs below do not have direct view of sky and can fit into the envelope
    * D=140 cm, F#=3.0, FOV=+/- 5 deg 
    * D=120 cm, F#3.5, FOV=+/-7 deg
  * Sidelobes still exist.