Telecon 20170926

Attending: Julian, Brian, Kris, Shaul, Qi, Karl, …

Agenda:

• optical system (Qi) crossdragone_with_fold_mirror.pdf (.pdf)
• Scan angles (.pdf) (Gorski, Delabrouille)
• noise model and focal plane options (Young) (.pdf)

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.