simulation in GRASP:only mirrors and stop; no sunshield, no baffle, no cold box
slide 2 & 3
theta: 0 deg is central ray; positive is going down in the right figure
the peak at 0 deg in upper left is corresponding to the “north pole” in lower left
going from north pole straight down to south in lower left is going positive in upper left; going from north pole along the rim to south is going negative in upper left
-75 deg primary sidelobe
spillover passing the primary
slide 4
Rejection needed; a measure of signal level
right side: Rejection needed below 1 um arcmin
slide 5
horizontal lines: below which the signal would be rejected. For example, the signal from galaxy would be rejected below purple line
vertical lines: middle red line is shield; pink and red are where moon and earth would appear
the area between the lines (~ -180 to ~ 40 deg) is the direct view
Closures are not included. Adding a closure similar to Planck, covers PR.
We are not going to calculate with shields at the moment. We are not sure if there will be issue. It's beyond the scope of current study.
Brian: one of main sidelobes could be from the bump close to focal plane, ADR. Shaul: the size of the bump has been reduced, the figure in slide 2&3 is not accurate, so it may not be a problem.
Moving ADR down: 1) magnetic field from SUIQD, 2) sidelobe, 3) cooling issue
imagerteleconnotes20180411.1523507022.txt.gz · Last modified: 2018/04/11 23:23 by wenxx181