Dec 7 2023.
Thinking about direct measurement of seeing right down the light path, no substitute for using the actual LATISS CCD and sending light down the optical axis. This measures exactly what we want.
Figure from CWS MNRAS paper on strobed dome imaging:
We could, in principle, use CBP for this on main telescope. So let's make one for AuxTel first.
To get 1 arcsec diffraction limit we need about a 4 inch aperture, at 400nm.
If system has 1m focal length, 1 arcsec is 5 micron diameter. How about this:
This is an f/7.8 RC system. 10" full aperture which with obscuration should give us about 4 inches for wedges. Assumes isoplanatic patch is at least 4 inches in extent, so we'll see about that.
Ten micron pinhole is one arcsec. Back focal length is 24.2 cm though. We've faced this issue before and done OK. Manual: 53809_1_EN_Omegon_Ritchey_Chretien_Full_Tube_IM_REV_C.pdf
Obscuration is 110 mm for 254mm aperture so annulus of illumination is (254-110)/2= 72mm or about 3 inches. Close enough. So we need 3-inch dia optical wedges that deflect the beam by up to a few arcmin
We could fit 6 wedges of 3 inch dia into this annulus:
What deflection do we want? For Auxtel the FOV is about 6 arcmin. From center to side it's 2000*0.1 arcsec = 200 arcsec = 3.33 arcmin. So a deflection of 2 arcmin seems decent. If we're 4m away from primary, spot is displaced by only 2mm.
Problem with this config is beams are not very separated, spatially. We need a precision periscope on some to get more displacement.
Meghan Notes
Note: start a parts list document!!
Mac mini control system
- newport - start reading control manual for 2 degrees of freedom setup
- system will now have beam splitters
- do beamsplitter mapping
- look at alternatives and categorize
- clear a workspace
- come up with plan and deadlines and weekly goals