Working with Pete and Mark on Monday, we took some data with the dewar cold. We are using the imaging mirror and seeing two spots at the detector. With a card, we can remove one spot or another at various places in the path (iris in front of bb, ellipsoid, entrance window). When we move fore optics mirrors, the spots move around together. When we tip the echelle into the beam, the two spots seem to diffract the same. When we have a slit, we seem to be able to get one or the other spot through.
We decided to image the two spots as a function of the echelle paraboloid position. We took images at "starting point", "6 turns in", and "12 turns in". At each position, we have an image of the two spots (slit open) and an image of the grid of pinholes with a BB spot coming through the central pinhole. As we went further in, the two spots came closer together.
The pinhole grid changed shape, too.
On the last night at the IRTF, we did similar pinhole test.
No comments:
Post a Comment