Some pictures from MMTF testing in the lab at OCIW.
Looking through the MMTF at a mercury lightbox. Because the wavelength
transmitted by the etalon depends on the angle of incidence, the strong
mercury line is transmitted at only one angle and the viewer, or in this
case the camera, sees a ring.
MMTF optical testing setup at OCIW. On the far right is a hydrogen
lamp, illuminating a diffusing disk at the focus of a Celestron 8-inch f/10
telescope (both lamp and telescope kindly lent by Caltech/Patrick Shopbell).
The telescope projects a collimated beam of light through the etalon,
mounted vertically at the center of the photo on fixtures designed
and constructed by Tyson Hare and the OCIW shop. Left of the etalon
is a narrow band filter, behind the foil light baffle. On the far
left, a 180mm f/2.8 Nikon camera lens images the collimated beam onto
an Apogee 1K CCD camera (lent by Maryland). The data acquisition laptop
is displaying a spectrum constructed by scanning the etalon gap over
more than a free spectral range: the two peaks are H-alpha transmitted
in two consecutive orders.
Looking through the MMTF at a mercury lightbox. Because the wavelength
transmitted by the etalon depends on the angle of incidence, the strong
mercury line is transmitted at only one angle and the viewer, or in this
case the camera, sees a ring.
MMTF optical testing setup at OCIW. On the far right is a hydrogen
lamp, illuminating a diffusing disk at the focus of a Celestron 8-inch f/10
telescope (both lamp and telescope kindly lent by Caltech/Patrick Shopbell).
The telescope projects a collimated beam of light through the etalon,
mounted vertically at the center of the photo on fixtures designed
and constructed by Tyson Hare and the OCIW shop. Left of the etalon
is a narrow band filter, behind the foil light baffle. On the far
left, a 180mm f/2.8 Nikon camera lens images the collimated beam onto
an Apogee 1K CCD camera (lent by Maryland). The data acquisition laptop
is displaying a spectrum constructed by scanning the etalon gap over
more than a free spectral range: the two peaks are H-alpha transmitted
in two consecutive orders.