CASS BlogTelescope
Assesment of Gaia Guiding Stars
15/02/19 11:10
We use the Gaia database through the astroquery interface to generate sky fields with stars. For the Schmidt scale at the focal plane of 86.20 arcsec/mm and a typical guiding detector of size 4x4mm (e.g. a CMOS 1000x1000 pixels of 4micron each) the FoV to search for guiding stars at any one location on sky is 5.75’x5.75’. To study the availability of stars for guiding, we generate random locations on a sphere and select 10000 fields with declination above -22.78º (so that maximum airmass < 2). We then count the stars brighter than a given magnitud (Gaia ‘phot_g_mean_mag’). The figure shows the percent number of these fields with at least one guide star brighter than a given magnitude. Clearly, basically almost any 5.75’x5.75’ location on the sky has guide stars brighter than 16 mag, which guarantees that we can guide by having a single CCD located at the Focal Plane next to the IFU (credit: Enrique Pérez).
First actions on the Schmidt telescope
13/02/19 11:01
Assessment of the Focal Plane Assembly at the Schmidt telescope by a member of our engineering team. Work done in collaboration with the CAHA staff.
The Schmidt telescope at Calar Alto Observatory
02/02/19 15:47
The Schmidt telescope at Calar Alto Observatory was installed there in 1980 by the Max-Planck-Institut fuer Astronomie, Heidelberg, and originally it was located at the Hamburg Observatory since 1955. The corrector plate and mirror have 80 cm and 120 cm diameter respectively; focal length is 240 cm and focal ratio f/3. A field-of-view of 8 deg (335 mm) diameter is available with a plate scale of 86.2 "/mm. More details on the telescope can be found in this paper by Birkle et al. (1994).
Thousands of photographic plates taken with the Schmidt telescopes were scan as part the HDAP - Heidelberg Digitalised Astronomical Plates - project. The digitalised images can be downloaded form the GAVO database.
A digital image of 5.5 deg by 5.5 deg of the M31 field photographed on a Kodak 24 cm x 24 cm curved plate using the Schmidt telescope at Calar Alto (credit: HDAP).
Thousands of photographic plates taken with the Schmidt telescopes were scan as part the HDAP - Heidelberg Digitalised Astronomical Plates - project. The digitalised images can be downloaded form the GAVO database.
A digital image of 5.5 deg by 5.5 deg of the M31 field photographed on a Kodak 24 cm x 24 cm curved plate using the Schmidt telescope at Calar Alto (credit: HDAP).