Arops: The Asiago Red Objective-Prism Survey

Abstract

AROPS is an objective-prism survey conducted at high galactic latitudes with the 67/92 cm (f=205 cm) Schmidt telescope of the Asiago Astrophysical Observatory (Italy). The basic technical data are:

• TP4415 high resolution plates, 20×20 cm, treated in forming gas (H₂+N₂) and covering 24 deg² on sky

• 4° UBK7 objective prism, for a dispersion of 1490 Åmm^-1 at Nal D

• blue side cut-off at 4980 Å using a 2mm GG14 filter, for a recorded λ range 5000-7000 Å

• untrailed spectra to record V ~ 16.5 mag stars with 40 min exposures

Two main criteria have guided the selection of the AROPS fields:

• at least 15 direct imaging plates of a given field (in any photometric band, at any exposure date since 1956) must exist in the Asiago Schmidt Plate Archive. They will help in positional measurements and will also provide information about variability and colors

• 4° UBK7 objective prism, for a dispersion of 1490 Åmm^-1 at Nal D

• the fields must be at |b| ≥ 20° and widely distributed in galactic latitude and longitude

• 151 fields were originally selected (for a total area of 3650 deg²). An additional ~100 fields (2400 deg²) have been later added on with relaxed adherence to the above selection criteria.