The DFBS Spectroscopic Database and the Armenian Virtual Observatory
The Digitized First Byurakan Survey (DFBS) is the digitized version of the famous Markarian Survey. It is the largest low-dispersion spectroscopic survey of the sky, covering 17,000 square degrees at galactic latitudes |b|>15. DFBS provides images and extracted spectra for all objects present in the FBS plates. Programs were developed to compute astrometric solution, extract spectra, and apply wavelength and photometric calibration for objects. A DFBS database and catalog has been assembled containing data for nearly 20,000,000 objects. A classification scheme for the DFBS spectra is being developed. The Armenian Virtual Observatory is based on the DFBS database and other large-area surveys and catalogue data.
Linearization of characteristic curves in photographic photometry.
After a survey of various definitions of the photometric characteristic curve of photographic emulsions, this paper reintroduces a long forgotten photometric parameter, the opacitance omega = opacity - 1 = 10(D) - 1 and describes its application to a characteristic function I = Aomega(n)(n approximately (1/2)), Which is linear in log-log co-ordinates over the whole range of densities of practical interest in photographic photometry. In a special case n = 1 and J = I/A = omega.
The Automated Plate Scanner Catalog of the Palomar Observatory Sky Survey. II. The Archived Database
The Minnesota Automated Plate Scanner Catalog of the POSS I has been available on‐line since 1994. We are now archiving it for distribution to the national and international data centers. In this brief paper, we describe the calibration of the digitized data and the characteristics of the archived database.