Digitized First Byurakan Survey - DFBS

 

 

 

 

 

 

First Byurakan Survey

                            Technical data

                            FBS zones statistics

                            Markarian galaxies

                            FBS based projects

                            Publications

                            B.E.Markarian

DFBS

                            About DFBS

                            Institutes

                            Collaborators

                            Digitization

                            Extraction

                            Download

                            Sample spectra

                            Data visualization

                            Science with DFBS

                            Publications

                            DFBS at Roma

Virtual Observatories

                            Armenian VO

                            IVOA

                            Euro-VO

                            AstroGrid

                            Grid

Other related links

                            Armenian Astronomy

                            Byurakan Observatory

                            WFPDB

                            PDPP

                            SCAN-IT

 

DFBS: EXTRACTION OF SPECTRA

The identification of the objects present on the plate and the extraction of their spectra is presently made by us with a catalogue-driven procedure, written by Prof. R. Nesci as an IRAF script, including two simple FORTRAN programs for format conversion and checks.

         First, a list of all the objects present in the USNO-A2 catalogue down to the plate limit and included in sky area covered by a given plate is converted into pixel coordinates with the IRAF task cctran.

         Then an image section of 21x150 pixels including one well exposed star is selected and the spectrum is extracted with IRAF/apall in interactive mode (the typical FWHM of a spectrum is 5 pixels and the length 106). This process allows derive the orientation of the spectra on the plate and defines the template for subsequent automatic extractions.

         Finally all the spectra of the list are extracted automatically by apall, assuming as sky value the mode of an area 21x150 pixel centered on each spectrum.

 

 

 

For further info and use of the DFBS contact Dr. Areg Mickaelian

2002-2004 Digitized First Byurakan Survey