SPECTRO-NEBULAGRAPH - A TRIDIMENSIONAL-SPECTROSCOPIC SYSTEM BASED ON A LOCAL-AREA NETWORK OF PERSONAL COMPUTERS

Spectro-nebulagraph (SNG), a tridimensional-spectroscopic system, has been developed as a versatile observation system attached to the Cassegrain focus of the 1.88-m telescope at the Okayama Astrophysical Observatory. Tridimensional spectra, i.e., so-called data cubes, are obtained by sweeping the telescope in the direction perpendicular to the slit of a spectrograph step by step. From the data cube, various monochromatic images can be extracted by data processing. SNG consists of four devices, i.e., the telescope control system, the autoguider, the spectrograph, and the CCD camera, which are distributed on a personal-computer network. The control software for SNG performs cooperative control of four devices in an automated fashion according to a programmed sequence of procedures. Some observational results taken with SNG are shown for 3C 120, NGC 4449, and NGC 3646.