AbstractI have investigated the value of the contribution of small telescopes to the success of a whole WET run. To this end, I have applied different data weighting schemes to two extreme WET test data sets. I find that weights proportional to the inverse local scatter in the light curves produce Fourier Transforms of best signal-to-noise. Weighting data stronger than their inverse scatter does not yield optimal results because of the reduction of the effective number of data points.The contribution of the small telescopes to the combined WET results was found to be very important. They do not only improve the spectral window, but they can reduce the noise in the total FT by more than their light gathering power would imply. Some suggestions for the optimal use of small telescopes in the WET are given.
The desire of astronomers for wide field telescope systems which surpass the
RCC (1:8 max. 1.5 degree) in light gathering power and field of view are relative
concrete today. For this type of telescope, detectors planned ARE CCDs in
multichip arrangement.
During the past winter I have continued my studies on the spectrum of the night sky, and the connected subject of the auroral spectrum. The present paper reports the results obtained. The spectrographs used in this work are two of nearly identical construction. In designing them the paramount consideration was to obtain the greatest possible light gathering power, all other considerations being kept subordinate to this. It was accordingly decided to use the minimum number of optical pieces—one prism, one collimating lens, one camera lens, neither of the latter to be achromatic.
Most of the results reported thus far of image tube spectroscopy as applied in astronomy have been concerned with emission features and have been the result of a combination of the largest available light gathering power of large telescopes with the improved sensitivity of image intensifiers. We consider here the application of image tube techniques to moderate sized telescopes; concretely, we describe the first program of spectral classification using absorption features as carried out with the image tube spectrograph of the Vatican Observatory attached to the Zeiss 60-cm reflector at Castel Gandolfo. Treanor (1970) has described the optical design, construction and the first tests of this instrument. The receiver is an RCA cascaded image tube loaned to the Vatican Observatory by the Carnegie Image Tube Committee.
A 1-in. Fabry-Perot interferometric spectrometer employing mechanical scanning has been constructed to operate at low order. Such an instrument gives a resolution similar to that of a grating spectrometer but has, at that resolution, a much higher light gathering power. The spectrometer is capable of resolving the sodium D lines in the twilight airglow, scanning once per minute. Some preliminary results on the variation of D2/D1 ratio during twilight are presented. This type of spectrometer should be useful for a number of other applications.
Wide-Field-Imaging 3-Mirror-Systems by High Light Gathering Power and a
Wide-Field Optical System for the ‘Large Imaging Telescope’ (Lite)