Rapid Scan Mode Research Articles

High resolution Michelson interferometer for airborne infrared astronomical observations 1: Concept and performance

A Michelson interferometer has been built for use with the 91-cm telescope on NASA's Gerard P. Kuiper Airborne Observatory primarily to measure ir line emission from H 11 regions. Operation is in the rapid scan mode, and the achievable resolution is 0.02 cm(-1) in the wavelength range from 10 micro to around 300 micro. A minicomputer is used to provide on-line spectrum displays and to control and monitor the instrument performance. The design and use of the instrument is discussed, and a comparison is made between the theoretical performance and that actually achieved on the first flights when measurements of line emission from the Orion nebula and from the atmosphere were made.

High resolution Michelson interferometer for airborne infrared astronomical observations 2: System design

A Michelson interferometer for high resolution (lambda/Deltalambda approximately 10(4)) spectroscopic observations of astronomical ir ionic line emission has been built and flown on the NASA 91-cm airborne ir telescope facility (G. P. Kuiper Airborne Observatory). In Part 1 of this paper the requirements for such a system were outlined, and the scientific basis for the choice of instrumental parameters and the rapid scan mode of operation were discussed. In this paper design details of the instrument are presented. These include the optics, control He-Ne laser interferometer, helium-cooled bolometer detector, and cooled passband filters. In addition, the on-line computer software which enables the operator to interact rapidly with the system to produce inflight spectra and control accordingly the observational parameters is described, as are elements of the electronics hardware developed specially for airborne observations.

A RAPID-SCANNING PHOTOELECTRIC SPECTROPHOTOMETER

ABSTRACT A new photoelectric spectrum scanner was constructed for use at the Cassegrain focus of the one-meter reflector of the Lindheimer Astronomical Research Center. The spectrometer is interfaced with a small digital computer and is operated in a rapid-scanning mode to compensate for poor observing conditions. The spectra of various sources were observed with a resolution of 20 A for stars and 35 A for extended objects. The instrument is capable of producing good quality results even under adverse seeing conditions. Its performance and applicability to various problems are discussed. Key words: instruments - spectrum scanner