Abstract :
The astronomical observations which can be made from the surface of the earth are severely limited by the presence of the earth´s atmosphere. These limitations can be overcome by conducting observations from a vehicle at a sufficient height above the earth. The inaccuracies introduced by atmospheric refraction (scintillation and apparent displacements) are extremely small. The vehicle stability required to offer significant advantages for astrometric observations is perhaps too great for serious consideration at the present time, but ultimately a system with a short-term drift of less than 0.01 sec of arc per minute will require study. At the present time, the most significant advantage to be obtained from the use of rockets lies in the extension of the observable spectrum to wavelengths less than 3000 Ã…. The experiments so far carried out have involved the installation in rockets of detectors sensitive to wavelengths within a band of a few hundred angstroms centred in the 1000 Ã… to 2000 Ã… region. The limitations of this technique lie in the short observing times dictated by the roll rate of the vehicle, and a vehicle with a certain degree of stability is urgently required. With the ¿pre-determined¿ vehicle it will be possible to obtain crude spectra of selected bright stars in the short time offered by a sounding rocket flight. The more stable vehicle would enable spectra of good resolution to be obtained from a satellite, or detailed broadband photometry to be carried out from a rocket.
