Engineering Papers⌕ Search

Engineering topics

Pope, T. P.

Publications and source records attributed to Pope, T. P..

5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

A statistical study of spicule inclinations

The apparent angles of more than 5000 quiet region spicules situated at various position angles around the sun's limb have been measured on off-band H-alpha filtergrams taken during the years 1972-1975. The counts were made exclusively in projection on the disk, within 5.25 deg of the limb. The tendency of the average spicule to lean towards or away from the pole is small at most, and at no latitude exceeds 8 deg. The spread in angles is 30-35 deg.

Mosher, J. M.↗
NASA NTRS1976

Development of birefringent filters for spaceflight

The critical problem for flight of a birefringent filter is the shock mounting of the calcite. The design presented here bonds the calcite block with silicon rubbers to the calcite holder. The calcite together with its all necessary polarizers and rotating achromatic plates are mounted together in units called a filter module. By using a set of modules containing calcite crystals of differing lengths, a filter can be produced. A description of the modules is given. Also described is a container for the filter modules, which can be used both to hermetically seal the system or contain an index matching oil. The response of a filter element while being controlled by the Lockheed Temperature Control is described and the determination of the wavelength sensitivity to temperature of calcite is explained. Operation of the filter using a software control algorithm instead of a hardware temperature controller is shown. Some radiation considerations of filter systems are given.

Title, A. M.↗
NASA NTRS1974

Drift in interference filters. I

Studies of narrow-band interference filters have shown that two mechanisms exist that cause drift to shorter wavelengths. One is dependent on the thermal history of the filter, and the other depends on the radiation history. The present paper presents experimental results on thermal effects; and it is shown that by a proper bake cycle, ZnS-cryolite filters are stable for years if stored at less than 38 C.

Title, A. M.↗