Smithsonian Contributions to Astrophysics

Observations of only two components have been reported to the Astrophysical Observatory at the Smithsonian Institution. Fourth magnitude corresponds approximately to the brightness of the three fainter stars in the handle of the small hoop (Ursa Minor).

FIGURE 1.—Harvard Announcement Cards giving preliminary orbital characteristics for Satellites 1957 a l and al.

Cunningham, of the Leuschner Observatory University of California, Berkeley, calculated for the Astrophysics. Based on the above considerations, the same c as for Satellite 1957 a l was used.

FIGURE 1.—Harvard Announcement Cards giving preliminary information on orbital characteristics for Satellites 1957 a l and al (for No

Glossary of Astronomical Terms for the Description of Satellite Orbits 1

The celestial equator is the great circle on the celestial sphere, formed by its intersection with the plane of the Earth's equator. The ecliptic is the great circle on the celestial sphere formed by its intersection with the plane of the Earth's orbit.

The distance FP' of the satellite from the center of the Earth is called the radius vector r. The XON angle is the right ascension of the ascending node and is denoted by O.

FIGURE 1.—Satellite orbits, a: The elliptical orbit of a particle P' around mass point F is the simplest model of an artificial satellite's motion, b: The arc NAP' is a portion of the satellite's orbit, specified by the orbital elements defined in the text

Washington Georgetown Rio de Janeiro Siudad ti Kansas San Jose Buenos Aires Los Angeles Puego Daga Graham Daga Mlkolayev-on-Amur. Washington Caracas São Paulo Dallas San Jose San Francisco Tierra del Fuego Graham Daga Windhoek.

Table 2 . — P r e d i c t i o n s 0909 091 3,100810331 0 5 0IO511111115311591204122712501335140414321511151415241633165116551709175218251831184019051953200520072021202521102120

HJ] (6) where P b and p b are the pressure and density

Revising the Minzner-Ripley-ARDC model to fit the value p=4.5X10~10 kg/m3 to a geometric height Z of 220,000 meters, derived from satellite observations in an earlier report (p. 207), was performed by modifying the TM-H ratio. However, somewhat the same objection can be raised against the Minzner-Ripley model itself, even though the present authors think that it is one of the best atmospheric models devised. If values of the density, p, in kilograms per cubic meter are required at higher altitudes, these can be calculated from the equations.

The preceding model atmospheres provide the best estimates of atmospheric density that the authors have been able to derive. At least in part, the high temperatures in all the models are a consequence of the adoption of the Minzner-Ripley temperatures below H' and of a constant gradient of temperature above H', and are not implied by the observed density at Z = 220,000 meters alone . The observed density at 220,000 meters strictly implies that somewhere in the region between sea level and 220,000 meters the molecular scale temperature TM is higher than the value adopted by Minzner and Ripley of the ARDC.

The authors hope that future satellite data will provide observational values of atmospheric densities at new altitudes and make it possible to replace current temporal atmospheric models with more realistic, less speculative and arbitrary ones. As reported earlier, preliminary values of atmospheric density are derived from artificial U observations.

Figure 1 exhibits the temperature-altitude re- re-lation for the Minzner-Ripley-ARDC model, and for the three revised models

Soviet Orbit Information for Satellites 1957 a2 and

Preliminary report on the flight of the sputniks, prepared by the Soviet International Geophysical Year Committee, is being circulated to the organizations participating in the International Geophysical Year. This official report did not contain scientific data or specific findings; it only repeated general statements previously published by Radio Moscow and the Soviet press. This data was released in the form of predictions one to two days in advance.

The geographic latitudes are plotted against the date of the forecast and are corrected only for obvious transmission errors and errors. Although the values for 01 show quite a characteristic behavior with respect to time sequence, the al forecasts after about 25 November can appear somewhat confusing. It is interesting to compare these Soviet predictions with actual data on optical observations.

FIGURE 1.—Soviet predictions of zones of visibility.

IIS 959

After sunset Before sunrise After sunset Before sunset (?) After sunset Before sunrise After sunset Before sunrise After sunset Before sunrise Before sunset Before sunset of the sun (?) After sunset Before sunrise After sunset.

Basic Orbital Data for Satellite 1957

It should therefore be noted that Pic du Midi gives time as 1* and positions as 0?l. Pic du Midi Woomera Woom* ra VAenna Vienna Vienna Woomera Woomera Perth Perth Perth Perth Perth Adelaide Mt, Stromlo Mt, Stromlo Mt. Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Manhattan Manhattan Manhattan Manabattan Milton Milton Schenectady Sacramento A Cambridge Bedford Bedford Bedford Bedford.

Sydney nga pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi Bratlslava-Koliba Dunsink. Albuquerque pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi college, Alaska Mt. Hlgashlmatsuyama Hanazuru Manazuru Manazuru Sandaler Sandaler Musashino Musashino Nagoya Takamatsu Adelaida Adelaida Middag nga Nasingil Middag Middag Nasingil Middag Middag Nasingil Middag Billed.

Los Angeles Oakland TUBS iti Los Alamos Albuquerque Whlttier Whltttitr Portland Mannanakaw Sapporo Mitaka Sandals Kiryu Mizukaido Sacramento Retrato iti malem Retrato ti malem Pezi

Table 1.—Analysis of optical and radio observations of S a t e l l i t e 1957 PI (1)

Lawton Oakland Sacramento Fort Worth Bryn Athyn Cambridge Cambridge Thief Shizuoka Manazuru Osaka-Yomlurl Kochl Mttaka Musashino Klryu Mlzukaldo Hlmejl Cambridge Walnut Creek. Cambridge Cambridge Cambridge Cambridge Cambridge Washington, D.C. Washington, D.C. Sacramento B Sacramento B Sacramento B Middag Peak Middag Peak Middag Peak Noon Peak. College, Alaska Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Dunslnk Obs.

Wichita Los Alamos Los Alamos Los Alamos Milwaukee Milwaukee Milwaukee Milwaukee Albuquerque Tucson Tucson Albuquerque Albuquerque Albuquerque Sacramento C Sacramento C Sacramento C Sacramento C Sacramento C Sacramento C. C Sacramento C. Washington, Washington, Washington, Cambridge Cambridge Cambridge Cambridge Cambridge Cambridge Cambridge Cambridge Cambridge Cambridge Cambridge Cambridge Cambridge Cambridge Cambridge Cambridge ti maysa a tao. College, Alaska Pic du Midi Pic du Midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic du midi pic de midi

III 337 339

Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi. Suwa Sendai Sendai Sendai Québec Québec Québec Cambridge Cambridge Cambridge Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi Pic du Midi. Photo photo photo photo photo de P.lc du Pic du Pic du Pic du Pic du Pic du Pic du Pic d'l.

Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi. Canaveral B College, Alaska Johannesburg Johannesburg. Midi-billeder Billede du Pic du Pic du Pic du Pic du Pic du Pic du Pic du Pic du Pic du Pic du Pic du Pic du Pic du. Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi.

Pic du pic du Pic du Pic du Pic du Pic du Pic du Pic du Pic du Pic du Pic du Pic du. Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi Midi.

Table 3.—Processed optical observations of S a t e l l i t e 1957 Beta (continued) OBS.

Successive Revisions of Orbital Elements for Satellite 1957 Beta

Time of Ascending Node Crossing Mar. W )2 2At the current acceleration rate, the satellite should complete its final revolutions. Under these conditions, predictions become very difficult and can be expected to be in error by many minutes after only a few days.

Table 1.—Successive revisions of prediction elements for Satellite 1957 Beta [t In year days")

A Chart for Finding a Satellite's Distance and Elevation 1

Recent Orbital Information

Jacchia and published on card 1389 describes the life history of Satellite 1957 a\ with a fairly accurate picture. Approximate determinations of any current location of the Satellite 1957 Alpha launch vehicle can be made with the information provided. Subsatellite points were calculated using the same values of « and q u for 1957.1 (see MAC. 1389) and from these, assuming i = 653, equatorial crossings were derived which can be fairly well represented by.

Bibliography