Bruce MacDonald wrote:
> Thanks to everyone who replied to my message about elsets for
> Sputnik 1 and the R-7 rocket.
>
> I have another question. When working out the brightness of
> the payload and rocket I calculated that the payload would be
> around mag 6 and the rocket mag 0 (based on 50% phase at
> 500km range). I would be interested to learn from anyone who
> may have seen them what the brightness of each object actually was.
The observation reports of the rocket published by the SAO ("SAO Special Report
10 - Processed Observational Data for U.S.S.R. Satellites 1957 Alpha and 1957
Beta", Mar 1958) ranged in brightness between mag 0 and 4, typically mag 1 or 2.
The satellite ranged between mag 4 and 7, typically mag 5 or 6.
When I complete my orbital analysis of this data, I will determine standard
magnitudes. For now, I suggest std mag 1.7 for the rocket, and 9.6 for the
payload, both 1000 km, 90 deg phase angle. I have verified the value for the
rocket against a small number of observations; the value for the payload is
based upon its diameter, 0.58 m, and a brightness chart in Observing Earth
Satellites, by Desmond King-Hele. It yields mag 6 predictions for favourable
passes near perigee.
Ted Molczan
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