RE: Brightness of Sputnik 1 payload and rocket?

From: Ted Molczan (
Date: Mon Sep 10 2007 - 15:30:17 EDT

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    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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