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Captain Mário Gama's Direct Method for Star-sight Reduction

Published online by Cambridge University Press:  18 January 2010

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In a very interesting paper which appeared recently the author, Capitão Mário Gama of the Portuguese Merchant Navy, describes a direct method for computing position lines from star (or planet) observations.

The principal feature of Captain Gama's method is the systematic manner in which he arrives at an intercept to the extent, not only of saving time in sight reduction, but also in reducing the possibility of blundering.

The method employs the Computed Tables of Altitude and Azimuth (HD 486) and involves timing a series of star-sights, the ship making headway meanwhile, by means of a stop watch which is set at zero at a noted chronometer time shortly before the observations commence. The following example, given in the original paper, in reducing sights of Vega and Denebola observed during morning twilight of 25 Feb. 1959, in D.R. position Lat. 10°10′ S., Long. 73°48′ E., will serve to illustrate the method.

Type
Forum
Copyright
Copyright © The Royal Institute of Navigation 1970

References

REFERENCES

1Método directo para o cãlculo do ponto astronómico por observacão de Estrelas ou Planetas. Mário Gama, Capitão da Marinha Mercante. (Neptuno: Revista da Marinha Mercante National, No. 211, Jan./Mar. 1969, 42–54.)Google Scholar