A Plan for Securing Observations of the Variable Stars
A Plan for Securing Observations of the Variable Stars
Pickering, Edward C. (Edward Charles), 1846-1919
The book A Plan for Securing Observations of the Variable Stars was written by author Pickering, Edward C. (Edward Charles), 1846-1919 Here you can read free online of A Plan for Securing Observations of the Variable Stars book, rate and share your impressions in comments. If you don't know what to write, just answer the question: Why is A Plan for Securing Observations of the Variable Stars a good or bad book?
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Exceed one magnitude. Estimate the brightness of v in tenths of the inter- val from a to b. Thus, if v is midway between a and b the interval will be five tenths, and we may write a 5 b. If v is nearly as bright as a, we may have a 1 b or a 2 b ; if v is not much brighter than 6, we may have a 8 b or a 9 b. An advan- tage of this method is that larger intervals in brightness may be used between the comparison stars, and accordingly less distant stars employed. An increase in distance of the sta...rs always renders the comparison more difficult. We can also obtain many independent comparisons by using several comparison stars. If we have m stars brighter and n fainter, we shall only have m -\- n independent measures by the method of grades, while we may have m n comparisons by estimating tenths, since estimates may be made in terms of the intervals between each brighter and each fainter star. On the other hand, especially when observing stars not very near together, it is a decided advantage to have to com- pare two stars rather than three.
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