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I suggest you to take a look at the Amateur Astronomy Observers Log Web Site, where everybody can share their astronomical logs. The logs contain: Instrumentation used Sky condition (seeing, light pollution, ...) Accurate date and time of the observation Specific informations that you could add depend by the kind of object that you are watching. For ...

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If you have yet to plan your adventure and the moon is not you main target, be sure to set your date nearest a "New Moon". During this phase the moon will not be visible at night, reducing the light pollution that much more. This will increase the amount of stars you should be able to see. Peak of any meteor shower event would be a bonus aswell. Red light ...

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Rob Jeffries nailed it, but I'll add a few points. 25-30 stellar mass stars are quite rare. O-type stars begin at a mass of about 16 suns and they're about 0.00003% of the main sequence (that's 1 in 3 million). They're also short lived, a few million to maybe 10 million years in main sequence. That's part of the reason there are so few of them. If ...

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There aren't any. A 25-30 $M_{\odot}$ main sequence star would have a spectral type of $\sim$ O7 and an absolute $V$ magnitude $M_V \simeq -5$ (see Zombeck 1982). A giant star with this mass would be even more luminous. At a distance of 30pc, the apparent magnitude of such a star would be $V=-2.6$. Closer examples would of course be brighter. Sirius is the ...

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One way to determine the luminosity of a star is to first determine its distance, d. Then one can use the formula, Luminosity = Flux * 4 * Pi * d$^2$. Flux is related to the apparent brightness that is measured with a telescope (and CCD or photometer). mag = -2.5 * Log(Flux) + c. If the star is relatively nearby, one can use parallax to get the ...

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