Quote:Observation from Kirby Storter Roadside Park in Big Cypress National Preserve, Florida. 1025 UTC - C/2007 N3 (Lulin). Wow! Very bright. Very easy at 90x in the XT8. Nicely formed coma like an unresolved globular, centrally concentrated with an even linear dropoff in brightness from center to halo. About 3' across. No tail seen. Using the defocused-star method, I estimate magnitude at around 8. About 5 degrees above horizon. Considering this is well within the Miami light cone and at a very low elevation, this should be at least a suburban object with any kind of scope. Also observed at 120x and 170x. Visible with effort and averted vision in the 10x50 Resolux's. This soon switched to direct vision as the comet rose away from the Miami light cone (1050 UTC).
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Mark Seibold, Artist-Photographer-University Instructor-Lecturer, Record holder for most sketch awards and un-broken record over the astro-photographers for over five years
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Psalms 147:4 He determines the number of the stars and calls them each by name.
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Quote:In other circumstances this would have been a very dangerous comet, since it moves in the same plane as Earth.
Quote:Aaron, thanks for posting that link, and Tonk, thanks for the analysis. That sounds like a good forecast.
Quote:I would say this comet is a long period comet to which Jupiter gave a "reverse slingshot," trapping it in this bizarre orbit. It is definitely a potential threat to Earth, one that should be closely watched like Apophis and Toutatis.
Quote:Tails and Antitails
Because the comet stays nearly on the ecliptic, its tail (which points away from the Sun) aligns with the ecliptic and with the comet's own direction of motion across the sky. ...
Moreover, because Earth remains in the comet's own orbital plane, we're likely to see the comet with a very thin tail and an antitail, a spike pointing in almost the opposite direction from the main tail, for months on end. Why? In three dimensions a comet's dust tail is often wide but it's always thin, confined to the comet's orbital plane. When we are in or near this plane, we can sometimes see parts of the wide, thin dust tail on opposite sides of the comet's head. We pass through most comets' orbital planes briefly. But this time, the situation will last and last.
A comet's blue-green gas tail, on the other hand, always points nearly in a straight line away from the Sun in space. Cometary gas is blown directly away from the Sun at high speed by the solar wind.
Quote:They confirm what Tony Cook has already explained earlier in this thread about the orbital geometry.
Quote:genuinely hyperbolic orbit