Zodiacal light semantics (25 Sep 2007)

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Expand view Topic review: Zodiacal light semantics (25 Sep 2007)

Dusk, not dawn

by Mkellogg » Tue Sep 25, 2007 5:01 pm

The picture was taken at dusk, not dawn. The bright "blob" near the horizon is Venus, and Regulus can be made out below it. Lower still, Saturn is about to set. Arcturus, Spica, Porrima, and Denebola are clearly visible in the central area. The first clue was the angle of the ecliptic, which leans to the left at dawn and to the right at dusk in the Southern Hemisphere.

by Chris Peterson » Tue Sep 25, 2007 4:31 pm

geckzilla wrote:According to a wiki entry on the topic it can happen both during spring and autumn, signots. In spring it happens after the evening twilight while in autumn it happens before the morning twilight.
From a dark site it is visible year round. It's simply more prominent near the equinoxes. The bottom image at http://www.cloudbait.com/gallery/gallery_meteor.html was taken in mid-November.

by geckzilla » Tue Sep 25, 2007 1:49 pm

According to a wiki entry on the topic it can happen both during spring and autumn, signots. In spring it happens after the evening twilight while in autumn it happens before the morning twilight.

http://en.wikipedia.org/wiki/Zodiacal_light

False dawn

by signots » Tue Sep 25, 2007 12:37 pm

It says in the last sentence it's also bright for people in the Northern Hemisphrere in March and April. Shouldn't, then, the reference in the first sentence be Southern Hemisphere? Steve

by l3p3r » Tue Sep 25, 2007 12:12 pm

Excellent piece of photography!

It'd be a pain setting the camera movement up, I would think!

Zodiacal light semantics (25 Sep 2007)

by Axel » Tue Sep 25, 2007 11:37 am

Okay, a "false dawn" isn't a dawn by self-definition, so "false dawn" is obviously a metaphorical term applied to a phenomenon. Yet the phrase "Once considered a false dawn" implies that people who used the term were misguided. Surely the phenomenon was just called a false dawn, and now it's called something else.

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