Periodic Comet 46P/Wirtanen (3 Dec 18)
Taken by Jan Curtis on December 3, 2018 @
Vail, Arizona
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Camera Used: Unavailable Unavailable
Exposure Time: Unavailable
Aperture: Unavailable
ISO: Unavailable
Date Taken: Unavailable
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Details:
1st image:
The bright star at top center is Pi Ceti.. It is visible to the naked eye with an apparent visual magnitude of 4.238. Based on this image of 6x60s, iso 2200, 180mm ED f/2.8 @ f/4.0, Nikon d7100, Comet 46p nucleus is brighter than 5th magnitude. However, this comet's coma is so large and spread thinly out to beyond 1.5 degrees, its total integrated brightness is considerable fainter.
Since last observing on 29 Nov, I would say the comet is brighter but has slowed in brightening. It's tiny tail is barely obvious at the 10 o'clock position and is lost completely in longer exposures due to coma over exposure.
2nd image:
Taken during its transit (highest point in the sky) @ ~10:15PM, this 72x60s, iso 2200, 180mm ED f/.8 @ f/4, Nikon d7100 image is fixed on the comet as stars trail. The comet's movement is ~ 1 degree in 15 hours. This limits integrated exposures of just a few minutes depending on aperture (magnification). This is actually a difficult comet image because of the nature of its shape, brightness and rapid movement.
Recommendation:
In the coming days, weather permitting, I think the best exposures should be <3 minutes with low iso (single frame), or several high iso with very short exposures (<15 secs).
Photographer's website:
No URL provided.
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