Lemmon Of A Comet Slices Through The Southern Cross

The Southern Cross, officially named Crux, is tipped on its side in this photo taken off Comet F6 Lemmon on Jan. 18, 2013 local time in Bright, Victoria, Australian by amateur astronomer Rob Kaufman. He used a 134mm telephoto lens setting. The inset photo is a blowup from the main image.

I apologize. I discovered the joy of puns around the age of 13 and have been making family and friends groan ever since. The title refers to Comet C/2012 F6 Lemmon, which has turned out to be anything but.

Lemmon was discovered in March 2012 by A.R. Gibbs during the Mount Lemmon Survey based in the Catalina Mountains north of Tucson. At the time it was spectacularly faint. Not anymore. The comet became much brighter than expected when it first appeared in the morning sky late last fall. I recall it as a big, puffy glow shining at 10th magnitude in my scope one chilly December dawn.

Comet Lemmon’s been on a roll ever since; this week it’s 7th magnitude glowing ball with a bright center easily visible in binoculars from a dark sky. One caveat. The comet’s moving south through the famed Southern Cross in the pre-dawn sky. While you might just catch sight of it from Key West, where it clears the horizon before the start of twilight, southern observers have the edge on this fuzzy blob. From Down Under, Lemmon’s very well placed for viewing between 2 and 4 a.m.

It’s not often a brighter comet crosses in front of the Southern Cross. This compact constellation has three stars (labeled) around 1st magnitude. Acrux is the brightest. The tick marks show the comet’s position each morning (Australian Eastern Daylight Time) starting Jan. 18. Created with Chris Marriott’s Skymap software

Comet Lemmon reaches perihelion – closest approach to the sun – in late March, when it could gleam at 4th magnitude, bright enough to see with the naked eye. Unfortunately, it will be too near the sun to see at that time. We’ll hope that when it slips into a dark morning sky in May, it will still be bright enough to see in a small telescope for observers in both hemispheres.

Comet L4 PANSTARRS in mid-March, Lemmon (perhaps) in May and Comet ISON in fall. Keep the comets coming I say!

3 Responses

  1. Bob Crozier

    I was checking out JPL’s orbit diagram (linked above) for the L4 Pannstarrs comet and it occurred to me that we would probably have a pretty good view of that comet’s closest approach to the Sun if we could hang out somewhere above the clouds on Venus. And then I thought, “Wait a second! There are human made satellites orbiting Venus!” Is there any way that any of them will be taking pictures of that event? Or any of the other several (hopefully bright!) comets making passes at the Sun this year?

    1. astrobob

      ESA’s Venus Express is the only craft orbiting Venus. It’s been studying clouds and atmosphere there since 2006. It hasn’t taken photos of any other bright comets over the past six years and I’m not aware of any plans to do so this year.

      1. Bob Crozier

        hmmph! Do you suppose if we sent them an email and asked them really nicely…? Close approach is still 7 weeks or so away. They could probably program the appropriate commands and get them uploaded to that craft by then! Hey Bob! You might have more influence with them than any of us do! What do you say? Wanna write an email? 😉 (I am just kidding, of course!)

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