Local viewers take in grandeur of Comet 46P/Wirtanen

December 18, 2018

HARLINGEN — The green comet, 46P/Wirtanen, became the 10 th -closest comet to Earth in modern times yesterday, and for some amateur astronomers in the Valley it didn’t disappoint.

Tom Hopkins and Sem Vargas were able to photograph the comet earlier this month at a remote area in Willacy County.

“ We went to the east of Raymondville so it was fairly dark out there,” Hopkins said yesterday. “Then what we do is we have a tracking mount that we put the camera on but we did use regular camera lenses. It was a 200-millimeter camera lens.

“ Then we tracked it with multiple exposures — I think that one (pictured) was like four separate exposures of about a minute each. Then we used software to stack the multiple exposures together so that you get better signal-to-noise ratio so you end up with a cleaner photo.”

Hopkins has been tracking comets for the past 40 years, and this latest comet was No. 20.

“ The very first one I ever saw was probably the best one I ever saw, to be honest,” Hopkins said of Comet West in 1976. “It was when my father took my bother and I outside and this one had a really long tail. This one has like no tail that you can see visually.

“ That kind of like got me hooked on it,” he added.

Comet 46P/Wirtanen might be visible in the night sky tonight and maybe tomorrow, but as the full moon approaches on Dec, 22, it will gradually flood everything in the sky with too much light.

“ I was able to finally observe it actually from my home here in town (Harlingen),” he said. “That was the past week and this weekend. In fact, as recently as last night I was able to see it again with a break in the clouds. It does require binoculars. They don’t have to be particularly large. In fact a sturdy pair of 10 x 50 binoculars from Wal-Mart will even do the trick.”

46P/Wirtanen is now traveling away from Earth but still might be viewable west of the constellation Orion (the archer) across Taurus (the bull) and near the Pleiades cluster.

To locate Taurus, look for the constellation right after sunset by facing east and looking up at an altitude of about 30 degrees.

The green coloration of 46P/Wirtanen isn’t unusual among comets, Hopkins said, although there has been some misinformation about why a comet takes on a green hue.

“ It’s caused by what’s called carbon-nitrogen,” Hopkins said. “I know there was a misconception — even a NASA astronomy picture-of-the day referenced cyanogen, which is not correct. It’s definitely carbon-nitrogen.”

For those who missed 46P/Wirtanen’s swing past earth in its orbit around Jupiter and the sun, there will be other chances.

The comet will return and pass by Earth in 5.4 years.


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