Photographing Comets ISON and Lovejoy

I was fortunate to have a clear morning on Nov 20th to setup the telescope a few blocks away from my apartment at Observatory Park in Denver, CO. Despite the light dome from the city and the still nearly full moon, I managed to capture some decent images of both C/2012 S1 ISON and C/2013 R1 Lovejoy. A dark sky site would have allowed for much more of the tails of both comets, but even in the city with a moderate telescope or binoculars, there comets are worth waking up early for.

C/2012 S1 ISON

ISON will reach perihelion, grazing by the sun at a distance of less than the sun’s own diameter on November 28th! It is still anyone’s guess as to whether it will break apart, or become a brilliant naked-eye comet if it emerges again once past perihelion. See the Sky and Telescope ISON blog page for the latest, along with an observing chart.

12/7 Update: ISON disintegrated as it looped around the sun. There is no nucleus left, just a very diffuse dust cloud that continues to dissipate. A good telescope and seeing conditions are needed to view what remains.

I observed ISON @ 5:50-5:54 AM, and would estimate it as magnitude 4-5; not naked eye visible at this location. The comet was viewed about 12° above the E horizon, just below and left of Spica, with Mercury below and left of the comet at about equal distance.

Comet C/2012 S1 ISON

This image is composed of 3 1-min subs taken with 1 min intervals between tracking on the comet. Canon T3i prime focus with 6″ F/9 1370mm Astro-Tech ritchey-chrétien astrograph plus Astro-Tech field flattener. Celestron CG-5 eq mount, and Orion Magnificient Mini Autoguider.

Comet C/2013 R1 Lovejoy

Lovejoy is less talked about, but is actually easier to observe because it is so much higher in the morning sky away from the horizon.

As of early December, Lovejoy is now visible (with binoculars) in the NW after sunset, and again in the NE about 2 hours before sunrise. It will reach perihelion on Christmas Day. (ISON and Lovejoy are our holiday comets!) Unlike ISON, Lovejoy is not a sungrazer. It will be .8 AU (4/5ths the distance of the Earth’s orbit) from the sun, so it will loop back around. This also means it will probably remain a binocular comet, not a naked eye comet, unless you are under very dark skies.

I observed Lovejoy @ 5:31-5:38 AM. Estimated magnitude 4-5; not naked eye visible at this location. Lovejoy was in Ursa Major, forming a right triangle with the comet in the 90° corner, and the stars Phecda in the big dipper and Cor Caroli in Canes Venatici forming the other corners. Alkaid at the end of the big dipper handle lies opposite the hypotenuse from the comet.

Comet C/2013 R1 Lovejoy

Image composed of 7 1-min subs  tracking on the comet. Canon T3i prime focus with 6″ F/9 1370mm Astro-Tech ritchey-chrétien astrograph plus Astro-Tech field flattener. Celestron CG-5 eq mount, and Orion Magnificient Mini Autoguider.

Spotting Comets

A great resource for knowing what comets may be visible is the Weekly Information on Bright Comets page by Seiichi Yoshida. Also, the Sky Safari App for iPhone has very accurate coordinates for these comets. (I also tried Star Walk, but soon discovered the location information was inaccurate for both these comets, and very likely for others.)

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