Prime time for comet hunting arrives

Last week I described the impending apparition of Comet C/2022 E3 (ZTF) in southern skies. Tonight is the night things start to get real. Weather permitting, after sunset, stargazers across Otago have our first decent chance to spot a relatively bright comet close to the planet Mars in the sky. With the moon not rising until the early hours, conditions should be perfect for hunting this giant celestial snowball. The comet should, just, be visible to the unaided eye. However, a pair of binoculars will make it much easier to see.

This particular comet was discovered in March 2022 using the Zwicky Transient Facility (ZTF) in California. It has brightened as it enters the inner solar system. Thanks to a highly tilted orbit, the comet has been invisible from New Zealand until now.

If you have not seen a comet, this evening is a great opportunity to "knock one off" from your cosmic bucket list.

Thanks to the comet’s proximity to Mars, it should be particularly easy to find tonight. Mars is, by far, the brightest object in the Northern sky after sunset. Look for a bright red "star" low down as darkness falls. The comet is less than a degree to the right of the red planet. The pair should be easily visible in the same binocular field of view. C/2022 E3 will look like a greenish circular "smudge" of light. The green colour is caused by a spherical cloud of diatomic carbon surrounding the comet’s icy nucleus.

Over the next few weeks, the comet will get higher in the northern sky with each passing night. Later this week (on Tuesday and Wednesday) it can be found close to Aldebaran, the brightest star in the constellation Taurus.

This comet was last visible when Neanderthals roamed Eurasia. After this visit, astronomers have calculated that gravitational interactions will expel it from the solar system. The comet is beginning to fade, so, if you miss it, you won’t get another chance to see it!