A Distant Visitor to Our Sky - Comet ZTF

By Alastair Brickell

This week we could have a special treat as Comet ZTF will briefly pass through the heavens. It will be very faint and probably require binoculars to spot but should be easy to locate in the sky and fun to watch this strange visitor moving rapidly from night to night. Named after the Zwicky Transient Facility at Mt. Palomar in California, it was first discovered on March 22, 2022.

Comets are small objects only a few kilometres across from the extreme depths of our solar system that are on very long elliptical orbits around the Sun. It is estimated that this comet last visited us about 50,000 years ago, just as we were approaching the coldest part of the last ice age. Comets are very loose aggregates of material only just held together by their extremely weak gravity and often described as dirty snowballs or snowy dirtballs. This one is approaching us from high above the plane of the solar system, so was at its closest and brightest in the northern hemisphere last week at about 100x the distance to the Moon and we will have to wait until about Friday, February 10 for it to move down our way.

Unfortunately, a relatively bright Moon will make viewing a bit difficult for the first couple of nights it is in our skies. However, we can use Mars and the red giant star Aldebaran to help us find it and track its movement as listed in the weekly viewing notes on page 2. Its position for this week is also shown in the illustration as it moves past Mars and Taurus, or ‘Marte’ and ‘Tauro’ on this Spanish map. Do not expect to see a huge thing streaking across the sky but rather a faint fuzzy blob in binoculars or a small telescope; but this is a blob that moves each night! Pointing a camera or phone in the right direction and taking a time exposure for 20-30 seconds may show the fuzzy visitor which you can then search for in binoculars or with the naked eye. See if your photo picks up any of the reported bluish tinge to this comet.

It is the first decent comet we’ve had since spectacular Comet McNaught appeared back in 2007, so do try and have a look if you can…we will never see it again!

Photo credited to 'Sky and Telescope' magazine and is in Spanish.