This Week’s Sky at a Glance, 2021 February 20 – 27
~by Curt Nason
Winter is open cluster season for stargazers; star clusters that have formed from the same vast cloud of gas and dust and which usually hang around together for half a billion years. They are also called galactic clusters because these vast clouds typically appear in the spiral arms of our galaxy. In winter we are looking toward a spiral arm opposite the centre of our Milky Way galaxy. Two of these clusters, the Pleaides (M45) and the Hyades, form the shoulder and face of Taurus the Bull and they are bright enough to be seen within urban areas. Other clusters are visible to the naked eye but require a clear sky with minimal light pollution.
One of those objects is the Beehive star cluster (M44) in the constellation Cancer the Crab, which lies between Gemini and Leo. The Beehive is a large glowing patch of haze and its many stars fill the view in a telescope, but large clusters like this are appreciated best with binoculars. In times long past the cluster was used as a storm predictor. It would be one of the first objects to disappear when the light clouds that often precede a weather system would move in.
The Coma Star Cluster, or Melotte 111, lies in the constellation Coma Berenices between the tail of Leo and Canes Venatici the Hunting Dogs. It is a large, somewhat sparse cluster that spills beyond the view of most binoculars, and centuries ago it was regarded as the tuft of Leo’s tail. The other one, or two, is the Double Cluster between Perseus and Cassiopeia. This pair fits within the view of a low power telescope eyepiece, but binoculars give a better perspective. Following a nearby string of stars with binos will bring you to the large Stock 2 star cluster, less spectacular but delightful to observe.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 7:13 am and sunset will occur at 5:53 pm, giving 10 hours, 40 minutes of daylight (7:17 am and 5:59 pm in Saint John). Next Saturday the Sun will rise at 7:01 am and set at 6:03 pm, giving 11 hours, 2 minutes of daylight (7:05 am and 6:09 pm in Saint John).
The Moon is at first quarter on Friday, February 19 and full on Saturday, February 27. With Orion and Taurus up high in the evening, compare the colour of their red giant stars Betelgeuse and Aldebaran with that of Mars to their west. Betelgeuse is a little brighter than Mars and Aldebaran currently is a little dimmer. Mercury will be 5 degrees left of Saturn on Wednesday morning, with both rising more than an hour before sunrise. Jupiter will be 5 degrees lower left of Mercury.
With astronomy meetings and outreach activities on hold, you can watch the local Sunday Night Astronomy Show at 8 pm and view archived shows.
Questions? Contact Curt Nason.