Follow the trail of Hydra, the Snake, catch three comets in the night sky and visit Castor in Gemini
When to use this chart
1 Feb at 00:00 AEDT (13:00 UT)
15 Feb at 23:00 AEDT (12:00 UT)
28 Feb at 22:00 AEDT (11:00 UT)
The chart accurately matches the sky on the dates and times shown for Sydney, Australia. The sky is different at other times as the stars crossing it set four minutes earlier each night.
February highlights
Recommended equipment: Small/medium telescope
The evening sky is home to three comets which have past their perihelia and are near maximum brightness. First is 19P/Borrelly, the most luminous, around 8th magnitude, in Aries, the Ram, which sets an hour after twilight. Setting two hours after Borrelly is 104P/ Kowal 2, around 10th magnitude, which moves from Cetus, the Whale into Taurus, the Bull mid-month. Next is 10th magnitude C/2019 L3 (ATLAS) in Gemini, the Twins, which sets early morning.
Stars and constellations
Recommended equipment: Naked eye
Hydra, the Snake now meanders its way across the northern evening sky. Considering it’s the largest constellation by area, Hydra is also one of the faintest and difficult to recognise, except for its head. This faint asterism is comprised of six 3rd and 4th magnitude stars in a squashed semicircle. Being in a barren part of the sky it’s visible to the unaided eye under dark skies or fills the field of low power binoculars (5°). The head is 15° east of Procyon (Alpha (α) Canis Minoris).
The planets
Recommended equipment: Naked eye
With Jupiter and Neptune vanishing into the western twilight, the evening sky remains Uranus’s domain (leaving at 22:00). The sky is devoid of planets until Mars arrives about 03:00, which is followed by Venus, which reaches maximum brightness at mag. –4.9 mid-month. (These planets travel together for the next couple of months). Mercury is next, appearing before dawn for its best morning return for 2022. Saturn rises from the dawn glow joining it at February’s end.
Deep-sky objects
Recommended equipment: Small/medium telescope
This month we visit Gemini, the Twins, starting with Castor (Alpha (α) Geminorum) (RA 7h 34.6m, dec. +31° 53’). This 1st magnitude star is a wide multiple star system, but I’ll concentrate on its two brightest binary members, which have a 440 year-orbit. These mag. +1.9 and +2.9 components are separated by just 5.5 arcseconds, which is not as close as their last periastron passage, when they were just 2 arcseconds apart in the 1960s.
Recommended equipment: Large telescope
Next, we travel 12° southwest of Castor to discover the open star cluster NGC 2266 (RA 6h 43.3m, dec. +26° 58’). This 9th magnitude concentrated group, which is around 5 arcminutes across, is shaped like an equilateral triangle. A mag. +8.9 star, making its south-southwest corner, dominates this cluster of around 60 sparkling (9th to 13th magnitude) targets. Look for some curving lines of stars!