DSW Astronomer Martin Griffiths takes a look at the February sky.
The bright winter constellations still dominate the evening but by midnight and into early morning the spring constellations of Leo, Hydra and Bootes become visible and the galaxies of the Virgo cluster become prime objects for study.
Moon in February:
New: 26th February
First quarter: 4th February
Full: 11th February
Last Quarter: 18th February
Planets in February:
Mercury: is in conjunction with the Sun for most of this month as it lies in Capricorn.
Venus: is at greatest greatest brilliant on the 17th February dominating the evening sky to the southwest. And shining at magnitude -4.4.
Mars: lies in Pisces and continues to fade. It sets by 9.30 and is a tiny disc with no visible features in modest scopes.
Jupiter: Is a bright morning object in the constellation of Virgo, lying close to the first magnitude star Spica. Shining at magnitude -2. It rises just before midnight and is visible through the early hours
Saturn: Is in Ophiuchus and is visible in the early morning before dawn as a bright yellow star-like object shining at magnitude 0.5
Uranus: Is in Pisces, not far away from Mars and shows a tiny disk at magnitude 5.7 and is a fading object that sets about 10:00 PM.
Neptune: The furthest planet from the Sun remains in Aquarius and is not really visible this month as it sets shortly after sunset whilst twilight spoils any attempt at viewing.
Meteor showers in February.
There are no major showers this month though the little known or followed Leo Minorids fade out by February 4th. This long lasting but uninspiring shower starts on December 5th every year and ends by February 5th and at its peak has only 5 meteors per hours as a Zenithal Hourly Rate. Nevertheless, a sporadic and bright meteor seen in early February may belong to this little shower.
Interesting Events in February
On the 5th February the 8-day old moon is 0.2 degrees from the first magnitude star Aldebaran in Taurus in the evening sky and will thus make a pleasing photo opportunity.
This month sees a penumbral eclipse of the moon on the 11th February. From the UK, All of this phenomenon will be visible, but penumbral eclipses do not experience the darkening of the moon that a full lunar eclipse entails. The moon will appear just a few percent less bright and will not be readily perceptible to the naked eye. The eclipse starts at 22.34 hours UTC and ends at 02.53 UTC.
Constellation of the Month: Monoceros
Monoceros, “The Unicorn” is an ambiguous constellation that is very difficult to discern as it has few bright stars. It’s claim as a constellation of antiquity is debatable though it does appear on some old Arabic maps and spheres dating back to the 12th century. In its current form it was created by Hevelius to fill in a blank space between Orion to the west and Cancer to the east. Thankfully, although stars are few, deep sky objects are not, as Monoceros lies in a particularly fruitful part of the Milky Way.
This richness is derived from a huge molecular cloud of gas and dust that permeates this region of space and has outcroppings in the form of bright gaseous nebulae that make Monoceros a treasure house for the well-equipped observer. If you own binoculars or a small telescope, then do not despair, as there are plenty of objects to tantalize and astonish.
One of the best star clusters of the winter sky is to be found in the southern part of this constellation. M 50 is a bright nebulous patch of light in the field of a pair of binoculars, but under the scrutiny of a small telescope, it becomes a treasure trove of over 200 stars in a small compressed area of space. Not all these stars will be visible, but the primary stars will of course be relatively easy objects to see. One of the stars is a delightful deep red in colour and is immediately recognisable even in a small scope. The distance to this lovely cluster is 3000 light years, thus making the stars that create its 6th magnitude glow very luminous indeed. Its position in a lavish part of the Milky Way assures M 50 of a unique place in the memory of those that observe it.
A most beautiful cluster plus an attendant nebula is the next stopping point in our tour of Monoceros. In a tight group around the star 15 Monocerotis, is a wonderful pack of glittering points of light, all caught in a misty web of faint light. This is the cluster NGC 2244 and nebulae NGC 2237, otherwise known as the “Rosette Nebulae”. This is a fantastic sight in giant binoculars on a clear night, but is a disappointment to those with small telescopes. The cluster of 40 or so stars is readily apparent, but in the confined field of an eyepiece, the nebula lacks structure and disappears altogether. The Rosette nebulae is easily captured on photographic film, and is a beautiful orange red in colour, which contrasts wonderfully against the electric blue starlight of the cluster.
The Rosette nebulae lies at an approximate distance of 5200 light years, giving the cloud of gas a dimension of 55 light years in extent. The nebulae has been said to contain enough matter to form 11,000 Suns, and indeed such stellar births are still occurring in this magical region of our galaxy. Large telescopes show several knotty condensations of dark matter contrasting with the ruddy hue of the gas. This is where the next generation of stars is currently being formed, and the area is under intense scrutiny by astronomers.
Further to the north of this object is a lovely cluster around the star “S” Monocerotis. This cluster, NGC 2264 is commonly known as the “Christmas Tree” cluster, for reasons that become obvious the moment one views it. About 25 bright stars make up the illuminated Tree, most of which can be seen under good seeing conditions through binoculars, although once again, a telescope gives a finer view. This group lies at a similar distance to the Rosette nebulae adding further proof that this region is alive with stellar nurseries. NGC 2264 is also surrounded by faint nebulae, but this nebula is reserved for those owners of large telescopes, as its surface brightness is very low.
A little to the south of this cluster lies the enigmatic object known as R Monocerotis. This is a variable star of very unusual type, as it appears that it is struggling to throw off its swaddling bands of gas and dust and emerge as a young main sequence object. However, it seems to be experiencing difficulty in this quest, as occasionally, R Monocerotis disappears from view behind a rather interesting faint nebula first discovered by the eminent astronomer Edwin Hubble. This object is easily visible in a small telescope to the southwest of the Christmas tree cluster as a small smudge of white light amongst a rich field of stars.
The only fairly bright star of the constellation, b Monocerotis is also a fine triple star, one of the most splendid stars in the winter sky. The components are widely separated and of almost equal magnitude range all around mag. 5.5 and of similar colours.
Being a part of the Milky Way, Monoceros abounds in star clusters, many of which are easily visible in binoculars or a small telescope. The only problem the observer has is trying to find them among the plethora of faint stars in this extremely rich region! One of the nicest of these clusters is NGC 2301 at RA 06h 51m 48s Dec 00°28m, a fantastic arrangement of over 60 stars in a compressed group. Most are relatively bright at mag 8, so the cluster should be visible as a misty patch in a good pair of binoculars.
A slightly fainter but nevertheless rich object is NGC 2324, which contains 50 stars of around 10th magnitude in a small, condensed group that is a pleasant sight. One of the best-known star clusters in Monoceros is NGC 2506, at coordinates RA 08h 00m 12s Dec -10°47m; a beautiful gathering of 75 stars in a large group. The stars look like tiny needle points of light, shining at around mag 11, but the overall magnitude of the cluster is around mag 9, so it should not be too difficult to spot.
Scanning the Monoceros Milky Way with binoculars is well worth the effort. Mounted on a tripod, these instruments make effective wide field telescopes that can be comfortable to use. The constellation of Monoceros is filled with the interplay of light and darkness, which binoculars reveal, as dust clouds and star clouds compete for the observer’s attention.