What’s Up! February 2021

A monthly look at astronomical events in the sky and on Earth 

Compiled by John Rowland

February’s weather is obviously not designed to entice you out into your garden to look at the sky. But if you can catch the odd clear, windless evening when there’s no Moon, you will be rewarded with some of the most famous objects in the night sky.

Each month, we aim to highlight the objects that are conveniently placed for viewing in the four-hour evening slot of 1900 – 2300 hrs unless there’s a good reason to view earlier or later.

February Objects

The Sun

There was a brief period of activity last month and a rather fine aurora borealis show, so don’t assume our star is still asleep. It’s worth checking spaceweatherlive.com to see whether more activity may happen.

The Moon

The best evenings to observe the Moon are from the 14th (slender crescent) through to the 23rd (mid-gibbous). For those wishing to spot the earliest crescent moon, the best time will be at about 1730 on the 13th. (But see the Crescent Moon Watch page for more details.)

Mars

As explained in January’s What’s Up, Earth is leaving Mars behind now, and February is when this separation increases at the fastest rate. On the 1st, its diameter is 7.8 arc seconds, and by the 28th this has reduced to 6.4 arc seconds – far too small to see any of its surface markings.  It’s due south and high in the sky at 1755 (50 minutes after sunset) at the beginning of the month, but by the 20th is transiting at sunset so beginning to head towards the bright western sky. One thing that might be worth looking for is that on the 19th, the Moon, Mars and the Pleiades are fairly close together in the early evening sky.

Mercury, Venus, Jupiter and Saturn

All these planets are too close to the Sun to be observable this month.

Uranus

Uranus continues to be eminently observable as a magnitude 5.8 early evening object in Aries. A decent telescope will show it as a turquoise disc 3.5 arc seconds in diameter. There’s a finder chart included in this in-the-sky.org web page. Grab it while you can, because by March it will be lost in the sunset glow.

Deep Sky Objects

Winter is without question the season that presents us with the richest, most diverse and spectacular objects to observe. These objects (and in particular the nebulae) are best seen against a dark and moonless sky so try to observe them during the first three weeks of February when the Moon is out of the way. The diagram below shows the sky from SE to SW and up to the zenith at 2100 on the 14th.

February 14th 21:00 hrs - captured from SkyViewCafe.com

Fig.1 February 14th 21:00 hrs – captured from SkyViewCafe.com

All the Deep Sky Objects on the chart above are of 6th magnitude or brighter, and therefore visible in even the most modest telescope. Many are also well seen with binoculars.

Please see January’s What’s Up for references and finder charts to M31 (The Great Nebula in Andromeda), NGC869/884 (The Double Cluster in Perseus), M45 (The Pleiades), and M42 (The Great Nebula in Orion). The following is a further selection you might like to have a go at.

The Rosette Nebula

You’ve probably heard of the Rosette Nebula but may not know where it is or whether you could see it. Its correct designation is NGC2237 but at its centre is NGC2244 which can be spotted (position is shown on the chart above) as a 4.8 magnitude,24 arc minute diameter open cluster. The much larger 1° diameter Rosette nebula is only visible against the clearest and darkest sky background, but it’s worth having a go whilst you’re in that part of the sky. Use binoculars or a low power [eyepiece] and make sure you’re completely dark-adapted. The red colour however only comes out in photographs.

The Rosette Nebula

Fig.2 The Rosette Nebula as imaged by YAS’s Graham Moore, York (UK)

Please see the YAS Gallery page for other Deep Sky Objects by YAS member, Graham Moore.

And now for a Clutch of Clusters

Galactic Cluster M35

A fine half-degree diameter fifth magnitude open cluster. Look out for the much smaller and tighter NGC2158 cluster, of magnitude 8.6 (similar magnitude to the Crab) to its lower right.

Galactic Cluster M36

6th magnitude cluster of about 60 stars. best seen in binoculars or low power eyepiece.

Galactic Cluster M37

A fine 6th magnitude open cluster of about 150 stars. As usual, best seen in binoculars or low power telescope eyepiece.

Galactic Cluster M44 – The Beehive or Praesepe

A famous open cluster in Cancer, and at magnitude 3.3, easily visible to the naked eye. It has about 350 stars, 40 of which are visible in good binoculars or a small telescope.

Galactic Cluster M47

In the southern hemisphere and therefore often forgotten, this 5th magnitude open cluster is visible to the naked eye under good conditions. It’s about half a degree in diameter and worthy of your attention. An excellent object for binoculars.

Galactic Cluster M48

Nearer to the celestial equator than M47 and at 5th magnitude, this open cluster contains about 80 stars within a 50 arc minute circle.

Galactic Cluster M50

The last of the clutch. 6th magnitude and containing about 200 stars. It’s about one third the apparent diameter of the Moon so is more compact and easier to see than some of the others. A fine sight in high power binoculars or a telescope on medium power.

And finally, while you’re out there, have a look at Castor, the second brightest star in Gemini. It’s the higher one of the pair, Castor and Pollux. A telescope will soon show it as a double (magnitudes 1.9 and 3.0) separated by about 6 arc seconds. However, it is actually a fascinating multiple star system comprising three doubles. The Wikipedia description of it is worth a read.

Man’s Space Activities

Spotting the International Space Station (ISS)

The ISS will be visible on numerous occasions during the year. The Heavens Above web site gives details for the very date it can be seen. The link above is preset to return the data for sightings from York. Use the left and right chevron buttons to change the date range.

Perseverance landing

18 February means touchdown for NASA’s latest Mars rover, Perseverance and helicopter, Ingenuity. The 4×4 sized mobile science lab will employ a complex landing sequence featuring a sky crane. A series of cameras on the rover will record the event so you can marvel at this real feat of engineering taking place on another planet! Perseverance will study Martian soil for past and present signs of life and test out new technology for future human missions. Check out this NASA site for the latest updates and live coverage.

General Space News

There’s always something of interest going on in space. See the space.com web site for the latest news. And for a detailed timetable of projected launches and other space-related activities, the Wikipedia web site is an excellent place to start as it has links to each project/mission mentioned.

Note particularly that the James Webb Space Telescope (JWST) is due to be launched in October. This enormous telescope is a marvel of engineering as well as being the largest telescope by far to be positioned at the Sun-Earth Lagrange 2 point, nearly a million miles from Earth.

I wish you clear skies and good viewing. Stay safe.

John Rowland

 

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