Sky Notes for February 2020

The moon this February

The Full Moon on the 8th / 9th is called a Supermoon by some, it should be large. That’s because it is at the Perigee of its orbit, the closest it gets to Earth. When it’s at its furthest from us, its Apogee, it looks its smallest. However, as this slide from NASA shows, the difference in size is not that great. Based on the American Indian name, this is a “Snow Moon” – because it’s cold and snowy in North America at this time.

Comparison of Perigee and Apogee moon sizes

The planets

Mercury and Venus are currently evening planets, whereas Mars, Jupiter and Saturn are morning planets.

Mercury

Mercury’s orbit is closer to the Sun than the Earth’s – so it always appears close to the Sun and therefore difficult to observe. At its greatest separation from the Sun (its greatest elongation), it is observable. When Mercury lies to the East of the Sun it rises shortly after the Sun, and therefore remains invisible. It sets a short time after the Sun, so it will be visible at twilight. The best time for this will be next Monday (the 10th) at 6:30 in the evening when Mercury will look like a small orange dot.

One word of warning! If you do want to use your telescope to view Mercury, please wait until the Sun has dropped below the horizon before pointing your telescope anywhere near that area.

The locations of Mercury and Venus

Jupiter

Jupiter will be at -1.8 magnitude near the waning crescent moon at about 0700 on the 19th. A low South-East horizon is needed, and the depth of atmosphere hinders the seeing. Just East of South you can see the Moon, and to its East: Jupiter. Mars and Saturn are also in the picture, but I doubt at that time there will be sufficient darkness to identify them.

As big as Mercury, and indeed the third largest moon in the solar system, is Jupiter’s Callisto. It is Jupiter’s second-biggest moon (behind Ganymede) and smaller than Saturn’s Titan. On 26th February it will pass in from of Jupiter and can be seen (through a telescope) between 0630 and 0940.

The location of Saturn, Jupiter and Mars

Orion

Orion continues to dominate the evening sky in February.

The three stars that makeup Orion’s belt: ALNITAK, ALNILAM and MINTAKA, are easy to spot. South of them, and less easy to spot with the naked eye, is Orion’s sword. This area is known for M42 – the Orion Nebula, but in fact, the whole region is a great star-forming mass.


The Running Man Nebula

There is the Running Man Nebula, the Flame Nebula, the Horsehead Nebula and the Angelfish Nebula, to name just four more. Aiming your scope and moving around the area should provide some great views,but unless you have programmed your Raspberry Pi to control the Hubble Space Telescope, you’re not going to get a shot as good as this.

Moving West from Orion, past the Moon, past Taurus and the red/orange star ALDERBARAN, we come to The Pleiades – the Seven Sisters or Messier Object 45. This is a wonderful cluster of hot middle-aged stars. So a bit like Madonna. In their case, they probably formed in the last 100 million years and were probably more compact, rather like the Orion Nebula. They should be around for another 250 million years, after which they’ll disperse. So you have plenty of time to catch up with them. They are about 400 light-years away, and the nebula probably consists of over 3,000 stars.

Further prominent February constellation

Moving West towards Cassiopeia, we first come to our nearest major galaxy – Andromeda. A spiral galaxy numbered M31 about 2.5 million light-years away. Near the W of Cassiopeia is the “Double Cluster”. These are visible to the naked eye, and most impressive through even a low-powered scope. There are more than 300 blue-white super-giant stars, and the entire halo surrounding the clusters probably consists of over 20,000 solar masses.

Messier 33 – or the Triangulum or Pinwheel galaxy – is the third-largest galaxy in our local cluster, after our Milky Way and Andromeda. Even so, it is considered to be a satellite of Andromeda.

Just for completeness, here is the view to the North with Ursa Major – part of the Great Bear constellation. Polaris at the tip of Ursa Minor is a good alignment star for those with GoTo scopes.

ALCOR and MIZAR in the handle of Ursa Major are a “naked eye double”.

The locations of February constellation

Credit Phil Morris EAS.

See also Ian Morison’s Night Sky this Month on the Jodrell Bank site.



Boundary Bank where we meet (click to enlarge)

Next Observing Evening

Proposed observing Evenings Thursday January 16th

  • UPDATE Tuesday January 14th 6pm, – forecast is looking very poor – 100% cloud and heavy rain. It’s not looking good.
  • UPDATE Thursday January 16th 12pm – all my apps are saying 100% cloudy with strong winds and showers. Sorry, it isn’t going to happen.
  • Time: 6PM onwards
  • Place: Boundary Bank Lane car park
Watch here for updates as the weather conditions dictate when we can meet for an evening of observing. The Traffic Light System:
  1. When the forecast looks feasible the text here will change from red to amber.
  2. On the proposed afternoon, if and when the observing session is confirmed (by 4:30PM), the text will confirm the time and change from amber to green.
DO NOT TURN OUT IF THIS TEXT IS OTHER THAN GREEN, as there won’t be anyone there!