Planets
Mercury
Mercury passes through inferior conjunction on the 6th December and reaches greatest western elongation on the 25th. It is then a morning object. However, its southerly declination of -20o will make it hard to see in the northern hemisphere.
Venus
Venus remains an evening object with a magnitude of – 4.3 and it’s elongation increases to 47o, with a phase dropping to around 60%, and a l diameter of 20”. As with Mercury, it’s southerly declination also makes it hard to view as it is low in the sky after sunset, but can be seen if you have a good western horizon.
Mars
This is in Gemini and near Castor and Pollux. It rises about 7pm and so is well placed before midnight now. Its magnitude increases to -1.1 throughout the month and its diameter increases to 14 arcsec during the month. Its approximate position is RA 8h 30m, Dec +22o, but is easy to see in the south-east as its red colour will make it easy to identify.
Jupiter
Jupiter reaches opposition on 7th December and is therefore observable throughout the night. It is unmistakable, with a magnitude of -2.8, making it a great telescope object, so do get observing!
Saturn
Saturn is well past opposition but still visible throughout most of the evening. The rings have a tilt of about 4o. This could make a nice photo. It is still a bit low in the sky. Look for Titan, its brightest and biggest satellite which orbits every 16 days. On 8th December Saturn is 0.3o South of the Moon.
Uranus
Uranus is observable throughout the night (RA: 3h 28m, Dec +18.5o). It reached opposition in November. Its magnitude is +5.6 and diameter 3.8”.
Neptune
Neptune reached opposition in September, with a diameter of 2.4” and mag. +7.8.
Its approximate position is RA 23h 50m, Dec -2.4o. On the 9th, Neptune is about 0.8o south of the Moon. This should make it easier to find.
Anyone wishing to Uranus and Neptune, and who would like more details, should contact me at coord@cotswoldas.org.uk
Moon
30th December: New Moon 8th December: Moon is at First Quarter
15th December: Full Moon 22nd December: Moon is at last quarter
Sun
The Sun is remains active currently, so watch out for large Sunspot groups. Remember to never look at the Sun directly without a proper solar filter.
Aurora
The Sun is around its maximum activity and may produce more aurorae. I suggest you download an aurora alert App, such as Aurora Pro. The darker nights mean that there is a much better chance of seeing them.
Meteors
The Geminid meteor shower occurs between 4th and 17th of this month, reaching their maximum around the 13th. Unfortunately, that is just before full Moon, making this display less favourable. The ZHR can reach 100. You may still get to see the brighter ones.
The Ursid meteor shower is from the 17th to 26th of December and is therefore more favourable. Although the typical ZHR is only around 10, the shower does produce some outbursts, the last being in 2000 and 2014.
Dark Sky Objects
The long dark nights make deep sky objects much more accessible – if only the clouds get out of the way!
The Milky Way is well placed for photography and the Andromeda Galaxy (M31) is high in the sky, making it a good target for photography. A wide angle shot could take in the Milky Way as well. The Perseus Double Cluster is also high in the sky. The Pleiades and Taurus are getting well-placed for observing and photography, and Orion will soon be visible in the evening skies.
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