Derekscope

• The Ursid meteor shower will peak on the night of Sunday 21st thru Monday 22nd December 2025, with the best viewing hours from late evening through dawn.
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• Look northward – Meteors can appear anywhere, but they radiate from near the Little Dipper in the constellation Ursa Minor.
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• The 2025 winter solstice occurs on Sunday 21st December at 15:02 GMT (3:02 PM) in the UK ~ this marks the official start of astronomical winter and the shortest day of the year.
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• The winter solstice happens when the Sun reaches its lowest point in the sky at noon, resulting in the shortest daylight period of the year.
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Algol Minima
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• The bright variable star Beta Persei (Algol) reaches its minimum brightness at 21:38 pm in the evening on Saturday 20th December and will be visible from the UK.
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• Here’s a list of upcoming minimum brightness times for Algol – read more.
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Algol
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• The bright variable star Beta Persei (Algol) reaches its minimum brightness at 00:49 am in the early morning on Thursday 18th December and will be visible from the UK.
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• Here’s a list of upcoming minimum brightness times for Algol – read more.
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• The Moon and Mercury will be in conjunction, sharing the same right ascension.
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• However, they will not be easily visible from the UK due to low altitude and daylight timing.
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Algol Minima
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• The bright variable star Beta Persei (Algol) reaches its minimum brightness at 04:00 am in the early morning on Monday 15th December and will be visible from the UK.
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• Here’s a list of upcoming minimum brightness times for Algol – read more.
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• NGC 2420 known as a “twinkling comet cluster” and is a rich open cluster in Gemini, about 8,200 light-years away.
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• It’s not associated with comets, though its dense, glittering stars may poetically resemble a “twinkling comet cluster.”
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• Between Sunday 14th – Tuesday 17th December 2025, Jupiter remains over 3° south of NGC 2420, too far for a conjunction or close visual pairing.
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• This separation is significant – not close enough for binocular framing, though both are in Gemini.
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• The Geminid Meteor Shower reaches its peak on the night of 13th thru 14th December, with excellent viewing conditions this year.
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• The Moon, only 39% illuminated, will rise late around 23:30, providing minimal interference from moonlight.
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• Best viewing from mid-evening (after 9pm) through pre-dawn hours – the radiant is in the constellation Gemini, rising in the northeast.
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• Jupiter’s largest moon, Ganymede, will slip into Jupiter’s shadow at midnight, disappearing from view in telescopes.
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• This rare eclipse begins around 11:30pm on Saturday midnight – watch as Ganymede fades into darkness.
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• The Moon appears half-illuminated, with the left side 50% lit in the constellation Leo ~ it’s the final quarter of the lunar cycle, leading toward the New Moon on Saturday 20th December 2025.
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