Cold Supermoon 2025
This month we saw the final — and brightest — supermoon of 2025. The full moon in December gets the name "Cold Moon". Really.
The moment of full moon occurred at 07:13 GMT on December 5, when the Sun, Earth, and Moon align in a nearly straight line. At that time, the Moon’s reached its roundest phase.
Just hours earlier, at 19:07 on December 4, the Moon reached its closest point to Earth. With only around 12 hours separating the Moon’s closest approach and its roundest phase, this rare overlap made the full moon appear about 7.9% larger and 15% brighter than usual.
Although the Moon is perfectly full for only a moment, it remains nearly just as bright and round for about two days around the peak. If skies are clear, you may notice its subtle “magnified effect” with the naked eye. In the evening or early morning there is a radiant, low-hanging winter moon that feels as if it has quietly drifted one step closer. In the middle of the night it will as high in the sky as it can get.
Fortunately, my Seestar S50 can look up. This is what it saw at around midnight.
Two minute video, aligned and cropped in PIPP, stacked in AutoStakkert! 4, then AstroSurface for sharpening and colour saturation. Photoshop CS4 for labels.
Cold Supermoon 2025
This month we saw the final — and brightest — supermoon of 2025. The full moon in December gets the name "Cold Moon". Really.
The moment of full moon occurred at 07:13 GMT on December 5, when the Sun, Earth, and Moon align in a nearly straight line. At that time, the Moon’s reached its roundest phase.
Just hours earlier, at 19:07 on December 4, the Moon reached its closest point to Earth. With only around 12 hours separating the Moon’s closest approach and its roundest phase, this rare overlap made the full moon appear about 7.9% larger and 15% brighter than usual.
Although the Moon is perfectly full for only a moment, it remains nearly just as bright and round for about two days around the peak. If skies are clear, you may notice its subtle “magnified effect” with the naked eye. In the evening or early morning there is a radiant, low-hanging winter moon that feels as if it has quietly drifted one step closer. In the middle of the night it will as high in the sky as it can get.
Fortunately, my Seestar S50 can look up. This is what it saw at around midnight.
Two minute video, aligned and cropped in PIPP, stacked in AutoStakkert! 4, then AstroSurface for sharpening and colour saturation. Photoshop CS4 for labels.