December full moon

 The traditional name for the full moon of December is the "Cold Moon".  Full moon occurred near 2 am MST on 15 Dec.  These images were taken more than 15 hr later with an AT72EDII refractor (432mm FL, f/6).

Cold Moon rising over the Sangre de Cristo mountains.

Four hours later, above the clouds:

Jupiter is the second brightest object in the sky at this hour.

Jupiter (overexposed) and its Galilean moons (from LL):  Callisto, Europa, Io, Ganymede.

The four Galilean moons can be seen with very modest equipment.  I was able to spot them easily with a tripod-mounted 50-mm refractor at 10 x.  Twenty power (20 x) is enough to see not only the moons but the disc of Jupiter as well.  The moons should be visible with a 7x50 binocular if the instrument is on a stable mount.  I tried to spot them hand-held, but there is too much shake.  The telescope that Galileo used was a 20x30mm refractor (20 power, 30 mm diameter).

Another look at the seventh planet. Trying out a new "filter".

 Now is a good time to look for the seventh planet, Uranus.  It is about as bright as it ever gets, and it is near a celestial landmark, the Pleiades, which makes it relatively easy to find.

Uranus was discovered to be a planet by the English astronomer William Herschel in 1781.  He gave it the name "Georgium Sidus".  It wasn't until 1850 that its present name, Uranus, became universally accepted.

The Pleiades (left) and Uranus (white circle).  Olympus E-M5iii + Sigma 56mm f/1.4 + softon filter.  ISO 800, 15 s at f/2.8.

Uranus was easily visible in 6x30 binoculars, but not with a 1.8x40 wide-field binocular.  City lights and the quarter moon were too much for the low-power instrument to overcome.

The new "filter" that was tried was the Omegon cross-star plate for the Seestar S50.  It consists of two crossed wires.  The effect mimics the diffraction pattern created by the typical four-vaned secondary-mirror support of Newtonian and Cassegrain-type reflectors.

The Pleiades with the Omegon cross-star filter.

Hoya Softon-A filter.

No filter.

Omegon cross-star filter.

Aldebaran and the Hyades cluster.  Cross-star filter.

Softon filter.

The sky brightness was not measured for this session.  The quarter-moon was still high in the sky and there appeared to be a thin cloud layer.

Moon, Venus, Jupiter, Uranus

Back in Santa Fe for the winter.

 Venus, at magnitude -4.2, is the second brightest object in the night sky , after the moon.  Both have been close together recently in evening twilight.

Moon and Venus.  05 Dec.  E-M5iii + Sigma 56mm f/1.4

The third brightest object in the night sky is Jupiter.  Jupiter is near opposition, meaning that it crosses the meridian around midnight.  It currently shines at magnitude -2.8.

Jupiter, the Hyades, and Pleiades.  The white circle is centered on Uranus.  Lumix 20mm f/1.7 lens, softon filter.

The planet Uranus is near the Pleiades and shines at magnitude 5.6.  This means it should technically be visible to the unaided eye at a dark-sky location.  That would rule out urban Santa Fe, which had a sky brightness of sqml=19.75 last night.  It should be easy to find with binoculars, however.  I was able to spot it with a 6x30 binocular, an 8x32 monocular, and a 7x50 binocular.