Key Takeaways:
- Observation guidance is provided for the open cluster M103 in Cassiopeia, identifiable at magnitude 7.4, 1° northeast of Delta Cas.
- M103 is characterized as spanning approximately 6' in angular diameter, containing several dozen bright stars, positioned between 8,000 and 9,000 light-years from Earth, and estimated to be between 9 and 25 million years old, featuring a prominent central red giant.
- A specific celestial event, Titan's transit across Saturn, is noted for November 6, 2025.
- Astronomical ephemerides for November 6 include sunrise (6:36 A.M.), sunset (4:50 P.M.), moonrise (6:22 P.M.), moonset (9:29 A.M.), and a 90% waning gibbous moon phase, specified for 40° N 90° W.
Looking for a sky event this week? Check out our full Sky This Week column.
November 6: Titan treks across Saturn
Let’s look to Cassiopeia tonight to observe the open cluster M103. Shining at magnitude 7.4, you can find this group near magnitude 2.7 Delta Cas. Simply center this star in binoculars or a small telescope, then move 1° northeast to your target.
Spanning about 6’ on the sky, M103 contains a few dozen bright stars. At some 8,000 to 9,000 light-years from Earth, it’s one of the more distant open clusters that appears on Messier’s list. M103 is likely about 25 million years old, though that number is fairly uncertain and some estimates put it at a much younger 9 million to 12 million years.
Note the bright red giant in the rough center of this cluster — its hue may appear red or orange compared with the blue-white stars around it.
Sunrise: 6:36 A.M.
Sunset: 4:50 P.M.
Moonrise: 6:22 P.M.
Moonset: 9:29 A.M.
Moon Phase: Waning gibbous (90%)
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 10 P.M. local time from the same location.
