This is the Dudley Observatory Skywatch Line for Wednesday, December 2nd, and Thursday, December 3rd, written by Louis Suarato.
The 93% illuminated, waning gibbous Moon rises in Gemini at 9:11 p.m., Wednesday. Its most prominent feature during this phase is The Sea of Tranquility, or Mare Tranquillitatis. This bluish basin of basalt is thought to have been formed by a very large impact to the lunar surface about 3.9 billion years ago. After the impact, the basin was flooded with basalt. The Sea of Tranquility has a diameter of 542 miles, and an elevation range of over 1,600 feet. This mare was the landing site of Apollo 11, which featured the first humans to walk on the Moon. Last week China launched a spacecraft toward the Moon, which includes a lander designed to locate an ideal spot for a human colony. The mission, Chang’e-5, from launch to specimen recovery, is expected to be competed in less than 1 month.
Get out your PST’s (Personal Solar Telescopes)! The Sun has become active with sunspots again. After a longer than normal period of inactivity, known as solar minimum, large sunspots are returning. We are entering the 25th solar cycle since enough data was collected to determine that sunspots vary from minimum to maximum activity every 11 years. This cycle is expected to peak in 2025. Sunspot AR2786 is currently facing Earth, but will soon rotate out of view. If this sunspot erupts and sends a solar flare our way, it could cause aurorae. Follow www.spaceweather.com for updates.
In addition to PST’s, there are several other safe ways to observe sunspots. One device is known as a Herschel White Light Wedge. A Herschel Wedge is a diagonal that is placed between the telescope and eyepiece. Inside the diagonal is a prism that refracts most of the light away from the eyepiece. A lesser expensive alternative is a glass filter designed to fit the front of your telescope. These glass filters display a more natural yellow-orange image of the Sun. You can also purchase filters containing Baader film. Baader film allows only white light to filter through your optical device. Baader film can also be purchased separately, and constructed to fit your telescope or binoculars. Several websites provide instructions for making frames for Baader film.