Jared May: What's Up the last week of 2020

The wild year of 2020 is about to come to an end. This year gave lots of interesting and unique objects and events to look for in the night sky from comets to ultra-rare planet conjunctions. Hopefully 2021 is a friendlier year and will give great opportunities to explore the night sky.

The weather this week is once again classic Ohio for this time of year – cloudy and cold. There may be some gaps in the clouds on some nights. Sunset occurs just after 5:15 PM, so this time of year makes the night sky very accessible to busy people since you can see what’s up in the sky just after dinnertime.

This week gives us the full moon, the rising Christmas Tree Cluster, and Betelgeuse high in the sky. Read below for advice on how to shoot “star trail” images which are great for beginner astrophotographers and people looking to take easy yet impressive space pictures.

Tuesday will be the full moon. Since this means the moon will be opposite of the sun, it can be spotted rising just after sunset and setting right before sunrise. The full moon shines at a blinding -12 magnitude so many fainter objects in the sky will be washed out. If you decide to look at the lunar surface details through a telescope or binoculars, try buying a lunar filter (usually pretty cheap – it just “dims” the moon) or allow for lots of time for your eyesight to readjust to the darkness.

No more than 10° to the southeast of the rising full moon is the Christmas Tree Cluster that shines at magnitude 3.9. This open cluster makes a great target for binocular users as it is large and is comprised of brighter, easier to spot stars. In general, open clusters are made of several very bright blue stars that have all formed near each other and at around the same time. Their bright blue color is an indicator that the stars are young and extremely hot. The view will get better as the moon slides out of the way later in the week.

The moon, Orion, and the location of the Christmas Tree cluster, as seen on New Year’s Eve.

The famous star, Betelgeuse, crosses the zenith (an imaginary line drawn across the sky from north to south) at almost exactly midnight. This unmissable star is among the first to show after sunset low in the eastern skies. Betelgeuse glows a bright orange at magnitude 0.5 and makes up Orion’s right shoulder. This red supergiant is about 15 times the mass and 900 times the radius of the sun, and lives roughly 643 light-years away. The light you are seeing from Betelgeuse in your backyard left the star in the year 1377! This red beast is nearing the end of its life and is expected to explode (go supernova) anytime in the next 100,00 years (very short on the cosmic timescales).

At center, Betelgeuse, the bright orange star that forms the armpit (yes, the armpit) of the great hunter Orion.

Astrophotography is an art and science that pushes photography techniques, technology, and skill to their limits. Many practitioners of the art invest huge amounts of money and time to milk celestial images out of the faint light from space. However, there are many possibilities for taking impressive astro-photographs that do not require thousands of dollars’ worth of equipment.

The photographs that most impress me are star trail images. These images show long streaks in the sky caused by the stars’ apparent rotation about the North Star. The equipment that is required to take these images include a tripod, a DSLR, and a cheap intervalometer (if the camera doesn’t have an onboard timer/intervalometer). Equip a wide-field lens to your camera to start (18mm kit lenses work great). Frame up the shot you wish to take and set your ISO to 400-1600 (depending on the light pollution) and take 3 to 15-second-long exposures. Be sure to check the camera’s focus and that you are shooting JPG. RAW images are usually recommended and very high quality but difficult to batch process quickly. Use your intervalometer or onboard timer to loop these 3-15 second exposures for 90 minutes – be sure not to move the camera once this process has begun. Download and install the free software, StarStaX. Upload your images here and begin editing them and processing them. The software is very intuitive and straightforward. After adjusting the settings to your liking, you will have an impressive star trail image.

Jared May’s star trail image showing the region around the north celestial pole.

The weather this week may not be conducive to beautifully clear nights, but there may be some gaps in the clouds for some quick observing. The nighttime temperatures are in the 20s and 30s and frost may form on your astronomy equipment so be prepared. Be on the lookout this week for the bright full moon, the Christmas Tree Cluster, and Betelgeuse. Perhaps on a clear night in the near future try imaging some star trails and impress your friends and family. The new year will definitely give some interesting astronomical events so stay tuned. Clear Skies!