by Rex Parker, Director

Eyes and Instruments on Solar System Astronomy in 2019. A wonderful way to receive the new year’s promise of discovery is to get outside and engage in astronomy during these cold winter nights. Observing with whatever scope you have is best, and of course AAAP members have top notch instruments available at Washington Crossing Observatory. Historically our club has thrived on a steady diet of cosmology, but recent trends in solar system and exoplanetary astronomy are en vogue now for us as well as the professional community at Princeton and beyond.

This might reflect the remarkable and numerous exoplanet discoveries by NASA’s Kepler mission. The heliophysical boundary has recently been traversed by Voyager 1 & 2. Astrobiology and the origin of life is a hot, emerging interdisciplinary field in the scientific community. Both the Voyager and Cassini missions have revealed that Saturn’s moon Enceladus has conditions that are likely suitable to the origin extraterrestrial life. Ground-based telescopes have enticed the imagination with sightings of the enigmatic interstellar visitor, Oumuamua. NASA’s OSIRIS-REx arrived at the asteroid Bennu on Dec 3 after a 1.2 billion mile journey. The “Asteroid Redirect” project is advancing at NASA as a component of a future Mars mission. New data suggest hundreds of thousands of 100km class icy objects orbit within the Kuiper belt (outside Neptune) – and perhaps billions of comets! And the first human approach to a Kuiper belt object will happen around New Year’s Day, when NASA’s New Horizons spacecraft encounters the Kuiper Belt object “Ultima Thule”. The stage is set for the new year 2019 to fulfill a great potential for further advances in astronomy and allied sciences.

My First Asteroid. The idea that there are more, far more, solar system objects than commonly believed hit home for me this December. I had collected telescope imaging data overnight, photographing the seldom seen nebula LBN 741 located near the variable star Algol in the constellation Perseus. The LBN catalogue (Lynd’s Bright Nebulae) can be loaded with the database manager subroutine in TheSkyX software at AAAP Observatory. LBN 741 is a colorful though faint nebula unusual in having both emission and reflection components making it glow red and blue. When processing the data, a moving object that didn’t fit the main star chart jumped out. Might it be an asteroid? To check this I loaded The SkyX’s Large Asteroid Database (currently 789983 objects, available online from the Minor Planet Center of the Smithsonian Astrophysical Observatory) and set the Date/Time fields to match the image files. From this it was clear that I’d taken a photograph of Asteroid 584 Semiramis while it was crossing through Perseus that night, Dec 9. Semiramis of antiquity was the legendary queen regent of Babylon in the Assyrian empire in the 800’s BC. Semiramis of astronomy is a minor planet orbiting the sun in the main asteroid belt between Jupiter and Mars. It was discovered in 1906 and has since been found to have a radius of ~26 km, orbital period 3.7 years, rotation period of 5 days, and magnitude ~11 at the time of these images. Below is a video assembled from frames from the imaging, showing Semiramis moving across the field of the nebula over a couple of hours (taken with 12.5” telescope at f6.7 with SBIG-ST10 CCD camera). The finished astrophoto below the video link is LBN-741 showing its colors after about 18 hours of total data collection.

Asteroid Semiramis moving across the field ofLBN-741 in Perseus. Taken by Rex Parker with 12.5” f6.7 Cassegrain telescope and SBIG-ST10 CCD camera.

LBN-741 emission/reflection nebula in the constellation Perseus. The moving asteroid seen in the video has been “averaged out” in processing the final image. Astrophoto by Rex Parker from central NJ; taken with 12.5” f6.7 Cassegrain telescope and SBIG-ST10 CCD camera.