Capture the asteroid 3 Juno at its best

All oppositions are not equal. This week's celestial target is a good example, as the asteroid 3 Juno reaches its most favorable viewing position of the decade.

Juno in 2018

Juno reaches the opposition on Thursday 16 November^th, 2018 around 10:00 pm UT or 5:00 pm Eastern Standard Time (EST). This means that the asteroid gets up against the setting sun this week and climbs higher into the sky as it pbades through the south. It is also approaching the Earth about 14 hours before, on the same date, 159 million kilometers. From northern latitudes north, the asteroid pbades 45 degrees above the southern horizon at its highest level. The asteroid slowly crosses the constellation of the Eridanus River until the end of the year 2018, before entering the southern part of Taurus Taurus in early 2019.

3 Juno shines at a magnitude of +7.5, a shade brighter than usual, making it a telescopic or binocular object. Although the asteroid orbiting the Sun once every 4.4 years, it ranges from a perihelion of 2 astronomical units (AU) to the Sun to a 2.7 AU in the belt. 39; asteroids. With an orbit angled 13 degrees from the ecliptic, the shy Juno only gets a favorable opposition once every 13 years. Witness from last year unfavorable the opposition, when Juno lost two full magnitudes (more than six times) weaker, at a magnitude of +9.8.

This is the best viewing season of June 3 since 2005 and the best until its favorable pbadage of 2031. In fact, at 1,036, the appearance of 2018 is one of the best for the 21^st century, nudging out 2005 (1,063 AU) and 2031 (1,044 AU).

3 Juno was discovered by astronomer Karl Ludwig Harding on the night of September 1^st, 1804, using a small 5 centimeter refractor telescope at the Lilienthal Observatory in Bremen, Germany. This pbadage was also a favorable view of perihelion at 1.17 AU distance, leading to an early discovery of the 11^th the largest asteroid. Strange but true: at the beginning 19^th century, the large asteroids Ceres, Vesta, Pallas and Juno were all briefly considered planets in their own right!

Observing Juno

Watch 3 Juno a little more than one degree (two diameters of full moon) from +4.5 stars 32 Eridani the night of opposition, moving about 15 '(a quarter) of degree) per day. The asteroid is far too small to display a visible disc. watch his movement on the starry background of successive nights instead.

3 Juno also seems to have an interesting story to tell. It has a relatively high surface reflectivity (called albedo) of 24%, which is brighter than most stony chondrite asteroids. Sallie Baliunas, of the Harvard-Smithsonian Astrophysical Center, used an adaptive optical device on the 100-inch Hooker telescope based at the Mount Wilson Observatory. side. By rotating every 7.2 hours, it seems that the 3 Juno has had a significant impact in the not-too-distant past. This asymmetrical feature is consistent with the occultation observations of June 3 reported by amateur observers. 3 Juno was actually part of the very first occultation of a background star captured by amateurs on February 19^th, 1958.

3 Juno invites us to continue our exploration. For the moment, be sure to see this strange member of the solar system at its best.