A little known periodic comet graces northern hemisphere summer skies.
Short summer nights present a tough dilemma for nighttime astronomy: to stay up late, or wake up early? Summer 2024 gives you at least one reason to opt for the former, as periodic Comet 13P/Olbers graces the evening sky.
The comet was first spotted on the night of March 6th, 1815 by astronomer Heinrich Olbers (of Olbers’ Paradox fame) observing from Bremen, Germany. The orbit was later described by Carl Gauss and Friedrich Bessel as just shy of 74 years, about five years off of the present value.
A sketch of Comet 13P Olbers from 1887 by William Robert Brooks. Credit: Public DomainComet 13P/Olbers is on a 69 year orbit, which takes it from a perihelion 1.175 Astronomical Units (AU) from the Sun just outside of the Earth’s orbit, out to an aphelion of 32.5 AU out beyond the orbit of Neptune.
Perihelion for the comet occurs June 30th, 2024 at 1.175 AU from the Sun and 1.919 AU from the Earth.
The orbit of Comet 13P Olbers. Credit: NASA/JPLIn 2024, Comet 13P Olbers loiters low to the west this summer for northern observers at dusk. This is because it’s approaching Earth along our line of sight. The comet will seem to hang about 20-30 degrees above the horizon on summer evenings for mid-latitude northern hemisphere observers.
The location of the comet in the evening sky in mid-June. Credit: StellariumHere’s our look at what to expect from the comet month-by-month. Unless otherwise noted, ‘Passes near’ means a closest approach of less than one angular degree:
17-The orbital path of the comet is edge on as seen from our point of view, and the comet may exhibit a spiky anti-tail.
19-Passes into the constellation of the Lynx.
28-Passes near the +4.3 magnitude star 31 Lyncis.
The celestial path of the comet through September 1st.5-Passes near the +4th magnitude star 10 Ursae Majoris. (note: 10 Uma is one of the several ‘stray stars’ littered across the sky that found themselves on the wrong side when constellation borders were formalized in 1922. Thus, the star calls Ursa Major its home constellation, though it’s now located in the Lynx(!)
9-Crosses into the constellation Ursa Major.
11-Crosses back into the Lynx.
13-Crosses into the constellation Leo Minor.
20-Passes closest to Earth, 1.876 AU distant.
28-Crosses back into the constellation Ursa Major.
The observed and projected light curve for Comet 13P Olbers. Credit: Weekly Information on Bright Comets. 13-Crosses into the constellation Coma Berenices.
14-Passes in front of the open star cluster Melotte 111.
16-Passes 1.3 degrees from the +4.3 magnitude star Gamma Coma Berenices.
19-Passes near the +10th magnitude galaxy NGC 4565.
21-Passes three degrees from the North Galactic Pole.
25-Passes near the +9th magnitude galaxy Messier 65 (the Black Eye Galaxy).
1-May drop back down below +10th magnitude.
Observing a comet like 13P Olbers is as simple as sweeping the suspect target field at low power, and looking for a tiny ‘fuzz ball’ that’s out of place. Binoculars work great in the regard. Visually, binocular comets in the +6th to +10th magnitude range look lots like a bright globular cluster that stubbornly refuses to snap into focus. It was for this very reason that French astronomer Charles Messier established the first rough deep sky catalog in 1774, to mark the ‘false comets’ in the sky.
One thing’s for sure: we’re definitely due for the next naked eye ‘Great Comet’ for the 21st century… in the meantime, be sure to hunt down comet 13P Olbers on its 2024 apparition.
