Asteroid 2 Pallas at opposition

Dominic Ford, Editor
From the Asteroids feed


Objects: 2 Pallas

Asteroid 2 Pallas will be well placed, lying in the constellation Delphinus, well above the horizon for much of the night.

Regardless of your location on the Earth, 2 Pallas will reach its highest point in the sky around midnight local time.

From Fairfield, it will be visible all night. It will become visible at around 21:13 (EST), 43° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 00:13, 63° above your southern horizon. It will be lost to dawn twilight at around 04:40, 26° above your western horizon.

The geometry of the alignment

This optimal positioning occurs when it makes its closest approach to the point in the sky directly opposite to the Sun – an event termed opposition. Since the Sun reaches its greatest distance below the horizon at midnight, the point opposite to it is highest in the sky at the same time.

At around the same time that 2 Pallas passes opposition, it also makes its closest approach to the Earth – termed its perigee – making it appear at its brightest in the night sky. This happens because when 2 Pallas lies opposite to the Sun in the night sky, the solar system is lined up so that 2 Pallas, the Earth and the Sun lie in a straight line with the Earth in the middle, on the same side of the Sun as 2 Pallas.

On this occasion, 2 Pallas will pass within 2.502 AU of us, reaching a peak brightness of magnitude 9.4. Nonetheless, even at its brightest, 2 Pallas is a faint object beyond the reach of the naked eye; binoculars or a telescope of moderate aperture are needed.

Finding 2 Pallas

The chart below indicates the path of 2 Pallas across the sky around the time of opposition.

It was produced using StarCharter and is available for download, either on dark background, in PNG, PDF or SVG formats, or on a light background, in PNG, PDF or SVG formats.

The position of 2 Pallas at the moment of opposition will be as follows:

Object Right Ascension Declination Constellation Magnitude
Asteroid 2 Pallas 20h31m40s 14°17'N Delphinus 9.4

The coordinates above are given in J2000.0.

The sky on 9 Aug 2025

The sky on 9 August 2025
Sunrise
05:53
Sunset
19:59
Twilight ends
21:46
Twilight begins
04:06


Waning Gibbous

98%

16 days old

Planets
Rise Culm. Set
Mercury 05:01 12:01 19:01
Venus 02:59 10:25 17:51
Moon 20:04 00:54 05:52
Mars 09:41 15:44 21:47
Jupiter 03:07 10:36 18:06
Saturn 21:51 03:48 09:44
All times shown in EDT.

Source

The circumstances of this event were computed from orbital elements made available by Ted Bowell of the Lowell Observatory. The conversion to geocentric coordinates was performed using the position of the Earth recorded in the DE430 ephemeris published by the Jet Propulsion Laboratory (JPL).

The star chart above shows the positions and magnitudes of stars as they appear in the Tycho catalogue. The data was reduced by the author and plotted using PyXPlot. A gnomonic projection of the sky has been used; celestial coordinates are indicated in the J2000.0 coordinate system.

Image credit

© European Southern Observatory 2021. Credit: ESO/M. Kornmesser/Vernazza et al./MISTRAL algorithm (ONERA/CNRS).

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