© NASA/Galileo 1993. Pictured asteroid is 243 Ida.

Asteroid 89 Julia at opposition

Dominic Ford, Editor
From the Asteroids feed

Please wait
Loading 0/4
Click and drag to rotate
Mouse wheel to zoom in/out
Touch with mouse to dismiss
The sky at

Asteroid 89 Julia will be well placed for observation, lying in the constellation Aquarius, well above the horizon for much of the night.

Regardless of your location on the Earth, 89 Julia will reach its highest point in the sky around midnight local time.

From Cambridge, it will be visible between 21:40 and 03:51. It will become accessible around 21:40, when it rises to an altitude of 21° above your south-eastern horizon. It will reach its highest point in the sky at 00:48, 36° above your southern horizon. It will become inaccessible around 03:51 when it sinks below 21° above your south-western horizon.

Begin typing the name of a town near to you, and then select the town from the list of options which appear below.

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 89 Julia 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 89 Julia lies opposite to the Sun in the night sky, the solar system is lined up so that 89 Julia, the Earth and the Sun lie in a straight line with the Earth in the middle, on the same side of the Sun as 89 Julia.

On this occasion, 89 Julia will pass within 1.137 AU of us, reaching a peak brightness of magnitude 8.8. Nonetheless, even at its brightest, 89 Julia is a faint object beyond the reach of the naked eye or binoculars; a telescope of moderate aperture and a good star chart are needed.

Finding 89 Julia

The chart below indicates the path of 89 Julia 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 89 Julia at the moment of opposition will be as follows:

Object Right Ascension Declination Constellation Magnitude
Asteroid 89 Julia 21h23m20s -11°05' Aquarius 8.8

The coordinates above are given in J2000.0.

The sky on 11 August 2025
Sunrise
05:46
Sunset
19:50
Twilight ends
21:39
Twilight begins
03:56

18-day old moon
Waning Gibbous

91%

18 days old

Planets
Rise Culm. Set
Mercury 04:39 11:44 18:50
Venus 02:49 10:19 17:48
Moon 21:08 02:22 07:59
Mars 09:32 15:32 21:33
Jupiter 02:48 10:22 17:55
Saturn 21:31 03:31 09:27
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 DE405 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

© NASA/Galileo 1993. Pictured asteroid is 243 Ida.

Cambridge

Latitude:
Longitude:
Timezone:

42.38°N
71.11°W
EDT

Color scheme