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

Asteroid 192 Nausikaa at opposition

Fri, 20 Nov 2015 at17:10 EST(313 days ago)
22:10 UTC

Dominic Ford, Editor
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The sky at

Asteroid 192 Nausikaa will be well placed for observation, lying in the constellation Perseus, well above the horizon for much of the night.

Regardless of your location on the Earth, 192 Nausikaa will reach its highest point in the sky at around midnight local time.

From Newark (click to change), it will be visible between 17:51 and 05:05. It will become accessible at around 17:51, when it rises 24° above your north-eastern horizon, and then reach its highest point in the sky at 23:26, 82° above your southern horizon. It will become inaccessible at around 05:05 when it sinks to 25° 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 192 Nausikaa 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 192 Nausikaa lies opposite to the Sun in the night sky, the solar system is lined up so that 192 Nausikaa, the Earth and the Sun lie in a straight line with the Earth in the middle, on the same side of the Sun as 192 Nausikaa.

On this occasion, 192 Nausikaa will pass within 0.945 AU of us, reaching a peak brightness of magnitude 8.4. Nonetheless, even at its brightest, 192 Nausikaa 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 192 Nausikaa

The star charts below mark the path of 192 Nausikaa across the sky around the time of its opposition.

This star chart is also available as a PDF download, or in a light-on-dark color scheme, as an image file or PDF download.

The exact position of 192 Nausikaa at the moment of opposition will be as follows:

Object Right Ascension Declination Constellation Magnitude
Asteroid 192 Nausikaa 03h29m10s +32°51' Perseus 8.4

The coordinates above are given in J2000.0.

The sky on 20 November 2015
Sunrise: 06:48
Sunset: 16:34
Twilight from 05:12
until 18:10
All times shown in EST.

9-day old moon
Age of Moon:
9 days

Rise Culm. Set
Mercury 07:00 11:48 16:36
Venus 02:58 08:50 14:41
Moon 13:30 19:23 00:06
Mars 02:16 08:18 14:19
Jupiter 01:02 07:22 13:43
Saturn 07:25 12:17 17:08


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.




Color scheme