Asteroid 532 Herculina at opposition

2019 Feb 5

Asteroid 532 Herculina will be well placed for observation, lying in the constellation Leo, well above the horizon for much of the night.

Regardless of your location on the Earth, 532 Herculina will reach its highest point in the sky at around midnight local time.

From London, it will be visible in the morning sky, becoming accessible at around 18:34, when it rises 21° above your eastern horizon. It will then reach its highest point in the sky at 00:38, 67° above your southern horizon. It will be lost to dawn twilight at around 06:08, 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 532 Herculina 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 532 Herculina lies opposite to the Sun in the night sky, the solar system is lined up so that 532 Herculina, the Earth and the Sun lie in a straight line with the Earth in the middle, on the same side of the Sun as 532 Herculina.

On this occasion, 532 Herculina will pass within 1.422 AU of us, reaching a peak brightness of magnitude 8.9. Nonetheless, even at its brightest, 532 Herculina 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 532 Herculina

The star charts below mark the path of 532 Herculina across the sky around the time of its opposition.

This star chart is also available to download:

Light-on-dark PNG image PDF document
Dark-on-light PNG image PDF document

The exact position of 532 Herculina at the moment of opposition will be as follows:

Object Right Ascension Declination Constellation Magnitude
Asteroid 532 Herculina 09h37m20s +28°40' Leo 8.9

The coordinates above are given in J2000.0.

This entry in the observing calendar was provided by