SkyEye

Welcome to SkyEye, your guide to this month's celestial events. All dates are based on Universal Time (UT).

The Sun and Moon

There are three eclipses this month! The month begins with a partial eclipse of the Sun. A total lunar eclipse follows on 16 July and the month ends with yet another partial eclipse of the Sun.

The Earth is at aphelion on 4 July. As seen from the Earth, the Sun is moving from the constellation Gemini to the constellation Cancer.

The phases of the Moon are

New : 1 July
First Quarter : 8 July
Full : 16 July
Last Quarter : 24 July
New : 31 July

The Moon is at perigee on 1 July, at apogee on 15 July, and at perigee again on 30 July. Very high (and low) tides can be expected on 1 July with the coincidence of perigee with New Moon. The second Full Moon in a month is popularly known as a Blue Moon but what about the second New Moon in a month?

The Moon occults Mercury on 29 July during daylight hours in the Arctic regions of the western hemisphere. The following day, again during daylight hours, Mars will disappear behind the Moon's disk as seen from Brazil, the South Atlantic, and southern parts of Africa.

The Planets

The word planet is derived from the Greek word for "wanderer." Unlike the background stars, planets seem to move around the sky, keeping mostly to a narrow track called the ecliptic, the path of the Sun across the stars.
Mercury
The smallest of the inner planets reaches inferior conjunction with the Sun on 6 July. Later in the month, on 27 July, Mercury is at greatest elongation west. Because this planet begins retrograde motion on 17 July, it makes a loop in the constellation Gemini.
Venus
Venus takes its place as the brilliant "evening star" low in the western skies at sunset in the constellations Gemini, Cancer, and Leo.
Mars
The red planet is in conjunction with the Sun on the first day of the month, and impossible to see this month in the constellations Gemini and Cancer. It is farthest from Earth on 21 July.
Jupiter
You will need to get up before the Sun in order to view Jupiter, the "morning star," in the constellation Taurus.
Saturn
Saturn can be found not far from Jupiter in the constellation Taurus.
Uranus
Uranus is up nearly all night in the constellation Capricornus.
Neptune
The blue gas giant is at opposition on 27 July so it can be seen all night (with a telescope) in the constellation Capricornus.
Pluto
Pluto sets early in the morning in the constellation Ophiuchus. However, because it is so small and faint, a large telescope is always needed to see it.

Minor Planets, Comets and Meteors

Minor Planets
On 16 July, 4 Vesta will be at opposition in the constellation Sagittarius. The brightest asteroid at sixth magnitude, it can be seen with the naked eye.
Comets
Northern hemisphere observers have a chance to see Comet C/1999 S4 LINEAR this month.
Meteors
The delta Aquariids peak on 27 July. The waning Moon is just a few days from new and should cause minimal interference.

The Celestial Sphere

Constellations are patterns of stars in the sky. The International Astronomical Union (IAU) recognises 88 different constellations. The brightest stars as seen from the Earth are easy to spot but do you know their proper names? With a set of binoculars you can look for fainter objects such as nebulae and galaxies or some of the closest stars to the Sun.

Descriptions of the sky for observers in both the northern and southern hemispheres are available for the following times this month. Subtract one hour from your local time if daylight savings time is in effect. (Note: These times are approximate.)

Northern Hemisphere : 45° N

Southern Hemisphere : 30° S

For More Information...

Credits

Much of this information can be found in this month's issue of Sky & Telescope and in other fine amateur astronomy magazines available in your local bookshop. Another excellent source is the current edition of the Astronomical Calendar by Guy Ottewell and published by the Universal Workshop at Furman University.

The image of the Sun in the SkyEye banner is courtesy of the SOHO/EIT consortium. SOHO is a project of international cooperation between ESA and NASA.

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Last modified on 9 July 2000
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