October 1999

by Steve Stefanik

This October will host the annual opposition of the planet Jupiter on the 23rd. Look for the -2.9 magnitude giant orb rising in the eastern sky by mid-evening. You can’t miss this big 50 arc second disk because this year it will be the biggest it ever gets in its 12 year period because it will be as close to the sun (and earth) as it ever gets. Here’s your chance to see many of its features in close detail if you have even a small telescope. You can see its Great Red Spot transit its surface every 11 hours and many large white hurricane-like spots and smaller festoons which are all part of its dynamic atmosphere. In addition you can be entertained by the ever changing arrangement of it four largest Gallilean moons. Jupiter will provide hours of enjoyment for weeks in the long winter months ahead.

As an added bonus, the planet Saturn joins Jupiter 40 minutes later only a hand-width apart at arms length. Although Saturn is not as big and bright (-0.1 magnitude) as Jupiter it rivals it for beauty and mystique. This year Saturn’s rings are tipped 20 degrees away providing a splendid view of its southern hemisphere and ring structure.

Meanwhile the planet Mars is sinking slowly in the southwest amidst the stars of Sagittarius. Although waning in size and brightness it presents some interesting occultations with some of the Milky Way’s spectacular objects. One the night of the 17th its passes 0.3 degree south of M8 the "Lagoon Nebula". On the night of the 23rd it passses within 0.5 degree of the globular cluster M28 and 1 degree south of the globular cluster M22 on the night of the 27th.

The planets Uranus and Neptune can still be spotted amongst the dim stars of the constellation Capricorn the Sea Goat.. Scan about 20 degrees above the southern horizon with binoculars around 9:00 p.m. and look for what appears to be a 6th magnitude blue-green "star". This is Uranus. Much dimmer +7.8 magnitude Neptune is much harder to locate. You’ll need a telescope. Look between Capricorn and Sagittarius for this blue-gray planet.