Star Points for August, 1997; by Curtis Roelle Swift Mercury and Crippled Mir Visible in Early Evening Last month we discussed Earth's "twin sister" planet Venus currently shining proudly and brightly as an "evening star" in the western sky after sunset each night this Summer. (Of course Venus is a planet, not a star.) A bonus awaits sky watchers who get themselves outside early -- early in the month and early in the evening: Mercury, the innermost planet of our solar system, can also be glimpsed during the first week of August this year. Start your search by looking for Venus about 30 minutes after sunset, or approximately 8:50 p.m. EDT. If you face west you will see a bright star-like object 10 degrees above the horizon. This is roughly the width of your fist outstretched at arm's length, and applies to persons of all sizes and ages. Venus is easily seen with the unaided eye and appears brilliant and star-like. Mercury will be below and to the right of Venus. Remaining unseen until the sky has darkened somewhat, Mercury too is viewable by the unaided eye. If you have them, binoculars will assist in your search for Mercury. In some wide-field binoculars both Venus and Mercury may be seen in the same field of view. Venus is the more brilliant of the planetary pair appearing nearly 50 times as bright as Mercury. Don't wait too long to start looking because Mercury starts to dim as it slips into the low haze just above the horizon becoming difficult to see by 9:15 p.m. EDT. In the sky Mercury reaches greatest separation from the Sun on August 4, a position astronomers call "greatest eastern elongation". Western elongation occurs when Mercury achieves maximum separation from the Sun in the morning sky. The next western (morning) elongation will be on September 16. Mercury was named by the ancients for the messenger of the Greek gods. In mythology Mercury was swift of foot, a trait shared by the rapidly-moving planet. Mercury circles the sun in only 88 days, the shortest orbital period of the nine planets. When the Mariner 10 spacecraft visited Mercury in 1974 it found a battered Moon-like world marked with numerous impact craters lacking an atmosphere. However, because of its proximity to the Sun the daytime surface temperature of Mercury reaches 770 degrees Fahrenheit, compared to "just" 220 degrees on the Moon. But that's not all. Sky watchers who go outside tonight can see the Russian Mir space station flying high over Carroll County. Mir has been plagued by difficulties in recent weeks including a fire, collision with a cargo spacecraft, and a power blackout. Mir currently has a crew of three including one American astronaut. After spotting Venus and Mercury Mir is the icing on the cake. Tonight (August 1) Mir passes nearly overhead in Carroll County, traveling from southwest to northeast between 9:30 and 9:41 p.m. EDT. It will appear as a slowly moving light climbing higher in the sky as it draws closer to the observer. At its closest Mir will be only some 200 miles away. It's brightness should rival Venus as it sails silently overhead. Unlike an airplane there are no blinking or colored lights. Mir's light is steady, its color the yellowish-white of reflected sunlight. If it is cloudy tonight or you otherwise miss seeing Mir, there are two more good evening passes in mid-August. On August 16 Mir passes northwest to northeast between 9:38 and 9:43 p.m. EDT and reaches more than halfway up the sky before disappearing into Earth's shadow. On August 18 Mir floats from northwest to southeast between 9:19 and 9:25 p.m. EDT, reaching a maximum altitude of more than 70 degrees overhead. (Consider the times given in this article to be accurate within five minutes or so.) I would be interested in hearing how you succeeded in viewing either Mercury or Mir. You may either write to this newspaper or direct your e-mail to roelle@erols.com.