by Erich Karkoschka
Mercury is up at dawn far below Venus, but not much longer. The last naked-eye visibility ends August 7.
Venus rises at 2:30 am and is more than 40 degrees up at sunrise. It is at greatest elongation on the 12th, 46 degrees from the sun. It still is brighter than average and can be seen after sunrise, especially on the 15th when the lunar crescent is nearby. Of course, this pairing is best observed before sunrise.
The best night to watch the moon move is August 8/9, right next to Mars. When they rise, they are 1.6 degrees apart, narrowing to 1.3 degrees later and back up to 1.9 degrees at sunrise. A challenging first moon after New Moon will be visible on the 19th, but visible with naked eye only if it is completely clear, shortly after sunset.
Mars rises around 10 pm and is 60 degrees up at dawn. By the end of the month, it is even brighter than Sirius. In a telescope, its 15-19 arc-sec disk shows detail. During many years, it does not get that big.
The first minor planet Ceres is in opposition in southern
Aquarius, but with magnitude 8 not as bright as at other oppositions.
Jupiter and Saturn are well up all evening, just a few weeks past opposition. Saturn trails Jupiter by 8 degrees in their diurnal motion and also their current retrograde motion across Sagittarius. Ganymede will cast a shadow onto Jupiter on the 14th until 11 pm. On the 21st it will transit
8 – 11 pm and then show its shadow after 11:30. Another transit will start at 11:30 pm on the 28th. The night before one can see Callisto transiting 8:30 – 12:30, which will look like a shadow due to its dark surface.
August is the best month for watching meteors. The Perseids show up during the first three weeks, peaking on the night of 11/12. During dusk, the radiant is just rising, creating few meteors, but they can go for several seconds across the whole sky. By Dawn, we are heading right into the stream with up to 1 meteor per minute, but they only last less than half a second typically. The moon will rise at midnight on the peak night, so the evening will be dark.
