You may have noticed that two of the brightest objects in the sky have been getting closer together in the western skyeach night this month - what's going on?
Sky & Telecope image
The two objects are planets, and they are headed towards a close meeting in the sky - called a conjunction - on June 30th. Although appearing close in the sky, they're not physically close. The brightest, Venus, is about 90 million km from Earth, while the fainter, Jupiter, is 10 times farther away - almost 900 million km from us. From the 27th to July 4th they will appear wihtin 2 degrees (about a thumb's width when held at arm's length), with their closest spacing on June 30th - you'll be able to cover both with an outstreched finger tip!
For more on this event, check out the feature
on the Sky and Telescope website.
Sky & Telecope image: How to spot Perseid meteors
Head for a dark sky location with a blanket or your favourite reclining chair. It's time for the Persied meteor shower!
The meteor shower occurs when the Earth's orbit intersects the orbit of the cloud of debris shed by Comet 109P/Swift-Tuttle. Small pieces of the former comet hit the Earth's upper atmosphere at a relatively fast 60 km per second. The result is a trail of white-hot plasma (ionized air molecules) along each particle's path. It is this column of plasma that creates the momentary streaks of light we see in the sky.
The Moon will be two days past full on the peak Perseid night, August
12–13. So the "show" won't be quite as bright as when it's full, but it will
illuminate the sky all night, especially from midnight to dawn when the
shower's radiant (the area of the sky that most of the meteors appear to come from) in Perseus is high and the meteors should be most
At nightfall the Moon will still be low in the east,
and this is when to watch for "Earthgrazing" Perseids. These are the
infrequent, but unusually long and graceful, meteors that you may see
when a shower's radiant is low above the horizon.
On their peak night, the Perseids typically produce about 100 meteors per hour when the radiant is near the zenith (directly overhead) and the sky is very
dark. The peak rate typically runs for about 12 hours centered on the
predicted time, which this year is near nightfall on August 12th.
Moonlight will hide faint Perseid meteors, but a nice bright one might show through every few minutes late in the night.
See more at: http://www.skyandtelescope.com/astronomy-news/observing-news/
Also from Sky & Telescope Magazine:
is an illustrated guide to what to look for (and when) in the sky in the week ahead.
The Clear Sky Chart below indicates the latest hourly forecast for cloud cover (dark blue indicates no clouds, white is overcast), "seeing" (dark blue for stable air, white for turbulent), and darkness (darkest blue for no moon, pale blue-grey for full moon, white for daylight) for about 48 hours. Ideal observing conditions would have dark blue for all!
The Clear Sky Chart is generated from a forecast model developed by Allan Rahill of the Canadian Meteorological Centre. CMC's numerical weather forecasts are unique because they are specifically designed for astronomers. A script to summarize CMC's forecast images for requested areas is then produced by Attila Danko. For more information, please visit his excellent site.
Interactive Chart of the Messier Objects
In the later part of the 18th century, French astronomer and comet-hunter, Charles Messier complied a list of about 100 objects which were not comets - but whose fuzzy image might be mistaken for a comet.
The objects are now used as a compliation of different kinds of interesting objects - galaxies, star clusters, supernova remnants, bright nebulae - which are visible in a small telescope. They also serve as a challenge for some astronomers who want to "observe the list"!
For more information, click on any object at right, or see The Messier Catalog.