At this time of year as the nights continue to get shorter and warmer, many people get in to the spirit of Summer: barbecues, watching sunsets and taking advantage of longer periods of natural light for outdoor activities (and work). When darkness eventually falls they tend to notice the stars, the Moon and maybe the planets in the darkening twilight. And, because it is not as cold, they will stay out to look up for longer. For ‘real’ amateur Astronomers, this time of year is not always good.
For a start, Summer brings with it changing weather patterns that mean more haze and fog. This is not a hazard by any means but it does take away from the beauty of the night sky. Objects in a telescope under high magnification lose their brilliance and clarity. The planets do not always yield their individual features so plainly present under frigid skies. Even the Moon with all its brightness will be seen with a haze around it. After this, the length of time it takes to wait for proper darkness to occur means many will simply not bother with the trouble of setting up their equipment.
Despite these drawbacks, Summer still has its favourites for observers, all of them easy and within reach of any amateur astronomer, some of which are described here.
Not needing any optical aides whatsoever, meteor watching is probably the easiest of astronomical hobbies, requiring only a good eye and something comfortable to sit on and watch. Throughout the year there are many meteor showers, some prominent and others obscure. Summer doesn’t really have any major meteor showers since the hours of darkness are very few between May and July. August will be the next big show with the Perseids on August 12th. You will not have to wait till then to see meteors as they will appear on any night, any time of the year. A meteor shower is simply the term when a higher-then-normal rate of meteors are seen, usually for a couple of hours at its peak for greatest effect. So while there are no major showers to come, any clear night will offer this quick glimpse at something millions of years old flashing across the sky.
Probably the easiest target for telescopes and binoculars, an amateur observer requires virtually no training in how to find and point at the Moon. On a clear night between First and Last Quarters, lunar observing offers a little more than just craters and maria (seas). Scan along the terminator, the line that separates night from day with any high power magnification and you will spot mountain peaks otherwise in night catching the last glimpse of sunlight as they tower above the nightside of the terminator. The same can be said for craters where the nearside to the Sun casts a long shadow across the crater floor only for the central peak in the middle to catch some light out of the black. As you scan you will also notice craters within craters, many of which exist on the surface. Try your hand at finding some.
The International Space Station
With the final flight of the shuttle Atlantis and the final Space Shuttle flight ever happening in June, the ISS becomes the (almost) completed outpost that had an original completion date of 1999! It was only around that time that construction and assembly in space of the station began. Now it can house 6 astronauts on long-duration flights lasting an average of 6 months each. It circles the Earth every 93 minutes, experiencing 1 ‘day’ and 1 ‘night’ in that time.
You will next see the ISS between June 1 and June 28, sometimes being seen up to four times during dark hours. You can find accurate information on exact times each day by registering for free on www.heavens-above.com. The registration is to accurately find your geographic location on the globe. If in doubt, contact the Club (MAC) for more information.
Satellites & Iridium Flares
It is estimated that around 17,000 individual pieces of space debris and junk orbit around Earth. These include old satellites, pieces from others, spent rocket stages, lost tools from manned missions and even an astronauts work glove. Currently there are around 400 additional operational satellites in orbit from communications to space research and astronomy to geostationary and military. A satellite seen moving across the sky looks just like an average star, moving around the speed of a jet plane but with no blinking lights. It might waver in brightness in a pattern a number of seconds apart as it moves. Generally this would be a gently spinning satellite reflecting light (from Earth and the Sun) off different surfaces.
An Iridium Flare is a slightly different kind of satellite view. Iridium Corporation put into orbit 66 satellites in the 80’s and 90’s to develop the growing cellphone culture and aid satellite telephone communications. Most of these were used by Motorola. Each satellite includes a set of 3 polished tabletop-like antennae. As the satellite circles Earth, they slowly turn and at some point, to an observer on the ground, one of these panels captures the light of the Sun for a few seconds causing a sudden brightness rivalling the brightest planets and stars. This is called a satellite ‘flare’ and can be predicted when it will be seen. The aforementioned website Heavens Above will give you accurate prediction times for different Iridium Flares.
More of a meteorological (weather based) phenomenon than astronomical these NLC’s nonetheless excite astronomers when they are seen. In short, these are clouds that shimmer well after sunset (or well before sunrise) for a brief period at night from the end of May through to end of July. They are so high up in the atmosphere in the upper mesosphere, possibly around 45 to 55 miles up that they lie on the edge of space relative to other cloud layers. They are normally too faint to be seen and are visible only when illuminated by sunlight from below the horizon while the lower layers of the atmosphere are lying in Earth’s shadow. They appear as thin, silvery slivers of cloud that consist of dust particles coated in ice. Their height suggests that the dust is a direct correlation to that which is left behind from a meteor. Stay up late or get up early to see them, they are unmistakable.
More Info: To find out more information about what you can see in the night sky you can visit www.midlandsastronomy.com or www.irishastronomy.org – alternatively, you can come to any of the monthly public lecture nights (first Tuesday each month) hosted by the Midlands Astronomy Club.
Seanie Morris is the Secretary of the Midlands Astronomy Club (MAC) having been a member since 1990 when it used to be known as the Tullamore Astronomical Society (TAS). Seanie’s favourite astronomical interests include meteor watching, deep sky telescope objects and the Moon. See more of what MAC is about at www.midlandsastronomy.com