Click here to go ahead to Autumn 2013, or click here to go back to Spring 2013 "Eyes on the Sky" astronomy videos.
As our closest celestial neighbor, the Moon is the best object to observe craters, mountains, and other features on a non-Earth object. As the Moon revolves around Earth, despite showing us the same "face" towards Earth, the Sun reveals more and different features as the Moon moves from crescent towards a gibbous phase. This week, Eyes on the Sky takes observers through 39 different features and sights to see on the lunar surface, one day at a time. Don't worry if clouds block your view for a few days - many of these features can still be observed a day or two after the time they are highlighted in the video.
But the best part is that most any small telescope - even as small as 50mm in aperture - can reveal these selenographic sights. Use moderate to high magnification, as the brightness of the Moon can be overwhelming at the eyepiece without a filter to help cut down the glare. And very high powers will actually reduce the brightness somewhat. Use the Moon chart provided here for more detail, or if on a tablet or smartphone, click on this link for the lunar jpg file (600KB) that can be zoomed in our out.
Lunar map resource for waxing crescent, First Quarter, and waxing gibbous phases
The Milky Way runs right through Cygnus, and accordingly, there are a few open star clusters in this region of the sky. Both aren't too difficult to find, but each is a bit unique and may require a bit of help to find them. Messier 29 is a bit of an oddball cluster; fairly small, and can be easy to overlook. Given it's small size, close-spacing, and Messier's poor optics at the time, it's reasonable to understand why he chose to include this in his list of "non comets". Our modern small telescopes with achromatic lenses easily reveal it's true nature and structure.
Beyond the tail of the bird lies Messier 39, another open cluster that is quite a bit larger, and easier to locate with binoculars or a finderscope first. It's over half-degree size requires either a rich field telescope or a very long focal length eyepiece to avoid confusing it with the background stars of the Milky Way. A treat of a cluster to view, the near-perfect equilateral triangle shape of the cluster isn't hard to see in most any small telescope - even 60mm and 70mm ones. And because each of these clusters holds stars in the 7th - 9th magnitude range, most of their member should be readily visible even from most light polluted locations.
Download star chart #7 here for help with finding Messier 29 and 39
Messier 28 is an often-overlooked globular cluster, which is too bad, because it's not half-bad as a deep sky object. Moderately bright, and displaying some star resolution with telescopes 114mm and larger, it's a nice view to see near the Teapot region of Sagittarius. But the reason it is so overlooked is because from an observing perspective, the more impressive-looking Messier 22 is right nearby. But interestingly, these clusters bear some striking resemblances to each other, despite the differing views at the eyepiece. Check out this weeks video to learn what is the same, and different about these two deep sky objects i in the southern sky.
Download star chart #18 here for help with finding Messier 22 and 28
In the year 1054 AD, Chinese astronomers noted a "new star" in the sky, which today we observe as the Crab Nebula, the remnants of the supernova explosion that occured 959 years ago. On August 14, a Japanese amateur astronomer discovered a 'new star' in the sky in Delphinus, where previously there had not been one. At magnitude 6.8, it was on the verge of naked eye visibility at the outset, and increased to about magnitude 4.5 over the next couple of days. This "new star" - or stella nova as it might be called in Latin - is certainly one of the brightest and easiest to see in a very long time from Earth, and even as of Sunday August 18 was hovering in the 5th magnitude range.
Nova can be quite unpredictable in their brightness though. Often binary star systems where one star has pulled hydrogen and gas off another star, they may be recurring nova over time - sometimes in years, or again in millenia. So this is a good nova to look at now, this week and perhaps next, while it is still an easy star to spot. The video above shows how to find it, but there is more information available below as well:
Actual photo of Nova Del 2013 and surrounding area including Sagitta and Delphinus.
This star chart from Eyes on the Sky is probably the best one for locating the general area; look in the lower right side, and the nova will be very near where it lists NGC6905.
Current Light Curve data for Nova Del 2013
Create and print a customized star chart of the area near Nova Del 2013
Link to this week's Dark Sky Fact article.
Aquila and Cygnus are two well-known summer constellations that have a lot of interesting objects in and around them. This week, Eyes on the Sky star hops through Aquila into a small, dim constellation called Scutum the Shield, where we find some more bird-related deep sky objects. Messier 11, the Wild Duck Cluster, lies in Scutum just beyond the tail feathers of Aquila. Nearby is the globular cluster Messier 26, near a couple of 5th magnitude stars. And following some conveniently aligned stars that look like a high heeled boot, we can move binoculars or a finderscope to easily locate the Eagle Nebula, Messier 16, in Serpens. Find out how and where to find these objects in the night sky. Use Star Chart #12 for a downloadable PDF version you can use under the sky. And here are some general tips for deep sky objects observing too.
Messier 11, the Wild Duck Cluster: At 14 arc minutes across, medium magnification with a 1/2 degree field of view should frame this cluster nicely.
Messier 26: Similar in size to M11, but more than two magnitudes fainter, it also lies more deeply within thhe Scutum Star Cloud, making it a bit harder to pick off. Try similar magnification, and gauge the location based on the two 5th magnitude stars nearby.
Messier 16, the Eagle Nebula: Easy to see from moderately dark skies in binoculars, the nebula spans more than a half a degree across at 35 arc minutes, and has a similar integrated magnitude as Messier 11 (which is half it's size). Use a moderately low power eyepiece. Unsure what of what you might see? Check out some sketches others have drawn.
The Perseid meteor shower is probably one of the best to view, because it has the highest rate of meteors in one of the warmest months of the year. Learn when and where to look for these bits of sand and gravel that are traveling in excess of 100,000 mph when they burn up in our upper atmosphere. As for how to look, the video covers some of that too, but there are more meteor observing tips and tricks to help you see more and have a better experience. And don't forget to check out some of the prior week's videos here for more objects in the night sky you can easily find and observe.
Watch this week as Mars, Jupiter and Mercury - joined later by the Moon - all meet in the sky near morning twilight just before sunrise. Mars passed Jupiter last week, and Mercury reaches greatest elongation this week. Eyes on the Sky explains greatest elongation and what that means. Observe the Moon as it gets more slender each morning and decreases its crescent for New Moon next week. That, plus Venus and Saturn in the evening sky!
This week is the 100th episode of Eyes on the Sky. Originally a monthly video series when it began in early 2011, it moved to the weekly format in November of that same year, and has remained that way ever since. Looking back across the objects observed, updates, and fun/silly stuff that has been included, the important thing is that it could not have been achieved without the donations from regular viewers, and the sharing of these videos as well. A huge thank you to all who share this passion. Let's continue working for light pollution reduction over the next 100 videos!
Understandably, when many people think of amateur astronomy, they think "telescope." Binoculars don't really come to mind, and often it is only after being persuaded for a time that many realize just how important a tool binocs are in an amateur astronomers arsenal.
Consider this: Binoculars with 50mm aperture lenses can help you see up to 3 or 4 magnitudes fainter than you can see naked eye. So if 4th magnitude stars are visible for you, then Neptune is within your grasp with just binoculars. And even if it's just beyond visibility, binoculars can help you get acquainted with the stars you'll need to use to "hop" to the planet.
The furthest planet isn't exactly near anything bright, and the wide field of binoculars or a finderscope is the ideal way to hunt down this blue-hued planet - even for a telescope. And even then, you likely won't need much more than a 60mm to 80mm scope to track it down - see if you can find Neptune over the course of the next few months - it will be in the same general area of sky within Aquarius. See the chart below for more detail, and watch the video above to learn exactly how to find this part of sky.
Many professional astronomers spend their time studying stars. What better way to study stars though, than to study the one closest to Earth? Get a quality solar filter, and even on a small telescope you can see A LOT of detail for sunspots and faculae. Given that the peak of sunspot activity should occur later this year, now is a fantastic time to pick up a filter for solar observing. Another way to see the Sun is at the hydrogen-alpha wavelength of light, which allows us to see solar flares and prominences. Because the filters that allow us to see this wavelength are quite expensive, there is a lot cheaper and easier way to see them: Check out the SOHO site and see the sun in a variety of wavelengths of light. On this week, the sunspot group AR1785 moved across the surface.
Altair is one of the three bright stars that comprises the Summer Triangle of stars. But more importantly, it is the brightest star in the constellation Aquila, the Eagle. There are several mythological stories describing why the eagle was an important component of the night sky. In addition, there is some fascinating science and physics about the two other bright stars right next to Altair: Tarazed and Alshain (not to mention the meanings of the those words). Find out why we see these stars as we do, despite their differences in sizes and distance from us. And learn why the arrow Sagitta was "placed" in the sky so close to the Eagle, and as long as you have binoculars out (which may be required to see the 3-rd and 4-th magnitude stars of Sagitta), see if you can spot the dim, round shape of Messier 71 between the arrow's brighter stars. If not, use a magnified finderscope to "star hop" your way there from Altair, then look for the globular cluster with larger apertures to tease out some detail in this object.
The Summer Triangle of stars is an easy-to-find asterism in the eastern, evening sky for northern hemisphere observers shortly after dark. The star closest to the meridian or zenith will be Vega, in the small constellations of Lyra the Harp. Within its borders are a number of dim, but easy to find (thanks to Vega's brightness!) double stars such as Epsilon Lyrae, Delta Lyrae, and the eclipsing double Sheliak. Binoculars can help you find all of them, though a telescope will be required to split the "doubles of the double" in Epsilon. Also, around Delta Lyrae 1, there is a loose open cluster of stars called Stephenson 1 - a larger telescope will be required to see some additional stars in this area, but it is worth seeking out as the color contrast of Delta 1 and Delta 2 alone are worth the visit to the area.
The last few days of spring are this week, and that means summer constellation observing! The night sky has shifted from the area of sky we saw in spring, thanks to Earth's revolution carrying it another 90 degrees around the Sun. The places many constellations in a better place to view both them and the objects they contain, such as Ursa Minor, Draco, Cepheus, Cygnus, Aquila, Lyra, Hercules, Scutum, Sagittarius and Scorpius. Though some of these shapes have only 3rd magnitude or fainter stars, the brighter stars of summer can guide the way - such as the Summer Triangle asterism. Learn all about the summer sky in this week's video.