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Sunday, September 28, 2014

Observing the Summer Milky Way with Binoculars

Late summer is one of the best times of year to observe the full brilliance of our home galaxy, the Milky Way.

The Milky Way used to be visible on every clear, moonless night, everywhere in the world. Today, however, most people live in places where it's impossible to see the Milky Way because of overall light contamination caused by lights left on all night long. Seeing the Milky Way requires a special effort for most people, but it's well worth the effort. 

Milky Way with North America Nebula and Comet Hale-Bopp Image by Michael Petrasko, Muir Evenden and Tom Lucia
Milky Way with North America Nebula and Comet Hale-Bopp Image by Michael Petrasko, 
Muir Evenden and Tom Lucia
To see the Milky Way, you'll need to travel far from any city, to a rural area. Even in a rural farming country, there are still a lot of bright lighting fixtures that wipe out the night sky. I am fortunate to live in a dark area on Cape Cod where there are no street lights of any kind to hinder my view of our galaxy.

The clearest skies appear just after a cold front passes through. This time of the year in September, this happens more often. Even then, you need to spend some time under a dark sky before your eyes become fully adapted to the darkness. It takes about 15 to 20 minutes for human eyes to become fully sensitive to faint light.

What does the Milky Way look like? Not like any of the photographs you see online because those are made with cameras that accumulate light in ways the human eye cannot. What you will see is a faint, whitish glow, stretching in a huge arc from the southern to the northeastern horizon. It has a mottled effect, kind of like a fluffy cloud. There are brighter areas, especially down toward the core of the galaxy in the southern part of the sky. There are also darker patches, where nearby clouds of interstellar dust block the light from beyond.

Orion 9x63 Mini Giant Astronomy Binoculars
Orion 9x63 Mini Giant Astronomy Binoculars

The most obvious of these dark nebulae is the Northern "Coal Sack", just below and to the right of the bright star Deneb in the constellation Cygnus. Just below Deneb is one of the brightest parts of the northern Milky Way, worth examining with binoculars. This is the North America Nebula, famous in pictures for its resemblance to the continent of North America. Under a very dark sky seeing with my 9x63 Orion astronomy binoculars, I am just able to see the "continent" feature.

One thing you won't see in the Milky Way, either in binoculars or with the naked eye, is any color. Images register the reddish glow of hydrogen gas, but the light is too faint to trigger the color receptors in the human eye, so all you'll see are shades of grey.

In the northern range of the Milky Way's arc, you'll see the constellations Cassiopeia and Perseus. When you look in that direction, you're looking outward from the spot within the disk of the Milky Way toward its outer edge, and the stars are far less dense than when you look inward toward Sagittarius.

On a clear dark night, it's easy to see the grand sweep of the Milky Way galaxy and discover all of the deep-sky treasures it possesses.
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Sunday, September 21, 2014

Observing in the Age of Modern Technology

Last Sunday morning, my longtime friend and co-astronomy enthusiast, Muir Evenden and I went observing again together for the first time since 2006. Growing up together on Cape Cod in the late 1970s and 1980s, Muir and I continued to foster each other’s interest in the field of astronomy Back then Muir would bring along his Celestron 8 telescope and I would cart my Edmund Astroscan 2001 4.25" Wide-Field telescope. We would observe with these instruments through those years, bringing them to numerous observing programs for astronomy education and public outreach. After Muir relocated to the Phoenix, Arizona area back in the early 1990s, I would make a point to travel out there at least once a year. On those annual visits, we would travel down to the Tucson part of the state, rent telescopes for the week and observe at the base of Mt. Hopkins, site of the Fred Lawrence Whipple Observatory. Muir and I continued this tradition until the fall of 2006 as he then relocated to Poland shortly thereafter.

Image of NGC 253  - Image by Muir Evenden & Michael Petrasko
NGC 253  - Image by Muir Evenden & Michael Petrasko

Of course, Muir and I have always kept in touch through the years via Skype and eventually founded Insight Observatory together. However, because of the technologies that are available to amateur astronomers as well as students studying astronomy, Muir and I were actually able to observe the night sky while I was in my home office on Cape Cod and Muir at his residence in Poland. Via Skype, I shared my computer's desktop with Muir and we logged into the remote robotic telescope network located in New South Wales, Australia, operated by itelescope.net. As we chose their telescope T13, a Takahashi SKY90, 3" f/4.6 telescope with a One-Shot color CCD camera, we looked at the list of recommended images to shoot and we chose NGC253, a spiral galaxy in the constellation Sculptor. We took a series of 5, 10-minute exposures of the galaxy. After each one was taken, we could go to the feature itelescope.net provides called a "Last Image Preview" and glimpse at the results. Muir then stacked and processed the 5 images in the imaging processing software called PixInsight. NGC 253 is one of the brightest galaxies in the sky, the Sculptor Galaxy can be seen through binoculars and is near the star Beta Ceti. It is considered one of the most easily viewed galaxies in the sky after Messier 31, the Andromeda Galaxy.

The Sculptor Galaxy is a good target for observation with a telescope with a 12" diameter or larger. In such telescopes, it appears as a galaxy with a long, oval bulge and a mottled disc. Although the bulge appears only slightly brighter than the rest of the galaxy, it is fairly extended compared to the disk. In 16" telescopes and larger, a dark dust lane northwest of the nucleus is visible, and over a dozen faint stars can be seen superimposed on the bulge.

Image of "Grus Quartet" - Image by Muir Evenden &  Michael Petrasko
"Grus Quartet" - Image by Muir Evenden and Michael Petrasko

After imaging NGC253, we skimmed through the planetarium software, Stellarium, and saw there was an interesting quartet of large spiral galaxies, in the constellation Grus. This quartet of galaxies is known as "The Grus Quartet". The spiral galaxies are physically very close together and strongly interacting. The high starburst activity of two of the members, NGC 7552 and NGC 7582, is also thought to arise from tidal galaxy-galaxy interactions and subsequent formation of a bar in the disk. Several tidal tails are visible extending from NGC 7582, one pointing toward the neighbors in the east and the other toward NGC 7552, which lies at a projected distance of approx. 30' to the northwest. Muir and I then decided to take one 10-minute exposure of the group with T13. We were amazed to see how each galaxy in the image frame had a unique characteristic.

After spending those couple of hours remote observing and logging out of the remote telescope network, I said to Muir "I actually feel like I did in the old days after a good observing session."
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Saturday, September 13, 2014

5 Great Astronomy Apps for the iPad

One of the benefits of working in the field of astronomy education is the opportunity to try out all of the different astronomy apps designed for iPads and iPhones. iPhones have been very popular in the past couple of years. Exploring the objects in the night sky is fun on an iPhone, however, even better on an iPad. There is simply no comparison between the experience that you get from an iPad astronomy app and its counterpart for the iPhone. The larger screen, especially the iPad 3′s retina model, makes a whole lot of difference.

In the event that you are into stargazing and need to utilize your iPad to investigate the objects in the night sky more than ever, these 5 astronomy applications for the iPad will have you prepared:

Star Walk App Screen Capture

Star Walk: provides you with a breathtaking experience with the stars right on your iPad. Can identify the stars as you explore them on your device too.

Red Shift App Screen Capture

Red Shift: Is another wonderful astronomy app for the iPad. It covers around 100,000 stars and 500 plus Deep-Sky objects. This app provides support for iPad 3′s retina display. The 3D flights to the moon and planets are breathtaking.

GoSkyWatch Planetarium App Screen Capture

GoSkyWatch Planetarium: This astronomy app contains all the stars visible to the naked eye. This is not only a great learning tool for amateur astronomers, but it can also serve as a handy object identification tool. It also offers information on moon phases and sunrise and sunset times for all locations.

Solar Walk Planetarium App Screen Capture

Solar Walk: Assists you with investigating the Earth's planetary group to the fullest extreme. This app covers all of the planets and their satellites in our solar system.

SkySafari 3 App Screen Capture

SkySafari 3: Is an astronomy app that has everything you need to explore the stars and other objects. You can use this to identify the stars. The night mode allows an observer to preserve their night vision. The Pro version offers many more features.
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