Event Date: May 21st
Time: 12:00 AM
Brief
Yesterday while showing Hercules and its Keystone asterism, I asked readers if they could identify a bright star not far east in the sky, from the constellation. That star, which I have shown with two others forming another large asterism, is Vega-- forming one third of the Summer Triangle. If we forward the clock ahead two hours from yesterday, taking us into the next day, all three stars of the Triangle clear the horizon as seen from our latitude. I will include the Triangle figure in the image below, yet keeping Hercules and yesterday's feature as well labeled: the Hercules [star] cluster.
Time: 12:00 AM
Brief
Yesterday while showing Hercules and its Keystone asterism, I asked readers if they could identify a bright star not far east in the sky, from the constellation. That star, which I have shown with two others forming another large asterism, is Vega-- forming one third of the Summer Triangle. If we forward the clock ahead two hours from yesterday, taking us into the next day, all three stars of the Triangle clear the horizon as seen from our latitude. I will include the Triangle figure in the image below, yet keeping Hercules and yesterday's feature as well labeled: the Hercules [star] cluster.
How is Vega important in relation to the cluster? Along with the star Pi Herculis (spelling changed to indicate that it is a star within the constellation), Vega forms a line that takes a viewer almost straight to the cluster. Look at the zoom-in below, which gives a wide field of 30º.
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| click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp. |
Detailed
I didn't give stats about M13 yesterday, so will here. Some are similar to M3, which is the globular cluster that I displayed earlier in the season. M13 is listed as the exact same magnitude as M3, and about 12,000 light years closer. As a result of this, M13 is listed as the more "spectacular" of the two, if using the same size telescope especially. Some feel that M13 has more of a 3-D feel, and more "sparkly" or "snow-flakey". Use whatever words you like, and personally, I like both. Coincidentally, both are about the same latitude in the sky, putting them close to zenith at and near transit: M3 is at 28º, while M13 is 36º. Despite the 8º difference, when transiting, they both appear very high up. Just about every telescope used require a diagonal to attach to the eyepiece when this high, so viewers can view while directing their heads parallel to the ground. It is much better this way than perpendicular; this gets a little hard on the neck after a very short while!
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