AUGUST 2008 VIEWING LIST

Object Type Size Distance Coordinates

14” Scopes M13 GC 16’ 25,100 LY 16h 42’ +36 28’ M57* PN 1’ 2,300 LY 18h 53 +33 02’ M8 (Lagoon)* EN 90’ 5,200 LY 18h 04’ -24 23’ M20 (Trifid)* EN 28’ 5,200 LY 18h 03’ -23 02’ M17* EN 40’ 4,890 LY 18h 21’ -16 11’ M22 GC 17’ 10,400 LY 18h 36’ -23 54’ M27* PN 8’ 1,250 LY 19h 59 +22 43’ M15 GC 12’ 33,600 LY 21h 30’ +12 10’ NGC7331** Gal 11’ 46,000,000 LY 22h 37’ +34 25’

4” Refractor Mizar & Alcor MS - 81-78 LY 13h 28’ +54 55’ 95 Herculis MS - 470 LY 18h 02’ +21 36’ Epsilon Lyrae MS - 160 LY 18h 44’ +39 40’ Albireo MS - 380 LY 19h 30’ +27 58’ S Cephei Carbon Star - 1353 LY 21h 35’ +78 37’

Abbreviations: MS = Multiple Star, EN = Emission Nebula, RN = Reflection Nebula, Gal = Galaxy, GC = Globular Cluster, LY = Light Year, OC = Open cluster, PN = Planetary Nebula, SR = Supernova Remnant, CS = Carbon Star, * = Video imaging optional, ** = Video imaging recommended. 1 Astronomical Unit = 93,000,000 miles. OBJECT DESCRIPTIONS – AUGUST 2008

M13 At a distance of 25,100 light years, this globular cluster in the constellation Hercules (HER-cue- leez) is about 145 light years in diameter. The age of M13 has been estimated at over 10 billion years. It contains over 300,000 stars. At the center, stars are about 500 times more concentrated than in our solar neighborhood. To a being living near the center of M13 there would be no night sky as we know it. Due to its age, however, life as we know it would be highly unlikely because the elements necessary for life are not present. There is some current speculation that M13 is actually the ancient core of a small galaxy cannibalized by the Milky Way billions of years in the past.

M57 The Ring Nebula is an atypical planetary nebula in the constellation Lyra (LIE-ruh). Whereas for many years it was assumed that the parent star ejected a spherical shell of gas that we see as a ring, recent research indicates that we are actually seeing an expanding torus, or donut, of gas illuminated by an earth-size white dwarf star, and viewed from above. (Use an Olll filter for eyepiece viewing)

M8 The Lagoon Nebula in the constellation Sagittarius (Sah-jih-TAIR-ee-us) is an emission nebula about 140 x 60 light years in size. As the hydrogen gas that makes up the nebula absorbs ultraviolet radiation from nearby young stars, it re-radiates, or emits, photons in the red light of hydrogen. Our eyes are not normally sensitive enough to detect the red color in small telescopes.

M20 The Trifid Nebula in the constellation Sagittarius (Sah-jih-TAIR-ee-us) is famous for its characteristic visual three-lobed appearance. Dark gas and dust clouds in the foreground block light to produce the tri-lobed character of this emission nebula. However, the video clearly shows four distinct components. Look for an adjacent faint reflection nebula component. M17 is a bright emission nebula centered on an open star cluster in the constellation Sagittarius (Sah- jih-TAIR-ee-us). After the famed nebula in Orion, M17, known also as the Omega, Horseshoe, or the Swan, is the brightest emission nebula in the northern hemisphere. The total gas cloud contains an estimated 800 solar masses. Look carefully either through an eyepiece or with the video camera and decide which name is most fitting.

M22 is a globular cluster in the constellation Sagittarius (Sah-jih-TAIR-ee-us). At a distance of 10,400 light years, M22 is one of the nearest globulars in the northern sky. Brighter than famous M13, it glows at 5th magnitude. The diameter of the object is about 97 light years. Seen through a curtain of foreground stars in the Milky Way, M22 is an extraordinary sight, and, in my opinion, superior to M13 in Hercules.

M27 The Dumbbell Nebula in the constellation Vulpecula (vul-PECK-u-la) was the first planetary nebula discovered. Through the visual scopes, the brightest sections resemble an hourglass. The video camera reveals the outer gaseous regions that complete the spherical structure of the ejected gas bubble. The age is uncertain, with estimates ranging from 3,000 to 48,000 years. (Use an Olll filter for optimum eyepiece viewing)

M15 in the constellation Pegasus (PEG-uh-sus) is among the more conspicuous of the globular clusters. At a distance of about 33,600 light years, it has a diameter of about 175 light years. Having experienced a process called Core Collapse, M15 has what may be the densest core of any known globular cluster, with hints of a supermassive object at its center. M15 is approaching us at 107 km/sec.

NGC7331 Discovered by William Herschel in 1784 in the constellation Pegasus (PEG-uh-sus), this is a bright type Sb spiral galaxy viewed at a small inclination from edge-on. Look for evidence of spiral structure & the faint presence of neighboring galaxies in the field of view. Mizar & Alcor This pair in the constellation Ursa Major (URR-suh, MAY-jer) is a visual double. However, Mizar takes its place in the celestial hall of fame as the first known Binary Star, one that consists of a pair of gravitationally bound stars that orbit each other. Found to be double in 1650, the pair is about 500 astronomical units apart & takes at least 5000 years to orbit about each other. More remarkably, each of these two components is AGAIN a spectroscopic double star.

95 Herculis in the constellation Hercules (HER-cue-leez) is a binary with a visual separation of 6.3 seconds of arc. The two stars orbit 900 astronomical units apart. The orbital period is approximately 11,000 years. Note the interesting colors.

Epsilon Lyrae, popularly known as the Double-Double, is a multiple star system in the constellation Lyra (LIE-ruh). Appearing as a double star at low magnification, as power and resolution increase each star splits into a close binary. While some observers see color differences, most see the stars as two pairs of white headlights oriented nearly perpendicular to each other.

Albireo Beta Cygni, in the constellation Cygnus (SIG-nus) is probably not a true binary, but a visual double star with extraordinary color contrast. If it is a binary it would have an orbital period of about 75,000 years. The yellow star is actually a spectroscopic binary in its own right. The yellow primary shines at 950 times our sun’s brightness and 50 times its mass, while the binary’s invisible secondary star is 100 times more luminous than our sun with 3.2 times it’s mass. The striking blue star shines at 190 times the luminosity of our sun with 3.3 times its mass.

S Cephei in the constellation Cepheus (CEE-fee-us) is a Carbon Star, a red giant with a large amount of carbon dust floating in it’s upper atmosphere. The dust passes red light, making carbon stars the reddest stars to be seen through a telescope. At magnitude 7.5, it is a beautiful deep red and, at its high declination may be glimpsed all year long.

F. Lockhart