Astronomy 101 Whats up there?

Stellar Magnitude Stars are graded by how bright they are The brightest stars are stars of the 1st magnitude. The dimmest stars you can see (with just your eyes) are stars of the 6th magnitude. A star of the 1st magnitude is 100x brighter than a star of the 6th magnitude Thus a star of the 2nd magnitude is 2.512 dimmer than a 1st mag star.

Stellar Magnitude 0.03 Vega (chosen as the zero point) -1.47 Sirius (brightest star in the sky) -2.94 Maximum brightness of Jupiter -3.82 Maximum brightness of Venus -5.9 Brightness of ISS (space station) -9.50 Iridium flare -12.92 full moon -26.74 Sun

Oh Be A Fine Girl Kiss Me Class Temperature Color O 30,000 - 60,000 °K Blue B 10,000 - 30,000 °K A 7,500  - 10,000 °K White F 6,000  -  7,500 °K White (Yellow) G 5,000  -  6,000 °K Yellow K 3,500  -  5,000 °K Orange M 2,000  -  3,500 °K Red

What to look for? Star clusters Nebula Open clusters (M11) Globular clusters (M13) Nebula Planetary (M57) Dark (Horsehead Nebula) Emission nebula (M42) Supernova Remnant (M1)

What to Look for?

What to Look for? Comets - Watch the web…. Asteroids – Go to Minor Planet Center Satellites – http://heavens-above.com Planets Inferior – Mercury, Venus Superior – Mars, Jupiter, Saturn Telescope – Everything else.

List of things to look for Messier catalog – 110 objects List of things that are not comets… Caldwell catalog – 109 objects (list made by Patrick Moore) Herschel 400 catalog (400 of the 2000 or so objects found by William Herschel) NGC catalog - ~7000 objects

Focal Ratio The focal ratio is the ratio of the light path to the size of the objective. My telescope has a 8” mirror, and a 50” light path. Thus the focal ratio is F/6 (F6.25)

Magnification The magnification of your telescope is the focal length of your telescope divided by the focal length of your eyepiece. My 8” F/6.25 has a focal length of 50” = 1270 mm My widest field eyepiece is a 32 mm. SO: This gives me a magnification of ~40. My 10mm eyepiece give me 127x. Using my 2.5 barlow lens I can get 317.5x

Field of view Your dark adapted eye has a Pupil size of 4 to 9 mm Eyepieces are sold by size (25 mm) and field of view (50 deg). Field of view is Eyepiece FoV/Magnification Thus, for my telescope 50/(1270/25) = 1 degree