Astronomy 1020-H Stellar Astronomy Spring_2016 Day-4

Apollo-1 crew

STS-51-L Crew

Course Announcements Smartworks Chapter 1: Grades will be downloaded sometime this weekend. SW-2 … hop to it. 1 st set of Dark Sky observing nights: Tues. Feb. 2 & Mon. Feb. 8 – 7:30pm at the observatory. Tues. Feb. 9 is the weather backup if both are cancelled.

SDSS Site, telescope, camera drawing, and coverage area.

SDSS Filters The SDSS filter system: Defined in Fukugita et al. 1996, Astron. J., 111, 1748 Magnitudes: u, g, r, i, z: Defined by Smith et al. 2002, Astron. J., 123, 2121

The SDSS-I spectrograph

Some SDSS figures

The First Lab In the first lab, you will explore the SDSS-DR7 data base (feel free to use DR-12 if you want – just let us know this) to see what a variety of celestial objects (stars, galaxies) look like; what solar system objects look like (asteroids); and what other things look like (meteors, airplanes, “ghosts” – these are caused by internal reflections from bright objects). There are some comets in the data base, but the major planets were avoided (too bright). You will look for examples using the guide and give us information about them (position, type, brightness). There are about 400,000,000 objects in the data base, so you will probably all have different answers. The purpose of this lab is to have fun and explore.

The First Lab An example from the lab sheet: “ A star with 15 < g < 18” – this means “look for a star whose g-band magnitude (brightness) is between 15 and 18. “A very red star with r - z > 1.5” – this means “find a red star whose color (r minus z) is greater than 1.5” In the next 3 slides, don’t let the “math” bother you, want won’t have to determine any of this. It is shown if some you have an interest to investigate further.

Brightness = Magnitude Note that this compares two stars. If a “zero point” is defined, then where C is the zero point offset

Color = Magnitude Difference Where the two magnitudes are of the same object at two different wavelengths ( ). By definition a color is the (shorter – longer) value. That is “bluer” – “redder”

Celestial Coordinates - Equatorial  (Right Ascention) is the angle around from the Vernal Equinox. Think LONGITUDE.  (Declination) is the angle above (+) or below (-) the celestial equator. Think LATITUDE.

Types of Objects - Galaxies

Types of Objects - Stars

Types of Objects - Airplane DES image on , Observers: Smith & Balbinot

First Activity

4 X 6 Card Name, major, year. Astronomy experience (if any). Why you’re taking the class. What you hope to get out of the class. What scientist, living or dead, would you most like to meet?

Patterns We use patterns in our daily lives. Sunrise, sunset, moon rise, rainy season … Passage of time is important to humans. We can use the stars to help. There are 88 constellations in the modern sky. Semi-rectangular, recognized by the IAU. Northern : Latinized Greek-mythology names: Orion, Cygnus, Leo, Ursa Major, Canis Major Southern : Latin names: Telescopium, Sextans, Pyxsis

Use the Big Dipper in the northern sky as a way to find other groups of stars

Use Summer Triangle to find constellations during evenings

Use Winter Triangle to find constellations during evenings

Star Charts