Presentation on theme: "Astronomy 305 Exam Topics Exam I – Star Charts"— Presentation transcript:
1 Astronomy 305 Exam Topics Exam I – Star Charts Exam II –Coordinate Systems and TelescopesExam III – Planets, Comets and AsteroidsExam IV – Stars and Deep Sky Objects
2 Coordinate Systems 17 - Horizontal Coordinates 18 - Equatorial Coordinates19 - Ecliptic Coordinates20 - Galactic Coordinates21 - Converting decimal degrees to °, ’, ”22 - Converting Degrees to Hours23 - Converting between Coordinate Systems24 - Converting Right Ascension to Hour Angle25 – Equatorial to Horizontal Coordinate Conversation
3 Celestial Coordinate Systems These are coordinate systems with two angular measurements:GeographicalHorizontalEquatorialEclipticGalactic
4 Geographical System Latitude (f) Longitude (L) the angle of a city above the equatorLongitude (L)the angle around the equator from the Prime Meridian
5 17 - Horizontal System Altitude (a) Azimuth (A) the angle of a star above the horizonAzimuth (A)the angle around the horizon from the north point; measured eastward
6 18 - Equatorial System Declination (d) Right Ascension (a) Hour Angle (H)the difference between the right ascension of your meridian and the right ascension an object
7 24 – Converting between a and H LST = Local Sidereal TimeLST is the same as the right ascension of the meridian on your star chartsH = LST – aExamples:What is the hour angle of Regulus at 11:00 PM tonight?What is the hour angle of Sirius at 8:00PM tonight?
8 Hour Angle S H O R I Z O N Celestial Meridian d H Celestial Equator 90°- fSH O R I Z O N
9 Celestial MeridiandCelestial Equatora90°- fSH O R I Z O N
10 19 - Ecliptic System Ecliptic Latitude (b) Ecliptic Longitude (l) the angle of a star above the eclipticEcliptic Longitude (l)the angle around the ecliptic from the vernal equinoxmeasured eastwardlabeled along the ecliptic on the star chartsObliquity (e)the angle between the ecliptic and the celestial equator and is approximately 23.5 degrees
11 20 - Galactic System Galactic Latitude (b) Galactic Longitude (l) the angle of a star above the galactic planeGalactic Longitude (l)the angle around the galactic planemeasured eastward from the galactic center
12 Examples Problem For all of the planets find… Hint: Use Appendix 11 their ecliptic longitudesthe host constellationtheir equatorial coordinatesHint: Use Appendix 11
13 Planet Positions Planet l a d Constellation Mercury Venus Mars Jupiter SaturnUranus
14 Planet Positions Planet l Visible? Rise Time Set Time Mercury Venus MarsJupiterSaturnUranus
15 Example ProblemsCalculate the altitude and azimuth of Capella for 11:00PM tonight.
16 25 - Equatorial to Horizontal Step 1Find a, LST and H is decimal hours.Step 2Convert H to degrees.Step 3Convert d to decimal degrees.
17 Step 4 Step 5 Step 6 Find sin a = sin d sin f + cos d cos f cos H Find aStep 6Find
18 Step 7 Step 8 Step 9 Find A’ If sin H is negative, A = A’ If sin H is positive, A = 360° – A’Step 9Find a and A in degrees, minutes and seconds.
19 More ExamplesWhat are the coordinates of Jupiter on May 5, 2005 at 8:00PM?bladLSTHA
20 Reading Assignment Chapter 2 Chapter 3 Chapter 16 A Tour of the Sky The Monthly Sky MapsChapter 16Telescopes and Binoculars
21 More Examples What are the coordinates of Venus tonight at 7:00pm? b l LSTHA
22 25 - Equatorial to Horizontal Step 1Find a, LST and H is decimal hours.Step 2Convert H to degrees.Step 3Convert d to decimal degrees.
23 Step 4 Step 5 Step 6 Find sin a = sin d sin f + cos d cos f cos H Find aStep 6Find
24 Step 7 Step 8 Step 9 Find A’ If sin H is negative, A = A’ If sin H is positive, A = 360° – A’Step 9Find a and A in degrees, minutes and seconds.
25 More ExamplesSuppose that the Moon occults the star Antares on Feb 6th. Find the following for the Moon:adbl
26 Ecliptic Coordinates Step 1 Step 2 Step 3 Find a and d. Find a and d in decimal degrees.Step 3Find sinb = sind cose – cosd sine sina
27 Step 4 Step 5 Step 6 Find b. Find y = sina cose + tand sine Find x = cosa
29 More Examples On what day does Vega cross the meridian at 8:00 PM? What is the maximum altitude of the Sun for today in Nacogdoches?At approximately what time does the Sun cross the meridian today?What is the maximum altitude of the Sun over one year?