Astronomy 101 Lab 3-1

.pdf

School

Clark College *

*We aren’t endorsed by this school

Course

101

Subject

Astronomy

Date

Dec 6, 2023

Type

pdf

Pages

5

Uploaded by MateFire12601

1 Astronomy 101 Lab 3 Stellarium is a free, open-source planetarium program available for use online or to download. The program can be downloaded at: https://stellarium.org/ Or used on the web at: https://stellarium-web.org The advantages of using a computer- generated sky are numerous. First, and most obviously, it’s never too cloudy to observe the sky on the screen! Another powerful advantage is time. We can examine the sky on any day, at any time: past, present, or future. We can watch the stars and planets move quickly across the night sky in a way that would not be possible outdoors, or even with a professional telescope. We can change our location and see the sky from parts of the world we have never visited...or from other worlds entirely. Objectives ๏ Become familiar with the Stellarium program and its user interface ๏ Define and distinguish between systems of astronomical coordinates ๏ Examine the position of the sun in the sky over the course of a year Procedure 1. Launch the Stellarium program. When the program has loaded, your screen should show you located in a field of grass, facing north. You have multiple tools that you can use, located at the top and bottom of your screen. On the bottom left, click on the location label and make sure it is set to view from your current location. On the bottom right, click on the date and time and make sure it is set for today’s date and the current time. Play with the other screen options in the bottom center. What does each of them do?
2 Screen Option Icon What it Does Astronomical Coordinate Systems There are several systems that can be used to locate objects in the sky. We will distinguish here between two coordinate systems: azimuth/altitude (Az/Alt) and right ascension/ declination (RA/DE) . Either one of these systems is analogous to using x- and y-coordinates on a piece of graph paper. They are two-dimensional systems, which means that they can tell you where to look in the sky to find an object, but not how far away that object is from the Earth. 2. Turn and face north: Toggle on the Azimuthal grid , look up a bit, and examine the coordinate system. Azimuth is the angle measured in a horizontal circle, around your horizon. Due N = 0°. Head around the circle, and E = 90°, S = 180°, W = 270° and back to N = 360°. Altitude is the angle measured from the horizon (0°) to the zenith (90°, or directly overhead). Thus, any point in the sky that you can see can be specified by telling you which direction to face (Az), and how high up to look (Alt). This is the type of coordinates to use when specifying locations of objects in your Observation Log. OY GIIY YMK QOSKY IUSSKIYOSM YMK IUSYYKQQGYOUSY /Y UQGIKY YMK WKKKWKSIK OSGMKY UK YMK IUSYYKQQGYOUSY MUKY YU G ±²²³ IGWQ GYSUYUMKWK 'IIY GSI WKSU[KY YMK KGWYM GY G MUWO_US GSI WKKKWKSIK 'IIY YMK '_OS[YMGQ -WOI 'IIY YMK +W[GYUWOGQ MWOI OIKSYOKOKY UYMKW MGQG]OKY OS KGWG]G_ UGOKIYY 3OMMYSGWKY ]MGY´Y KGYOKW US _U[W K_KY OK _U[ [Y[GQQ_ YMOY MGY G WKKKWKSIK ]MOQK YYGWMG_OSM +[QQ YIWKKS SUIK
3 3. Set your time for today at 10:00PM (22:00). Locate the star Polaris and record its Az/Alt coordinates, which are given in degrees, arc minutes, and arc seconds. (When you click on a star, in the upper left hand of your screen you will see the information associated with that star. Keep in mind that Polaris should be located about halfway up the northern horizon). Pay attention to how these coordinates correspond to the star’s location in the sky. Polaris: Az:_______________, Alt: _________________ 4. Toggle between grids: Notice the difference between the equatorial and azimuthal grids! The azimuthal grid parallels the Az/Alt coordinates. The equatorial grid aligns with standard celestial sphere coordinates of right ascension (RA) and declination (DE). Does changing the grid change the actual location of the object? ___________________________________________________________________ 5. Turn off the azimuthal grid and toggle on the equatorial grid. You are now looking at the right ascension/declination coordinate system. Record these coordinates for Polaris, and notice that RA is not given in degrees. Polaris: RA:_______________, DE: _________________ 6. Locate the bright star Arcturus. Record both its Az/Alt coordinates and RA/DE. Move forward in time to three months from now at the same time of day and record the positions. Note that even if the star dips below your viewing horizon (alt < 0°), its position is still displayed. Continue to advance in three month increments for an entire year. Enter the values in the table below. Date Az. Alt. RA DE Today 3 mo. later 6 mo. later 9 mo. later 7. Change your location: Return to today’s date and the time of 10 pm (22:00). Remain centered on the star Arcturus but change your observation location. Pick any place you like: New York, Chicago, Paris...literally anywhere. Note your location, and record one more time the Az/Alt and RA/DE coordinates for the star. For the location you chose, is Arcturus visible above the horizon? Location: __________________________ Arcturus Alt: _____________, Az: ____________, RA: ______________, DE: _____________ Is Arcturus visible above the horizon? _______________ ²²²sµ¶´µ¶·¸¹ ºµ»s²µ´¼¸·¶¹ SU ²¸M ²¸Sµ½·¾Y º¿¾s½±´µ»·¾¹ ¸±¸sµ¶´²¶·¸¹ À±±sµ¼´½¼·» ±µM ±»Sµ¸·½Y º±¾s²¸´¸¶·¾¹ ²µ±s²»´¸¼·²¹ À±µsµ½´½»·½¹ ±µM ±»Sµ¼·µY º±¾s²¸´±µ·¼¹ ±²¶sµ»´²²·µ¹ ºµ½s½»´¸µ·¼¹ ±µM ±»Sµ¶·¼Y º±¾s²¸´±¼·±¹ ½µ»s²¶´½¸·½¹ ºµ»s¸¼´¸¼·»¹ ±µM ±»Sµ¶·±Y º±¾s²¸´½¼·¾¹ 'QGYQG ±µM ±»Sµ¸·½Y º±¾s²¸´¸¶·¾¹ ½¾±s²¿´¼²·²¹ º±±s²»´µ²·¼ _KY
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help