The Sky – An introduction and review
- Open TheSky (version 6, the blue icon) .
The screen should show the view of the sky looking due south. Even if the
sun is above the horizon, the sky will look black and show stars. The
green region is the horizon and ground. Notice the viewing directions are
labeled along the horizon.
- Set the date and time. For example let’s set the date
to 3 days from today’s date and set the time to 9:00PM. This is done under
the menu item Data>Time…. A new dialogue box comes up. To keep the time
from drifting make sure you stop the clock Set the time to 9:00pm. Now set
the date 3 days from today. Close the dialogue
box. If you wish to change
location, see #3, otherwise click OK (but read #3 to know how it’s done).
- If you
wish to change location, select
Data>Location. A new dialogue box comes up. Select the tab Predefined
Locations. Notice that the Current City is Sacramento. To choose another city in the US, choose
United States. Then you can chose from the list of cities, double click on
the cities note the change in Latitude and Longitude then click OK to
change locations. To select from an international list of cities, choose International
(instead of United States).
- Moving around the sky. Once everything is set, one can move
the sky around by clicking on the Green arrow icons at the top of the
can also look in the 4 cardinal directions of N, E, S, W. To
do that click on the appropriate lettered buttons at the top of the Sky6
window. . The Z button means looking toward the zenith (overhead). Our
“standard” direction will be looking south (S).
- Object Information. Now find a named star on the
screen (such as Sirius or Vega, scroll around if need be) and click on the
star. A box of information appears on the screen, this is called a dialogue box (see below). At the
top of this dialogue box is information such as the Name of the object,
Magnitude, Declination, Right Ascension, Altitude and Azimuth. Within the
dialogue box (where the scroll bar is) there is other info such as Flamsteed/Bayer designations and Spectral
classifications, and (if you scroll down) the rise, set and transit times
of the object selected. To center on the object selected click on the icon in the lower left corner of the
A Dialogue Box
- Finding the angular separation
between two objects.
Now select a second named star and click on it. Another dialogue box
appears with information about that star. Click on the green protractor at
the bottom of the dialogue box. When you do so, you’ll see highlighted
within the dialogue box the angular separation (in degrees, arcminutes and arcseconds)
from the object you have currently selected to the object you had most
- Finding an object. Instead of randomly searching for
an object using the scroll bars (or arrow icons), you can find a desired object
by hitting the F key and typing its name into the Find box. Alternatively,
one can click menu item Edit>Find or click on the Find icon .
Find either M27 or M42.
- Changing the View. TheSky
has two views of the sky which are accessed by the buttons at the top of TheSky window. There is one called Zenith Up (Z) in which the horizon is visible (this is the
default). The is also a view that has the North Celestial Pole Up (P) and
orients the stars like they are on your SC001 chart and removes that
horizon. This can useful if you wish to view an object that winds up the
below the horizon.
- Zooming in and out. To zoom in or zoom out of the
star field, click on the appropriate magnifying glass icon
To zoom in on a specific star/object/location, either click
on the object or Find it (see #7 above) and then use the centering icon in the dialogue box. Now zoom in on the
Right Click on a star that is not connected to a constellation line. When
you do you should get the following menu which includes Display Properties
of Star. Select that and this should appear:
allows you select which objects will appear on the screen and set how faint of
stars will appear on the screen. The Faintest magnitude of 5.0 is a good limit,
but if you wish to see more stars set that to a higher number. Setting it to 30
will show all the stars. Some of the fainter stars will not appear until one
zooms in closer. You can change other properties (such as constellation
boundaries or constellation figures) by right clicking on them.
To toggle the labels, press the label
- Time step feature. One can step forward or
backward in time by using time step buttons (located just above the stars
on the upper, right side). The
default time step is 1x (real time). Change this to one hour (by clicking
on the next to the time interval and selecting
“one hour”). If you now press the button, the sky will advance one hour. If
the sky will march forward continuously at one hour per frame. Pressing will cause the sky to step backwards and will “play” the sky backwards. The time
interval can be changed by selecting a different interval (by clicking on
the next to the time interval) and/or typing
in a new time interval. For example, if you wanted to choose 2 hours to be
your interval, change 1 Hour to 2 Hour. This is the easiest way to go from
say 9PM on a certain night to 11PM on that same night (as opposed to going
to setting the date and time as in # 2.
Close the program and
do not save.
- According to TheSky,
what is the Latitude of Sacramento?
- Change the time to 9PM tonight. Look towards the East
by pressing the yellow E icon at the top. Which planets (if any) can be
seen in the Eastern Sky (Do not move the sky around but look directly East).
- Find Neptune. What is its altitude and azimuth at the time and date
in Question 2?
- What are the Right Ascension and
Declination of the object in Question 3?
- Keeping the same time and date,
Change the Location to Honolulu, HI.
What is the latitude of this new location?
- Find the same object as in
Question 3. What are its altitude and azimuth of the object now? Are these
the same as in Question 3? Which of these two coordinates changed more?
- Look at the RA and Dec of the
object. Did these significantly change from Question 4?
- Return the location to the
location of Sacramento. Change the date to November 19 and make the time 6:45 PM. What is the angular
separation between Saturn and Antares (as given by TheSky)? What is this separation to the nearest
degree? If I had a pair of binoculars which had a field-of-view of 5 degrees, would you be able to
see both objects in the same field?
- On the date and time in Question
8, find M20. What type of
object is it? What is its more common name? How many degrees is it from M21? You will have to center and zoom
in to see and click on both objects clearly.
- On the date in Question 8, at what time
(to the nearest 5 minutes) will the first object in Question 9 be 50 degrees above the horizon for
the first time in the evening?
- Now change the time to 9:45 PM and find M45.Center and zoom in on it (Here
it might be easiest to center on it by right clicking on it and selecting
Center). How many stars do you see in this cluster (within the purple
cloud)? Now change the lower magnitude limit to 6.0. How many stars now
- Now go back to the standard South view by
pressing S (or the other methods as described in the Instructions. Now
find Uranus at the same time
and date as in Question 8. What constellation is it in?
Close the program and do