Star Chart Instruction Manual

This is a quick guide about how to use the star gazing app, Star Chart. When you begin your journey in Star Chart you are welcomed by a view of the horizon with over 100,000 stars all around you.

Star Chart will now look for your location, as it is doing so you can freely pan across the sky and visit all the stars and planets by giving them a quick tap. Tapping on an object will bring up an information box tailored to the object. For example, you can find out the brightness of a Star or the current distance to Mars.


	Minimises the data box. Tap on it again to maximise the data box again.
	Closes the data box
	Allows you to track objects in the sky. This is particularly useful when zoomed in on fast moving objects, such as planets
	Allows you to zoom in on one object, giving you a much better view of a planet or messier. Once zoomed in you can tap this button again to zoom out
	This button, exclusive to planets, allows you to visit the planet close up and in full 3D. Discover the majesty of Saturn's rings or fly around the craters of our Moon. To return back to the normal view just tap the icon in the top left corner of the screen.

Please note that in some cases there may be a lot of data available. To keep it neat the information box is limited in height; to view more data you can scroll through it by moving your finger along the scroll bar or statistics.

By default Star Chart is set to Auto AR mode which allows you to view the night sky in Augmented Reality as you move the device around. If you want to view a section in more detail you can pan and pinch the view with your fingers (this will temporarily disable the Augmented Reality mode until you move the device again). You also have the option to force the device into using Augmented Reality mode all the time or not at all in the Settings menu.

Interface (iPhone/iPad)

Opens up a menu which lets you search for any of the planets, stars, constellations and messier objects in our database to make it easier to find in the sky.
Opens up a settings menu. Here you can turn on night mode, adjust your display settings, measurement systems and how to filter stars as well as setting your location or visit our support page.

Along the top bar are two co-ordinates (3) and the time (4). Latitude (LAT) and Longitude (LON) show the current location set for Star Chart. This should automatically update when you enter the application, however you can manually change this by going to the settings menu (see above).

The time shows the current time, but can be tapped on and be adjusted. Before trying out this feature we suggest visiting Saturn or maybe looking down on Earth from space. Once you're in your chosen location just tap the time display. You can choose what to adjust going from day, month, year and finally hours and minutes (we suggest starting off with minutes).

Next flick the bar on the right forcefully upwards, this will cause it to continually move forwards in time at a relatively slow pace. Now sit back and enjoy space rotating before your eyes!

If you wish to return to the current time just tap the Now button in the top left.

Display Settings

Equatorial Grid: This enables a grid overlay which is used to find objects based on their quadrant.
Atmosphere: This setting allows you to enable the blue haze (and sunrise/sunset) for your hemisphere. This mimics the same effect astronomers have to deal with when observing the sky and shows why telescopes are normally in high places and point upwards (less atmosphere and ground lights), or ideally, in space.
Constellation Lines: This toggles the lines joining stars to form constellations as well as the lines depicting the area which the constellation occupies.
Constellation Images: This option enables the viewing of the constellations as first drawn by Johannes Hevelius in 1687.
Constellation Latin Names: This toggles switches the constellation labels between local language and Latin.
Labels: These toggles change whether the respectiveo bject names should be displayed.

Units of Distance

In this menu you can choose whether to display larger distances in either light-years or parsecs (roughly 3.2 light years) and shorter distances in metric, imperial measurements or astronomical units (AU) where 1 AU is the average distance between the Earth and the Sun (roughly 150,000,000 kilometres).

Location

Here you can manually adjust your location by tapping the numerical displays (and direction by tapping on the buttons) or ask Star Chart to pinpoint your location for you. By pressing Update from GPS Star Chart will try to pinpoint your location preferably using a Wifi or 3G connection; however, it will use GPS satellites as a third option. Depending on which method it uses can take seconds or minutes. This process will work in the background as you continue using the application.

Please note that objects will look out of place if you have not set your location or have an incorrect time on your phone. Star Chart will not be able to access any GPS settings if Allow GPS is disabled in the settings menu on your iOS device.

Online Support Page

Here you will be shown our support page with Frequently Asked Questions. If you continue to have problems or if your concerns are not addressed on this page please feel free to contact us at info@escapistgames.com.

Information Box

The information box is a delight for more serious star gazers or even those who wish to understnad the universe that bit more. Most importantly we have Right Ascension (RA) and Declination (DEC) as well as Azimuth and Altitude. These are two co-ordinate systems to pinpoint the object in the sky from Earth. This lets you find them using a telescope in your back garden or use software to calculate the next time it is visible (or use our time travel option).

Depending on the object Star Chart will provide different information, such as diameter and orbital period (the amount of time it takes to make one revolution around the Sun) for planets or absolute and apparent magnitude for stars.

Glossary of Terms

Absolute Magnitude (Abs Mag)

This is a similar measurement to Apparent Magnitude, however it removes factors like the atmosphere, intervening objects (like nebulae). This allows you to compare the brightness of stars more accurately. Note that while our Sun is very bright for us, it is actually a very dim star at an absolute magnitude of only 4.8.

Apparent Magnitude (App Mag)

How bright the star appears from Earth. This is a dimensionless number where negative values are brighter than positive values. For example, the Sun's apparent magnitude is -26.64 and a full Moon is at -12.74 while Sirius, the brightest star in the sky is -1.4. As a guide, the human eye can see stars at roughly apparent magnitude 6 and below, this includes nearly 5000 stars.

Axial Tilt

This is the angle at which the planet is tilted from its orbital plane. Of particular interest are Venus' and Uranus' axial tilts. Venus is upside down while Uranus is orbiting sideways.

Average Temperature

This is the average surface temperature of the planet. Note that for most inner planets the actual surface temperature will vary significantly between night and day, we are lucky that Earth has an atmosphere to keep us warm at night!

Azimuth and Altitude

Azimuth and Altitude are co-ordinates for a second co-ordinate system. The key difference between the two systems is that azimuth and altitude are co-ordinates which rely on your local latitude and longitude. Therefore, if you wish to provide co-ordinates using azimuth and altitude you would also have to provide the latitude and longitude and, most likely, time as well.
Azimuth is an angle on your horizon plane where 0° points North and 180° points South.
Altitude, sometimes referred to as elevation, is an angle from the azimuthal plane where straight up is 90° and straight down (through Earth) is -90°.

Distance

This can be measured in light-years (ly) or parsecs (pc). A light-year is the distance travelled by light particle in a year. They travel (in a vacuum) roughly 300,000,000 metres every second, so in a year they have traversed roughly 10 trillion kilometres of space!
A parsec, which is used more often in astronomy, is roughly 3.26 light-years.

HD

This is the designation of the star in the Henry Draper catalogue.

HIP

This is designation of the star in the Hipparcos catalogue.

NGC

New General Catalogue of Nebulae and Clusters of Stars (NGC) is a catalogue of nearly 8000 celestial objects ranging from nebulae (clouds of gas stretching out many times more than our solar system) to whole other galaxies.

Orbital Period

This is the amount of time it takes for the planet to make one revolution around the Sun.

Planetary Satellites

These are natural objects which orbit a planet, for example our Moon.

Right Ascension (RA) and Declination (DEC)

This is a co-ordinate system based around the Greenwich Meridian line. Right Ascension is measured in hours, minutes and seconds from Greenwich in an Easterly direction for 24 hours, at which point it loops. Declination is measured in degrees from -90° at the South Pole, 0° at the Equator and 90° at the North pole. Using these two values you can map a point on a Celestial Sphere and anyone can look up at it. A time is normally provided as objects could have moved since the event.

Rotational Period

This is the amount of time it takes for the planet to complete one revolution about its axis. On Earth this is a day, roughly 24 hours. You may notice that the gas giants all rotate incredibly quickly!

Spectral Class

This is a classification based upon the Morgan-Keenan System which classifies stars according to colour and size. The first letter is an indication of the stars colour including the letters O, B, A, F, G, K, M, where O is hottest at 'blue' and M is coldest at 'red'. This letter is followed by a number between 0 and 9 which is an increment to the next colour. Finally comes a Roman numeral from I to V which denotes its size, where I are super-giants and V are main-sequence stars.
For example, our Sun is G2V which implies it is a yellow, but two tenths towards red, main-sequence star.

Surface Gravity

This is the power of the planet's gravitational field measured in units of G. 1G is equal to the gravitational strength of Earth, so for example the moon is about one fifth as strong while Jupiter is 2.5 times stronger than Earth.

Type of Planet

There are two categorisations (until we find more!), rocky and gas giant.

Rocky is similar to Earth, with a tangible surface made up of any type of material.
Gas giant is a planet made up entirely of gas where there is no defined surface. The 'surface' of a gas giant is the point at which the pressure exceeds a certain value. These planets are known as giants because they need a large amount of matter to exist, if these planets are too small they would simply disperse.