# Activity

### Summary

In this activity, you’ll map your astronomical objects, taken using Serol's Cosmic Explorers, onto the night sky using RA and dec coordinates.

### Goals

Use the RA (right ascension) and dec (declination) celestial coordinates to find and map where your astronomical objects are in the sky.

### Planning

You can choose to create your poster using powerpoint, or create a larger printed DIY poster.

#### Materials

For both versions you will need:

For the powerpoint version you will need:

For the DIY printed version you will need:

### Background

#### Cosmic Coordinates

For a quick introduction to Cosmic Coordinates, you can watch our Cosmic Coordinates video on YouTube.

Astronomers keep track of where objects are in the night sky using the Equatorial Coordinate System. This system uses two measurements, right ascension (abbreviated RA) and declination (abbreviated Dec).

In this activity you’ll be using RA and Dec coordinates to find the position of your astronomical objects and map them on an all sky map.

If we take the whole night sky view from the northern hemisphere, and do the same for the southern hemisphere, we can combine the two views of the sky to get an all sky map.

All sky map with RA along the x-axis and Dec on the y-axis.

#### Right Ascension and Declination

Right ascension (abbreviated RA) is similar to longitude and is measured in hours, minutes and seconds eastward along the celestial equator. The distance around the celestial equator is equal to 24 hours.

Declination is similar to latitude and is measured in degrees, arcminutes and arcseconds, north or south of the celestial equator. Positive values for declination correspond to positions north of the equator, while negative values refer to positions south of the equator. The declination of the north celestial pole is 90° 0' 0" and the south celestial pole's declination is -90° 0' 0". The equator is 0° 0' 0".

To learn about cosmic coordinates, take a look at:

### Instructions

1. Download the poster template (for powerpoint), or the poster titles and info sheet, and the sky map (for DIY).
2. Download your picture sheets for Missions 1, 2 and 3 from the Stickers page on the Serol website (for DIY), or download each challenge image from their summary page (for powerpoint). If you're doing the powerpoint version, skip ahead to Step 6 next.
3. Cut out the titles, poster information, and sky map. Then cut out your images from the picture sheets.
4. Get a large piece of paper and stick the sky map in the centre. (Alternatively, you can use a cork board and pin the map and images to it).
5. Stick the poster information onto the left hand side of the map, and stick the Mission titles and pictures around the map (e.g. Mission 1 above the map, Mission 2 to the right hand side, and Mission 3 below).
6. For the powerpoint version, insert your images into the placeholders, and add in the name of your astronomical object and its RA and dec coordinates below.

7. To map where your image is on the night sky, look at the RA and dec coordinates. Use the map grid to find and mark the location. Once you’ve found the location, you can use a piece of string, or draw a line to connect your image with its place on the sky map.

### Evaluation

Have another person take a look at your poster and check you’ve mapped your objects correctly using RA and dec.

You might notice that your picture of the moon is positioned somewhere different on the map to someone else. Why could that be? To answer this, think about the Moon in relation to the Earth.

Just like the Earth orbits the Sun, the Moon is orbiting the Earth. This orbit of the Moon around the Earth means that it will change position in the night sky over time.

You can learn more about the position and phases of the Moon on our Moon Phases SpaceBook page.

• 7-11
• 12-16
##### Duration

Medium (30-60 mins)

Hands-on