These are the brighter stars and constellations that you should be able to spot easily. Take a step back to look at the bigger dots. The map might very well look like the remains of spilled ink.Telrad finder rings inside the Pocket Sky Atlas Things to Remember and Other Helpful Tips Traversing these rings across the map will give you a better understanding of what area of the sky you can expect to see while star-hopping (don’t be surprised if it is very little!). Next, make little wire rings, from fuse wire, or similar, that correspond to these field sizes you just calculated. Dividing this by 120 gives the diameter of the field in degrees. If you find it hard to pick a pair of stars to focus on, fix upon any star in the celestial equator such that it appears in the center of your field of view.įrom here, note the time taken (in seconds) for the star to drift from center to the edge.
Repeat this process to measure the field diameter of your telescope’s lowest power eyepiece. Locate the same constellation on your map to check the distance between the stars in degrees (the scale is mentioned on the map’s margins).
First, make sure that your and ready to be used.įirst, try locating two stars (preferable belonging to a constellation like the Big Dipper) that fit just inside the edges of your finderscope. To begin, you need to know the size of your finderscope’s field and then your lowest power eyepiece. This makes it much easier to use the chart for star hopping. We can create a little tool to help show how much of the star chart we can see in our eyepiece field of view. The outer edge of a circular map represents the horizon. The point directly overhead is called the Zenith and can be found in the center of the chart. Since the sky is above our heads, your star chart is designed to be held overhead when you read it. As the night progresses, this little dome turns so that the stars seem to rise in the east and set in the west. It helps to think of the sky as a dome around the Earth upon which stars and planets reside. We developed an in-depth guide to the celestial coordinate system, if you’d like to learn more detail. The celestial equator mirrors Earth’s equator and the north and south celestial poles are directly above those on Earth. They are called right ascension and declination respectively. The reference frames we use on star charts are equivalent to longitude and latitude used on maps of the earth. Likewise, locating objects in the night sky requires a reference frame for astronomers to navigate. Wouldn’t it be so much easier if you were given exact coordinates, that AZ is 34° North and 111° West? The state can now be located in a jiffy. Let’s say that you wish to locate Arizona on a map, but you only know that it is somewhere in the bottom left in the US. The Milky Way is often shown too, either as an outline or a slightly grayed out area.Ī Sky & Telescope Star Map Night Sky Coordinatesīefore we get into the details of reading star charts, it’s helpful to understand a little bit about night sky coordinates. Since not every night sky object is present here, astronomers use these brighter objects as references for star hopping to fainter ones. In addition to dots, there are gray circles that refer to star clusters and ovals to galaxies. The size of the dot reflects the brightness of the star, the bigger the dot, the brighter the star. Stars are represented as black dots on a white background, which makes it easier to read when observing at night. It’s similar to a planisphere but they have different uses. Normally, a star chart only shows what’s visible to the naked eye under dark skies. It represents the stellar dome with only the brightest stars and objects and the constellations.
Similar to how we use terrestrial maps to find destinations on Earth, a star chart is a map of the night sky and one’s guide to navigating the stars.