Astronomy Hacks

Learn to Star Hop

When a Telrad is not enough, find and focus on patterns, and then hop pattern by pattern to the target.

Although the Telrad allows you to locate many objects with amazing speed [Hack #20], it’s not a panacea. Some parts of the sky are simply devoid of the bright stars that you need to orient your scope with a Telrad. To find an object in those barren parts of the sky, you need to star hop.

Star hopping is the process of locating an object by beginning at a bright “guidepost” star and then using your optical finder to follow a trail of dimmer stars until you arrive at the object. The secret to star hopping is to plan the hops so that each hop provides a distinct pattern of reasonably bright stars in the finder. When the pattern is right, you know that the finder is pointed exactly where you think it is, and you can then move the finder to locate the next pattern of stars.

Tip

Before you attempt to star hop, you need to know the field of view of your optical finder and how objects are oriented in it. You can calculate the field of view precisely by drift testing [Hack #57] or by using the finder to look at star pairs with known separations [Hack #56]. A correct-image finder (rightangle or straight-through) provides an image that is correct top-to-bottom and left-to-right. A traditional straight through finder provides an image that is correct left-to-right, but inverted top-to-bottom. If you are using the latter type of finder, simply invert your star charts to make ...