Stargazing For Dummies
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Stargazing is a fascinating hobby, but there’s an awful lot to gaze at up there. Eighty-eight constellations and hundreds of other objects both bright and faint mean that wherever you look when you’re stargazing, there’s something to see. If you want to make sense of it all, and make sure that your kit is properly set up, this Cheat Sheet is here to help.

Aligning Your Telescope and Finderscope for Stargazing

When you use a telescope for your stargazing, it usually comes with a finderscope, a small attachment which allows you to focus on the correct part of the sky. To align your finderscope and telescope:

  1. Get your alignment target in the centre of the field of view of your main scope.

    Your scope may have come with a cross-hair attachment that you can fit to your eyepiece to help you get the target exactly in the centre.

  2. Adjust your finderscope using the small screws attached to it, so that your target is exactly in the centre of your crosshairs.

  3. Keep rechecking and adjusting until you’re sure your finderscope and telescope are looking in the same direction.

    Your telescope and finderscope will be aligned. This means that when you’re stargazing at night, you can use your finderscope to track things down and be confident that your target will be in view in your main scope, too.

Focusing with Binoculars for Stargazing

If you use binoculars for your stargazing, you need to get them into focus before you begin. Once your binoculars are focused, the stars you see should look incredibly sharp. You can focus most binoculars in the same way. Just follow this simple step-by-step guide:

  1. Adjust the separation between the two eyepiece lenses so that they’re at the same spacing as the distance between your pupils, called the interpupillary distance.

    You can usually adjust the separation by holding both halves of the binoculars and physically twisting them apart or together.

  2. Point your binoculars at something bright but distant.

    A planet or a bright star like Sirius or Canopus works well.

  3. Have a quick look through.

    You never know; they may already be in focus!

  4. Close the eye that looks through the eyepiece with an independent focus.

    You may find it easier to put the eyepiece lens-cap back on so that you don’t have to squint.

  5. Adjust the focus until your target looks sharp for your left eye.

    Use the focus ring normally found at the top of the binoculars on the bridge between both halves.

  6. Close your left eye and open your right eye (or swap the eyepiece cap onto the other side) and adjust the focus for your right eye using the eyepiece focus, called the dioptre corrector.

    The dioptre corrector is for people who have two eyes of slightly different strengths.

You’re now good to go, but keep in mind that everyone’s eyes are different. If someone else uses your binoculars, you may have to repeat the focusing process to get them back in focus for your eyes.

Using the Big Dipper as a Stargazing Signpost

One of the great signposts in the northern hemisphere sky is the Big Dipper, also known as the Plough, an asterism in the constellation of Ursa Major. If you can find the Big Dipper, then you’re well on your way to finding lots of other constellations.

‘Dipper’ is an American word for a large ladle for scooping liquid. The Big Dipper asterism has three stars in a curve representing the handle, and four stars at the end of the handle representing the scoop.

  • Pointers to Ursa Minor: The two brightest stars in Ursa Major, α Ursa Majoris and β Ursa Majoris, lie at one end of the Big Dipper asterism. If you picture this dipper lying down, with the base of the scoop on the ‘floor’, draw a line up from β Ursa Majoris through α Ursa Majoris and keep going until you get to the next bright star, which is Polaris, α Ursa Minoris, the North Star. Polaris lies at the end of the tail of Ursa Minor and the end of the handle of the Little Dipper asterism. The rest of Ursa Minor curves from the North Star towards the four stars in the scoop of the Big Dipper.

  • Carry on to Cassiopeia: Draw a line from α and β Ursa Majoris through α Ursa Minoris, the North Star, and go the same distance again on the opposite side of Ursa Minor, and you arrive near the distinct zigzag shape of Cassiopeia (which often looks like a W, an M or an E shape, depending on which position the constellation is in when you’re observing it).

  • Little Dipper pointers to Draco: After you find the North Star using the pointers of the Big Dipper, and once you’ve found the asterism of Ursa Minor, then lying between the Big and Little Dippers is the curve of stars making up part of the constellation Draco. Locate the head of Draco using the four stars that make up the scoop of the Little Dipper. Imagine the Little Dipper lying down, with the base of the scoop on the ‘floor’, with its handle rising up and to the left. The head of Draco sits ‘below’ the scoop.

  • Arc to Arcturus: Go to Ursa Major, to the handle of the Big Dipper. The three stars in this handle form an arc, and if you continue this arc, it will lead you to the bright orange star Arcturus, α Boötis. This pointer is easy to remember: just arc to Arcturus.

  • Spike to Spica: After you arc to Arcturus, continue in that direction in a straight line, driving a spike down to the next bright star, Spica, α Virginis. So remember arc to Arcturus and then drive a spike to Spica.

  • Little Dipper arcs to Camelopardalis: Another signpost in this part of the sky uses the tail of Ursa Minor, the handle of the Little Dipper, to arc to Camelopardalis. It’s not nearly as catchy as arcing to Arcturus, but Camelopardalis is a very faint constellation that’s hard to find, so having a signpost is very handy.

Using Orion as a Stargazing Signpost

Orion is great signpost constellation to use for your stargazing. In fact, it may be the very best, because you can use the stars of Orion to find seven other constellations immediately around it.

The objects you can find using Orion as a signpost are:

  • Orion’s Belt to Canis Major: Picture Orion as a hunter standing upright, with the stars Betelgeuse and Bellatrix marking out his shoulders, and Saiph and Rigel marking out his feet. You can then follow the three stars of Orion’s Belt down and to the left to find the bright star Sirius (α Canis Majoris) in the constellation Canis Major, the Big Dog.

  • Orion’s shoulders to Canis Minor: Draw a line from Bellatrix through Betelgeuse and keep going to find a solitary bright star, Procyon, α Canis Minoris in the constellation Canis Minor, the Small Dog. Procyon is one of the brightest stars in the sky, so it stands out in this blank patch to Orion’s left.

  • Rigel and Betelgeuse to Gemini: Draw a line from Rigel up past Betelgeuse and keep going until you reach two bright stars shining side by side. These stars are Castor and Pollux, α and β Geminorum, in the constellation Gemini the twins.

  • Above Orion’s head to Auriga: Travelling up from Orion’s Belt between his two shoulders and past his head, you’ll soon come to the bright star Capella, α Aurigae, in the constellation Auriga the charioteer.

  • Orion’s Belt to Taurus: Going back to Orion’s Belt, your next target lies up and to the right, following the line of the belt to the bright star Aldebaran, α Tauri, in the constellation Taurus the Bull. If you keep on following this line, a short distance later you’ll reach the Seven Sisters, or the Pleiades, star cluster.

  • Orion’s right leg to Eridanus: Just to the right of Orion’s right foot, Rigel, you’ll find the first few dim stars in the huge meandering constellation of Eridanus the River. The rest of this constellation snakes down a great distance, ending at the bright star Achernar, not visible from the northern hemisphere.

  • Beneath Orion’s feet to Lepus: Directly beneath Orion’s feet, you’ll find the faint constellation of Lepus the Hare.

  • Between Canis Major and Minor to Monoceros: Another faint constellation lies in the seemingly blank part of the sky between Canis Major and Canis Minor. If you draw a line from Sirius to Procyon, then you’ll be passing through Monoceros.

About This Article

This article is from the book:

About the book author:

Steve Owens is a freelance science writer and presenter with a passion for astronomy. He has been the recipient of the 'Campaign for Dark Skies' Award for Dark Sky Preservation, and he was nominated for the Arthur C. Clarke Award for public science engagement.

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