by Jim King
Learn the basics, then work on getting better and having more fun
BARLOW LENS: This type of lens which you install in your telescope's focuser (and then put an eyepiece into) increases the effective focal length of a telescope and magnifies its image. A 2x Barlow doubles the focal length and the eyepiece will provide twice the power. If you choose the eyepieces carefully, adding a Barlow can give you a much wider range of magnifications.
BINOCULARS: High-quality binoculars should be part of every observer's kit. For magnification, choose 7x, 8x or 10x. The front lenses should be at least 50 mm across. Smaller ones don't collect enough light. If your budget can stand it, check into Image Stabilized (Canon, Fuginon) binoculars to avoid having to rely on the availability of a tripod. I have the Canon 10X30s image stabilized which are a true "grab and go" accessory for astronomy, bird-watching, etc.
CIRCUMPOLAR STAR: This term describes a star that always lies above an observer's day or season. At the equator, no star is circumpolar. At the North or South Pole, all stars are circumpolar. At any other latitude, a star whose declination is greater than 90 degrees minus the observer's latitude will be circumpolar.