Eyepieces

Three covers almost everything: a low power one for finding things and for large objects, a medium one that becomes your default, and a high power one for the Moon, planets and double stars. Buying three good eyepieces beats buying seven mediocre ones. Most people start with the 82 degree series at $139.00 and build outwards.

Divide the telescope focal length by the eyepiece focal length to get magnification. A 1000mm telescope with a 25mm eyepiece gives 40x. As a rule, useful magnification tops out at roughly twice the aperture in millimetres, so a 100mm telescope rarely does better than 200x no matter what you put in it. Tell us your telescope and we will suggest a set.

It is how wide the circle of view looks to your eye, not how much sky you see. A 52 degree eyepiece looks like peering down a tube. An eyepiece at 100 degrees fills your vision so completely that you turn your eye to look around inside it. Wider fields also mean objects drift out of view more slowly in an untracked telescope.

No. Wide field eyepieces are heavier, more expensive and can need more careful eye placement. The 52, 62 and 68 degree series are lighter, cheaper and optically simple, which suits small refractors and grab and go setups. Width matters most at low power on large targets and least at high power on a planet.

For a hydrogen-alpha telescope, yes, it helps. The Lunt Solar Telescope Eyepiece range from $89.99 is designed around the very narrow bandpass and short back focus of solar instruments. The 7mm to 21mm zoom is particularly useful because solar seeing changes minute to minute and you can chase it without swapping glass.

Standard astronomical eyepieces will usually reach focus on a solar telescope, but the dedicated Lunt range is matched to the job. Never point any eyepiece at the Sun through a telescope that does not have a purpose built solar filter system. See solar telescopes and solar filters for the safe way to do it.

Eye relief is how far your eye can sit from the lens and still see the whole field. If you wear glasses while observing you need roughly 15mm or more. The 92 degree long eye relief series exists specifically so that spectacle wearers can use an ultra wide field without giving up the edges.

Extra low dispersion glass brings different colours of light to a closer common focus, which reduces the faint colour fringing you see on bright objects. In practice it shows up on the limb of the Moon, on Jupiter and on bright stars near the field edge. The 72 degree ED and 92 degree ED series both use it.

It varies by focal length. Long focal lengths in the wider series generally use a 2 inch barrel because the field stop physically will not fit in a 1.25 inch tube. Shorter focal lengths are usually 1.25 inch. The product page lists the barrel size for each option, and if your focuser only takes 1.25 inch we will point you at the right ones.

Because dew is the single most common way an observing session ends early. A sealed, argon purged eyepiece does not fog internally when you bring it from a warm car into cold night air, and it survives being left out in damp grass. Every Explore Scientific series on this page is waterproof.

Aperture wins first. A larger telescope with a decent eyepiece beats a small telescope with a superb one. Once you have the aperture you want, eyepieces are the cheapest way to change what the view feels like, and they carry over to every telescope you own afterwards. The buying guide works through how to split a budget.

Yes. Free shipping applies to everything in the store, from a $59.00 eyepiece to a telescope. No minimum order and no handling fee appearing at checkout.