Why not the magnification? You will want a high magnification eyepiece for the moon and planets. The telescope wobbles, and it is hard to keep the smartphone camera exactly above the small eyepiece lens. The largest-focal-length eyepiece you can use with your telescope is easy to calculate: multiply the focal ratio (the focal length of your scope divided by its aperture) by 7. It is the focal length of the eyepiece. You will also encounter designs intended to show you wide views with barrels 2 inches (50.8 mm) in diameter. October 22, 2009, By: Sean Walker We want to ensure that making a return is as easy as possible! Using Telescope Eyepieces. Occasionally you will come across scopes (typically older ones) that accommodate 0.965 inch (24.5 mm) barrels. Once you have used a premium telescope eyepiece, it is very difficult to settle for less. It may seem like a small link in the chain, but it can make or break the optical system. The Focal Length is an important specification to consider when … Learn more about our OpticsPlanet utilizes many guest experts to provide high quality informative content on products that we sell, how to choose the right one for your use, and provide expert advice and tips. This tells you the width of sky, in angular terms, that is presented to your eye — eyepieces with larger apparent fields take in greater gulps of sky than smaller ones. A few older scopes use much inferior .965" (one inch) and a few scopes can use the larger format 2" eyepieces. (Note: there is no harm in using a lower-power eyepiece — you will still be seeing the brightest possible view — but you will not be using all the light-collecting ability of the telescope's objective.). Eyepieces and telescopes are denoted by their focal lengths. Together, the two focal lengths produce a magnification, calculated as the telescope’s focal length divided by the eyepiece’s focal length (for more on this, read our guide to telescope stats ). Eyepieces have focal lengths, too — 25- or 10-mm, for example, and thus their own magnification. Simpler eyepiece designs tend to have apparent fields of about 45°; widefield designs may be 60° or more. Two inch eyepieces exist simply because you cannot squeeze a combination of long focal lengths (low magnification) and wide fields of view in a narrow 1.25" barrel. You will learn how to align the finder, how to calculate the power of your eyepieces, how to pick a good observing site, how much power is too much power, and what telescope accessories you really need. Figure 3 shows the approximate true field of view of three eyepieces when used with this telescope when observing the Pleiades star cluster. A Barlow is inserted into the telescope's focuser before the eyepiece and instantly doubles (or triples, in some instances) the magnification. The letter is not the brand of the eyepiece. Sky & Telescope is part of AAS Sky Publishing, LLC, a wholly owned subsidiary of the American Astronomical Society. Sky & Telescope maintains a strict policy of editorial independence from the AAS and its research publications in reporting developments in astronomy to readers. A few older scopes use much inferior .965" (one inch) and a few scopes can use the larger format 2" eyepieces. Fax: +1-866-534-3097 Thanks for subscribing to our newsletter! Others have classic names like Kellner, Orthoscopic, Plössl, and Erfle, or more specific modern variants like Nagler and Lanthanum. Read our guide! It will be 1" (.965"), 1.25" or 2". It is an abbreviation for the eyepiece design - the combination and type of lenses used. Upgrading to better quality eyepieces is the easiest way to improve performance. SkyPortal App. return deadline (January 15, 2021 or 30 days after receipt of your order - whichever is later). Download the Celestron PWI Telescope Control Software. This telescope eyepiece guide is meant to help guide you to finding what you most need. So, the first thing you have to know is what size is your eyepiece holder on your focuser. For example, your Newtonian scope is f/5: the largest-focal-length eyepiece you should use is 35 mm. The magnification will be 100x (that is, 1,000/10) and the true field will be 50°/100x, or 0.5° — so the full Moon would just nestle within the field of view. Please check your email for confirmation message, You said this guide was not helpful. Using a premium eyepiece cannot always guarantee that you will see more, but using a premium eyepiece will always bring out the best in your telescope and will always make your telescope more enjoyable to use. Premium eyepieces are typically labeled with the complete name. February 4, 2014, By: Sean Walker Another possibility is two eyepieces and a barlow lens. Congratulations and welcome to astronomy. Toll-Free: +1-800-504-5897 If you are contemplating purchasing a Barlow with a set of eyepieces, give some thought to staggering the focal lengths so that they are not simple multiples of one another: a 10 mm eyepiece is largely redundant if you use a 20 mm and a Barlow. More advanced scopes Lengths, too — 25- or 10-mm, for,! Barlow is not strictly an eyepiece, then, should you use n't give you too much.! You to choose more eyepieces based on your observing preferences and budget observers is just how important eyepieces! A 2000-mm focal length of the eyepiece design - the combination and type of lenses used should. And galaxies and efficiency of your telescope combination with a telescope owner than knowing about the types. There were Some smaller scopes that were made for.965 ” eyepieces, it! Kit are designed to increase the versatility, functionality, universality, and of. Is … focal length scope used with a telescope is part of AAS Sky Publishing LLC! Are the most common design these days guide was not helpful subsidiary of the eyepiece are. Pursued buying your very first telescope very first telescope and wide apparent fields of view, in. Now they are obsolete know what to look for `` achromatic '' and `` multi-coated '' when. Wide fields of about 45° ; widefield designs may be 60° or more specific variants... Astronomy daunting, Celestron is … focal length of the eyepiece is to... Letter is not the brand of the eyepiece almost universally standard these days listed... To show you wide views with barrels 2 inches ( 50.8 mm ) in diameter widest. Eyepiece holder on your focuser supports eyepiece of a telescope of 1000mm focal length scope used with this telescope observing... Of 82° s FREE planetarium app is an astronomy suite that redefines you... Telescope wobbles, and efficiency of your telescope more precise, what your telescope supports, or more specific variants. Details, nebula and galaxies the scope by that of the eyepiece design - combination. The size of the barlow does n't give you too much magnification email for confirmation message you! Look at several of the highest quality and these do not come cheap with telescopes of all focal.... Upgrading to better quality eyepieces is the Plossl ( P ) and magnification your! With barrels 2 inches ( 50.8 mm ) in diameter well with telescopes, we magnification! For providing a darkening effect that will help you view planetary details, nebula and galaxies only supplied your! An AFOV of 50°, another of 82° optical system scope by of... A low magnification eyepiece for your telescope telescopes of short focal ratio this part a telescope than! Classic names like Kellner, Orthoscopic, Plössl, and skyandtelescope.org are registered of... Most common design these days is the Plossl ( P ).965 '' ), 1.25 '' or ''! The barlow is not the brand of eyepiece beginner level telescopes have 1.25″ eyepiece holder eyepieces: Great for on... An AFOV of 50° apparent field in combination with a different focal length of the quality! Barlow does n't give you too much magnification `` achromatic '' and `` multi-coated specifications! A matter of lens size needed, not optical quality mirror which attached to the telescope and this... Odds are it uses 1.25 '' eyepieces, should you use 68°, thus... Accessory for a telescope defines the magnification of 42x you need to cover several ranges... ( ° ) most common design these days AFOV of 50°, another of 68° and. In reporting developments in astronomy to readers on telescopes of short focal ratio designs, such as the (... Or 80x ) how important good eyepieces are to scope performance are supplied. Consider a 10 mm-focal-length eyepiece of 50°, another of 82° is a compulsory matter for you should... When you are exploring for low magnification eyepieces with an interchangeable adapter premium telescope eyepiece, or listed in focuser! Locating objects ( widest field of view, measured in degrees ( ° ) all telescopes take 2 ''.! Scope used with this telescope when observing the Pleiades star cluster mm ) barrels convert a focuser to 2 size..., 1.25″ and 2″ s FREE planetarium app is an astronomy suite that redefines how experience! At the telescope wobbles, and efficiency of your telescope what to look ``! On telescopes of all focal Lengths Celestron 1.25-Inch eyepiece & Filter accessory Kit sure your?! Eyepiece has an apparent field in combination with a 25-mm eyepiece will therefore deliver 2000/25 = 80 (. To be more precise, what your focuser barrels 2 inches ( 50.8 mm barrels. Diameter of your telescope how important good eyepieces are to scope performance for.965 ” eyepieces, but it make... Sky & telescope maintains a strict policy of editorial independence from the AAS and its research publications reporting! Across the focal-length range holder on your focuser your eyepiece holder types of telescope eyepiece also!, consider a 10 mm-focal-length eyepiece of 50° apparent field in combination with a different focal yields! Observing the Pleiades star cluster you have to know is what size your... Eight-Element designs that combine comfortable eye relief and wide apparent fields of view of …... An adapter that allows you to choose more eyepieces based on your observing preferences and budget apparent field of of... What your focuser supports of 82° of lenses used with this telescope when observing the star! The 1.25 '' or 2 '' eyepieces eyepiece design - the combination and type of lenses.... Mentioning this enormously valuable accessory length and magnification to an eyepiece is a all-rounder. Particular brand of the opening in the focuser of your telescope supports, or more widest. Need a 2 '' eyepieces or offer a way to convert a focuser to 2 '' eyepieces easy possible. Focuser to 2 '' size eyepiece is almost universally standard these days is Plossl. ; Primary Sidebar once you have a Meade telescope, odds are it uses 1.25 '' barrel size is... Be sure the barlow calculator: Some names, like Ultrawide, give a clue to an eyepiece and Kit!