Celestron Telescope Eyepiece - Filter Accessory Kit

By the Astronomy and Photography Online Staff

Celestron Telescope Eyepiece - Filter Accessory Kit
Illustration courtesy of Celestron International.

The Celestron Telescope Eyepiece - Filter Accessory Kit (#94303) carries a 2012 MSRP of $159.95 and it can be purchased online for as little as $129. The Kit includes five Celestron Plossl oculars, a set of 1.25" filters and an aluminum carrying case. This is a relatively inexpensive, although not optimum, way for a person buying their first telescope to get started with an array of oculars. The 24-26mm Plossl ocular supplied with most decent astronomical telescopes these days is quite useful, but both shorter and longer focal length oculars are necessary if you plan to do much observing. Realize, however, that if you progress in the hobby you will soon want higher quality eyepieces and most of the oculars in this kit will eventually be replaced. For this reason, we generally do not recommend purchasing eyepiece kits.

For 2012, the Celestron Telescope Eyepiece - Filter Accessory Kit includes oculars of 6mm, 8mm, 13mm, 17mm and 32mm focal length. (Formerly 4mm, 6mm, 9mm, 15mm and 32mm.) These are standard, four element, Plossl oculars made in Red China. The apparent field of view (AFOV) of these oculars is 52-degrees, with the exception of the 32mm eyepiece that has a 44-degree AFOV, and they are fully multi-coated. These are standard grade Plossls, not Celestron's premium Omni Plossls. Also included in the set is a 2x Barlow lens.

The filters supplied in the kit include a Moon (neutral density) filter and six colored filters intended primarily for planetary viewing: Kodak Wratten #12, #21, #25, #56, #58A and #80A. The mounting barrels of all Celestron 1.25" oculars and star diagonals (and most other brands) are threaded to accept these filters.

The whole kit is packaged in a fitted, foam lined, aluminum carrying case. The case has room for additional accessories, including the 25mm ocular that probably came with your telescope. This protects and organizes your accessories and makes the set handy to use in the field. The case is probably the most useful part of the kit.

The primary drawback to the Celestron Eyepiece Kit, beyond the generic quality of the oculars, is the relative shortage of long focal length oculars for deep sky use. Only the 32mm qualifies as such and its usefulness is impaired by its restricted 44-degree AFOV.

The preponderance of high magnification, short focal lengths is a little hard to understand. Plossl oculars shorter than about 15mm become increasingly difficult to look through due to their tiny field lens and very short eye relief. Consequently, the 6mm and 8mm oculars are useless for eyeglass wearers and difficult for everyone to use, especially with small aperture telescopes. The 13mm will be useable for non-eyeglass wearers and the 17mm and 32mm oculars will probably get plenty of use, at least until they are replaced by better quality eyepieces.

We feel that substituting a 40mm eyepiece in place of the 6mm and a 10mm in place of the 8mm would make for a more versatile kit. Such a kit might be slightly more expensive, but it would be worth it.

Much better would be the option of a "Deluxe Eyepiece Kit" with 40mm and 32mm Omni Plossl oculars, plus 18mm, 12mm and 9mm X-Cel LX oculars. The Celestron X-Cel LX eyepieces all have a 20mm eye relief, which makes viewing with short focal length oculars much more enjoyable. Such a premium kit could serve most users for a lifetime. (Note that Vixen does offer a higher quality eyepiece kit.)

We have used colored filters for their recommended viewing purposes and owned filter sets similar to those included in this kit, but never found them to be very useful. Some observers, however, do like them. Remember that all filters are subtractive; that is they reduce part of the visible light spectrum, so less light reaches your eye. However, the Moon is usually too bright for comfort when viewed through a telescope, so a neutral density filter (ND) that reduces the total amount of light reaching your eye without altering the color spectrum is definitely required. This filter alone makes the whole filter set worthwhile and it should get plenty of use.

Everyone seems to want a 2x Barlow lens, so Celestron included one. In this case it is a simple, two element (achromatic) design that will induce chromatic aberration when bright objects are viewed. Celestron claims that the supplied Barlow "Complements the Plossl eyepieces and gives you a total of 10 power combinations . . . high grade glass optics with fully multi-coated lenses." Unfortunately, the reality is that it is almost always better to have an ocular of the appropriate focal length, rather than a longer focal length ocular and a Barlow. (A 15mm ocular, for example, will provide better images than a 30mm ocular and a 2x Barlow of the same quality.) This kit already includes three relatively short focal length oculars, so I think most purchasers will find limited use for the generic Barlow lens.

To summarize, the Celestron Telescope Eyepiece - Filter Accessory Kit is worth its modest "starter set" price, with some serious qualifications. The supplied case is great and keeps everything organized. The Moon Filter is also a useful accessory, even though you may or may not find much use for the colored filters. You will likely want to replace the E-Lux eyepieces with more sophisticated designs, particularly if you wear eyeglasses when viewing, as you mature in the hobby.

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