|Brand and Model:||Celestron X-CEL 21mm|
|Focal Length:||21 mm|
|Apparent FOV:||55.0 degrees|
|Field Stop Dia.:||0.0 mm|
|Eye Relief:||20 mm|
|Description:||This medium focal length parfocal Celestron X-Cel eyepiece is a good low to medium power long eye relief eyepiece at a very sensible price. For example, with a 10” f/4.5 Dobsonian it will give you 54x and a full 1 degree field that’s twice the diameter of the full Moon. This gives a Dobsonian owner four minutes to observe an object as it drifts from one side of the eyepiece’s flat field to the other. That’s plenty of time for multiple family members to see the object or for you to absorb as much detail as possible before having to reposition the scope. |
Its five-layer multicoated ED (extra-low dispersion) glass six-element optics provide high contrast, making it a good eyepiece for observing galaxy clusters, framing the more compact emission nebulas with the black of space, observing the nebulosity around the Pleiades, etc. It's a good choice to complement the 40mm eyepiece provided with some go-to Schmidt-Cassegrains.
A soft rubber eyecup shields the eye from ambient light and rolls down for more comfortable eyeglass use. A knurled rubber ring on the barrel provides a secure grip when changing eyepieces in cold weather.