Celestron Standard 2x Barlow and 3.6mm NexStar Plossl
14 September 2001
With such a short focal length telescope (400mm on the NexStar 80) a barlow and short focal length eyepieces are an absolute necessity for lunar and planetary viewing.
First the barlow. The Celestron standard 2x barlow (model # 93507) is well-made, but it is your basic short barlow. It is fully coated, but edges of the optics are not blackened. The inside of the barrel needs a better paint job - the flat black paint is a very thin application and does not cover all of the surfaces inside the barrel. It is not threaded for filters. Performance is acceptable for the price though and if you are on a tight budget, this barlow will serve you well.
Second the 3.6mm Plossl. While there are many styles of short focal length eyepieces on the market, most are 5 to 8 elements and thus decrease overall light transmission - very undesirable in a small scope like a short-tube refractor. The NexStar 3.6mm Plossl is quite a unique eyepiece, a fully coated 4 element Plossl design in such a short focal length. The eye relief is not too bad at 6mm and the apparent field is reported at 40 degrees. It is threaded for filters and also sports a fold-down rubber eyecup.
I like this eyepiece in my NexStar 80. It provides sharp views out to the edge of the field of view. By itself, this eyepiece provides 111x and gives great views of the planets. In the summer of 2001, I used it quite successfully to view detail on Mars. I also use it extensively on Jupiter and Saturn. Typically when viewing the Moon, I slip the barlow in and study detail at 222x in the steady, humid air here. Even though this is well-above the recommend "limit" of 160x for a 80mm scope, the views are very spectacular.
I also use this eyepiece on bright, globular clusters - particularly when viewing at dark-sky sites. I also like this eyepiece when splitting double-stars. I can definitely recommend this eyepiece, particularly for smaller aperture scopes of short focal length.