Stellarvue used to make some very good short focal length achromatic doublets (the Nighthawk I believe). For higher powers though a long focal length or ED glass is valuable. -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Chuck Hards Sent: Tuesday, August 16, 2011 7:06 AM To: Utah Astronomy Subject: Re: [Utah-astronomy] Small Refractor Suggestions One final note on refractive objectives. Our large astro-binos almost all use doublet objectives, albeit at relatively low powers, yet no-one ever seems to complain about uncorrected color in bino views. We're too busy enjoying the view! The short refractor can be a top-notch RFT. With this in mind, I may build my 6" f/5 Jaegers refractor first, out of all the lenses I recently purchased from Surplus Shed. As for long-focus refractors, I have a home-made 50mm f/20 refractor, built around a 50-year-old military surplus cemented doublet. This is one of the most fun telescopes I have ever used, having seen every Messier object and countless NGC/IC objects with it, from my light-polluted back yard. All with less than 2" of aperture. _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php