· Get a Cloudy Nights T-Shirt · Submit a Review / Article    Click here if you are having trouble logging into the forums Cloudy Nights - Official Forums of the 2009 International Year of Astronomy Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User   You are not logged in. [Login] Forum Archives · Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar Equipment Discussions >> ATM, Optics and DIY Forum Previous   Index   Next   Threaded   Pages: 1 arpruss scholastic sledgehammer Reged: 05/23/08 Posts: 855 Loc: Waco, TX Singlet + filter       #3365785 - 09/30/09 10:45 AM Edit   Reply   Quote Quick Reply   Here is a naive question. Let's say I bought an F/4 or F/3 200mm uncoated PCX condenser lens (about $80-84) from Anchor Optics, stuck it in a tube, and used it with, say, an O-III filter and a wide long FL eyepiece. Would this make a nice wide-field nebula scope, or would things look horrible? I am guessing the latter--or is it worth doing the experiment? -------------------- Coulter Odyssey 13.1" split-tube Coulter Odyssey 8" Home-made 7.8" F/4 dobsonian travel scope Home-made 68mm F/5.3 achro (typically used as finder on 13.1") Skymaster 15x70 BPTs4 8x30 32mm Plossl, 30mm Rini, 27mm Kellner, 13mm Hyperion, 6mm TMB/BO Planetary, Owl 2X Barlow Palm TX with AstroInfo and RescoViewer Post Extras:       walt r Post Laureate Reged: 02/13/07 Posts: 3462 Loc: Doylestown, PA Re: Singlet + filter [Re: arpruss]       #3366399 - 09/30/09 03:59 PM Edit   Reply   Quote Quick Reply   The OIII filter would probably reduce the CA (chromatic aberration) to reasonable limits. But simple PCX lens also have additional aberrations like SA (spherical aberration) especially at small focal ratios. Check here for more info. If you have an OIII filter and a simple lens give it a try. -------------------- Walt Obsession 18" f/4.45 #1370 AN/SC MK67 Deluxe 6" f/12 Mak-Cass, Super Polaris GEM, JMI MicroMax DSC DIY 60mm f/6 Achromat Cookbook 245 CCD Post Extras:       Pages: 1 Previous   Index   Next   Threaded   Extra information 3 registered and 2 anonymous users are browsing this forum. Moderator:  Don W, Mike I. Jones  Print Thread Forum Permissions       You cannot start new topics       You cannot reply to topics       HTML is disabled       UBBCode is enabled Thread views: 85 Jump to *International Year of Astronomy 2009* -----   Global Coordination   Cornerstone Projects   Special Projects   Special Task Groups   Global Activities   National and Regional Activities   IYA 2009 in Africa   IYA 2009 in the USA*Announcements and News* -----   Cloudy Nights Announcements   Discussion of CN Articles, Reviews, and Reports   Beginners Forum   Celestial Events   Light Pollution*Equipment Discussions* -----   ATM, Optics and DIY Forum   Binoculars   Binoviewers   Cats & Casses   Classic Telescopes   Equipment   Eyepieces   Mounts   Observatories   Reflectors   Refractors    Celestron SkyScout and Meade mySky   Video and Electronically Assisted Astronomy*Astrophotography and Sketching* -----   Beginning and Intermediate Imaging   Film Astrophotography   DSLR & Digital Camera Astro Imaging & Processing   CCD Imaging & Processing   Solar System Imaging & Processing   Sketching   Astro Imaging/Sketching Contest *Observing* -----   NEO   General Observing   Planetary and Solar System Observing   Lunar Observing   Deep Sky Observing   Double Star Observing   Solar   Variable Star Observing and Radio Astronomy*Telescope Specific Forums* -----   Celestron NexStar    NexStar GPS / CPC Telescopes   Questar Forum   Meade ACF/RCX / LX / GPS    Meade ETX*Other* -----   Science of Astronomy & Space Exploration   AstroWebsites   Space Rocks*Speciality Forums* -----   AstroArt   Astronomy Software & Computers   Stellar Media   Astro Outreach, Clubs and Star Parties*CN Feedback and Vendor Announcements* -----   Vendor and Group Announcements CN Forums Home

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