Re: [APML] Tele Vue & Field Flatteners for Refractors?

["Chris Cook" <ccjd@ix.netcom.com>]

Hi Jim -

The Ranger FF (or 1.1x unit) is a piece of s**t.  I used it back in 1998 on
the then new TV85.  At the time, it was the only FF TeleVue made.  It
introduces severe chromatic aberration.  It takes a nice scope like the
TV85, and turns it into a Tasco achromat...... <g>  Soon after I started
shooting with the TeleVue scopes, TeleVue came out with the .8x R/F's.  The
.8x does not introduce any unwanted aberrations and is a very nice
accessory.

Chris

----------------------------------
Chris Cook
Astronomical & Nightscape Photography
www.abmedia.com/astro

-----Original Message-----
From: Jim Vineyard <mojjv@hotmail.com>
To: astro-photo@seds.org <astro-photo@seds.org>
Date: Tuesday, February 03, 2004 3:54 PM
Subject: [APML] Tele Vue & Field Flatteners for Refractors?


>
>Hello All,
>
>  I'm trying to figure out the *real* difference between the "Ranger" and
>"Pronto & TV-85" field flatteners.  Both are described on Tele Vue's page
as
>follows:
>
>http://www.televue.com/engine/page.asp?ID=169
>
>  I'd much prefer to use the "Ranger" version, both for price ($84) and
>because it does not reduce the focal length but actually increases it
>slightly by 1.1x.  The thing is, it is listed for use on quote: "the
Ranger,
>Pronto and TV-85."
>
>  The "Pronto and TV-85" version costs $265 and reduces the f.l. by 0.8x
>*BUT* is listed for use on ANY brand refractor from 400mm to 600mm.
>
>  I want to use a flattener on a non-Tele Vue brand scope of simular
>aperture, 600mm f. l. with a 2" focuser integrated T-thread adapter.  I
>don't want vignetting, or I'd at least like to reduce it to a minimum on
>35mm film.  This'll be my first refractor since my first-ever scope some 12
>of them ago!  It's a semi-apo.
>
>So can I get away with using the "Ranger" field flattener?
>
>
>Mucho - Thanks In Advance (M-TIA) for any guiding wisdom, or even an
>alternative brand which might work!
>
>
>Jim Vineyard
>www.deepskyphotos.com
>
>(I'm once again behind some 2 to 3 hundred APML postings and need to catch
>up!  Plus there's that CCD list.  I don't know how you guys do it, fast
>computers and speed reading?)
>
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