Aesthetic Astronomy Views from the WO 80mm ED
- Hi Group,I recently purchased a WO 80mm ED and the images (Lunar, Planetary and Stellar) are the sharpest, color free images I've ever seen in 30 years of amateur astronomy. At least the best of all the telescopes I've own. Yes, a larger telescope will bive you more light grasp and more expensive flourite apos (like Takahashi) will give better color correction and better edge of field views, but I have reached the peak of telescopic performance and personal satisfaction. $798 gives us an awesome view of our universe!Enjoy it!It's very clear sky today so I'm going to set it up again tonight. First stop is Pleiades (seaching the nebulosity). Next is Rigel (looking for the faint companion to verify the "seeing"). Then it's Orion Nebula (looking for contrast of the fainter swirls and the elusive fifth star in the trapezium). I'll try to find the Crab Nebula and M-78. A tour of the double cluster in Perseus, NGC457 in Cassiopiea, the three clusters (M-37, M-36, M-38) in Auriga and M-35 and the faint NGC cluster near by in Gemini. A last view will be Saturn.I've seen these objects dozens of times before, but the new 80mm ED gives me a sharper, satisfying image. That's what I'm after. Personal enjoyment of Astronomy.Are you going out observing tonight? I'll think about all of us. Clear Skies and Happy Holidays!--HalP.S. Any personal favorites of deep sky or doubles? Let me know!
[Jandorf, Hal (NAVAIR)]-----Original Message-----
From: James Stephens [mailto:j_m_step@...]
Sent: Friday, December 10, 2004 2:49 PM
Subject: RE: [William-Optics] Re: I thought the 80mm ED triplet was considered a Apo scop
We're getting hung up on terminology. An achromat brings two colors to a
coincident focus, and his can be achieved with a doublet. A apo brings
three colors to a coincident focus, and this is a triplet lens. An ED
triplet and a fluorite triplet will show different degrees of color
correction, but if they are both triplets designed to bring three colors to
a coincident focus, they are both apo's, by definition.
James Stephens, PhD 601-599-4260 (h)
29 Park Place #301 601-268-2681 ext. 40 (w)
Hattiesburg MS 39402
>Hi Again Chris,
>I have always believed the ED is as much an APO as Flourite. I also
>have 'read' that a lot has to do with the quality of the glass and
>optical design, and of course the focal ratio and seeing conditions.
>There are trade offs. It is also my understanding that generally
>speaking, Flourite will correct color better than SD; but at an
>expense. If anyone can speak from experinece in the field for having
>compared the Megrez triplets in both SD and Flourite versions, it
>would be most interesting to hear from them. I wouldn't think there
>would be much difference visually... Perhaps a bit more difference
>when imaging... A 80 mm objective has only so much chromatic
>abberation anyway unless you really get to a very fast focal ratio
>and in the old f/15 ratios, a good quality 80 mm achromat shows
>little color, at least under the most common observing conditions...
>Clear Skies I am hoping for,
>-- In William-Optics@yahoogroups.com, "Chris Appleton"
> > Hi Group
> > I have a Megrez 80mm SD refractor and a WO110mm triplet
> > I am considering the purchase of a 80mm Megrez either the Fluorite
> > triplet or the ED triplet. I do like the results so far with the
> > version, but when I heard some people saying they might buy a true
> > Apo 85mm TV, I get a little discouraged. I want to sell my old
> > SD Megrez and buy a Megrez triplet for CCD imaging (widefield
> > and a great travel scope for visual use. I used to have a 85mm TV
> > and that was a good scope for viewing (never tried it for
> > but the focuser had too much image shift and would not hold it's
> > position properly. The 85mm TV is only a doublet like my current
> > Megrez, but I believe one of it's lenses is an SD (NOT LIKE THE
> > MEGREZ SD) special dispersion glass. I thought ED glass was Apo
> > material esp. having the scope setup as a trplet?
> > Could someone please clarify this issue for us future potential
> > Megrez buyer's. There is a huge difference in price between the
> > Megrez 80mm Fluorite and the ED version.
> > Thank you!
> > Regards,
> > Chris A
> > Toronto
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