Posts Made By: Dan Lamoreaux

EXCELLENT NEWS! I hope the switchover goes smoothly. I sincerely hope Bill genuflects over what has transpired here and begins to repair his public relations image. I would still like to own one someday, but for now I will have to take a wait and see attitude. I truly believe that when manufacturers realize each customer is no longer an isolated and abuseable individual, it is better for all of us.

DanL

Paul,

You can contact your buyer via email or Astromart private message and ask him to delete his rating for you if in fact he intended to leave you 5 stars. If you did not delete your ad he can find it doing a search for the ad number. He can then reply to the ad again with any new comments he wishes to make or use his old ones being sure 5* is selected and the problem is fixed. To delete a rating, have him go to Account Menu in the My Account box. Go down to the Ratings box then select ratings I have given. Each one listed has an option to delete at the right of the rating.

DanL

Paint it desert sand and sell it to the military as a missle launch tube. Probably get $20K out of em for it. Tell them you can supply all they need at that price.

DanL

Thank you Lucien for a very interesting and informative post. I would be very curious if you tried to post this very same information in the CN forums if you would get banned for VENDOR BASHING. :S

DanL

ATWB just posted the price for the Ethos @ $620 and started a signup list. Anyone ready to jump on the wagon at this price? Doesn't seem out of line considering what it is designed to do. I use my 13T6s extensively in my binoviewer. Don't think a pair of Ethoses will work in my Denks though. 8O

Here is a post from the Yahoo groups from Chris Lord of the Brayebrook Observatory. It is a bit technical but explains what is going on.

There are two types of eyepiece distortion, Angular Magnification
Distortion (AMD) & Rectilinear Distortion (RD). It is not possible to
correct for both simultaneously because AMD is proportional to the
tangent of the field radius and RD the field radius (expressed in
radians).

Once tangent field radius and radius in radians begin to significantly
depart (afov > 1 radian ~ 57º), distortion (lack of Orthoscopy) becomes
a design issue. Astronomical eyepieces are corrected for AMD, which
typically results in +ve RD (pincussion); binocular / military
eyepieces for RD, resulting in +ve AMD (pincussion). Residual
distortion is played off by deliberately introducing astigmatism,
pulling the Petval surface onto the sagittal surface.

An eyepiece designed for a specific OG can be corrected for distortion
more effectively by playing the field curvatures off against one
another, whilst at the same time correcting for hypochromatism
(eye-eyepiece-objective combination).

The way round the problem is aspherics, and it surprises me that given
all the patents recently taken out (since 1998) for moulded optical
aspheric shells, which have found there uses in telephoto zoom lenses,
that few have been used in uwa eyepieces. An aspheric eye lens shell
can also eliminate spherical aberration of the exit pupil.

Chris

I can only assume that Televue considers correction for rectilinear distortion is less of a priority than other design aspects they want to have in their eyepieces. Ocular design is always a tradeoff. Only Al could explain why he does what he does. I'm just happy he does.

DanL

While we are on this subject, it brings up a question I have been meaning to pose to this group. When I am using a scope to just pan about the skies using I do find using a 31 Nag a bit dizzying after a while. So I would like recommendations from the group as to what you feel is a good wide field eyepiece (30mm +) with at lease a 70* afov and is well corrected for rectilinear distortion and minimal pincushion effect.

DanL

Sweeeeeeeeeeeeet.

I have never owned a Nagler that has both the 1.25" and 2" skirts. With my bad habit of standing eyepieces on their end while I am switching back and forth, this looks like a disaster waiting to happen. I am wondering if the 1.25" skirt can be removed without bits falling out? Is that the purpose of the screw pictured on the right side of the 2" skirt? If not then what is it's purpose?

DanL

8O WOW!!! $15K per element less a little for the housing. Must be made from the finest glass in all the land. The head optician at Zeiss must be handed a blank and a box of abrasives then locked in a room for 3 months and grinds it all down by hand.

Dan

Mine just arrived yesterday. Due to the late sunset and my early work hours, I won't be able to look through it until tomorrow. This is my first Nagler that has the dual format sleeve. I must say I do not care for it at all. I will have to be very conscious of not setting it up on end when not in the diagonal. That's a small price to pay though for what I expect to be a real viewing treat. Is there really that many 1.25" only format scopes out there that the owners would buy a $620 eyepiece for? :S

DanL