Pentax XL Vs. Radian
Michael/Mary Byrne
Has anyone reading this ever compared the shorter focal length Pentax
XLs to the Televue Radians of similar F.L.?
ANY comments would be helpful
Thanks! Mike Byrne
TWFORTE
The Pentax eyepieces are the ugliest in the business. But they perform great.
The twist adjust eye-cup on the Pentax stays put better than the Radian's click
stop. I think the performance is comparable and you would be happy with
either. In a direct comparison we did between the 6 Radian and the 7 Pentax,
the Pentax was the winner on both a f/4.5 and f/5 for sharpness and brightness
(of course the magnification difference accounts for most of that.) Both
maintain good sharp image to the edge of field and have similar "flatness".
The Pentax have a wider apparent field.
On my 18" Dob, the Pentax focus in so far that they are at the bottom of my
focuser travel and some viewers can't get a perfect focus. The Radians focus
out a good deal farther and are the series I'm collecting (I have three so
far). But I don't know an eyepiece that can beat the 10.5 Pentax; it's a real
keeper.
Ted Forte
Mike Byrne wrote (snip):
brien stratton
When I purchased some pentax XL eyepieces, they did as you say focus inwards
a lot. I had to cut my truss tubes, and now every eyepiece can focus
properly.
Brien
TWFORTE <twf...@aol.com> wrote in message
news:19991227175244...@ng-cc1.aol.com...
RAnder3127
> Has anyone reading this ever compared the shorter focal length Pentax
>XLs to the Televue Radians of similar F.L.?
I like the Radian in the 8mm size more than any other eyepiece in that range
i've
used.
-Rich
Did you know Col. Kurtz was referring to Clinton when he
mention, "the stench of lies?"
CHASLX200
>From: rande...@aol.com (RAnder3127)
>Date: Mon, 27 December 1999 08:16 PM EST
>Message-id: <19991227201654...@ng-fr1.aol.com>
>Rich wrote.
>
>I like the Radian in the 8mm size more than any other eyepiece in that range
>i've
>used.
>-Rich
*********************************
I agree! I love my 8mm Rad, i plan to get a 3mm Rad , now that i placed a order
for a new 12.5" Star Master...
Chas P.
William E. Byrd
> I agree! I love my 8mm Rad, i plan to get a 3mm Rad , now that i placed a order
> for a new 12.5" Star Master...
Hey Chas! I thought you were going to get the 14.5" StarMaster. Why
12.5" instead?? Just curious. (living vicariously through other's
purchases I guess <g>)
Happy New Year!
Bill
--
Bill Byrd we...@flash.net San Antonio, Texas
Del Johnson
will allow it to be parfocal with most Televue eyepieces. This is
possible as the black skirt of the Pentax is less than 2" OD. I am
considering doing so for my 14mm Pentax XL so that it fits my Paracorr
properly.
Del Johnson
In article <I8T94.26304$uj2.7...@newscontent-01.sprint.ca>,
> > >Has anyone reading this ever compared the shorter focal length
Pentax
> > >XLs to the Televue Radians of similar F.L.?
> >
> >
>
>
Sent via Deja.com http://www.deja.com/
Before you buy.
PhotoKing
Ortho, Ultrascopic, Meade MA, Takahashi LE, and Vixen Lanthanum) - The
Pentax XLs are my favorite, and the ones I have kept. The Radian (I only
tried the 6mm) was fairly comparable, but the Pentax (I have the 5.2, 7 and
10mm) edged it out in two ways --- 1. Seemed slightly contrastier and 2. I
prefer the twist top rather than click top for adjusting eyerelief.. That's
NOT a huge point, and initially the click stops seems nicer. But after a
little irritation at having it collapse while viewing, I started liking the
Pentax design better. Again, this is a fairly minor point, but you know how
it is with these expensive eyepieces -- you start to really knit pick. In
truth they are both superb. I'd say the Pentax are most comfortable for my
eyes, but the verdict may be the opposite for others.
In any case, they are both noticeably superior to the 9mm Nagler I tried.
Michael/Mary Byrne <mby...@inetex.com> wrote in message
news:3867d...@139.142.118.11...
> Hi everyone,
> Has anyone reading this ever compared the shorter focal length Pentax
> XLs to the Televue Radians of similar F.L.?
TWFORTE
>In any case, they are both noticeably superior to the 9mm Nagler I tried.
I agree. I own a 9mm Nagler. It is the one "premium" eyepiece I most want to
replace. It works well in my 8" SCT but on the 18" its nothing to write home
about.
My favorite eyepiece on the 18 is a 12mm Radian or the 10.5 Pentax.
Ted Forte
Brian Hamilton Day
shoot-out this past year up at Foothill Observatory comparing Pentax XLs,
Naglers, Radians, Panoptics, and Lanthanum Superwides. Of these, the Pentax
and Nagler series were judged to be best, with superior contrast, sharpness,
and brightness. Nagler's wider field of view was balanced by Pentax's better
eye-relief. Lanthanum Superwides were next, with somewhat less brightness
and contrast, and less sharp toward edges (but also less dollars!) Panoptics
suffered from significant barrel distortion. While the Radians were
certainly nice, they ended up at the end of the list with what were
considered to be very sharp but somewhat dull images. Tests were done in a
number of scopes including 10-inch f/4.5 Dob, 16-inch f/6 Newt, 4-inch and
7-inch AP refractors.
Brian Day
Del Johnson
so I agree. Radians are better at 8mm and the very short focal lengths.
Del Johnson
In article <3868D281...@best.com>,
Ross Bench
>
> >"PhotoKing" wrote:(concerning Pentax XL and Radians)
>
> >In any case, they are both noticeably superior to the 9mm Nagler I tried.
>
> I agree. I own a 9mm Nagler. It is the one "premium" eyepiece I most want to
> replace. It works well in my 8" SCT but on the 18" its nothing to write home
> about.
Got rid of my 9 Nagler a couple years ago for just that reason.
Earl Frank
Re: Pentax XL's
Where can I find the specs on these ep - and which dealers carry them?
Thanks!!
Earl
PhotoKing <no-spam...@earthlink.net> wrote in message
news:849v4q$cnm$1...@oak.prod.itd.earthlink.net...
> Of the various eyepieces I've tried, (Nagler, Radian, Pentax XLs, Pentax
> Ortho, Ultrascopic, Meade MA, Takahashi LE, and Vixen Lanthanum) - The
> Pentax XLs are my favorite, and the ones I have kept. The Radian (I only
> tried the 6mm) was fairly comparable, but the Pentax (I have the 5.2, 7
and
> 10mm) edged it out in two ways --- 1. Seemed slightly contrastier and 2. I
> prefer the twist top rather than click top for adjusting eyerelief..
That's
> NOT a huge point, and initially the click stops seems nicer. But after a
> little irritation at having it collapse while viewing, I started liking
the
> Pentax design better. Again, this is a fairly minor point, but you know
how
> it is with these expensive eyepieces -- you start to really knit pick. In
> truth they are both superb. I'd say the Pentax are most comfortable for
my
> eyes, but the verdict may be the opposite for others.
>
> In any case, they are both noticeably superior to the 9mm Nagler I tried.
>
> Michael/Mary Byrne <mby...@inetex.com> wrote in message
> news:3867d...@139.142.118.11...
Bill Becker
Earl Frank wrote:
> Re: Pentax XL's
>
> Where can I find the specs on these ep - and which dealers carry them?
> Thanks!!
>
> Earl
>
Lumicon, Pocono Mts., Woodland Hills camera, Apm. Tech. specs on the APM page:
http://apm-telescopes.com/ then click on specialty eyepieces. Hope this
helps. Bill
David Smith
> I see a lot of these reviews out here and wonders what are the "scientific"
> criteria for determining what EPs are better than another. All of this
> seems pretty subjective to me since you're not testing in a controlled
> environment. BTW, what is "significant barrel distortion?"
He meant to say "significant pincushion distortion." Barrel distortion is when
magnification is reduced toward the edge of the field, and pincushion distortion
is when magnification rises toward the edge of the field. Suppose you use the
scope to look at a telephone pole near the right edge of the field. With barrel
distortion, the pole will appear bowed out (concave toward the center). With
pincushion distortion, the pole will appear bowed in (concave outward).
David Smith
Frank Varisco
criteria for determining what EPs are better than another. All of this
seems pretty subjective to me since you're not testing in a controlled
environment. BTW, what is "significant barrel distortion?"
Frank
Baltimore, MD
Brian Hamilton Day <bria...@best.com> wrote in message
news:3868D281...@best.com...
> A number of us in the Peninsula Astronomical Society did an eyepiece
> shoot-out this past year up at Foothill Observatory comparing Pentax XLs,
> Naglers, Radians, Panoptics, and Lanthanum Superwides. Of these, the
Pentax
> and Nagler series were judged to be best, with superior contrast,
sharpness,
> and brightness. Nagler's wider field of view was balanced by Pentax's
better
> eye-relief. Lanthanum Superwides were next, with somewhat less brightness
> and contrast, and less sharp toward edges (but also less dollars!)
Panoptics
> suffered from significant barrel distortion. While the Radians were
> certainly nice, they ended up at the end of the list with what were
> considered to be very sharp but somewhat dull images. Tests were done in
a
> number of scopes including 10-inch f/4.5 Dob, 16-inch f/6 Newt, 4-inch and
> 7-inch AP refractors.
>
> Brian Day
>
> Michael/Mary Byrne wrote:
>
Sandy McNamara
<frankan...@home.com> writes:
>I see a lot of these reviews out here and wonders what are the "scientific"
>criteria for determining what EPs are better than another. All of this
>seems pretty subjective to me
You're quite correct. While such things as FOV, eye relief, astigmatism,
kidney or other optical distortion, transmission, reflectivity, etc can be
measured, deciding which eyepiece is "better" IS highly subjective. Which is
why various reviews, while certainly helpful, are no substitute for borrowing
or begging various brands/styles/sizes to try on YOUR telescope with YOUR eyes.
Even the same person using the same set of personal standards can make
different decisions under different circumstances -- the eyepieces that I
prefer to use with my 8-in SCT are different from the ones that perform "best"
with my 12.5-in reflector and the ones that perform best for deep sky are not
necessrily the same as those that give the best planetary views!
Cheerfully muddling the waters,
Sandy Mc.
Sandy...@aol.com (Sandy McNamara)
40d 26' N 89d 13' W
Ratboy99
>>seems pretty subjective to me
>
It is subjective, that's why there is so much opinion here. You have to weigh
size and weight, contrast, eye relief, light scatter, cost, field of view and
other criteria against each other to determine which is best for you. For
example, the very sharpest eyepieces very well may not be your favorites unless
you are willing to permanently cement them to your eyes. On the contrary, it is
very likely that it will take a combination of the above attributes to make you
happy with a given eyepiece.
rat
~( );>