Takahashi LE 5mm or Pentax SMC XL 5.2mm? (A bit long)
Ron Winner
many dealing with observing the planets or double stars.
However, I have one for critical deep sky observing.
I use an 18 in. f/5.5 Dob for observing very faint
tiny galaxies in Abell clusters of galaxies, Hickson's
Compact Groups, WBL galaxy groups, and others. Many of
these objects are are only 0.1 arcmin across and as faint
as 18+ total B magnitude. Usually these can only be
observed with high magnification when seeing permits.
I have found that a 5mm eyepiece (499x) is perfect in
my scope for this purpose. Currently I use a 15mm TV
Plossl with a TV 3x barlow to achieve this. Since I
need all the light throughput, contrast, and image
sharpness I can get, I think it is now time to upgrade to
a high quality dedicated 5mm eyepiece. Reading over
the reviews, I have narrowed it down to a Pentax SMC
XL 5.2mm or Takahashi LE 5mm. Ortho's might be good
too, but their eye relief is tight at 5mm FL. I don't
wear glasses while observing but the extra eye relief
is useful on extremely cold nights to minimize fogging
the eyelens. I might mention too that the AFOV is not
an issue here. It doesn't matter to me that one is only
52 deg versus 65 deg for the other. I am used to 50 deg
AFOV anyway. I already have an idea which one most
would choose for critical planetary observing (namely,
the Tak LE). But what about observing tiny faint deep
sky objects? It would seem to me that the Tak LE would
again be the better choice because it has fewer lens
elements (5 vs. 7 in the Pentax). I would guess that it
would deliver greater light transmission and higher
contrast than the Pentax XL on them.
Unfortunately I do not have access to either EP for
testing in my scope. Has anyone else used one or
both of these on DSOs, especially tiny faint galaxies?.
Which one would you recommend? TIA - Ron Winner
Richard Anderson
seems easier to look though, has less lateral colour and produces
a blacker background (more contrast). Plus, it's small compared
to the Pentax and less expensive. If you can do without the extra
field, get the Tak.
-Rich
Brian Murphy
I'm not a dep sky observer, but; you might want to try the Tak Hi Ortho 4mm
too. It has about 6mm ER. Truer color and better edge than the Tak 5mm LE
(which I own and like). I've not tried the Pentax XL. I've found you can
re-sell the Tak ortho's for about $10-20 less than what they cost new.
Fairly cheap cost to test.
BPM
"Richard Anderson" <rande...@aol.com> wrote in message
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Del Johnson
8mm Radian, and used to have the 5.2mm Pentax XL. The 8mm Radian produces
much brighter and more contrasty images than the other two (or higher
powered Radians), more so than just due the difference in magnification. I
have used my 8mm Radian on deep sky objects with great success with my 12.5"
f/5 reflector, but usually reserve the 5mm Takahashi for planets where there
is brightness to spare.
Del Johnson
"Ron Winner" <tac...@NOSPAMinfomagic.net> wrote in message
news:3aba4160...@news.infomagic.net...
Ron Winner
the Tak LE having a blacker background. I suspected the Tak LE would
be slightly better in that regard. It looks like I will be getting
the Tak.
On Fri, 23 Mar 2001 01:52:02 GMT, rande...@aol.com (Richard
Anderson) wrote:
>I've owned/own them both. I prefer the Tak LE 5mm because it
>seems easier to look though, has less lateral colour and produces
>a blacker background (more contrast). Plus, it's small compared
>to the Pentax and less expensive. If you can do without the extra
>field, get the Tak.
>-Rich
>
>On Thu, 22 Mar 2001 19:13:46 GMT, tac...@NOSPAMinfomagic.net (Ron
>Winner) wrote:
>
>>I know eyepiece questions pop up quite often in S.A.A.
>>...
Ron Winner
have or have owned both of the 5mm eyepieces under consideration.
I do own an 8mm TV Plossl which probably cannot compare to an 8mm
Radian. This eyepiece does not bring the faintest galaxies into view
as well as my 15mm Plossl + 3x barlow. Of course that in no way can
be extrapolated to mean that the 8mm Radian is not capable either.
But magnification does appear to make a significant difference in
detecting faint galaxies. So I would certainly need to test out the
8mm Radian in my scope before I would decide getting it instead of the
Tak LE or Pentax XL. Were you by any chance able to compare image
contrast/brightness in the 5mm Radian compared to the 5mm Tak LE or
Pentax XL in the same scope? That would be of great interest to me.
On Fri, 23 Mar 2001 06:21:57 GMT, "Del Johnson" <dela...@san.rr.com>
wrote:
>You might consider the 8mm Radian instead. I have both the 5mm Tak LE, the
>8mm Radian, and used to have the 5.2mm Pentax XL. The 8mm Radian produces
>much brighter and more contrasty images than the other two (or higher
>powered Radians), more so than just due the difference in magnification. I
>have used my 8mm Radian on deep sky objects with great success with my 12.5"
>f/5 reflector, but usually reserve the 5mm Takahashi for planets where there
>is brightness to spare.
>
>Del Johnson
>
>
>
>"Ron Winner" <tac...@NOSPAMinfomagic.net> wrote in message
>news:3aba4160...@news.infomagic.net...
>> I know eyepiece questions pop up quite often in S.A.A.
>> ...
Richard Anderson
with a 2500 mm f.l. results in considerable differences in
magnification. If the observer wants to, they can get the
other f.l.s later, but for now if 5mm is what he wants, then
he should stick to eyepieces in that f.l.
-Rich
Fri, 23 Mar 2001 06:21:57 GMT, "Del Johnson" <dela...@san.rr.com>
wrote:
>You might consider the 8mm Radian instead. I have both the 5mm Tak LE, the
maxwe...@mindspring.com
also a Tak5mm & a 5mmRadian(sold the Radian)
The 8mm plossl is tight on eye Relief, but you already know that the 8mm Rad
is not
The 8mm Plossl is a tad crisper at the edges has no lateral color on or off
axis
the 8mm Red had some Lateral color more so off axis than on, but was sharp
on axis, the 60º field of view is great , but for planetary who views off
axis?
so my thought was this . On axis, both Eps were fairly equal but the 20mm ER
of the Radian was the kicker I found the Radian more pleasing to use
The5mmTak was crisper & sharp & produced more of a black background than the
Radian, but not by much. The Tak was noticeably Brighter than the Radian,
Caveat-the 4,5,6mm Radians produced really bad reflections of my own eye
on bright object,, maybe im the exception & not the rule,, I don't know?
But Al Nagler toldme this was due to the shap on my pupil in relation to the
eyelens of the Radian,,,try before you buy
all these comparisons were done on a TV85,TMB105& a AP130EDF
over the course of several nights specifically slatted to compare these EPs
I'm a Woodworker, not a optical expert
I report what my eyes showed me
HTH
Ron Winner <tac...@NOSPAMinfomagic.net> wrote in message
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Alan French
and is not something you should find at the center of the field. All the
eyepieces I have tried show at least a little at the edge of the field.
Clear skies, Alan
<maxwe...@mindspring.com> wrote in message
news:99h4ss$ksr$1...@slb1.atl.mindspring.net...
> [SNIP]
> The 8mm Plossl is a tad crisper at the edges has no lateral color on or
off
> axis
> the 8mm Red had some Lateral color more so off axis than on, [SNIP]
Del Johnson
truth is that it may not get any better than what you currently have as all
of the 5mm candidate eyepieces are also Barlow/eyepiece hybrids.
I selected the Tak LE because it showed the most detail, though there was
some dimming with the Takahashi. This is of no concern to me when viewing
Jupiter through a 12"!
Del Johnson
"Ron Winner" <tac...@NOSPAMinfomagic.net> wrote in message
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Del Johnson
satisfy the need.
Del Johnson
"Richard Anderson" <rande...@aol.com> wrote in message
news:3abc7aaf.768941570@news...
Ron Winner
>I own a 8mmTV Plossl & a TV 8mm Radian
>also a Tak5mm & a 5mmRadian(sold the Radian)
>The 8mm plossl is tight on eye Relief, but you already know that the 8mm Rad
>is not
>The 8mm Plossl is a tad crisper at the edges has no lateral color on or off
>axis
It is a good performer in my scope too at 312x giving pinpoint star
images right to the edge of field. I own all the TV Plossls up to
32mm. The 8mm does beat the rest in image sharpness. But it does
not provide the power I need for some of the more difficult objects.
For some reason it does not barlow well. The 11mm with 3x
TV barlow gives sharper images than the 8mm with the 2x barlow.
Neither of these combos however is a match for the 15mm Plossl with
the 3x barlow on faint galaxies. The 20mm with 3x barlow is also
excellent on fainter galaxies and a good substitute when the seeing is
not quite so good.
>the 8mm Red had some Lateral color more so off axis than on, but was sharp
>on axis, the 60º field of view is great , but for planetary who views off
>axis?
>so my thought was this . On axis, both Eps were fairly equal but the 20mm ER
>of the Radian was the kicker I found the Radian more pleasing to use
>The5mmTak was crisper & sharp & produced more of a black background than the
>Radian, but not by much. The Tak was noticeably Brighter than the Radian,
>Caveat-the 4,5,6mm Radians produced really bad reflections of my own eye
>on bright object,, maybe im the exception & not the rule,, I don't know?
Yes, I read about that problem too with the 5mm Radian somewhere in
one of the reviews. That made me turn away from it. The 20mm ER is
definitely a plus though . Yet 10mm ER is still quite comfortable for
me. The extra sharpness and blacker background of the Tak LE is what
I need the most. The Tak LE 5mm really looks like it is the best
choice for my needs.
>But Al Nagler toldme this was due to the shap on my pupil in relation to the
>eyelens of the Radian,,,try before you buy
Try before you buy sounds like a good idea. Do you know of any
dealers that actually have such a policy?
Kevin & Monika
more contrasty, and the sky is really blacker.
You cannot lose with the Taks They are genuinly superb.
I had the Rads, before I bought an FS128 which came with the LE's
Hope thats of some help
Kevin
--
kevs...@globalnet.co.uk
www.kevsmith.com
Supported by www.metprep.co.uk and www.archive4images.com Market leaders in
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<maxwe...@mindspring.com> wrote in message
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Ron Winner
wrote:
>Of the three 5mm candidates, you might like the Pentax XL the best, but the
>truth is that it may not get any better than what you currently have as all
>of the 5mm candidate eyepieces are also Barlow/eyepiece hybrids.
>
Del, that was one of my concerns too. I thought about that after
reading several eyepiece reviews. Still, observers say they can see
significant gains in image sharpness, brightness, and contrast. I
contribute these improvements to several factors: Quality of glass,
smoothness, and polish; high quality multicoatings/anti-reflection
coatings on all air/glass surfaces; the barlows are precisely matched
and optimized with the other lens elements to further reduce various
aberrations; eyepiece barrels are precision machined to hold all the
optical elements in precise alignment; thoroughly blackened inside the
barrels and lens edges. True the law of diminishing returns rules
here too as it does elsewhere (ie. audiophile sound systems] where one
has to fork out vast sums of money for miniscule gains in performance.
This is for the observer to decide. It could well be worth the extra
cost particularly where the main optics are up to par and top notched.
Hence the various incongruities one can read in the reviews or
observer reports I have no doubt are mostly genuine but stem from the
differences in the quality of the main optical systems, the
observer's experience, and the meteorological conditions at the time
observations were made. Still, in the end you might be right. The
15mm and 3x barlow is such a perfect match it cannot be beat except
perhaps in ER and FOV. That's what I don't know. I have never owned a
premium eyepiece. Just as curiosity killed the proverbial cat, I am
willing to take the risk to find out. I just wanted to hear what
others had to say first before making a decision.
>I selected the Tak LE because it showed the most detail, though there was
>some dimming with the Takahashi. This is of no concern to me when viewing
>Jupiter through a 12"!
OTOH, it would be something to be concerned about if the object is so
faint that it can barely be seen at all. I assume you are comparing
the 5mm Tak LE to the 5mm Pentax XL when you reported that the Tak LE
showed some dimming. Is that correct? Which object did you make the
comparison on? I mean was it on a bright one like a planet or a deep
sky object?
Del Johnson
for the faint fuzzies. I did compare my 13mm TV Plossl (now discontinued)
coupled with a 2.5x Powermate to the other 5mm solutions. The clarity and
brightness was quite good. Eye relief was the main reason that I did not
pursue this route. I would say that the real reason to pay the big bucks is
for wide fields and/or extra eye relief, and probably not for what you want.
maxwe...@mindspring.com
enhanced the color,,, the plossls showed noneoff axis, Ion onw of the test
nights Iwas observing low in the sky,, probably atmospheric(sp) aberrational
color was introduced
Alan French <Sue_and_A...@email.msn.com> wrote in message
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