Tom Back's Top Planetary Eyepieces

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Bob Chu

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Sep 29, 1998, 3:00:00 AM9/29/98
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Awhile ago there was posted a list (either here or on AOL) that
contained Tom Back's choices in planetary eyepieces by individual
eyepiece focal length. If anybody happens to have a copy of this
list, could you either please post it or E-mail it to me at
Rober...@ln.ssw.abbott.com. Thanks.

Bob C.

TMBack

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Sep 30, 1998, 3:00:00 AM9/30/98
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Hi Bob,


>Awhile ago there was posted a list (either here or
>on AOL) that contained Tom Back's choices in
>planetary eyepieces by individual eyepiece focal
>length. If anybody happens to have a copy of this

>list, could you either please post it or E-mail it to me...


I posted a line up of the best short focal length
planetary eyepiece on AOL. Here goes:

3.8mm - Pentax .965" XP
4.0mm - Zeiss 1.25" Abbe Orthoscopic
5.0mm - Nikon .965" Abbe Orthoscopic
6.0mm - Zeiss 1.25" Abbe Orthoscopic
7.0mm - Pentax .965" SMC Orthoscopic
8.0mm - TeleVue Plossl
9.0mm - Intes Micro Monocentric (bad
ghost -- must be slight de-centered. -OR-
9.0mm - Nikon .965" Abbe Orthoscopic
10mm - Zeiss 1.25" Abbe Orthoscopic
11mm - TeleVue Plossl
12.5mm - Hastings Triplet (optics from
Edmund).
16.1mm - Monocentric Triplet (optics
from Rolyn).

Thomas Back

lude...@my-dejanews.com

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Sep 30, 1998, 3:00:00 AM9/30/98
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In article <19980929202322...@ng01.aol.com>,

tmb...@aol.com (TMBack) wrote:
>
> Hi Bob,
>
> >Awhile ago there was posted a list (either here or
> >on AOL) that contained Tom Back's choices in
> >planetary eyepieces by individual eyepiece focal
> >length. If anybody happens to have a copy of this
> >list, could you either please post it or E-mail it to me...
>
> I posted a line up of the best short focal length
> planetary eyepiece on AOL. Here goes:
here my own favourite list
> Takahashi Hi-2.8 mm or
> 3.8mm - Pentax .965" XP Tak. Hi 4mm or + Zeiss 4 mm Abbe
> 4.0mm - Zeiss 1.25" Abbe Orthoscopic Pentax 5mm SMC or
> 5.0mm - Nikon .965" Abbe Orthoscopic Pentax 6 mm SMC or (better as Zeiss)
> 6.0mm - Zeiss 1.25" Abbe Orthoscopic Pentax 7 mm SMC or
> 7.0mm - Pentax .965" SMC Orthoscopic Pentax 9 mm SMC or
> 8.0mm - TeleVue Plossl Zeiss 10 mm Abbe
> 9.0mm - Intes Micro Monocentric (bad Pentax 12 mm SMC or
> ghost -- must be slight de-centered. -OR- Zeiss 16 mm Abbe

> 9.0mm - Nikon .965" Abbe Orthoscopic
> 10mm - Zeiss 1.25" Abbe Orthoscopic Markus Ludes
> 11mm - TeleVue Plossl Nikons no more available, therefore
> 12.5mm - Hastings Triplet (optics from out of this list.

> Edmund).
> 16.1mm - Monocentric Triplet (optics
> from Rolyn).
>
> Thomas Back
>

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samw...@my-dejanews.com

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Sep 30, 1998, 3:00:00 AM9/30/98
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In article <19980929202322...@ng01.aol.com>,
tmb...@aol.com (TMBack) wrote:

> 3.8mm - Pentax .965" XP

> 4.0mm - Zeiss 1.25" Abbe Orthoscopic

> 5.0mm - Nikon .965" Abbe Orthoscopic

> 6.0mm - Zeiss 1.25" Abbe Orthoscopic

> 7.0mm - Pentax .965" SMC Orthoscopic

> 8.0mm - TeleVue Plossl


> 9.0mm - Intes Micro Monocentric (bad

> ghost -- must be slight de-centered. -OR-

> 9.0mm - Nikon .965" Abbe Orthoscopic
> 10mm - Zeiss 1.25" Abbe Orthoscopic

> 11mm - TeleVue Plossl


> 12.5mm - Hastings Triplet (optics from

> Edmund).
> 16.1mm - Monocentric Triplet (optics
> from Rolyn).

Hi Thomas,

Noticed the Zeiss Abbes had risen to the top (of course) and the Pentax XL
(5.2) has gone by the wayside. I have been gathering Tak orthos of late and
have been impressed by the 4mm HI as well as the 11mm projection eyepiece
(PJ?). Have been looking for a better alternative to the 2.5mm Vixen Lanthium
and will pick up a Tak 2.8mm HI ortho from Land Sky and Sea today. Any
experience with these Tak orthos or projection eyepieces?

Thanks


Stew

Thomas Back

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Sep 30, 1998, 3:00:00 AM9/30/98
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Hi Stew,


>Noticed the Zeiss Abbes had risen to the top (of course) and the
>Pentax XL (5.2) has gone by the wayside.


Nothing quite like the Zeiss Abbe's. The Pentax XL's are a fine
design, but with the 5 to 8 elements, there is a slight loss of
contrast and a bit of scatter that I don't see in the 3 - 4 element
oculars.


>I have been gathering Tak orthos of late and have been impressed by
>the 4mm HI as well as the 11mm projection eyepiece (PJ?). Have been
>looking for a better alternative to the 2.5mm Vixen Lanthium and will
>pick up a Tak 2.8mm HI ortho from Land Sky and Sea today. Any experience
with these Tak orthos or projection eyepieces?


The Tak 2.8mm Hi ortho (best of the super short FL eyepieces) and the
4mm HIortho are both superb. I have not tested the Tak projection eyepieces,
but my guess is that they would be less than ideal, like the 6 element 8mm
and 14mm Pentax XP. The 5 element 3.8mm Pentax XP, does seem to work extremely
well, however.


Markus'es picks of Pentax SMC-ED orthos instead of the Nikons (not
available anymore) in their respective focal lengths, would also be my
choice.


Thomas Back

bratislav

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Oct 1, 1998, 3:00:00 AM10/1/98
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Thomas Back wrote:

> Nothing quite like the Zeiss Abbe's.

Unless you have long f/ scope. In which case they may be (even
better I dare say) alternatives. I've seen homemade Tolles and
simple doublets work nothing short of phenomenal in f/16 Cassegrain
and f/22 Schiefspiegler. I doubt that even Zeiss bothers to polish
their eyepieces with pitch and rouge (I haven't seen the latest
Zeiss 1-1/4 Abbes, but no other eyepieces I've seen including
Clave, Masuyama and old Zeiss have polish as good as glass pusher
can do in his/her garage). And coatings, even the best ones,
_will_ scatter more than no coatings at all. Yup, multielement
eyepieces and wide angles are out, but remember that even at 600X
no planet will subtend more than ~8 degrees.
Of course, we're talking icing on the cake here, but you did
say 'nothing' :-)

Bratislav

Todd Gross

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Oct 1, 1998, 3:00:00 AM10/1/98
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> Markus'es picks of Pentax SMC-ED orthos instead of the Nikons (not
>available anymore) in their respective focal lengths, would also be my
>choice.


>Thomas Back


Thomas.. have you tried the Univ. Optics Orthos? Very impressed with them
(esp. considering the price) I do have the Pentax 12mm Orthos

also...
have you ever viewed through an Aries refractor? What did you think?

Todd

TMBack

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Oct 1, 1998, 3:00:00 AM10/1/98
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Todd wrote:


>have you tried the Univ. Optics Orthos? Very
>impressed with them (esp. considering the price)

Yes. The UO Orthos are excellent eyepieces.
While not quite up to the Zeiss and Pentax orthos,
a set of UO orthos and the shorter FL TeleVue
Plossls would make a great set of planetary oculars,
at a super price.

>have you ever viewed through an Aries refractor?
>What did you think?

No, I have not. I do know the designer, and know
that the triplet design is very good. If I do get a chance
to test one, I will post a full report.


Thomas Back

TMBack

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Oct 1, 1998, 3:00:00 AM10/1/98
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Bratislav wrote:

>> Nothing quite like the Zeiss Abbe's.
>
>Unless you have long f/ scope. In which case they
>may be (even better I dare say) alternatives. I've
>seen homemade Tolles and simple doublets work
>nothing short of phenomenal in f/16 Cassegrain
>and f/22 Schiefspiegler.

Oh, Bratislav, you are just a trouble maker. :-)

>I doubt that even Zeiss bothers to polish their
>eyepieces with pitch and rouge (I haven't seen the
>latest Zeiss 1-1/4 Abbes

OK, they don't rouge polish them, but you really
must see the new 1.25" Zeiss, as the old .965s were
dogs.

> but no other eyepieces I've seen including
>Clave

Slight scatter problem, yellowish coloration.

>Masuyama

Another dog planetary eyepiece. Very good
in the long focal lengths, however, for low power
viewing.


>old Zeiss

See above.

>And coatings, even the best ones, _will_ scatter
>more than no coatings at all.

Well, yes, but there is the question of internal
reflections (even in the two air-to-glass designs),
which can be much more destructive to contrast
than a slight increase in scatter from coatings.

>but remember that even at 600X no planet will
>subtend more than ~8 degrees.

That reminds me about how the Pic-du-Midi
observers using the 24" refractor on Jupiter
at 1000x, said that the planet subtended 14 degrees
in the eyepiece field! That's 28 Moon diameters.
Imagine that view!


Thomas Back

bratislav

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Oct 2, 1998, 3:00:00 AM10/2/98
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TMBack wrote:
>
> Oh, Bratislav, you are just a trouble maker. :-)

Umm, if you say so ...

> OK, they don't rouge polish them, but you really
> must see the new 1.25" Zeiss,

Unfortunately, fat chance. As they are not made anymore, and
none of my buddies Down Under has them, unless someone brings
them over for a star party or somesuch, I doubt I'll get the
chance. And, no, I do not plan to visit US starparties in forseable
future.

> > but no other eyepieces I've seen including
> >Clave
>
> Slight scatter problem, yellowish coloration.
>
> >Masuyama
>
> Another dog planetary eyepiece. Very good
> in the long focal lengths, however, for low power
> viewing.

Dog ? The ones I've seen have great polish. Not so great coatings,
but glass is very clear. They are definitely better polished than
my SHOWA 'plossl' (same design).

> >old Zeiss
> ... as the old .965s were dogs.
> See above.

Now you got me REALLY itchy to see those new Abbes.



> >And coatings, even the best ones, _will_ scatter
> >more than no coatings at all.
>
> Well, yes, but there is the question of internal
> reflections (even in the two air-to-glass designs),
> which can be much more destructive to contrast
> than a slight increase in scatter from coatings.

Can, but not necessarily will. Radii on Tolles are VERY steep,
and all reflections are dispersed so much that they are all but
invisible (definitely so with a bright planet in the field). The
doublet may have problem with a reflection from your eyeball
getting returned straight back, but it is easy to dodge it.
Anyway, the differences we're talking about are so small -
I have to admit that it took me more than one night to convince
myself of superiority of Masuyama over Tanny (as sold by UO)
Orthos. We're almost getting into a 'hearing different cables'
territory :-)

> That reminds me about how the Pic-du-Midi
> observers using the 24" refractor on Jupiter
> at 1000x, said that the planet subtended 14 degrees
> in the eyepiece field! That's 28 Moon diameters.
> Imagine that view!

I can imagine the size (I've cranked the magnification that
much for the heck of it), but I'm sure I have no idea of the
detail that could be seen. BTW, I did have chance to peek thru
a 25.5" (65cm) Zeiss once, but seeing was gross.

Bratislav

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