Star Diagonals, Orientation and Navigation

Hallo all. When I first started observing as a kid I used a cheap
refractor with an equally cheap prism star diagonal. I can't recall
having any problem with the reversed, upright, image when navigating
by eye or using charts. After a break from astronomy of some years, I
now find using a diagonal a pain in terms of navigation, with or
without maps/charts - I find even the moon irritating to explore.

Could it be that my brain has aged and is now less able to make the
mirror-image correction as to relationships between physical features?
Has anyone else here experienced this phenomenon? Luckily perhaps,
I've never regularly used a scope with an inverted image, though I'm
guessing the adjustment is less "difficult" compared with a
mirror-image.

If it turns out that I am indeed on the verge of senility :-) are any
correct image star diagonals available of sufficiently good quality
for astronomy?

Regards,

Anthony

On Sun, 28 Sep 2003 16:27:14 -0400, Anthony PDC lound_at_charter.net ...reflected:

Hallo all. When I first started observing as a kid I used a cheap
refractor with an equally cheap prism star diagonal.

If they had been made in Japan, then they might not have been
too bad. I have a Sears 60mm refractor, circa 1973, and it's all
made in Japan. It's very good, for a proverbial department-store
refractor...very little plastic, if any, and the optics gave me my
very first view of Saturn, albeit in a weird, fluorescent green.
Of course, I understand that to be merely a characteristic
dictated by aperture rather than by the quality of the optics.

I would love to have the optics restored, for there's scratches
and perhaps even the wearing away of the magnesium
fluoride coatings. If only I could get the scratches ever
so gently polished out, and then recoated...

I can't recall
having any problem with the reversed, upright, image when navigating
by eye or using charts. After a break from astronomy of some years, I
now find using a diagonal a pain in terms of navigation, with or
without maps/charts - I find even the moon irritating to explore.

Could it be that my brain has aged and is now less able to make the
mirror-image correction as to relationships between physical features?
Has anyone else here experienced this phenomenon? Luckily perhaps,
I've never regularly used a scope with an inverted image, though I'm
guessing the adjustment is less "difficult" compared with a
mirror-image.

If it turns out that I am indeed on the verge of senility :-) are any
correct image star diagonals available of sufficiently good quality
for astronomy?


http://www.telescope.com/shopping/pr...=yes #tabLink

Orion has enough of a reputation to warrant a gamble, notwithstanding
their 30-day money back guarantee, but it's the only one of their diagonals
where the housing is of plastic rather than anodised aluminum(would you
believe that Takahashi's 1.25" prism diagonal housing is plastic, too?
I sent it back, even though the prism was first-rate.)

I got Orion's 1.25" variable polariser, and on sale at the time for $20. It's
very well made, but it's now back up to $30.

In the case of Orion's 2" mirror diagonal, however, I'd get a William
Optics instead for only $20 more, as I've read nothing but accolades.
Mine'll arrive sometime this week, and from Kendrick Astro Instruments.
Anacortes carries them, too, but were backordered at the time.

Alan

On Sun, 28 Sep 2003 16:50:08 -0500, Alan W. Craft
wrote:

On Sun, 28 Sep 2003 16:27:14 -0400, Anthony PDC lound_at_charter.net ...reflected:

Hallo all. When I first started observing as a kid I used a cheap
refractor with an equally cheap prism star diagonal.

If they had been made in Japan, then they might not have been
too bad. I have a Sears 60mm refractor, circa 1973, and it's all
made in Japan. It's very good, for a proverbial department-store
refractor...very little plastic, if any, and the optics gave me my
very first view of Saturn, albeit in a weird, fluorescent green.
Of course, I understand that to be merely a characteristic
dictated by aperture rather than by the quality of the optics.

I very much doubt that *aperture* was the culprit - more likely
optical quality, but having said that..."fluorescent green"? Saturn
never appeared green to me, nor did any other object. Chromatic
abberation was tolerable in my scope, but the offending colours were
the typical red and blue, the edge.

My "mail order" scope was indeed Japanese - f16 job; came with a
crappy alt-az mount in black crackle paint (grin) and a lovely wooden
case with three kellner eyepieces and thick glass, dark green "Sun
Filter" which screwed into the filter threads of the ep's (eek!) - I
shudder to think what damage I did to my eye(s)! However, I loved that
scope and whilst I recognised its limitations (a 3" refractor or a 6"
reflector was considered to be the barest minimum then). At any rate,
my little 2 1/2" scope certainly taught me a lot and gave rise to my
love of astronomy.



I would love to have the optics restored, for there's scratches
and perhaps even the wearing away of the magnesium
fluoride coatings. If only I could get the scratches ever
so gently polished out, and then recoated...

Prolly not worth the money Alan. A gust of wind blew our conservatory
door open, crashed into my scope and smashed the flint/crown glass
achromat objective to bits. The suppliers sent me a replacement lens
in a new cell for free! (they must have felt sorry for me because I
was a teen tyro, suddenly deprived of his hobby). I am pretty sure you
could buy a new objective for MUCH less money than doing a restoration
job.

SNIPPED some of my earlier post

If it turns out that I am indeed on the verge of senility :-) are any
correct image star diagonals available of sufficiently good quality
for astronomy?


http://www.telescope.com/shopping/pr...=yes #tabLink

Orion has enough of a reputation to warrant a gamble, notwithstanding
their 30-day money back guarantee, but it's the only one of their diagonals
where the housing is of plastic rather than anodised aluminum(would you
believe that Takahashi's 1.25" prism diagonal housing is plastic, too?
I sent it back, even though the prism was first-rate.)

I got Orion's 1.25" variable polariser, and on sale at the time for $20. It's
very well made, but it's now back up to $30.

In the case of Orion's 2" mirror diagonal, however, I'd get a William
Optics instead for only $20 more, as I've read nothing but accolades.
Mine'll arrive sometime this week, and from Kendrick Astro Instruments.
Anacortes carries them, too, but were backordered at the time.

OK - but that yields a mirror-image too. What I really covet is a high
quality correct-image star diagonal for astronomy. I know the rule
about more glass/surfaces affecting quality blah...just was curious if
some breakthrough had occurred in the reasonably recent past. And
talking about surfaces and extra chunks of glass, when one looks at
the pounds of glass in thse awesome Naglers and other ultrawide ep's
one is apt to question this rule of thumb (I own a Meade 14mm
Ultrawide, and astonishingly wonderful it is too - in spite of its
complement of EIGHT lenses!)

So, I'm wondering - is there some optical rule which gives the OK to
use multiple glass elements in eyepieces for example, but any optical
device which gives a correct image for astronomy is anathema?

Regards,


Anthony

On Sun, 28 Sep 2003 19:44:03 -0400, Anthony PDC ...reflected:

On Sun, 28 Sep 2003 16:50:08 -0500, Alan W. Craft
wrote:

On Sun, 28 Sep 2003 16:27:14 -0400, Anthony PDC lound_at_charter.net ...reflected:

Hallo all. When I first started observing as a kid I used a cheap
refractor with an equally cheap prism star diagonal.

If they had been made in Japan, then they might not have been
too bad. I have a Sears 60mm refractor, circa 1973, and it's all
made in Japan. It's very good, for a proverbial department-store
refractor...very little plastic, if any, and the optics gave me my
very first view of Saturn, albeit in a weird, fluorescent green.
Of course, I understand that to be merely a characteristic
dictated by aperture rather than by the quality of the optics.

I very much doubt that *aperture* was the culprit - more likely
optical quality, but having said that..."fluorescent green"?

If you have some older Orion catalogs, particularly around
1992 or thereabouts, you'll see a small inset of Saturn, and
precisely as described, and within the ad for their 60mm alt-az
refractor, which were made in Japan at that time. They really
were of very good quality, both optically and mechanically,
although the eyepieces did leave much to be desired, as they
still do. The Orion was virtually a carbon copy of the Sears,
therefore I've little doubt that both were produced in the same
factory, albeit twenty years or so apart.

When I first saw the inset I thought, "Oh, wow, I've seen that
before."

Saturn appears that way in a small achromat at a low-to-mid-
range magnification, for since the only decent eyepiece within
our setup was a yellow-painted 20mm Kellner, with the other
being an "HM 6mm", then it must've been the one with which
my father primarily observed, and the magnification at which I
in turn must've observed the planet when having noted the
strange coloration, that is, 35x.

I still have the owner's manual, and most every accesory,
including a solar projection screen, rather than an eyepiece
filter.

Saturn
never appeared green to me, nor did any other object. Chromatic
abberation was tolerable in my scope, but the offending colours were
the typical red and blue, the edge.

My "mail order" scope was indeed Japanese - f16 job; came with a
crappy alt-az mount in black crackle paint (grin) and a lovely wooden
case with three kellner eyepieces and thick glass, dark green "Sun
Filter" which screwed into the filter threads of the ep's (eek!) -

That smacks of Vixen's solar observation "technique," which also
employs a hole in a prism diagonal housing in order to exhaust most
of the heat and light away from the observer's eye...

I don't believe that your setup would've included that extra diagonal?

Do you recall the brand of that telescope?

I shudder to think what damage I did to my eye(s)!

So do I! Have you noticed any damage?

My father's side of the family is most prone to cataracts. So far,
and at 39, I've been spared.

I think that some of my paternal ancestors must've been Druids...

However, I loved that
scope and whilst I recognised its limitations (a 3" refractor or a 6"
reflector was considered to be the barest minimum then). At any rate,
my little 2 1/2" scope certainly taught me a lot and gave rise to my
love of astronomy.



I would love to have the optics restored, for there's scratches
and perhaps even the wearing away of the magnesium
fluoride coatings. If only I could get the scratches ever
so gently polished out, and then recoated...

Prolly not worth the money Alan.

That's what I've been told...

A gust of wind blew our conservatory
door open, crashed into my scope and smashed the flint/crown glass
achromat objective to bits. The suppliers sent me a replacement lens
in a new cell for free! (they must have felt sorry for me because I
was a teen tyro, suddenly deprived of his hobby). I am pretty sure you
could buy a new objective for MUCH less money than doing a restoration
job.

I'm sorry yours is no more, but I wouldn't dream of discarding the
objective of my youth.

SNIPPED some of my earlier post

If it turns out that I am indeed on the verge of senility :-) are any
correct image star diagonals available of sufficiently good quality
for astronomy?


http://www.telescope.com/shopping/pr...=yes #tabLink

Orion has enough of a reputation to warrant a gamble, notwithstanding
their 30-day money back guarantee, but it's the only one of their diagonals
where the housing is of plastic rather than anodised aluminum(would you
believe that Takahashi's 1.25" prism diagonal housing is plastic, too?
I sent it back, even though the prism was first-rate.)

I got Orion's 1.25" variable polariser, and on sale at the time for $20. It's
very well made, but it's now back up to $30.

In the case of Orion's 2" mirror diagonal, however, I'd get a William
Optics instead for only $20 more, as I've read nothing but accolades.
Mine'll arrive sometime this week, and from Kendrick Astro Instruments.
Anacortes carries them, too, but were backordered at the time.

OK - but that yields a mirror-image too.

I know, but the link also advertises Orion's 2" mirror diagonal.

What I really covet is a high
quality correct-image star diagonal for astronomy.

Did you click on the link and take a look at Orion's offering? It may
be the only way to go, unless you might locate someone who could make
you one, but for a price, of course.

about more glass/surfaces affecting quality blah...just was curious if
some breakthrough had occurred in the reasonably recent past. And
talking about surfaces and extra chunks of glass, when one looks at
the pounds of glass in thse awesome Naglers and other ultrawide ep's
one is apt to question this rule of thumb (I own a Meade 14mm
Ultrawide, and astonishingly wonderful it is too - in spite of its
complement of EIGHT lenses!)

I've yet to sample the world of 2" oculars, but its time is coming.

So, I'm wondering - is there some optical rule which gives the OK to
use multiple glass elements in eyepieces for example, but any optical
device which gives a correct image for astronomy is anathema?

Not that I'm aware of, other than having read that said diagonals
are primarily recommended for terrestrial use.

Regards,


Anthony

Alan

On Sun, 28 Sep 2003 20:28:02 -0500, Alan W. Craft
wrote:

On Sun, 28 Sep 2003 19:44:03 -0400, Anthony PDC ...reflected:

On Sun, 28 Sep 2003 16:50:08 -0500, Alan W. Craft
wrote:

SNIP

I still have the owner's manual, and most every accesory,
including a solar projection screen, rather than an eyepiece
filter.

Saturn
never appeared green to me, nor did any other object. Chromatic
abberation was tolerable in my scope, but the offending colours were
the typical red and blue, the edge.

My "mail order" scope was indeed Japanese - f16 job; came with a
crappy alt-az mount in black crackle paint (grin) and a lovely wooden
case with three kellner eyepieces and thick glass, dark green "Sun
Filter" which screwed into the filter threads of the ep's (eek!) -

That smacks of Vixen's solar observation "technique," which also
employs a hole in a prism diagonal housing in order to exhaust most
of the heat and light away from the observer's eye...

I don't believe that your setup would've included that extra diagonal?

Do you recall the brand of that telescope?

Alas, no But from what you have said here, it sounds like mine in
most respects Alan.

I shudder to think what damage I did to my eye(s)!

So do I! Have you noticed any damage?

Nope, thank goodness! At around the same time, I thought my Mum's
Tanning Lamp was cool; I sneaked into my parents' bedroom and messed
around with it, without eye protecton. I dug the effects!. A few hours
later, I was in agony . Spent the next two weeks blind - the UV lamp
burned away the epithelium from my corneas.

My father's side of the family is most prone to cataracts. So far,
and at 39, I've been spared.

I think that some of my paternal ancestors must've been Druids...

HA! Did I ever see you at Stonehenge?

SNIPPED

OK - but that yields a mirror-image too.

I know, but the link also advertises Orion's 2" mirror diagonal.

What I really covet is a high
quality correct-image star diagonal for astronomy.

Did you click on the link and take a look at Orion's offering? It may
be the only way to go, unless you might locate someone who could make
you one, but for a price, of course.

Yes Alan, I did. What worries me is that the correct-image diagonal is
nearly half the cost of my reversed image Orion Mirror diagonal.

about more glass/surfaces affecting quality blah...just was curious if
some breakthrough had occurred in the reasonably recent past. And
talking about surfaces and extra chunks of glass, when one looks at
the pounds of glass in thse awesome Naglers and other ultrawide ep's
one is apt to question this rule of thumb (I own a Meade 14mm
Ultrawide, and astonishingly wonderful it is too - in spite of its
complement of EIGHT lenses!)

I've yet to sample the world of 2" oculars, but its time is coming.

No need to wait: the Meade 2" 14mm Ultrawide ($300) comes with an
integral 1.25" barrel. I assure you, if you haven't observed with this
naked clone of the Nagler, you owe it to yourself as they say....
Simply breathtaking. I know I'm not alone in this opinion.

So, I'm wondering - is there some optical rule which gives the OK to
use multiple glass elements in eyepieces for example, but any optical
device which gives a correct image for astronomy is anathema?

Not that I'm aware of, other than having read that said diagonals
are primarily recommended for terrestrial use.

Yeah I know - still wondering why this is so.

Regards,

Anthony

Regards,

Anthony

As is often the case, much depends on details.

For observing and/or making sketches I'm satisfied with simply noting
which direction in the field is west (or 'preceding') and which
direction is north. The former can be found easily enough by noticing
the direction the images drift when no drive motor is running. The
latter can be found just as easily by moving the telescope slightly
toward the north celestial pole and noting the part of the field in
which new stars enter (or the direction opposite that in which the
object exits the field of view).

I can always rotate a rough sketch to south (or north) up if I so
desire. Likewise, I can trace the sketch onto the back side of the
paper if I want to correct for a mirror reversed image; or I can scan
the sketch and then let the computer mirror-reverse the image.

I don't usually concern myself with identifying lunar features until
after I've completed a sketch (I generally sketch what looks
interesting with no concern over the feature names. Craters, etc. can
be easily enough identified at some later date). The more obvious
features I already know. It doesn't matter how the moon is oriented
in the telescope. I suppose I recognize the familiar craters, etc.
largely by their appearance along with their positions and
orientations relative to other landmarks on the moon. After a person
has had enough experience looking at the moon it becomes just as easy
to navigate regardless of the orientation of the image. There are
plenty of familiar landmarks to serve as guide posts.

For deep sky observing I sometimes use a refractor straight through,
sometimes with a star diagonal; and sometimes I use a Newtonian.
Consequently I must deal with all manner of image orientations.

For most of my navigational purposes I simply point the telescope at
the right piece of sky. Usually a Telrad is sufficient if I'm using
my Newtonian. In addition to the Newtonian's Telrad I can use an
erect-image, magnifying finder on either the Newtonian or the
refractor. I've measured the true fields of view of my finders as
well as for all my eyepieces as used with any of my telescopes.
Knowing the field sizes can be a real asset for navigation! (An
inverted finder is just as easy to navigate with as an erect-image
finder. All one need do is rotate the chart one is using
accordingly).

For 'extreme' astronomy I use the view in the primary telescope along
with a highly detailed chart (in addition to first using one finder
and/or the other). For one project involving relatively faint
galaxies I used the field of a 200x eyepiece with the Newtonian as a
part of my finding routine. Of course, that means using charts that
go rather deep. Anyone who's found Pluto has probably used one
variation or another of this approach.

For similar projects with a refractor (with star diagonal) I've
sometimes used computer generated charts custom printed in a
mirror-reversed format. At other times I've reproduced a printed
chart by hand and mirror reversed it by hand. I'm not very talented
in accomplishing the mirror reversal mentally, though I have tried to
do so on a few occasions.

In all cases the charts should be rotated to match the image
orientation as seen in whatever device is used as a finder. (This is
one of the reasons for my second paragraph at the top of this
posting).

So, to make a longer story shorter, when it comes to navigating I use
whatever tools I have at my disposal in whatever manner works for me.
The tools and methods vary for different projects. After gaining
sufficient experience people find ways of dealing with these things.
Some people rely on computer pointed telescopes. Some prefer to
'go-to' without computer controlled motors; but we all eventually find
ways that work. Just keep in mind that what works well for one person
may not be the correct solution for another. People are different, as
are telescopes, sky conditions and observing projects. Stick with it
for long enough and you'll find the right tricks that work for you!

P.S. We all still fail from time to time for one reason or another --
usually due to inadequate preparation resulting in the use of a method
that is poorly suited for the particular object one is looking for ;-)

Bill Greer

On Sun, 28 Sep 2003 22:29:10 -0400, Anthony PDC ...reflected:

On Sun, 28 Sep 2003 20:28:02 -0500, Alan W. Craft
wrote:

On Sun, 28 Sep 2003 19:44:03 -0400, Anthony PDC ...reflected:
snip
burned away the epithelium from my corneas.

shakes head I hope that didn't produce any lasting damage.

You certainly were a devil-may-care sort in your youth. I suppose
we all were to varying extents.

My father's side of the family is most prone to cataracts. So far,
and at 39, I've been spared.

I think that some of my paternal ancestors must've been Druids...

HA! Did I ever see you at Stonehenge?

In that I've been here in the States all of my life, I doubt it.

snip

Did you click on the link and take a look at Orion's offering? It may
be the only way to go, unless you might locate someone who could make
you one, but for a price, of course.

Yes Alan, I did. What worries me is that the correct-image diagonal is
nearly half the cost of my reversed image Orion Mirror diagonal.

puzzledly That's not good?

snip

Alan

On Sun, 28 Sep 2003 22:26:27 -0500, Alan W. Craft
wrote:

On Sun, 28 Sep 2003 22:29:10 -0400, Anthony PDC ...reflected:

On Sun, 28 Sep 2003 20:28:02 -0500, Alan W. Craft
wrote:

On Sun, 28 Sep 2003 19:44:03 -0400, Anthony PDC ...reflected:
snip
burned away the epithelium from my corneas.

shakes head I hope that didn't produce any lasting damage.

Evidently not


You certainly were a devil-may-care sort in your youth. I suppose
we all were to varying extents.

My father's side of the family is most prone to cataracts. So far,
and at 39, I've been spared.

I think that some of my paternal ancestors must've been Druids...

HA! Did I ever see you at Stonehenge?

In that I've been here in the States all of my life, I doubt it.

snip

Did you click on the link and take a look at Orion's offering? It may
be the only way to go, unless you might locate someone who could make
you one, but for a price, of course.

Yes Alan, I did. What worries me is that the correct-image diagonal is
nearly half the cost of my reversed image Orion Mirror diagonal.

puzzledly That's not good?

snip

Alan

Ummm...yes - it implies an inferior performance if one subscribes to
the principle that u get what u pay for

Regards,

Anthony

On Sun, 28 Sep 2003 21:10:43 -0600, Bill Greer
wrote:

As is often the case, much depends on details.

For observing and/or making sketches I'm satisfied with simply noting
which direction in the field is west (or 'preceding') and which
direction is north. The former can be found easily enough by noticing
the direction the images drift when no drive motor is running. The
latter can be found just as easily by moving the telescope slightly
toward the north celestial pole and noting the part of the field in
which new stars enter (or the direction opposite that in which the
object exits the field of view).

I can always rotate a rough sketch to south (or north) up if I so
desire. Likewise, I can trace the sketch onto the back side of the
paper if I want to correct for a mirror reversed image; or I can scan
the sketch and then let the computer mirror-reverse the image.

I don't usually concern myself with identifying lunar features until
after I've completed a sketch (I generally sketch what looks
interesting with no concern over the feature names. Craters, etc. can
be easily enough identified at some later date). The more obvious
features I already know. It doesn't matter how the moon is oriented
in the telescope. I suppose I recognize the familiar craters, etc.
largely by their appearance along with their positions and
orientations relative to other landmarks on the moon. After a person
has had enough experience looking at the moon it becomes just as easy
to navigate regardless of the orientation of the image. There are
plenty of familiar landmarks to serve as guide posts.

For deep sky observing I sometimes use a refractor straight through,
sometimes with a star diagonal; and sometimes I use a Newtonian.
Consequently I must deal with all manner of image orientations.

For most of my navigational purposes I simply point the telescope at
the right piece of sky. Usually a Telrad is sufficient if I'm using
my Newtonian. In addition to the Newtonian's Telrad I can use an
erect-image, magnifying finder on either the Newtonian or the
refractor. I've measured the true fields of view of my finders as
well as for all my eyepieces as used with any of my telescopes.
Knowing the field sizes can be a real asset for navigation! (An
inverted finder is just as easy to navigate with as an erect-image
finder. All one need do is rotate the chart one is using
accordingly).

For 'extreme' astronomy I use the view in the primary telescope along
with a highly detailed chart (in addition to first using one finder
and/or the other). For one project involving relatively faint
galaxies I used the field of a 200x eyepiece with the Newtonian as a
part of my finding routine. Of course, that means using charts that
go rather deep. Anyone who's found Pluto has probably used one
variation or another of this approach.

For similar projects with a refractor (with star diagonal) I've
sometimes used computer generated charts custom printed in a
mirror-reversed format. At other times I've reproduced a printed
chart by hand and mirror reversed it by hand. I'm not very talented
in accomplishing the mirror reversal mentally, though I have tried to
do so on a few occasions.

In all cases the charts should be rotated to match the image
orientation as seen in whatever device is used as a finder. (This is
one of the reasons for my second paragraph at the top of this
posting).

So, to make a longer story shorter, when it comes to navigating I use
whatever tools I have at my disposal in whatever manner works for me.
The tools and methods vary for different projects. After gaining
sufficient experience people find ways of dealing with these things.
Some people rely on computer pointed telescopes. Some prefer to
'go-to' without computer controlled motors; but we all eventually find
ways that work. Just keep in mind that what works well for one person
may not be the correct solution for another. People are different, as
are telescopes, sky conditions and observing projects. Stick with it
for long enough and you'll find the right tricks that work for you!

P.S. We all still fail from time to time for one reason or another --
usually due to inadequate preparation resulting in the use of a method
that is poorly suited for the particular object one is looking for ;-)

Bill Greer

Thank you very much Bill. You obviously know what you are doing, and I
hope to refine my mental skills at adjusting for orientation given
inverted and mirror views through my scope.

Nonetheless, I pose the same question: namely, can we obviate the need
for all this tortuous compensation with an optical device that
sacrifices little for the benefit of a correctly oriented image? I
mean, if we can now get 84 degree apparent fields with UW oculars
containing as much as eight elements, why can't we achieve correct
images (at a standard consistent with astronomical observing) with
similar optical wizardry?




Regards,

Anthony

On Sun, 28 Sep 2003 23:36:17 -0400, Anthony PDC ...reflected:

On Sun, 28 Sep 2003 22:26:27 -0500, Alan W. Craft
wrote:

On Sun, 28 Sep 2003 22:29:10 -0400, Anthony PDC ...reflected:

On Sun, 28 Sep 2003 20:28:02 -0500, Alan W. Craft
wrote:

On Sun, 28 Sep 2003 19:44:03 -0400, Anthony PDC ...reflected:
snip
burned away the epithelium from my corneas.

shakes head I hope that didn't produce any lasting damage.

Evidently not

Thank goodness!

snip
Yes Alan, I did. What worries me is that the correct-image diagonal is
nearly half the cost of my reversed image Orion Mirror diagonal.

puzzledly That's not good?
snip
Ummm...yes - it implies an inferior performance if one subscribes to
the principle that u get what u pay for

I'm just beginning to drift away from that view myself, that is, concerning
only optics however, as the Chinese have, here lately, been rather full of surprises,
though still not enough to make me a convert...yet.

In browsing the web, I think I found just what you're looking for, made in
Japan, and for only $42.95...

http://www.universityoptics.com/acc.htm

You'll need to scroll down almost to the bottom.

I know that it's not much more than Orion's, but it might very well be of better
quality.

Alan