And I own a short focal ratio refractor, so I know something from personal
experience,
*I can imagine, you own one those 80mm f/5 Chines achromat, great experience
in refractor county. Good luck guy!
You can suck on your Mak. If it would be that good, every ones choice would
be a 5-6" Mak, but most pro astronomers go out and spend 3-5 thousand for
4-5 APO refractor.
if you're going to tout that out as your badge of authority. And one
thing I would not do, which you do, is to think that a refractor is a
refractor is a refractor. Focal ratio and objective design DOES MATTER,
but I doubt you understand this, given your responses to my messages.
Whatever experience you think you have, it's clear to me you need a lot
more before you can make cogent and fact-backed statements. That, and
read the messages your responding to more carefully.
I owned all those scopes, but I don't give up my refractor. After owning
many telescopes, I settled to C102F APO refractor (most used), 4" Mak(
MTO-11CA 10/1000 Telephoto Lens) for portability and a Ultima C-11 OTA
for DSO's. They all fit on my EQ mount or the GiroII for alt/az movement.
All these telescopes are very portable and easy to store, I know the pros
and cons of these scopes also.
My 4" Mak don't even come close to my TV Pronto I use to own. I heard
good things about the Orion80ED.
So have I, but the fact remains that those reports I've gotten from
observers who I know to have lots of experience evaluating telescopes of
various designs and makes have said it was good for a two-element short
focal length refractor, meaning it will perform within the expectations of
such a telescope, and NOT like a longer focal ratio one, or a
three-element one, or an expensive one, et al.
One has to use barlows for short focus length refractors, to get higher
magnification, that's all. I hate to use a Mak for terrestrially, long
focus length, narrow field. Yak!!!!
But the Mak will deliver 2.4 times the magnification for the same
eyepiece, so it is also capable of delivering higher magnification,
important for planetary viewing. And in any case, I don't think that,
given what I've heard and seen of the Orion 80ED at star parties, that you
can push it much past 30x per inch of aperture, so your objection that
this is the "limit" on the Mak (something I also disagree on, from
collective experience) is moot.
*Hey, guy get lost, I can't tell, you don't know what **** you talking
about.
30x /inch on an 80mm or 3"+ ED refractor would be only 90 x power. A cheap
achromat can do better than that. My 60mm Tasco outperforms that. You should
have your examined first.
And the original poster asked specifically for planets and the Moon. Why
drag terrestrial viewing when it was not specified?
*It was not specified, but when buy a small portable scope there's all ways
time to use for that. He's not going to look it only the Moon 24 hours, 7
days a week.
In this case, the Mak is an
instrument he should consider, given that for a given eyepiece it will
deliver more magnification,
*I'll eat my hat, if you can do 600x magnification with your 5" Chines Mak.
Get real guy!
Stop reading the Orion catalogs.
less color dispersion, and potentially sharper views, if the
contrast isn't too bad.
*Bull ****. That's why they advertising the Mak-Newt, "refractor like
images", he? I did look through a 6" Mak-Newt, my friend had one, it's close
but not quite. Mak-Newt has 19% CO.
Why don't you read Suitor's book some times,than come back and argue.
JS
--
Sincerely,
--- Dave
----------------------------------------------------------------------
It don't mean a thing
unless it has that certain "je ne sais quoi"
Duke Ellington
----------------------------------------------------------------------
"David Nakamoto" wrote in message
news:i6UKd.1078$UB6.973@trnddc01...
Szaki, you're thoughtless in your answers, as simple math will show.
We're talking about an f/7.5 system in the 80ED, which you would have
known if you took the time to visit the Orion website, and thought
anything about giving correct answers instead of "showing off", and
doing research before writing anything down. This means the focal
length is 600mm. Since "focal length of telescope" / "magnification" =
"focal length eyepiece", 600 / 250 = 2.4 mm. Even if such an eyepiece
exists, it also means you're pushing 80x per inch aperture in a two
element 80 mm telescope, only possible with the best optics (which the
Orion is not), long telescope focal ratios, and under absolutely steady
nights.
And your comparison is not correct either. You're comparing a 3-inch
f/15 refractor to a 3-inch f/7.5 refractor (the Orion ED). No matter
what you do, you cannot achieve as much magnification through the same
eyepieces from the latter as through the former. As anyone who knows
optics knows, figuring and testing long focal ratio systems is easier
than short focal ratio systems (steepness of curves as well as tighter
requirements on the figure of the curves for the short focal ratio
systems are two reasons). I have no doubt that a 3-inch f/15 refractor,
if properly made would outperform a similarly sized Mak (127 mm aperture
and f/12 focal ratio) but we're not comparing such a Mak to an f/15
instrument, but a much shorter focal ratio instrument. Color dispersion
is greater in such systems and affects performance, while the Mak is
more immune to such effects.
--
Sincerely,
--- Dave
----------------------------------------------------------------------
It don't mean a thing
unless it has that certain "je ne sais quoi"
Duke Ellington
----------------------------------------------------------------------
"Szaki" wrote in message
...
"David Nakamoto" wrote in message
news:wqQKd.403$zb.85@trnddc07...
While I agree with other posters about the optical properties of the
refractor, there are two things that you should also keep in mind.
First, the Mak you mentioned is capable of over 2.5x the magnification
of the refractor you mentioned due to its focal length,
That's a bull! Orion 80ED should do 250x or more any day, so 2.5x the
Mak127 magnificatain, as you suggesting, would put it over 600x. Never
happened!Hahahaha!
I owned 6" Intes-Mak-Cass, much finer and more expensive OTA than the
Orion 127 Mak, but it had to have excelent seeing to perform. My 3"
f/15 Edscorp refractor regularly out perfomed the 6" Mak when the
seeing was not there.
Mak has a larger central obstruction (37%) than an SCT has, so one has
to deal with large, multable diffrection rings around stars or the
moons of Jupiter.
Person who used to refractor images, would puke.
Julius
|