This is tiresome. You spout arbitrary assertions without giving the facts,
other than some short sentences about your experience, to back them up. You're
obviously a troll. On my kill list from now on.

As for the others that might be reading this, I think it's safe to say that most
professional astronomers do not own their own equipment. They're into research,
which requires very large permanently mounted telescopes. A few do use
equipment amateurs use, but this is the exception rather than the rule. The few
I personally know, mostly from JPL, own a wide variety of telescopes, because
other factors come into play, just as they do for any amateur astronomer,
because when they use their own instruments, professionals become amateurs, for
reasons I laid out above.

As for the arbitrary assertion that I own an 80mm f/5 Syntha, totally wrong, but
then since none of your statements are based on fact Szaki, why should anything
you state about me be based on fact?

Go away little man. I'll be willing to bet that I've been an amateur astronomer
longer than you've been on this earth, with strong ties to a lot of people with
a lot of experience that I find both enlightening and entertaining, unlike you.
--
Sincerely,
--- Dave
----------------------------------------------------------------------
It don't mean a thing
unless it has that certain "je ne sais quoi"
Duke Ellington
----------------------------------------------------------------------

"Szaki" wrote in message
...


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