127mm Mak-Cas or Orion 80ED?

Szaki wrote:


"Gaz" wrote in message
ups.com...

hi all,

I'm looking for a small scope to use on the moon and planets, assuming
cool down isn't a problem, has the refractor got anything to offer over
the Mak-Cass?

cheers
gaz

The Mak will provide more contrast and higher magnification than the 80mm ed
you've mentioned. I own 3 refractors, a mak, and a 25" dobsonian. The mak is
also by far a lot more portable because of size. Views of the planets have
been excellent and I've pushed its magnification upwards using a 3.5mm
eyepiece successfully. IMO the mak would be a better buy.

Richard

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

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

You told me a refractor can only do 30x/inch at best. Now that tells me,
you don't know what the hell you talking about.
50x/inch rule is for compound telescopes, a good refractor able to do twice
as much. My TV Pronto 70mm f/6.8, on a good seeing night can hold 250-300x
magnification on planets, using TVs 5x barlow, that's 100x/ inch. My old 3"
f/15 Edscorp performed even better. That's why some people love those f/15
achromatic refractors, cost and performance. I was on a star party, one guy
had 8" f/15 refractor, it was huge, but he had the longest line at the
scope.
Resolving power is another question, larger aperture can resolve more. But,
still there is a limitation of seeing and atmospheric distortion. You may
say theoretically an 8" or 10" SCT can resolve 1/2 arc-second or less, but
you'll find very few days to achieve that, be cause the seeing, upper
atmosphere turbulence etc....
Told you, go read Suitor's book on optical theory JPL guy.
I worked for Loral Space company 12 years and others before, you don't
impress me.
JS


"David Nakamoto" wrote in message
news:zp2Ld.7590$RI.6871@trnddc06...
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

"Gaz" wrote:
I'm looking for a small scope to use on the moon and planets, assuming
cool down isn't a problem, has the refractor got anything to offer over
the Mak-Cass?


How do you propose to get to the Moon? ~`8^)

"Tim Killian" wrote:
In terms of resolving power, the equivalent refractor aperture is
roughly equal to the aperture of the Mak minus the diameter of its
central obstruction. Collimation and cool down are not big issues with
small aperture Maks.
snip


Cooldown of a 127mm Mak is an issue here in MD's winter.

JJK wrote:
"Gaz" wrote:
I'm looking for a small scope to use on the moon and planets,
assuming
cool down isn't a problem, has the refractor got anything to offer
over
the Mak-Cass?


How do you propose to get to the Moon? ~`8^)
Duh! Thats why I'm going for a portable scope....

;O)

Gaz

"Gaz" wrote:
I'm looking for a small scope to use on the moon and planets,
assuming cool down isn't a problem, has the refractor got
anything to offer over the Mak-Cass?

JJK wrote:
How do you propose to get to the Moon? ~`8^)

Gaz" wrote:
Duh! Thats why I'm going for a portable scope....
;O)


Makes sense, now that you mention it. ~`8^)

The Mak will have better resolution. Resolution has to do with the
distance between the boundary of the element collecting photons, and
little or nothing to do with the central obstruction. The primary
effect of the central obstruction is to reduce contrast. The loss of
light resulting from the central obstruction is probably in the
neighborhood fo 10%-12%. The Mak will still collect move than twice as
much light.as the 80mm refractor I'd go for the Mak (and in fact I
have a 5" Skywatcher Mak, purchased from Khanscope in Canada for $400;
I'm told it's quality is much better than the Orion version.)
Clear skies,
Shneor Sherman

In article . com,
"Gaz" wrote:

hi all,

I'm looking for a small scope to use on the moon and planets, assuming
cool down isn't a problem, has the refractor got anything to offer over
the Mak-Cass?

cheers
gaz

I have both the Orion 80 ED and Orion Mak 127 (as well as a 8" LX-90
SCT). I use the LX-90 only at dark sites, and bought the Mak 127 for
use at home in the city (Portland, OR) for the moon and plants. Later,
when the 80ED came out, I bought it for its flexibility for both wide
fields and planets. I mount either the 80 ED or the Mak 127 on an Orion
AZ-3 alt-az. I use wide field Nagler eyepieces on both: 5 & 7 mm on the
80ED (86x & 120x), and 7 & 11 mm on the Mak (140x & 220x). A wide
field EP makes using an alt-az reasonable, as do slow motion controls.

If I had to choose just one of the two Orion scopes, I would pick the
80ED, since it can also do wide fields at dark sites. It is a great
travel scope, since I am suspicious of the durability of compound scopes
to survive bumps and stay collimated. If I only wanted high mag for
planets at home, I would choose the Mak, because of its extra 47 mm of
aperture.