the refractor craze??

Subject: the refractor craze??
From: RichA
Date: 11/20/2004 5:38 PM Eastern Standard Time
Message-id:


Portable.
Have any of you ever used a refractor over 6?"
-Rich
************************************
My Meade 7" ED was a monster to setup.

Just think how heavy a 9" APO or bigger OTA would weigh!!!

Chas P.

"Juan Calculus" wrote in message
ink.net...
Now getting back into the astro hobby after a few years recess, I've
noticed
a trend towards refractors. I visited a local SP a few weeks ago and I'll
bet close to 70% of the scopes there were refractors. I'm curious as to
what's caused this trend or shift as when I was active in the past, close
to
15 years ago, the "light bucket" Dobsonian seemed to be the favorite at
star
parties. How does a refractor, which I seldom see in apertures greater
than 100mm due to expense, compare with a light bucket Dob or reflector?
It
certainly can't be DSO's as an 18" Dob would win that battle hands down.
I
would also think that the larger reflector would be the winner for planets
too, especially if it has a good mirror. So, what is the appeal?
Portability, but what else? There must be something I'm missing regarding
their appeal especially when you compare the cost per aperture differences
between refractors and other scopes.

Juan,

Just like other folks have different hobbies, people approach astronomy
differently. There are folks who like as much aperture as possible, and
there are other folks, who are also serious observers, who are quite happy
with modest apertures. The local club holds many public star parties, and
has an active group of observers who use our dark sky sight on a regular
basis. Some have Dobs of varying sizes, some have SCTs from 8" to 14", and
some have modest refractors. They are all enjoying what they do, and having
a good time under the stars. Indeed, I have been surprised and enlightened
by the number of folks who started years ago with a modest aperture and
never found a reason to move to a larger scope. We have telescopes from a
90mm APO up to a 15" Dob, and my wife could be quite happy with any one of
them on a clear night.

Today's amateur astronomers are fortunate in having such a vast array of
telescopes to choose from, and so many different ways to approach the hobby.
Amateur astronomers just have to decide is what approach makes them happy.

My last two trips outside under clear skies were with a lawn chair. Once
for a beautiful display of northern lights, and once to prowl around with
binoculars.

Clear skies, Alan

I have no idea what you are talking about here, though I have built lots
of top fuel cars, and driven more than I've built. And incidentally, my
personal car is a pickup...

But I think the perfect telescope is what the individual NEEDS or WANTS it
to be; not what you and I think...
--
Jan Owen

To reach me directly, remove the Z, if one appears in my e-mail address...
Latitude: 33.662
Longitude: -112.3272

"CLT" not@thisaddress wrote in message
...

"Simple Traveler" wrote in message
Roland's right, you're wrong.

That's funny! They were talking about two different uses.

Refractors are a better instrument for their size than newts or dobs.
they're better for photography, deployment, contrast, and ease of use.

"for their size" ie, to simply say refractors are better instruments is
like saying a top fuel dragster is the best car because it goes the
fastest.
(and some here would agree! vbg)

At the same time, I don't want to bring the groceries home (or haul a
telescope to a dark site) in a dragster. A pickup will haul a lot more
than
a dragster, even if it isn't as fast. In the same way, scopes have
different
advantages.

Big dobs/newts are a drag to move around, the tracking is cumbersome,
and they require ladders/stools/etc to have on hand to cover the
zenith,
or anywhere near it.

"Jan Owen" wrote in message
news:VBSnd.125195$cJ3.32553@fed1read06...

But I think the perfect telescope is what the individual NEEDS or WANTS it
to be; not what you and I think...

Jan,

Amen to that. Why folks fret about which telescope others pick escapes me.
Perhaps some folks feel there is only one "right way" to do things, or maybe
there is more comfort in a world where descisions are quite black and
white - I don't know.

Clear skies, Alan

I think the buyers
of the SCT's are disappointed with these instruments and in someway regret
their purchasing decisions or at least long for another instrument with
complimenting features.

No disappointment.
No regrets.
No longing, except for more clear nights.

I recommend mid-sized SCTs specifically for the
combination of portability, ease of use/set-up, and good optics.
Visual or otherwise.

SSX

Aperture for aperture an f/6 (or there about) apochromat refractor is
the closest thing to an all-around-do-anything-telescope. Why?
(keeping in mind "aperture for aperture".)

1) For all practical purposes image quality is 'perfect'. The
aperture is totally free from any and all obstructions. It has the
highest (percentage) concentration of light within the Airy disk
that's possible. Scattered light is at a minimum. Contrast is at a
maximum.

2) equal suitability for low-power, wide-field work and high power
planetary or double star work. At equal apertures the apo isn't
likely to be bested in either area by any other telescope. It's
literally the best of both worlds.

3) For refractors in general: Thermal cool-down takes less time.
Tube currents are less of a problem.

4) Collimation is 'dead-on' when received and tends to stay that way
indefinitely. Minimal maintenance is necessary.

5) Mounting options are 'open'. The apo can be mounted in whatever
manner is necessary for whatever task the owner may desire to put it
to.

6) The only way it can be bested (in one way or another) is by
utilizing a scope of smaller or larger aperture; but that other scope
will not be able to best the original apo in all areas for all
purposes (portability is an important consideration for many
amateurs).

The above may not be reasons enough for all people to go with a high
quality refractor; but it's sufficient for some -- and that's all
that's needed to satisfactorily answer the original question.

Note: Not all of the above points apply to all refractors. OTOH, a
major component to any perceived 'refractor craze' *is* the fast, high
quality, apochromat refractor. The portability of small, fast,
achromats like the ST-80 provide another component to the perceived
craze. Many amateurs -- regardless of what kind of 'large' telescope
they use, also own a small refractor that bears at least some
resemblance to an ST-80.

Final (Personal) Note: For myself, under my relatively dark sky, a
small refractor can surpass the deepsky performance of larger
telescopes used under poorer skies. My largest refractor has a 13cm
aperture. Nevertheless I've visually observed Pluto, the Horsehead
Nebula (no filter used), and other objects (with my refractors) that
some people considered doable only with significantly larger
apertures.

Bottom Line: Aperture is *not* everything!

Sketcher
To sketch is to see.

Ah, now I get it. You're just a TROLL!

Clear Skies

Chuck Taylor
Do you observe the moon?
always less of the most expensive/desirable


You have only made yourself look silly by posting this rambling drivel.

Your post makes absolutely no sense.

Way to play the troll card to try and look self-important.

thanks for contributing.

Thanks to all for your responses. Someone asked if the star party I
attended was a spur of the moment occasion and indeed it was so I could have
been mislead. However, there were a lot of refractors there. I seem to
remember seeing "Orion" on most- if it's the same firm I'm thinking of,
about the only thing I remember buying from them were eyepieces in the late
1980's or early 90's, so they must have grown quite a bit since that time.

Browsing around the web and through Astronomy and other magazines, I do
notice these ED and semi-APOs going for excellent prices, especially
compared to when I left off in about 1990 or so. I also see a large
increase in imports from mostly China(?) which makes me wonder what's going
on there- are they producing lenses at lower cost?

In the 80's or 90's, I wouldn't have even considered a refractor due to
cost. Now, however, it does seem a possibility. As I mentioned in another
post, I do have an ETX-90 and a C-8 but tests showed that the C-8 had 1/2
wave SA so pretty bad images. I guess I still have a bias when I think of
the days when SCT's were considered bad- have they been improved? The ETX,
for the cost, has proven a very capable scope with excellent optics and I
have been well pleased.

Thanks for the numerous opinions above!

Juan

"Juan Calculus" wrote in message
ink.net...
Now getting back into the astro hobby after a few years recess, I've
noticed
a trend towards refractors. I visited a local SP a few weeks ago and I'll
bet close to 70% of the scopes there were refractors. I'm curious as to
what's caused this trend or shift as when I was active in the past, close
to
15 years ago, the "light bucket" Dobsonian seemed to be the favorite at
star
parties. How does a refractor, which I seldom see in apertures greater
than 100mm due to expense, compare with a light bucket Dob or reflector?
It
certainly can't be DSO's as an 18" Dob would win that battle hands down.
I
would also think that the larger reflector would be the winner for planets
too, especially if it has a good mirror. So, what is the appeal?
Portability, but what else? There must be something I'm missing regarding
their appeal especially when you compare the cost per aperture differences
between refractors and other scopes.

Thanks,
Juan

I have no idea what you are talking about here, though I have built lots
of top fuel cars, and driven more than I've built. And incidentally, my
personal car is a pickup...

All I'm saying is there is no such thing as a best type of telescope.
Different types of cars have different strengths and weaknesses. So do
telescopes. An apo presents a great image for the aperture. They excel at
photography and planetary work. But they lack the aperture of a big dob.

Big dobs gather lots of light. They are great for the faintest fuzzies. But
they are not portable.

An SCT is very portable. The cats are the most portable for their aperture.
But the large CO eats contrast so they suffer on the planets as well as
structure in the faint fuzzies.

But I think the perfect telescope is what the individual NEEDS or WANTS it
to be; not what you and I think...

Agreed. The *best* telescope is the one that gets used.

Clear Skies

Chuck Taylor
Do you observe the moon?
Try http://groups.yahoo.com/group/lunar-observing/
And the Lunar Picture of the Day http://www.lpod.org/
************************************

Jan Owen

To reach me directly, remove the Z, if one appears in my e-mail address...
Latitude: 33.662
Longitude: -112.3272

"CLT" not@thisaddress wrote in message
...

"Simple Traveler" wrote in message
Roland's right, you're wrong.

That's funny! They were talking about two different uses.

Refractors are a better instrument for their size than newts or dobs.
they're better for photography, deployment, contrast, and ease of use.

"for their size" ie, to simply say refractors are better instruments is
like saying a top fuel dragster is the best car because it goes the
fastest.
(and some here would agree! vbg)

At the same time, I don't want to bring the groceries home (or haul a
telescope to a dark site) in a dragster. A pickup will haul a lot more
than
a dragster, even if it isn't as fast. In the same way, scopes have
different
advantages.

Big dobs/newts are a drag to move around, the tracking is cumbersome,
and they require ladders/stools/etc to have on hand to cover the
zenith,
or anywhere near it.

**********************************
After owning over 150 scopes i can say there is no such thing as the
perfect
scope. And the few starparties i do go to, i see more Dobs that APO's!!!

Chas P.

I sure am glad there are far biggers NUTS in the astro tree than lil 'ol me.