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Equipment Discussions >> Refractors

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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Something I like about refractors...
      #5756025 - 03/25/13 11:57 AM

It's the silliness and passion they inspire.

Taking a step back, when we talk about refractors we're almost always talking about telescopes with small or at most medium apertures. Small aperture does impose certain undeniable limitations on what is practically possible with a scope, and while the capabilities of refractors are often underestimated that's more because fewer and fewer amateurs actually have any real observing experience with small aperture scopes. Aperture is cheap courtesy of the Newtonian revolution of the 50s and 60s, the SCT revolution of the 70s and Dobsonian revolution of the 80s.

But on the topic of silliness, I read something on CN in this form a few days ago that has tickled my funny bone. It was a statement to the effect that apochromatic refractors aren't all that special because no professional/scientific discoveries were made using them, in contrast to the achromats used by Galileo, Hevelius, Flammarion, Smyth, Messier, Menchain, etc., etc.

That must have been two days ago and I haven't stopped chuckling since. I think it's utterly silly, of course, in that it ignores an awful lot of other history happening during the same period (i.e, the period between when achromatic refractors became scientifically irrelevant and trickled down to use by hobbyists, and the advent of the ability to make higher quality and special dispersion optical glasses). Put another way, there's no question whatsoever that using space age lightweight composites, modern metallurgy, suspension technologies and the like, we could make a much, much better Baroche Box.

http://upload.wikimedia.org/wikipedia/commons/6/6e/Prince_William_of_Wales_%2...

But who cares? Why would we want to? The relevance of the carriage as a means of conveyance for anyone but a re-enactor or tourist concessionaire is nil. Better (in the sense of more efficient, rapid, comfortable, convenient, safe and reliable) modes of conveyance have relegated older modes to mere "quaintness".

Saying that apochromats are nothing special compared to achromats because back when only achromats existed, all of the "low hanging fruit" discoveries available to visual use of small aperture were made, unsurprisingly, with achromats, is a little like saying the airplane isn't all that special considering the New World was discovered first by humans on foot, then later by humans in wind and muscle powered seacraft. I think most of us would rather fly a jumbo jet across the pond than paddle a kayak, and for good reason.

The significance of the apochromat is that now that refractors have been relegated to the realm of consumer hobbyists, modern technologies in glass making and design have been applied to eliminate and/or mitigate all but one of the principal drawbacks of the achromat. Specifically, use of new materials and design tools has allowed creation of shorter, more convenient to mount and operate OTAs with superior color correction. The deficiency of small aperture remains, but two out of three ain't bad.

To get from point A to B, I'd take a Prius over a Barouche any day and twice on Sundays. On the other hand, for a twaddle around the park on a lazy summer day, the clop-clop of the Barouche has a certain, limited charm.

- Jim


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GOLGO13
Carpal Tunnel


Reged: 11/05/05

Loc: St. Louis area
Re: Something I like about refractors... new [Re: jrbarnett]
      #5756114 - 03/25/13 12:40 PM

For me it's more about what you see when comparing scopes. With achromats (unless they are very long and hard to mount), there is a bunch of junk around bright objects. It's annoying, but it's not the end of the world. With Apochromats, the annoying color is gone and it's pleasing.

Small aperture comes down to costs and design. Costs are pretty darn high even for small apertures. Thus most people with apos have small apertures (and small aperture complexes). If cost is not as much an issue, then mounting is as refractors get larger. This is not too different then really large reflectors though. You may need to climb a ladder, have a permanent observatory for it, etc.

Based on my lack of funds for the hobby, I choose to have the best of both worlds. A small grab and go apo refractor and a larger dobsonian mounted reflector. Most of the people I know who do strictly visual follow that mindset. With imaging it gets more complicated.

Not sure how discoveries really matter though. I'd say those people either use what they like, or use what makes sense monetarily. But what design they use makes no difference to what I would use in my backyard.


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Sean Puett
Carpal Tunnel
*****

Reged: 09/06/10

Loc: always cloudy, washington
Re: Something I like about refractors... new [Re: GOLGO13]
      #5756509 - 03/25/13 04:13 PM

People do get defensive about THEIR telescope type whatever it may be.
If it is refractors as a whole, the newts or cats CO makes them all but useless.

If it is a cat guy he says that his telescope will not dictate what vehicle he owns.

The giant achro guys "well I didn't want to come to your star party anyway" or "I leave it setup in my observatory so it is not an issue (but I have to drive 3 hours each way to work)"

Big newt guy " your telescope is the size of my finder" (I got a great deal on a truck to haul my scope to star parties) makes the scope a bit less economical...

The apo guy has to "blow away that 25" dob" really he can't admit to his wife that the big cheap scope shows more on most objects. The apo is just as close to perfect as possible in its size range. My wife is a photographer so she understands that quality costs more and she was ok knowing that my $700 dob really does show more detail on nearly everything. (really she was just happy I didn't buy another gigantic dob...


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snommisbor
scholastic sledgehammer
*****

Reged: 06/15/09

Loc: Cedar Park, TX
Re: Something I like about refractors... new [Re: Sean Puett]
      #5756512 - 03/25/13 04:20 PM

I love my refractor and the HD views it gives me. It is nice to view through the light buckets to get deep into the universe, but for me I get my fill of that when going to star parties or get togethers. Then I just keep enjoying my small refractor views in 1080p. I'm happy with mine the big Dob guys are happy with theirs so everybody is happy.

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Mark Costello
Post Laureate
*****

Reged: 03/08/05

Loc: Matthews, NC, USA
Re: Something I like about refractors... new [Re: snommisbor]
      #5756695 - 03/25/13 05:52 PM

.... And even some owners and observers with achros are happy with them....

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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Something I like about refractors... new [Re: Sean Puett]
      #5756708 - 03/25/13 06:02 PM

So what do people who own multiple examples of each type of telescope defend?

- Jim


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MooEy
member


Reged: 10/02/07

Re: Something I like about refractors... new [Re: jrbarnett]
      #5756744 - 03/25/13 06:21 PM

oh, i always thought there are some coronagraphs that are refractors?

and what about the small little scope that discovered planets? http://www.astronomy.ohio-state.edu/Dept/Dissertations/Pepper.pdf

and i'm pretty sure there are some comet hunters that are using large binos with ed glass.

Edited by MooEy (03/25/13 06:23 PM)


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roscoe
curmudgeon
*****

Reged: 02/04/09

Loc: NW Mass, inches from VT
Re: Something I like about refractors... new [Re: snommisbor]
      #5756745 - 03/25/13 06:21 PM

Somehow, I'm thinking that if Charles Messier walked out onto his roof one night and discovered that the astro-fairies had changed his trusty long-focus 4"achro into a fancy 6"apo, there would have been 220 messier objects, not 110. I, too, believe that those folks found about everything visible in a fine-for-its-day 2" or 3" or 4" scope. It wasn't till the Herschels started aiming 12", then 24" mirrors at the sky that other stuff became visible, and even then, had they had modern silvered-glass mirrors instead of speculum, (or an 8" APO) their list would have been twice as big, too. ...and had anyone dropped anything as 'midrange' as an ortho EP in any of their laps, they would have about died of joy.
All the bru-ha about color correction is totally true on brighter objects, but at the edge of visibility, which is where most of this stuff is, I don't see that the difference between two pieces of glass and three makes all that much difference. And, deep-pocket observatory-grade glass, whether at the top or the bottom end, has never been assumed to be portable, so size and weight has never been an issue. I think any one of us who looked out in the back yard and found a well-mounted 6" f/18 achro standing there with a big red bow on it would be just as happy as can be....300-year-old technology or not! Are APO's useful, yep, you can carry one in your arms and fit one in your car. And they make Saturn look absolutely stunning! They're a clear step forward in eye-candy....and price.
For light-gathering ability, mirrors work best. For 1080p views (a great description, by the way) glass works best.....the more you pay, the better you get....same as 300 years ago. Think of where we'd be now if Gallileo had used an 80ED!
There's my two cents.....
Russ


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MooEy
member


Reged: 10/02/07

Re: Something I like about refractors... new [Re: roscoe]
      #5756753 - 03/25/13 06:25 PM

actually, we might be nowhere if gallileo had used an 80ed. he might be too busy star testing the scope... :x

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buddyjesus
Carpal Tunnel
*****

Reged: 07/07/10

Loc: Davison, Michigan
Re: Something I like about refractors... new [Re: jrbarnett]
      #5756773 - 03/25/13 06:32 PM

they defend their ability to make up their mind!

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buddyjesus
Carpal Tunnel
*****

Reged: 07/07/10

Loc: Davison, Michigan
Re: Something I like about refractors... new [Re: buddyjesus]
      #5756778 - 03/25/13 06:35 PM

I actually think it is the glass in the lenses that make people silly as they are the same way with eyepieces.

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RGM
scholastic sledgehammer
*****

Reged: 09/15/03

Loc: Burks Falls, Ontario, Canada
Re: Something I like about refractors... new [Re: buddyjesus]
      #5756816 - 03/25/13 06:51 PM

I like my refractors better than my other designs. It is a simple fact of where I live. That is, north of the Great Lakes under the jetstream. My 3" and 5" refractors constantly put up better and more pleasing images than my C8 or 10" Dob.

I do not get the achro vs apo threads. It is as if refractors are only used to view the Moon, Jupiter, Venus and the 5 brightest stars in the sky. Those objects are less than 1% of my viewing volume.


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Astrodj
professor emeritus
*****

Reged: 08/24/11

Loc: Missouri
Re: Something I like about refractors... new [Re: jrbarnett]
      #5756856 - 03/25/13 07:24 PM

Quote:

So what do people who own multiple examples of each type of telescope defend?

- Jim




Their observing philosophy differing from yours: Find out what it is that your telescope doesn't do well, then instead of not doing those things, get a whole bunch of scopes that will.


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Scott BeithAdministrator
SRF
*****

Reged: 11/26/03

Loc: Frederick, MD
Re: Something I like about refractors... new [Re: RGM]
      #5756953 - 03/25/13 08:19 PM

Quote:



I do not get the achro vs apo threads. It is as if refractors are only used to view the Moon, Jupiter, Venus and the 5 brightest stars in the sky. Those objects are less than 1% of my viewing volume.




LOL If you add in Mars, Saturn and the Sun these objects are more than 95% of my viewing volume.

There is no right way or wrong way to observe. We just pick the tools that work best for our individual needs.


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microstar
Pooh-Bah


Reged: 01/05/08

Loc: Canada
Re: Something I like about refractors... new [Re: jrbarnett]
      #5756960 - 03/25/13 08:22 PM

Quote:

So what do people who own multiple examples of each type of telescope defend?

- Jim




190 Mak-Newt for deep imaging. SV Raptor 90T for wide-field imaging and for collecting color while the Mak-Newt is collecting the detail and as a grab-and-go when I need something portable. Lunt LS60 PT DS because there's nothing better for solar viewing. What's to defend? Since getting the Raptor and following this forum I've learned that you guys are REALLY serious about your refractors, but I inhabit a comfortable world where I'm happy with each of my scopes for their intended purpose.
...Keith


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stevew
Now I've done it


Reged: 03/03/06

Loc: British Columbia Canada
Re: Something I like about refractors... new [Re: jrbarnett]
      #5757051 - 03/25/13 09:27 PM

Quote:

So what do people who own multiple examples of each type of telescope defend?

- Jim



Like you I have Refractors, Newtonian's, and Schmidt Cassegrains.
Each design has it's own benefit.

I love the crisp clean high contrast images, and wide field views of my refractors.

My large aperture Dobsonian provides very detailed views of faint deep sky objects that the other two designs could only hint at.

The SCT provides a level of portability and aperture that the other designs can't compete with.

I defend them all.....
From my nearly 30 years of observing and telescope collecting I have learned that there is no one perfect design.


Steve


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MooEy
member


Reged: 10/02/07

Re: Something I like about refractors... new [Re: stevew]
      #5757123 - 03/25/13 10:18 PM Attachment (43 downloads)

u mean you guys have scopes other than refractors?

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herrointment
Post Laureate
*****

Reged: 03/12/11

Loc: North of Hwy. 64
Re: Something I like about refractors... new [Re: MooEy]
      #5757185 - 03/25/13 10:54 PM Attachment (30 downloads)

"So what do people who own multiple examples of each type of telescope defend?"

Ah, I'll fight for my right to party!


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Something I like about refractors... new [Re: herrointment]
      #5757253 - 03/25/13 11:41 PM

I'm on my way up with my chainsaw and a snow blower. I'll save those beauties and fix your horizons issue in one vainglorious assault.

- Jim


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Kunama
professor emeritus


Reged: 10/22/12

Re: Something I like about refractors... new [Re: buddyjesus]
      #5757324 - 03/26/13 12:54 AM

Quote:

I actually think it is the glass in the lenses that make people silly as they are the same way with eyepieces.




I tend to agree with this statement although I must admit I am feeling better since I have been getting regular doses of lanthanum from my new Vixen LVW 3.5,5,8,13,17 &22mm.


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