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Equipment Discussions >> Refractors

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watcher
Carpal Tunnel
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Reged: 11/21/07

Loc: St. Louis, MO
Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5755280 - 03/25/13 12:18 AM

1. Visual only
2. 9, maybe a 10 inch. Why? because I have come to the conclusion that, for me at least, big glass has to be no more than about 1800mm long, I want wide field for the most part from a light bucket lens.I'll go with some species of Cass for planets and the moon.
3. much worse is fine for the uses I have for a large refractor.
4. About 3500 sounds right for an 8" achro 5000 for something with a little extra OOMPH, like Istar's R30.
5. Don't care much as long as it's made well, But the USA would be preferable as long as it can be done competitively.
6. I'm pretty patient, but no multi-year waits PLEASE.
7. I would prefer light weight "standard" materials. I really don't think that "built like a tank" translates well to large refractors.
8. Everyone is different. I think if your intelligent enough to be interested in astronomy in the first place, you can figure out what pier height you need, and how to put one together or have someone fashion it for you.
9. Again, not tough to DIY, but It might be nice to have a ready made solution if you wanted this scope to be a longer focal length.
10. Should be an option depending on individuals usage. I would only have, pretty much any refractor bigger than a shortish 6", permanently mounted.

With Istar, D&G, and APM, there are already some pretty good choices for big refractors. I think what we really need is a high capacity mount maker that can offer sturdy mounts for visual use. IE something like the CG-5 on steroids. I don't see why Synta couldn't make mounts with 150, 200, and 300 pound capacities, "good enough" for visual for under 10,000.00


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De Lorme
professor emeritus
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Reged: 12/30/08

Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5755282 - 03/25/13 12:20 AM

Your right Jim, I have a CR6" and I'm waiting for the Raycorr. The most important thing to me though is my rool off roof. Oh Comfort! The rool off roof is allowing me to think of the BIG 8" achro! Just set it up once and I'm done.
The convienvce factor is what people think of last.
No matter what your taste, put up an observatory. De Lorme


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Sean Puett
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Reged: 09/06/10

Loc: always cloudy, washington
Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5755363 - 03/25/13 01:17 AM

Quote:

Scott, what if you could get an 8" refractor with color correction on par with a 5" f/9 FPL-51 doublet, for significantly less than you paid for the TEC 140?

Another thought: what if the KUnming 6" f/5.9 achro came bundled with a Chromacorr-type device. How much would such a bundle be worth to you (or anyone else reading this thread)? The OTA along in Astrotelescopes guise is about $950. Would the addition of a color correction device make it worth $3000? $2750? $2500? Less?

Thanks.

The responses thus far are interesting. Thanks to everyone who has responded thus far. I'll add my $0.02 to the thread tomorrow, point for point.

Regards,


Jim




That is genius. Why hasn't anyone done this?. Now that would sell me on a large refractor. An 8"f6 with chromacorr built in. Even the 6" f5.9 with chromacorr would be interesting. I think his name is Dr dub, but anyway his images with that scope and the chromacorr showed very little, if any, color.
You could be starting the large refractor revolution. How fast can you correct with a chromacorr?


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De Lorme
professor emeritus
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Reged: 12/30/08

Re: The market for big refractors: Your opinions? new [Re: Sean Puett]
      #5755409 - 03/25/13 02:09 AM

Sean, A 8"f/6lens weight's aprox 10.75. Hastings tubing 7lbs,Tub rings 10lbs. The lenght{48"} is the same as a AT 10" reflector which my CGEM handled without any problems.
I'm thinking of flocking it with Prostar because it's easier
and read it gives good results. De Lorme


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RAKing
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Reged: 12/28/07

Loc: West of the D.C. Nebula
Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5755678 - 03/25/13 08:47 AM

Quote:

I'd like to do an informal poll getting your preferences for large refractors. By large, I mean 150mm and larger. Things I'm interested in are the following:

(1) Are you a visual user or an imager?

Visual only for now.

(2) How big is "big enough" and why?

For me, 160mm is big enough. I have to have a scope I can physically handle and I have to switch to a mirror if I go above that size.

(3) Using the old 127mm f/9 Meade ED doublet as a benchmark, would color correction be acceptable to you if it was about the same? A little worse?

Equal or better is fine.

(4) How much would you be willing to pay for a (i) 150mm?, (ii) 160mm?, (iii) 180mm?, (iv) 200mm? (That's not a typo - yeah, an 8-incher. )

I have a very nice 140 and cannot gamble my retirement funds on something too expensive. Get me a decent 160mm f/7.5 doublet for around $6K and I would be tempted. I realize I might have to wait for something on the "used" market with that budget.

(5) Would it be a plus (in the sense that you'd be willing to pay a bit more) if the optics were designed by a well-known designer? If the optics were manufactured in Europe?

If it's a good design and well executed, I'm not picky about where it is made.

(6) Is ready availability (i.e., no more than a 3 month wait) a major plus in your view, or if the price were a bit lower, would you be willing to wait a bit longer?

With my current inventory, I can wait a reasonable amount of time.

(7) What would you think about the manufacturer designing the refractors so that they use ultra-light materials (composites, magnesium and titanium fittings, etc) so that a CGEM/Atlas class EQ head could deal with the moment arm?

I prefer aluminum, but would consider alternate materials. The manufacturer MUST use a decent focuser. No cutting corners on the mechanics of the scope. Nothing less than the FeatherTouch design will do. I have seen enough bad focusers to last my entire life.

(8) What would you think about the manufacturer offering pier assemblies of appropriate height, set up for common EQ mount heads (again Atlas, CGEM, CGE Pro, G-11, etc.), to accommodate the length of the OTA?

OBE - I have a Mach 1 on an Eagle pier (with extension). Whatever is on the market has to fit on this combo for me to be interested.

(9) What if the manufacturer also offered hargreaves struts for the tube assemblies?

Not necessary for my desired aperture.

(10) Would a modular tube be desirable even if it drove up costs a significant amount (i.e., the tube breaks into 3 sections, fits in a matched hard case, and fits in the back of the average compact SUV (Forester, CR-V, RAV-4, Equinox, Escape, etc.)?

This sounds interesting, but in reality it's just more hassle than it's worth. When I'm breaking things down at "zero dark something", I want the fewest pieces possible and I don't want to be disassembling something as valuable as my telescope.

Thanks in advance for playing along. I have my opinions on these items, but would rather share them after others have had a chance to give their views.

Regards,

Jim





Thanks for the poll, Jim. I look forward to your ideas.

Cheers,

Ron


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Stellarfire
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Reged: 07/10/11

Loc: Switzerland
Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5756322 - 03/25/13 02:43 PM

Quote:


(1) Are you a visual user or an imager?
Visual only (mainly lunar and planetary) with TAK TOA-150B.

(2) How big is "big enough" and why?
Without permanent setup: 150-180mm, not slower than f/8; with permanent setup or observatory: 180-200mm, not slower than f/10.

(3) Using the old 127mm f/9 Meade ED doublet as a benchmark, would color correction be acceptable to you if it was about the same? A little worse?
I have no experience with it. I consider APO's from TAK, A-P and TEC as benchmark refractors.

(4) How much would you be willing to pay for a (i) 150mm?, (ii) 160mm?, (iii) 180mm?, (iv) 200mm? (That's not a typo - yeah, an 8-incher. )
Speaking of APO's with benchmark quality: 150mm = up to $12,000; 160mm = up to $14,000; 180mm = up to $17,000; 200mm = up to $ 24,000 (If funded to buy... These figures reflect the current price situation, I don't think that this price level may be substantially lowered. At least if benchmark APO quality is wanted.)

(5) Would it be a plus (in the sense that you'd be willing to pay a bit more) if the optics were designed by a well-known designer?
Perhaps. But just a slight surcharge would be accepted.
If the optics were manufactured in Europe?
No.

(6) Is ready availability (i.e., no more than a 3 month wait) a major plus in your view, or if the price were a bit lower, would you be willing to wait a bit longer?
Waiting time not more than 6 months please. A-P-style 10year waiting list system is a total NO-GO to me.

(7) What would you think about the manufacturer designing the refractors so that they use ultra-light materials (composites, magnesium and titanium fittings, etc) so that a CGEM/Atlas class EQ head could deal with the moment arm?
Without importance to me.

(8) What would you think about the manufacturer offering pier assemblies of appropriate height, set up for common EQ mount heads (again Atlas, CGEM, CGE Pro, G-11, etc.), to accommodate the length of the OTA?
TAK does this, I highly appreciate it.

(9) What if the manufacturer also offered hargreaves struts for the tube assemblies?
I don't have an opinion on this.

(10) Would a modular tube be desirable even if it drove up costs a significant amount (i.e., the tube breaks into 3 sections, fits in a matched hard case, and fits in the back of the average compact SUV (Forester, CR-V, RAV-4, Equinox, Escape, etc.)?
Not interested in modular OTA's.





Stephan


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hfjacinto
I think he's got it!
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Reged: 01/12/09

Loc: Land of clouds and LP
Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5756371 - 03/25/13 03:05 PM

Quote:



(1) Are you a visual user or an imager? I do both
(2) How big is "big enough" and why? A 130MM would be big enough, if I wanted larger than you have SCT's and Newtonian

(3) Using the old 127mm f/9 Meade ED doublet as a benchmark, would color correction be acceptable to you if it was about the same? A little worse? Don't know that scope, the worse I would take is my 80MM EON, which is an F6.25.

(4) How much would you be willing to pay for a (i) 150mm?, (ii) 160mm?, (iii) 180mm?, (iv) 200mm? (That's not a typo - yeah, an 8-incher. )

I wouldn't, like I said 130MM is abou as big as I want.

(5) Would it be a plus (in the sense that you'd be willing to pay a bit more) if the optics were designed by a well-known designer? If the optics were manufactured in Europe? Not really, as long as the quality is good, that is more important, while some people like labels, I like quality

(6) Is ready availability (i.e., no more than a 3 month wait) a major plus in your view, or if the price were a bit lower, would you be willing to wait a bit longer? I wouldn't wait longer than 3 months

(7) What would you think about the manufacturer designing the refractors so that they use ultra-light materials (composites, magnesium and titanium fittings, etc) so that a CGEM/Atlas class EQ head could deal with the moment arm?
Hmmmmm I would consider it.
(8) What would you think about the manufacturer offering pier assemblies of appropriate height, set up for common EQ mount heads (again Atlas, CGEM, CGE Pro, G-11, etc.), to accommodate the length of the OTA?

Hmmmmm I would consider it.

(9) What if the manufacturer also offered hargreaves struts for the tube assemblies?

Hmmmmm have no idea what a hargreaves is, so I guess the answer is no

(10) Would a modular tube be desirable even if it drove up costs a significant amount (i.e., the tube breaks into 3 sections, fits in a matched hard case, and fits in the back of the average compact SUV (Forester, CR-V, RAV-4, Equinox, Escape, etc.)?

Like I said 130MM, no reason to have a modular tube

Thanks in advance for playing along. I have my opinions on these items, but would rather share them after others have had a chance to give their views.

Regards,

Jim




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snommisbor
professor emeritus
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Reged: 06/15/09

Loc: Cedar Park, TX
Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5756500 - 03/25/13 04:07 PM

(1) Are you a visual user or an imager? 75% Imaging 25% visual

(2) How big is "big enough" and why? If I dont have a permanent location probably 160mm, think for portable or setting up in the backyard if I want to go bigger and deeper I would get a SCT or Reflector

(3) Using the old 127mm f/9 Meade ED doublet as a benchmark, would color correction be acceptable to you if it was about the same? A little worse? Never looked through it but I want the best color correction.

(4) How much would you be willing to pay for a (i) 150mm?, (ii) 160mm?, (iii) 180mm?, (iv) 200mm? (That's not a typo - yeah, an 8-incher. ) All pertaining to IF I had the funds but I would 19,000 for a 180mm which happens to be a TEC 180 : )

(5) Would it be a plus (in the sense that you'd be willing to pay a bit more) if the optics were designed by a well-known designer? If the optics were manufactured in Europe? Yes it would, call me a snob but I like having the best, feel the premium will make it cheaper in the long run should I ever sell.

(6) Is ready availability (i.e., no more than a 3 month wait) a major plus in your view, or if the price were a bit lower, would you be willing to wait a bit longer? I waited 10 months for the TEC 140 would say 18 months would be pushing the limit for me, even though I am on a list that could be 9 more years for me. But if it was a scope I was wanting for an observatory 18 months would be my max.

(7) What would you think about the manufacturer designing the refractors so that they use ultra-light materials (composites, magnesium and titanium fittings, etc) so that a CGEM/Atlas class EQ head could deal with the moment arm? Not important to me, if I had a world class telescope I would want it on a world class mount.

(8) What would you think about the manufacturer offering pier assemblies of appropriate height, set up for common EQ mount heads (again Atlas, CGEM, CGE Pro, G-11, etc.), to accommodate the length of the OTA? Sure that would be fine.

(9) What if the manufacturer also offered hargreaves struts for the tube assemblies? Wouldnt change why I would buy a certain one. For me it is all about the glass.

(10) Would a modular tube be desirable even if it drove up costs a significant amount (i.e., the tube breaks into 3 sections, fits in a matched hard case, and fits in the back of the average compact SUV (Forester, CR-V, RAV-4, Equinox, Escape, etc.)? No because if I go that big it will be in an observatory.


I am about the optics, so that is very important to me and it is worth it for the premium. An analogy for me would be why do people buy Canon and Nikon DSLR's and then proceed to put third party lenses on them. Sure they are cheaper and can take great photos but the reason you buy these cameras is to have the excellent glass that is made by these companies. Cameras will become obsolete but fine glass will always be in demand.


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Mark Costello
Carpal Tunnel
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Reged: 03/08/05

Loc: Matthews, NC, USA
Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5756688 - 03/25/13 05:50 PM

Before answering, I'll mention a couple of things.

First, although I consider myself a bit of a "refracto-fanatic," I draw the line at 5" - or maybe 140mm. The only 6" refractor I've seen that I might want to handle is the Celestron C150R, and its chromatic aberration may be a bit too much even for me. Otherwise, any system 6" or larger that I get will work mostly or completely with mirrors.

Second, while I have no problems with the superiority of apos, I can make do fine easily with achros like the one I have right now, and am not motivated to buy any apo, unless again it's the kind that works with mirrors.

Now here are my answers to your questions:



I'd like to do an informal poll getting your preferences for large refractors. By large, I mean 150mm and larger. Things I'm interested in are the following:

(1) Are you a visual user or an imager? Visual observer only

(2) How big is "big enough" and why? 5" or maybe 5.5". Anything bigger that I own will work with mirrors.

(3) Using the old 127mm f/9 Meade ED doublet as a benchmark, would color correction be acceptable to you if it was about the same? A little worse? Um, see my signature. Any more questions on that line?

(4) How much would you be willing to pay for a (i) 150mm?, (ii) 160mm?, (iii) 180mm?, (iv) 200mm? (That's not a typo - yeah, an 8-incher. ) Maybe up to a couple of grand, given that it'll work with mirrors. Otherwise, I'm sticking with my current 5"-er.

(5) Would it be a plus (in the sense that you'd be willing to pay a bit more) if the optics were designed by a well-known designer? If the optics were manufactured in Europe? It does not matter to me, as indicated by what I own now. OTOH, it has not escaped my notice that the 2 grand that I might throw at a good 4" or 5" apo can get a nice premium 8-11" Dob from at least one maker.

(6) Is ready availability (i.e., no more than a 3 month wait) a major plus in your view, or if the price were a bit lower, would you be willing to wait a bit longer? Yes, although I could wait longer - maybe up to a year given periodic updates or at least a willingness to answer an occarional question on status. A big negative for me is an indeterminately long "wait to order" list.

(7) What would you think about the manufacturer designing the refractors so that they use ultra-light materials (composites, magnesium and titanium fittings, etc) so that a CGEM/Atlas class EQ head could deal with the moment arm? Not enough to want to buy one. What are the heat transfer characteristics of these?

(8) What would you think about the manufacturer offering pier assemblies of appropriate height, set up for common EQ mount heads (again Atlas, CGEM, CGE Pro, G-11, etc.), to accommodate the length of the OTA? It would not attract me. Mounts that large are too much for me....

(9) What if the manufacturer also offered hargreaves struts for the tube assemblies? No.

(10) Would a modular tube be desirable even if it drove up costs a significant amount (i.e., the tube breaks into 3 sections, fits in a matched hard case, and fits in the back of the average compact SUV (Forester, CR-V, RAV-4, Equinox, Escape, etc.)? No.

Thanks in advance for playing along. I have my opinions on these items, but would rather share them after others have had a chance to give their views.


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jrbarnett
Eyepiece Hooligan
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Re: The market for big refractors: Your opinions? new [Re: Mark Costello]
      #5756740 - 03/25/13 06:19 PM

Mark, is your self-imposed 5" or 5.5" limit based on assumptions about the possible color correction of larger faster scopes? You mentioned the C6R in your preface, and that's a pretty long OTA at f/8. There are 6" achromats at f/6.5 and f/5.9 as well. What if you could get a 6" f/5.9 achromat with color correction comparable to that of a 5" f/9 ED doublet, all for a "reasonable" price (say $2500 for sake of argument). Such a scope would ride comfortably on a CGEM/Atlas class mount and in a pinch could make due with a Sirius or CG5.

Would that make you more interested in something larger?

Thanks!

- Jim


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Gord
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Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5757155 - 03/25/13 10:34 PM

So Jim,

I've been looking into the alternative to a big APO like you are hinting at for some time now. It's a good approach for visual observers (IMHO), but it isn't quite a pure refractor like as some might like. By this I mean, there is a little more work involved, a little bit of "fiddling" that is possible (but may not really be required). I've noticed that there are a number of refractor people (lets call them...) that have no interest in this and in fact go so far as to despise it and any situation/setup/use-case where it could occur. Not sure how big of a group that is...

Anyway, the other point to it is that things may not be as cheap as you are indicating if you are going for more "top-shelf" performance. In the 6" size you are mentioning if you were to go with run of the mill decent Asian scope performance, then I could see it being possible to be done in the price range you are thinking. But at larger sizes and getting into the good quality offerings, it will start to cost. That being said, it's in a whole different league than the true APO's!

Here's an example:

D&G 8" scope is around $4000. Add in the corrector and some special parts to adjustments and tuning and you'll add $1500 to closer to $2k. The D&G backlog is 1-2yrs and I think it's because they are somewhat under-priced. At $5000 for the OTA, I think the wait's would drop a bit.

So, in the $7000 range for a very nice, ED to APO performer on axis. Is that good value? In comparison to other APO's, absolutely!! But compared to other alternatives, well, it gave me some pause. Not saying that I won't eventually end up at one of these anyway, but not right now. And I wouldn't see this as a replacement for something like the C14 for example.

The one thing about the D&G's though, is F12 is as fast as they come. I went looking to see about something faster with the above idea in mind. APM is now out (not doing achro's anymore). I'd like to see if there is something at the next quality level up from IStar as well.

I inquired with Bob Royce about a custom project and it isn't cheap (although the quality is I'm sure there). $4000 for a 7" lens in cell. I also found another possibility at 8" (and F8) for in the $4000 range. That would be the one I would likely pick if I go this route. The quality level here is going to be at the level of what the LZOS APO triplets are, so this is the "good stuff" (tm).

But as I was saying above, you have to build a quality scope around that and add the corrector. When you start looking at the Astro-Physics focusers and such, there's a fair amount to add on top of the lens. Still, $7-8000 for a premium 8" is a bargin compared to the APO triplets.

So the real question is, is there a market out there for something like this?

Clear skies,


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jrbarnett
Eyepiece Hooligan
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Reged: 02/28/06

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Re: The market for big refractors: Your opinions? new [Re: Gord]
      #5757272 - 03/25/13 11:58 PM

That is the real question. I don't think there's much of a market for $7-8k non-perfectly-apochromatic, visual-use refractors. Key, I think, is getting someone with mass-production muscle to be able to churn out larger aperture scopes of decent (better than 1/4 wave) quality, fast doublets in decent tube assemblies, and then add to that something that corrects for false color, which would be the expensive bit. Royce and D&G don't mass-produce so their costs are very high. I think you need a partnership between a mass-producer and a seriosuly innovative and savvy optical expert and manufacturer. I figure a ~1/4.5 to 1/5 wave 180mm f/6 doublet with correction bringing it in line with a 5" f/9 FPL-51 doublet, if possible, would have takers in the $4000-$4500 range. The OTA would be only about 4-feet long and 35#, so not especially hard to handle for a CGEM/Atlas class mount for visual.

I dunno if this is possible. I just think that combination of size, quality and price would sell. With such a scope available what visual user would instead buy a $5k to $7k mass produced 6" ED triplet? But I'm getting ahead of myself. I owe some answers to my own questions which I will provide in a few.

Regards,

Jim


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FirstSightModerator
Duke of Deneb
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Reged: 12/26/05

Loc: Raleigh, NC
Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5757348 - 03/26/13 01:13 AM

Visual only.

In my current situation, a TV NP-101 is both the largest refractor and the most expensive refractor I'd consider. Maybe if I unexpectedly became wealthy, I'd buy a used Astro-Physics f/6 ish 130mm when one eventually became available, because the extra inch of aperture is just enough to begin to resolve some things that 4 inches simply doesn't.

However, beyond 5 inches, IMHO the advantages of the pure, unobstructed planetary or widefield APO view become heavily outweighted (both in performance and cost-effectiveness) by the greater resolution power of aperture from a large reflector with good optics and collimation. Returning to the "if I became wealthy enough to afford it" theme, a 20" f/3.3 Starmaster would be at the head of my priority line ahead of a 130mm Astro-Physics refractor, nice as it would be to someday have both.

A well-balanced visual observer needs both a good versatile 100mm refractor (manageable size for grab n'go) and a good quality reflector with enough aperture for some serious reach and resolution, while still being able to keep one's feet on the ground without needing a ladder. That's the perfect combo to me.


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Illinois
Carpal Tunnel


Reged: 12/18/06

Loc: near Dixon, Illinois USA
Re: The market for big refractors: Your opinions? new [Re: FirstSight]
      #5757682 - 03/26/13 08:32 AM

Visual only

I like my 100mm F9 but I would love to own 6" ED F9 with very good micro-motion altazimuth mount. It would be max weight that I can carry to outside from my garage. I dont like heavy mount like german type mount with weight.

5" F8 or 9 great
6" F9 is super for me It would be good for everything from bright deep sky object, planets, moon, double stars and some faint deep sky objects.

7" and up is too big and heavy and $$$$!
7" F6.5 maybe!


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Mark Costello
Carpal Tunnel
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Reged: 03/08/05

Loc: Matthews, NC, USA
Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5757806 - 03/26/13 09:53 AM

Quote:

Mark, is your self-imposed 5" or 5.5" limit based on assumptions about the possible color correction of larger faster scopes? You mentioned the C6R in your preface, and that's a pretty long OTA at f/8. There are 6" achromats at f/6.5 and f/5.9 as well. What if you could get a 6" f/5.9 achromat with color correction comparable to that of a 5" f/9 ED doublet, all for a "reasonable" price (say $2500 for sake of argument). Such a scope would ride comfortably on a CGEM/Atlas class mount and in a pinch could make due with a Sirius or CG5.

Would that make you more interested in something larger?

Thanks!

- Jim





Hi Jim, sorry for the late response.

Sorry also for any confusion about my reference to the C150R as a refractor I was considering. I meant the 6"F5 refractor Celestron was offering in the Omni-Xcel rig. I was considering it as an alternative to the AR127, especially since its lens cap had a 115mm stop. But it didn't take much for the dealer (OPT) to convince me that the ES AR127 would be a better buy. In addition to the color error of a 6"F5 achro, there was the concern I had - rightly or wrongly - that very fast "mass produced" lens might have some significant other errors (e.g. spherical aberration).

Otherwise, my limit of 5-5.5" has more to do with how well and easily I can handle the optical tube assembly (OTA), set up and tear down without some accident like dropping the OTA (I've actually did this a while back with my 4" achro and had to get it replaced ) and - how a large rig might demotivate me from going out on a nice night. The Astro-Telescope 6"F5.9 and ES AR152 weigh in at about 25 lb give or take a tad, and with the needed accessories (diagonal, eyepieces, rings), might approach 30 lb. I'd rather stick with a 5" or at largest 5.5" (and here I'm thinking more of the Vixen 140NA which is very light weight).

As to color correction, I can tolerate the color error in my ES AR127. I've actually gotten a couple of pretty decent drawings of Jupiter with it this season, and it's given pretty nice images of lunar landscapes. Of course, better color correction would serve me better. But the only scenario in which I might buy a refractor with better color correction would be if - horrible dictu (as the French might say) - something happened to my ES AR127 OTA. Then in that case, I MIGHT replace it with an ED refractor. But it might not necessarily be a true apo and if I did that, it might be in the 4.5" class - 110mm-115mm. That would be in the interest of saving money and getting a manageable OTA. So a 6" ED for $2500 might not appeal to me as much as the idea of keeping my achro and matching it with a 8-11" STS Dob from Teeter or 8-9.25" HD or ACF rig for about the same amount of money....

Best regards,


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t.r.
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Re: The market for big refractors: Your opinions? new [Re: Mark Costello]
      #5757875 - 03/26/13 10:25 AM

You hit the mark Jim with the 180mm but I'd go with f/9...similar to the Meade 178ED. I got to play with one of these a couple of times and put it through its paces. It did show CA, but I didn't think it was knocking contrast at all and I could live with the amount produced. I know a group of us had a GREAT time binoviewing through it at various targets. The idea of a 7"F/9 Ed doublet is right on the mark for a purely visual SLAP observer. I have stated my interest in such a scope many times on CN and have discussed custom builds with Markus and Robert Royce. But, custom costs! Markus has hinted that if the 152 doublets take off, a 7" could be next...the price and color correction is what is left to be seen. The 152 I think is a pretty good product, but why not just go a touch bigger to the 7" class, which I had no issues weilding, and get a little more oomphf for planetary and good reach for DSO's all in one package. A 7" doublet ED is on my short list...if only someone made it! And yes, I've looked at the Aries, but it is a one-off.

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jrbarnett
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Re: The market for big refractors: Your opinions? new [Re: t.r.]
      #5757888 - 03/26/13 10:32 AM

Hi t.r.

Any reason you'd want f/9 if you could get an f/6 with at least as good and possibly superior color correction to the f/9 (and obviously a much easier to mount size and mass)?

Regards,

Jim


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Sean Puett
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Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5758034 - 03/26/13 11:46 AM

I would like the fastest possible with good color correction. I like petzvals but, I believe that they would end up way above the targeted price. With the Vixen NA140 as a starting place, could a 160-170 be done for 50% or less added to the price? Then add a chromacorr type device. Then you could have a flat field f5. The scope would be longer and heavier than a standard scope of that size and focal ratio. Or you could add a ed element to the flattener/reducer like on the TV petzvals. It has to be too expensive or they would make them now, don't you think?
Ok so some reality has hit me regarding the 6"f5.9 with chromacorr. There would still be field curvature that needs to be dealt with. I have become to intolerant of edge issues and that would keep me from buying unless dealt with.


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Eddgie
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Re: The market for big refractors: Your opinions? new [Re: jrbarnett]
      #5758090 - 03/26/13 12:18 PM

The three most important letters in the telescope making business are not APO.

They are "ROI."

Not to try to divert the thread, but I could see exactly what you were trying to find out from the very beginning.

Please, no offense intended.

I did business in China for 10 years, and I have people over there dying to make something for me.

The sad reality is that when I have had ideas and done business cases for them, the economics simply were not there to justify the return on the investment required (ROI).

I see questions like "Why don't they make _____________ ?"on these forums all the time.

And the reason is because what is a hobby to us is a business to them.

The road-side is littered with the empty husks of companies that have tried to get into a niche market and failed.

Why would someone take valuable resources from producing thousands of __________ a year to produce a few hundred 6" refractors a year when they can only make a few hundred dollars on each one?

The answer is because a few hundred dollars of profit on each one doesn't make it worth doing.

That is always the stumbling point in my own business cases. I am not going to put a big up-front manufacturing cost on my books for a few hundred units (about the minimum anyone will make for me) only to make a few thousand dollars in profit.

And if it is something you think you want to do, just be willing to write the check, and you can get someone to produce your design, but do the math, and what you will find is that the risk is simply to high.

Bottom line? There are easier ways to make money for these companies, and most of the people on this forum will not have the stomach for the risk. I am a pretty good investor, and I would rather put my money at risk in the stock market. For what I would need to put up front to make a 6" ED scope in quantities needed to get it produced, I could get more dividend payment for the money from my oil stocks than I could earn in profit on the units I would sell. Why would I want to sell my oil stock to do it?.

Edited by Eddgie (03/26/13 12:29 PM)


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jrbarnett
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Re: The market for big refractors: Your opinions? [Re: Eddgie]
      #5758233 - 03/26/13 01:18 PM

That's not quite right. There are plenty of examples of specialty businesses that do not optimize with respect to ROI. A-P is a prime example. They could grow to make more scopes and make more money. They could raise the price of the scopes without changing production capacity, and make more money. The mega-year waitlist proves this.

Optimized ROI is a driver for large scale, mass-production businesses, but for businesses serving niche markets with educated consumers, not as much. Specialty producers are as often motivated by the personal satisfaction of the owner/operator as they are the bottom line. If the products are good, the bottom line pretty much takes care of itself.

Kunming seems to be having no trouble selling 6" achromats. At ~$900 a pop I suspect that the rebrander offering the scopes it pocketing a few hundred dollars per unit. Figure the cost per unit in lots of 10 or 20 might be $500 or $600.

Now what if small shop optics expert "Company X" can make a false color correction device that greatly reduces the CA of this $600 scope, for, say $1200 per unit in cost? At $3000 the bundle (scope plus CA corrector) has $1200 margin per unit built in for the bundler. Sell all 20 of them and that's $24k profit. Sell 200 per year and that's $240k profit. Move 1000 units and you've put $1.2 million in the bank. For context, you'd be undercutting the APM FK-61 doublet by a grand at a $3k price and assuming similar or better color correction and comparable figure quality, doable? A visual only user looking at one of the 127-130mm triplets (AT, TMB SS, WO, ES127, Meade 130, etc.) for $1.6k to $4k could for similar money have your easy to mount 6-incher instead. How low would the price of the bundle need to be to be totally disruptive of the "visual user market for mid-aperture ED doublets and triplets"?

Now supplement the $1200 bread & butter margins on the off-the-shelf 6" with some more custom 7" and 8" scopes following the same profile. Your color corrector cost remains the same. Only the cost of the optic and tube assembly goes up.

I dunno, I think for a small business, potentially there's a solid business opportunity there. Not so much for a Kunming, JOC, Synta, etc., though, who has to move thousands of units to keep the lights on.

- Jim


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