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Chopin
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 Posted: Thu Sep 02, 2010 5:32 am
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| Velocepedist |
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Joined: Tue Mar 18, 2008 6:28 pm
Location: In search of the ultimate switchbacks and single tracks
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Erik
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Posted: Thu Sep 02, 2010 4:06 pm
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Location: Off Grid in Paradise... Mag 7 skies
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Wow, that does sound like quite a deal! I wonder if these are rebranded scopes that also sell under a different name? That might be the way to get a review on one.
_________________ -Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount
"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman
Evolution is both fact and theory. Creationism is neither. -Anonymous
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Chopin
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Posted: Thu Sep 02, 2010 6:45 pm
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| Velocepedist |
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Location: In search of the ultimate switchbacks and single tracks
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Erik
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Posted: Thu Sep 02, 2010 10:17 pm
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Although they call these scopes "APO's", I'd be curious to see how good the color correction really is. I looked through an Orion ED 120 a while back and found that the color correction wasn't nearly as good as the Orion ED80. Of course, the ED 120 is f/7.5 which is frankly too fast to offer color free images with FPL53 ED glass. Still a great scope but not quite an "apo"- at least if the definition is "perfectly corrected for color".
Not that it matters unless you're doing serious astrophotography. My little SV 80ED shows a touch of color on Vega and other bright stars, but i'd prefer that over the poorer build quality, larger physical size, and slightly better color correction of the Orion ED 80.
_________________ -Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount
"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman
Evolution is both fact and theory. Creationism is neither. -Anonymous
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Square_peg
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Posted: Fri Sep 03, 2010 8:02 am
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| The Blacksmith |
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Joined: Sat Feb 16, 2008 11:51 am
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Of course, the ED 120 is f/7.5 which is frankly too fast to offer color free images with FPL53 ED glass.
I disagree. I think a well made FPL-53 triplet can easily be color free at f/7. The 92mm f/7 FPL-53 triplet Stowaway is an example of such a scope.
The Astro-Tech 106mm f/6.5 FPL-53 triplet was reviewed in S&T as being truly color free, "had absolutely first-class color correction. There was no visible chromatic aberration, even on the brightest targets. When defocused, star images presented nary a trace of false color."
So I believe that "true Apo" performance is certainly acheivable with FPL-53 down to at least f/7._________________ Tom (Pegster)
subvert the dominant paradigm
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Square_peg
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Posted: Fri Sep 03, 2010 8:51 am
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| The Blacksmith |
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One other thing, Jason. Remember that an air spaced triplet will have a longer cool down time than a doublet or an oil spaced triplet. Probably wouldn't make much difference for daytime photography but it's something to think about for night time work.
_________________ Tom (Pegster)
subvert the dominant paradigm
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Kawx4d
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Posted: Fri Sep 03, 2010 9:40 am
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| Steely-Eyed Missile Man |
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Location: According to Heisenberg, I'm uncertain...
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The 92mm f/7 FPL-53 triplet Stowaway is an example of such a scope.
This is the version of the Stowaway I have Erik, and the actual focal ratio is f/6.565. I'm not sure why Roland chose to market it at f/7 but the focal length is only 604mm. It is very much color-free. Vega, Sirius, and Venus are pure white both in and out of focus. Also, no color on the lunar limb, terminator, or on crater shadows at any magnification up to 402x, which was the limit of my EPs for that scope at the time I tested it._________________ Kerry
![[ img ]](http://cleardarksky.com/c/ChndlrAZcs0.gif)
Oh, yeah. The Stifmeister's coming back to Grand Harbor. Deck the halls. Bye-bye, Great Falls. Wipe my a$$ and lick my ba!!s It's Stifler time, baby. Whoo-hoo-hoo. Whoo-hoo-hoo. ~Steve Stifler-American Pie 2 
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Erik
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Posted: Fri Sep 03, 2010 9:58 am
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Of course, the ED 120 is f/7.5 which is frankly too fast to offer color free images with FPL53 ED glass.
I disagree. I think a well made FPL-53 triplet can easily be color free at f/7. The 92mm f/7 FPL-53 triplet Stowaway is an example of such a scope. So I believe that "true Apo" performance is certainly acheivable with FPL-53 down to at least f/7.
I should have worded my comments better- what I was saying is that at that level of aperture (120mm), a scope with FPL53 glass needs to be longer than f/7.5.
As I mentioned, the Orion ED80 at f/7.5 has virtually perfect color correction. The Orion ED100 is f/9 and has perfect color correction. The ED 120 should've been at least f/9 to maintain that level of color correction. It's still an awesome scope- it's just not on par with the 80 or 100 for color free images. With larger aperture refractors, the f/ratio must be increased to maintain good color correction-assuming the same glass is used._________________ -Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount
"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman
Evolution is both fact and theory. Creationism is neither. -Anonymous
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Square_peg
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Posted: Fri Sep 03, 2010 10:23 am
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| The Blacksmith |
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What type of glass is used in the 130mm f6.3 StarFire EDF?
_________________ Tom (Pegster)
subvert the dominant paradigm
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Erik
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Posted: Fri Sep 03, 2010 3:35 pm
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I'm not sure- I don't think I've looked through the 5", though I believe I have looked through the 6"- though it was several years ago.
I'd be surprised if AP used the same type of glass as Orion does in their apochromaric scopes.
_________________ -Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount
"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman
Evolution is both fact and theory. Creationism is neither. -Anonymous
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Square_peg
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Posted: Fri Sep 03, 2010 4:19 pm
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| The Blacksmith |
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Numerous AP scopes are confirmed to have been made with FPL-53.
http://geogdata.csun.edu/~voltaire/tmb/tmb1.html
I'm not suggesting an ES scope is necessarily built to the standard of an AP scope. Just that a very well corrected scope can be made at f/7 with FPL-53.
And whether AP sources their FPL-53 from the same place as Orion is another question I can't answer.
_________________ Tom (Pegster)
subvert the dominant paradigm
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Chopin
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Posted: Fri Sep 03, 2010 4:26 pm
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| Velocepedist |
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The problem with comparing different scopes under different manufacture, or even by technological changes from year to year, is that there are too many variables. I understand that four major features define the color correction of a refractor: focal ratio per aperture (the inch X 3 or 5 rule), the abbe index of used glass, the number of elements, and the curvature/placement of elements in the objective design. Change any one of those variables and you may end up with a completely different scope.
I read the specs on this ED102 triplet as a solid design with regards to:
a) f7 medium speed
b) Hoya FCD1 glass (abbe number ~81)
c) Three element
It's the way the lenses are designed and ground, and spaced, that I wonder about. Ultimately, an Orion ED100 f9 doublet also interests me, especially considering a slightly lighter weight, and currently very low price. But the single speed focuser is a drawback for bird photography (a forseen secondary use for the scope), as is the slower focal ratio. And of course, I'd still need to add a 2" diagonal, rings, a finder scope, and a dovetail, which no longer makes it such a savings.
There is just something about a 4" triplet with high index glass that seems hard to screw up. Maybe I'll just have to pick one up to check it out. I'm sure there are a few retailers I could buy from with a provision to return if I'm not satisfied.
_________________ Jason® (Admin...and spoke-folk)
![[ img ]](http://cleardarksky.com/c/VnVlckCTcs0.gif)
![[ img ]](http://cleardarksky.com/c/PrrsObCTcs0.gif)
![[ img ]](http://cleardarksky.com/c/JhnMcrthcs0.gif)
![[ img ]](http://cleardarksky.com/c/WilcoxPkNYcs0.gif)
Veritable Imagery
Single ride personal records: Distance-76.7miles, Max Speed-50.4mph, Max sustained speed (20miles) 19.5mph
“Life is like riding a bicycle. To keep your balance, you must keep moving.” ― Albert Einstein
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Square_peg
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Posted: Fri Sep 03, 2010 4:35 pm
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| The Blacksmith |
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Astronomics just dropped the price of their AT106LE to $1,195.00 for Labor Day Weekend!
I'd jump on that before I bought the ES 102.
Link to sale
_________________ Tom (Pegster)
subvert the dominant paradigm
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Kawx4d
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Posted: Fri Sep 03, 2010 5:30 pm
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| Steely-Eyed Missile Man |
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Location: According to Heisenberg, I'm uncertain...
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Chopin
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Posted: Fri Sep 03, 2010 5:33 pm
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Chopin
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Posted: Fri Sep 03, 2010 5:36 pm
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Square_peg
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Posted: Fri Sep 03, 2010 5:38 pm
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| The Blacksmith |
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Yep, and it's FPL-53 not Hoya 'FPL-51 equivalent' glass.
_________________ Tom (Pegster)
subvert the dominant paradigm
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Chopin
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Posted: Fri Sep 03, 2010 5:40 pm
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Kawx4d
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Posted: Fri Sep 03, 2010 5:46 pm
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Kawx4d
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Posted: Mon Sep 06, 2010 10:24 am
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Chopin
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Posted: Mon Sep 06, 2010 3:26 pm
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Hey thanks, Kerry. I have been incredibly tempted to jump on that AT106 sale, but I'm still trying to figure out what I really want to do with the scope (is this going to be used more for bird photography, or night time astro viewing?). That, and I'd need to bend the plastic to buy right now, and I've improved my purchasing habits over the past few years so I'd rather not fall back into that hole.
Ultimately the 4" range is certainly where I want to be. But I'm also factoring in the best compromise of size/weight (less is better), price (less is better), and violet fringing (you guessed it...less is better). I'm starting to lean to the Orion ED100. It's 3 lbs less than any of the other three I'm looking at, being the ES102, the Orion 110 ?7, and thanks to Tom, the AT106. Actually, I believe the ES102 is more than 10 lbs. I'm sure the ED100 is better color corrected than the 110 ?7, simply based on design, and especially based on reviews. I'd bet the ED100 is on par with the ES102, and probably close to the AT106. After pricing the ED100 with rings, dovetail and dielectric diagonal, I'm at $840. Seems like a deal, and it feels like a low risk investment with solid optics. I'm pretty wishy washy about purchases like this, and I'll probably go back and forth another 20 times before making the plunge. I do fear, though, that the ED100 is destined for history if I don't buy soon.
_________________ Jason® (Admin...and spoke-folk)
Veritable Imagery
Single ride personal records: Distance-76.7miles, Max Speed-50.4mph, Max sustained speed (20miles) 19.5mph
“Life is like riding a bicycle. To keep your balance, you must keep moving.” ― Albert Einstein
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Erik
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Posted: Mon Sep 06, 2010 7:36 pm
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The ED100 is a nice scope but it's loooooong! At f/9, it's physically larger looking than its aperture would suggest- at least that was my take on it when they first came out. It is very well color corrected though. If you've got a mount that doesn't mind the long tube that might be the way to go.
_________________ -Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount
"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman
Evolution is both fact and theory. Creationism is neither. -Anonymous
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Chopin
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Posted: Tue Sep 07, 2010 3:39 am
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| Velocepedist |
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Joined: Tue Mar 18, 2008 6:28 pm
Location: In search of the ultimate switchbacks and single tracks
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The ED100 is a nice scope but it's loooooong! At f/9, it's physically larger looking than its aperture would suggest- at least that was my take on it when they first came out. It is very well color corrected though. If you've got a mount that doesn't mind the long tube that might be the way to go.
Erik,that is an issue, for sure, and the one thing holding me back. I have a newt that is about the same dimension as the ED100, but comparing the two designs (refractor vs reflector) is misleading since the eyepiece is so low on a refractor.  There is no question I would prefer a shorter tube, say 750mm or less. But in the end, regarding mount sturdiness, will a tube that is six inches shorter really make much of a cantilever difference if it adds 3 lbs of weight in the process? I wish I could just compare these side by side, but I don't have that luxury.
As for having a mount strong enough, I'm playing guess work here. I will start off with my Bogen 393 gimbal head for mounting, which is easily as strong as the Televue Gibraltar. The only problem is it's vertical design , rather than 45?, limits how high in altitue I will be able to swing the scope. Here is an image of the mount with my lens:
![[ img ]](http://i519.photobucket.com/albums/u358/fowlmouth76/_MG_4637.jpg)
The saddle can sit above or below the lens (scope) offering some flexibility. I'm looking at the Stellarvue M2 mount a a possible alternative, so that I can achieve full zenith movement. Are there any other readily available mounts similar to the M2 with relative handling and price?
As for the tripod, I have a set of Bogen 3246 legs which have a load capacity of 27 lbs. They handle a pair of 10 lb. binos now with aplomb. Although I have two GEMs (one with a 10 lb limit, the other with a 25 lb limit) I expect to use this scope in alt-az configuration more often for grab and go work.
Lastly, does anyone have experience with the Orion ED102 or ED110 (or similar ED doublets from other manufacturers)? I've read mixed "reviews" with regards to false color. At what magnification does it become an issue? The only refractor I've owned and used extensively was an Orion 100mm ?6 achromat. It was sharp, but suffered from violet severely beyond 50x, IIRC. Are these doublets only being bagged by people who expect Takashashi performance, or is the violet fairly noticeable on bright objects. If a scope is good up to 150x before a tinge of color is visible, I'd be fine with that. But if 100x is the limit I'd hesitate._________________ Jason® (Admin...and spoke-folk)
Veritable Imagery
Single ride personal records: Distance-76.7miles, Max Speed-50.4mph, Max sustained speed (20miles) 19.5mph
“Life is like riding a bicycle. To keep your balance, you must keep moving.” ― Albert Einstein
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