Megrez 102

[aldora]

Czy wiecie coś więcej na temat tego sprzętu ,czy jest wart 1250 Euro ,a może ktoś z forumowiczów lukał przez ten sprzęt.

 

[Gość Janusz_P.]

Niestety jeszcze go niem miałem w ręku ani w serwisie i raczej nie mam się jak wypowiedzieć obiektywnie w tej kwesti, ale sądząc po jakości Megreza 80 myślę że to będzie bardzo dobry wybór w tej cenie 8)

[zbig_wawa]

bardzo zainteresował mnie ten sprzęt bo właściwie czekam na megreza 80mm f6.25, pomyślałem że to jest sprzęt, który mógłby zakup dużego APO odsunąć w nieokreśloną przyszłość :!: , znalazłem niewiele info na ten temat, ceny w walutach europejskich... , na oficjalnej stronie ani słowa, po amerykańskich info wnioskuję że w Stanach tego więcej nie sprzedają, jeśli ktoś wie coś więcej niech da znać, proszę

 

na william optics newsgroup znalazłem ciekawy, chyba pouczający post, który niniejszym cytuję (dla tych, ktorzy nie mają czasu się zarejestrować tam, sorki za sporą objętość) :

 

I agree also. Problem is there is a perception that you have either scopes

with a lot of chromatic aberration, like standard short achromats, and APO

scopes which come close to perfection in that area in most cases. The

problem arises from the vague definition of the term "semi-APO". If you mean

the term from today's usage it can mean any observable reduction of color

errors that is less than an F10 achromat, which seems to be today's

standard. By that definition any good F12-F15+ achromat from the 50-70's

would meet that definition. But current scopes aren't made in those ratios

much anymore. If you compare a Vixen F10 to a Sinta F10 you may find the

Vixen has noticeably less color than a Sinta, but the detail level between

them might be pretty close.

Or you can say a scope sold as ED is possibly a "semi-APO". If made at

F8-F10+ it can often rival a shorter focus true APO that is in the F6-F7

range, at least visually (QC issues aside look through a good example of a

Meade APO). But what happens is that the makers are so enamored over the

improved optics they shorten the F-ratio (that is what people want) and end

up increasing the level of color errors. Extremely low dispersion glass can

only do so much and when you shorten the F-ratio the light cone gets steeper

and harder to fully correct. That's why most true APO scopes have either 3-4

elements or one of which is a non-glass fluorite crystal (current champ for

Abbe distortion index) as opposed to ED scopes which generally use a

fluoro-crown element.

Problem is actually one of definition. Definition of APO (term is

apochromatic) is at least 3 of the primary optical colors are brought to a

common focus. Not all, just 3. Achromatic means 2. By the true definition

most ED scopes would meet the definition of apochromatic. However now people

use the term to mean all visible wavelengths, which only the highest

quality APO scopes can approach. So now the term "semi-APO" might mean the

same thing as the definition of APO where the 3 primary visual colors focus

at a common spot and the rest give it a little color.

But the term itself is so vague that people tend to at least hope that their

"semi-APO" is close to a true APO and when it isn't they get disappointed.

Basically they have unrealistic goals. What they really want is a cheap APO,

which by today's standards is not realistic.

Basically they would be just as well off buying a Sinta 6" F8 and a light

violet filter to eliminate the purple halo. And at that price range it is

hard for a "semi-APO" 100mm scope to compete. Especially against a 6" F5 or

120mm F5 for portability and performance for the dollar.

Kent Gittings

 

-----Original Message-----

From: dowen0@a... [mailto:dowen0@a...]

Sent: Saturday, September 01, 2001 9:31 PM

To: William-Optics@yahoogroups.com

Subject: [William-Optics] Re: Megrez 102 where are you?

 

 

OK, I'll be the one to disagree.

 

I think that there is a huge gap between the cheap Chinese import 4"

scopes at $375 and the TV/Tak 4" scopes for $2,100 (stripped down).

There is a market for a $995 - $1,000 scope that CONSISTANTLY

provides better optical performance (chrom. aber, astigmatism, zonal,

color control, etc) combined with upgraded mechanics (focuser) than

the cheap imports.

 

I disagree with the comment that people expect APO performance at the

$995 price range. Sure, it'd be great to achieve. One problem, I

would suggest, is calling this scope a "semi-APO". That leads one to

expect something that the scope can't deliver. The other problem,

from what I can gather, is that the manufacturer couldn't produce

this particular model with the level of consistancy that the consumer

expected. I wouldn't be happy either if I'd paid over $1,000 for a

scope that a)had to be returned to get it fixed the day after I had

received it or performed optically no better than a Celestron

102HD.

 

All this seems obvious to me....but then I may be a minority of one.

 

David

 

--- In William-Optics@y..., "Robert Schmall" <mbschmall@c...> wrote:

> Eric:

>

> Regardless of our individual viewpoints, it appears that all of us

agree that the marketplace was not ready for this scope at more than

$1000.

>

> Bob

> ----- Original Message -----

> From: Eric Faust

> To: William-Optics@y...

> Sent: Thursday, August 16, 2001 11:27 PM

> Subject: [William-Optics] Re: Megrez 102 where are you?

>

>

> For what it's worth, as one of the few that purchased and

returned

> the Megrez 102, it was not color correction that was the reason

for

> return. It was a consideration though. I did not expect an APO,

but a

> semi-APO. If you accept the definition from "Telescope Optics" by

> Rutten and Venrooij, that should mean similar to a 4" f/13.6

achromat

> for the Megrez 102. My minimum expectation for the Megrez was

color

> correction equal to an f/10 achromat, and that is approximately

how

> the Megrez performed. The bigger issues for me were contrast and

light

> scatter. The mechanics were superb and it was tough to send it

back. A

> week after I returned the scope, I was camping at 10,000 feet in

Utah

> and wished the little scope was with me. If I had paid the

> introductory $1,000 price instead of $1,150, and not got stuck

paying

> CA 8% tax, I probably would have kept it.

>

>

> Eric

>

>

> --- In William-Optics@y..., "Herb York" <ztrmann@f...> wrote:

> > Beg to differ.

> > People spending $1000 + for a 4" scope want it to perform like

an

> Tak 102 or TV 102.

> > This is our experience. Not blaming anyone and not referencing

your

> experience. Collimation is one thing - color correction

expectations

> are another.

> > Thanks

> > Herb

> > Anacortes Telescope

> > www.BuyTelescopes.com

> > www.AstroMart.com

> > 360-588-9000

> > 800-850-2001

> > ----- Original Message -----

> > From: Robert Schmall

> > To: William-Optics@y...

> > Sent: Wednesday, August 15, 2001 10:58 AM

> > Subject: Re: [William-Optics] Megrez 102 where are you?

> >

> >

> > Herb:

> > With all good feeling for Anacortes, which has been most

helpful

> to me, the implication that the consumer is responsible for the

> failure of a product is going to be hard to sustain. As proof,

the 80

> is still selling, and the public's expectations for it are no

> different than for the 102--that it perform at its price level.

> >

> > Bob

> > ----- Original Message -----

> > From: Herb York

> > To: William-Optics@y...

> > Sent: Tuesday, August 14, 2001 9:20 PM

> > Subject: Re: [William-Optics] Megrez 102 where are you?

> >

> >

> > Our feeling was that expectations of performance

outstripped

> reality of the

> > price.

> > In other words we felt that it was expected to perform at

APO

> levels for

> > achromatic prices. We asked William to not provide it here

any

> longer.

> > Herb York

> > Anacortes Telescope

> > www.BuyTelescopes.com

> > www.AstroMart.com

> > 360-588-9000

> > 800-850-2001

> > ----- Original Message -----

> > From: <kjackson@g...>

> > To: <William-Optics@y...>

> > Sent: Tuesday, August 14, 2001 7:03 PM

> > Subject: [William-Optics] Megrez 102 where are you?

> >

> >

> > > Hi,

> > >

> > > I just noticed that the Megrez 102 appears to be

discontinued.

> All

> > > mention of it is missing from the WO and Anacortes web

sites.

> > >

> > > Anyone (William and Herb in particular) have the scoop?

> > >

> > > I certainly hope it is not lost for good!

> > >

> > > Keith

> >