1° Forum di Astronomia Amatoriale Italiano

infatti i "suoi" rifrattori sono in realtà TMB - APM

mi sembrerebbe strano...
io gli ho mandato una foto della cella (come la vedi sul mio sito) e mi ha confermato che e' un ottica progettata da lui...

boh

salve cmq homi sono informato su yahoo groups supeapo e ho scoperto che i vetri dell'astrya non sono ED(o meglio non sono i vetri comunemente usati per ridurre lo spettro secondario tipo fpl53),ma vetri esotici in grado di ridurre notevolmente lo spettro secondario forse anche più degli ED,
leggete quà osa di ce markus ludes:

From: "Markus Ludes" <apm_telescopes@w...>
Date: Sat Apr 20, 2002 5:19 am
Subject: Re: [Refractors] Re: 6`` f7 Super APO


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----- Original Message -----
From: "Stewart Squires" <ssquires@h...>
To: <Refractors@yahoogroups.com>
Sent: Friday, April 19, 2002 11:09 PM
Subject: Re: [Refractors] Re: 6`` f7 Super APO


> Couple more small points.
>
> Roland tested those 130 f/6 lens sets on Vega. From the Airy disk size
> I think we're looking at ~800x not 200x (Airy disk is white also, hmmm -
no green filter there).

Next week I will make a few images , using same defocused size as roland
used, with 200 power and 500 power and 800 power, than you can repeat again
what you say here.

No green filter ? Look again at the image

without using a filter, lenses from any manufactor will show on one side a
bit more redisch and on other side a bit greeninsh, on Rolands image you see
greeninsh on both sides, a clear sign for use aof a light green filter

> This magnification again is supported by the size of the diffraction image
and the number of rings displayed.
> There was a lot of discussion on the group when he posted those images. I
need to go back and review the specifics.
>
> Looking at a very fine Tak doublet startest you provided below. (Might be
the FC125 you had
> previously; should have bought that one) notice just how nice this test is
compared to the 155
> image you posted. Especially the 3-4 ring image. You will not be able to
convince me that a 155 EDF,
> or a 130 for that matter, from AP, will be less better corrected than a
Tak doublet - period, no way, no how. (My
> FC100, which is really excellent, shows more color at f/8 than my Traveler
at f/6)
>
> While only you know for sure, my opinion is that your 155 image is not
from a properly collimated and settled AP EDF from 2000. It might be from
> an early AP triplet, or from some other 155 f/7. If it is a 2000 AP EDF,
then my opinion is that it isn't settled, or the lenses are not collimated,
or something
> else is wrong and it needs to be returned to AP for service.

the lens was 2 days settled down in test roiom, i think thats more than
enough
>
> Markus, in my opinion, you as a vendor, are only going to lose credibility
no matter what you say about someone else'e optics.
> Valid comparisons can really only be valid when the person doing them is
not affiliated with one scope or the other. It's why
> Cloudy nights and Ed Ting and Todd Gross were and are so useful. I have
never purchased a single telescope from Roland.
> I bought all mine used except the 130 f/8.35 which came new through
Baader. In the early years of my venture into this hobby (1996-97)
> I got into a number of heated discussions with AP and its supporters about
the APOMAX. I have always tried though to be objective and have
> probably done myself a disservice should I ever want to come up on an AP
list. Even then I doubt that I will ever be in a position to purchase
> from AP direct because I hate to wait As a consumer though I HAVE
learned to judge optics. I know how good my really good
> optics are. I also have seen enough of these late model AP scopes to feel
pretty darn good about consistency. The image you posted
> I would have to see in the eyepiece to believe.
>
> I hope to get to Astrofest and maybe RTMC this year. I would really like
to star test YOUR telescopes and talk about THEIR correction.
> My opinion of the quality of AP optics has been building for some years.
The only TMB scope I've seen is Dave N.'s at Astrofest when all
> we could do is look AT it not through it. And I am interested in these
scopes because Thomas is actually testing them before they go out the
> door, and I greatly respect his experience. As such I would buy one if it
struck my fancy, counting on its image to at least meet the specs of the
> sales agreement.
>
> Lastly, I, and many here, appreciate all the awareness of technology you
have published for our use. I encourage you to continue to educate. But I
also
> urge you to find a way to promote only YOUR products. Leave these
criticisms or comparisons to others. On the field, and at the eyepiece, is
where you
> will find converts (and customers) if your products are what you say they
are.

This above discussion came up by the Silverstar lens and not believe that a
silverstar lens could be as well or better colorcorrected than an AP lens,
but non of you who declined that a silverstar lens could be so good , have
ever seen one. I show real images and you say I am liering, you talking
about never seen lenses and say something you couldn't know , whats the
reason for such messages ?

I am not a fan of Silverstar lenses due its cell problems and have had lots
of trouble with it , but since I know the optical quality, I cannot accept
that a unknown lens will be made worser than an known lens, if the unknown
lens is not worser and I have real images to proove my words and I am able
to show it to anybidy if he comes to me or if we meet tpogether and thats
what i am able to do if we ever meet you with your AP lens.

continue with what you want, i know what i know , i cannot coinvience you,
you cannot convience me, so best is to stop the discussion, since it makes
no more sense

regards

Markus
>
> Stew
>
>
>
> >>> apm_telescopes@w... 04/19/02 09:52AM >>>
>
> ----- Original Message -----
> From: "Stewart Squires" <ssquires@h...>
> To: <Refractors@yahoogroups.com>
> Sent: Friday, April 19, 2002 1:58 PM
> Subject: Re: [Refractors] Re: 6`` f7 Super APO
>
>
> >
> >
> > >>> apm_telescopes@w... 04/19/02 01:23AM >>>
> > you may dont see it , like some others see nearly no color in Synta,
lets
> > come together and do together observaing and I show you the color
> > Markus
> >
> >
> > Markus,
> >
> > I'm always happy to compare telescopes, and I see color just fine; but
> let's get real. The image of the bench star test you show for a 155 f/7
on
> the abberator website looks very LITTLE like the star tests I have seen in
> two AP 130 f/6, one AP 130 f/8.35, two AP 155 f/7's, and two AP 105
> Travelers. All of these are post 1997 EDF builds. Heck, even my 1991 178
> f/9 Starfire shows less color than this display.
>
> Stew,
>
> the tested scope was from 2000 and any such scopes show some amount of
> color.
> >
> > Roland published a star test image on the 130 f/6 on the ap-ug Yahoo
group
> files section. I urge any of you to look at this image and then compare
to
> the image that Markus has posted. The image is down to FOUR rings.
> Extremely tough star test. There is a little color variation between
> images. But nothing like the more typical star test image that Markus is
> showing, and certainly not like the three to four ring images on his
> display. Look at the differences in outer ring brightness.
>
> compare yourself
> http://aberrator.astronomy.net/scopetes ... 55_01.html
>
http://groups.yahoo.com/group/ap-ug/fil ... 30F6b%20In
> -OutSmall.jpg
>
> and see the diffrence of the power. I used at least douplet or triple
power
> for my image, usual around 500 power, the AP image looks around 200 power,
> than there will be of course a big diffrence.
>
> http://aberrator.astronomy.net/scopetes ... 125_1.html
>
> see here a Tak
>
> what you see on the AP Image ? Green , Roland used a green filter to make
> the other colors from my image invisible and even wih the used slightly
> green color his image show some amount of color.
>
> Now you say you see no color, where even Rolands lower power image used a
> slight green filter show still color ?
>
> >
> > The star tests that I have seen in my and other's EDFs, all post 1997,
are
> VERY similar to the images that Roland has posted. When observing with
> another highly talented star testor, we both noticed that the color seen
in
> the defocused images DOES vary with focal ratio. It gets BETTER corrected
> as you get longer. So the image that Roland posted at f/6 changes quite a
> bit towards more color balance at f/7. The 130 f/8.35 is better yet!
>
>
> >
> > I think it prudent that we get a little more specific about this 155
f/7.
> You seem to imply that it is an AP EDF. If so I would like to know it's
> year of manufacture.
>
> year 2000
>
> I reported a zone once on one of Roland's lens sets, a 130 f/8 Brandon
from
> the mid 80's. Definitely was there. Yet on the post 95 stuff, I don't
> believe that ANY zone of the type seen Markus' image would ever make it
out

_________________
C8 - skywatchered80- eq6
Canon 40d mod,
magzero mz5 e molta passione.

ops scusate forse ho confuso post dovrebbe essere questo l'articolo:
Roland christen parla ha proposito dei nuovi TMB da 92mm e pare che gli astreya si.ano proprio disegnati con qusto sistema
ixio

It uses one crown glass and two flint glasses with wide airspace. It has 3 color crossings, but there are a number of issues that prevent this simple triplet from being a good alternative to modern apos. First it is considerably longer than its focal length. Of course, so is a Petzval, and it seems that most amateurs don't seem to realize this, or mind. The next problem is that it is difficult or impossible to correct for lateral color with only 3 lenses. This is the same problem that you have with the chromacor. On-axis the images are quite good, as good as most apos, but as you go out toward the periphery, the colors begin to separate into short spectra. The only way to correct this, in my opinion, is to add some more small lenses toward the rear. Third, the radii and spacing are somewhat critical. This makes low cost production not practical, at least not easy.

I do not believe that the announced TMB lens that was shown at NEAF is any sort of large airspaced lens along these lines. Let's just say that I am skeptical that it uses 3 glasses that do not have some sort of small deviation from the Abbe Normal line. My guess still would be that it is along the lines of the short flint triplets, but using Russian or Chinese glasses instead of Schott versions. Schott glasses are very expensive and their Chinese equivalents can be purchased for a song. Lzos also makes some very interesting non-ED glasses that can be used to make highly corrected triplets. Astreya uses them to make their apos, which by all accounts seem to be extremely well corrected.

In any case, unless you are an optical designer, you would never know by looking at the glass whether it was normal crown and flint, or some glass with abnormal dispersion properties. There is no question that the lens is an apo. From my perspective as a designer it is interesting to speculate what type it is, and I hope it is not construed as bashing by anyone.

As far as cost, I don't think it makes a huge difference whether you use normal glasses or somewhat abnormal glasses to make a triplet. The cost of the raw glass will be about the same. Even first generation ED is not that expensive any more, and I see where the Chinese are beginning to offer this material now in small diameters (about 80mm size). It's only when you start getting into 3rd generation ED or Fluorite that you have to bite the bullet. Of course, that stuff is not needed in smallish lenses. You can get decent color correction with inexpensive ED also as long as you keep the focal ratio reasonable.

_________________
C8 - skywatchered80- eq6
Canon 40d mod,
magzero mz5 e molta passione.

diffido sempre dai prodotti meno costosi perchè credo fortemente che la qualità del prodotto sia quasi sempre proporzionale al prezzo (a parità di condizioni e salvo bidonaggi).
OK4 e SFPL53 sono vetri di altissimo livello e con caratteristiche uniche , basta osservare il grafico disponibile sul sito di una delle più importanti vetrerie (la OHARA)

http://www.oharacorp.com/pdf/Ohara%20Op ... 0Chart.pdf

il resto lo fanno la meccanica , la selezione delle celle e un buon assemblaggio del prodotto

ciao alessandro volendo seguire il tuo discorso,ti volevo chiedere come mai secondo te o secondo voi, il takahasi TOA 130 costa <quasi> come il TMB130,mentre il Takahashi 150 TOA costa 3000 euro di più del TMB 152?.
Forse il motivo potrebbe essere che il Toa è migliore del TMB?
che mi dite?

_________________
C8 - skywatchered80- eq6
Canon 40d mod,
magzero mz5 e molta passione.

Esattamente i medesimi quesiti che mi pongo spesso pure io

A proposito il TMB 130 costa leggermente più del Taka 130

http://www.buytelescopes.com/product.as ... id=4827&m=

http://www.tmboptical.com/itemsRecord.a ... &cat_id=4&

il 150 ha un prezzo simile

http://www.tmboptical.com/itemsRecord.a ... &cat_id=4&

http://www.buytelescopes.com/product.as ... id=8381&m=

non saprei dirti quale di questi 2 abbia una resa migliore in quanto non li ho mai provati

Mma ..... IMHO giudicare un oggetto solo in base al prezzo è giusto in determinate condizioni .... (parità di manodopera, tasse del paese ecc).
Altrimenti no!

p.s: Ma secondo voi ....l'idea di fare una bella rivista online, totalmente gratis, supportata solo dagli sponsor .....sarebbe un'idea folle?
Qualche cosa di serio pero'.
Potremmo avere strumenti in prova .....anche dagli utenti e non solo dai rivenditori ...
Gente in grado di testarli seriamente su questo forum esiste eccome!

_________________
--------------------------------------------------------

Video divertentissimo di Corrado Guzzanti

scusa alessandro io mi riferivo sempre alle sole ottiche TMB intubate da astrotech,è lì che c'è differenza di prezzo con il TOA da 150,ma le ottiche sono sempre le stesse,cioè alla tmb ti fanno pagare un sacco di soldi in più l'intubazione?
se è cosi conviene prendersi Il nostro astritech da 152 con ottiche TMB ad un prezzo decisamente inferiore al loro,che ne dici?

_________________
C8 - skywatchered80- eq6
Canon 40d mod,
magzero mz5 e molta passione.

Il fatto è proprio questo , il TMB e il Taka sono "fatti" in paesi progrediti , non sono made in China e pertanto i valori sono molto simili.