Mak MTO 100/1000 telescope
Siegfried Gonzi
I came across to that telescope advertisement by chance. It is stated
there that the MTO is much different from some MTOs which someone can
encounter at flea markets (I know such a guy and he swears that it is
impossible to focus that Mak). That (from the dealer) specific MTO is a
pure astro-version which lets you magnify to 200x without any noticeable
image degradation.
I own a Meade ETX 90. But I am so annoyed because my ETX is plagued by
the problem that the secondary tube holder is moving off its place. I
red that such a fix woul cost many dollars. I am not ready to spend for
something which is due to low quality control by Meade (no one else can
afford to do that; I send in my Powerbook to Apple for a repair service
without that they charged anything, and even though I was a second-hand
buyer!).
My question: has anybody compared the above mentioned MTO 100/1000 astro
version! (I am not sure whether on Todd's test report site he is testing
the MTO 100/1000 astro version -- the emphasize lays at
"astro version"-- with the ETX 90 ?
Regards,
S. Gonzi
Michael Mushardt
"Siegfried Gonzi" <siegfri...@kfunigraz.ac.at> schrieb im Newsbeitrag
news:3A9B7D85...@kfunigraz.ac.at...
> Has anybody got experience with the Maksutov MTO 100/1000?
>
> version! (I am not sure whether on Todd's test report site he is testing
> the MTO 100/1000 astro version -- the emphasize lays at
> "astro version"-- with the ETX 90 ?
>
>
> Regards,
> S. Gonzi
>
although I never dircetly compared an "astro version" or A-code MTO to my
flee market types I can say that most of the MTO are quit good, but
sometimes the lenses and mirror suffer from severe astigmatism from
overtightened lens holders.
If you untighten them it will help in most cases.
If you have a look at http://home.t-online.de/home/mmushardt/rb4.htm you
will find a description and some general remarks on those "Russian barrels".
If I was you I would try to get a "Rubinar", on my page you can see the
reasons. Anyway, I doubt if a "A-code" or a very good flea market type
really stands 200x. But, there are a few very good ones, and I have tested
more than 100 of those lenses.
Hope it helps,
Michael
Siegfried Gonzi
> If I was you I would try to get a "Rubinar", on my page you can see the
> reasons. Anyway, I doubt if a "A-code" or a very good flea market type
> really stands 200x. But, there are a few very good ones, and I have tested
> more than 100 of those lenses.
I red on your homepage. You mention that the MTO optic is sometimes too tight
placed. That dealer (it is a German one; maybe you can imagine who) assures
that it will be checked upon that and even the optic is tested on an artificial
star.
What was your motivation in testing more than 100 of these scopes?
Regards,
S. Gonzi
Siegfried Gonzi
> My motivation was and still is to deliver good quality optics with those
> little telescopes. (About 20% of the flee market lenses were returned to the
> Polish guy because they were really bad even with relaxed lenses)
Do you have any values concerning the obscuration of those scopes. I am
interested in comparing the MTF of the 10cm Max to the 9cm ETX (about 30%
obscuration).
How reliable are your tests? Did you estimate or evaluate the peak-to-valley
error near the focal point? My ETX was sure better than lambda/4 (based on the
assumption that the Suiter star test is somewhat subjective).
Regards,
S. Gonzi
[Anybody interested in the program which calculates the MTF according
Fresnel-FFT calulation can get my implementation in Yorick. Yorick is platform
independent and similar to for example Matlab. Yes I know there is Aberrator
out there, but for Windows only. Yorick is in no way that comfort as a
stand-alone, but you get interactively the images in postscript format.)
>
Michael Mushardt
> Do you have any values concerning the obscuration of those scopes. I am
> interested in comparing the MTF of the 10cm Max to the 9cm ETX (about 30%
> obscuration).
>
around 30%, too.
> How reliable are your tests? Did you estimate or evaluate the
peak-to-valley
> error near the focal point? My ETX was sure better than lambda/4 (based on
the
> assumption that the Suiter star test is somewhat subjective).
>
about 100 to 150x) Cross checking and star testing under the real sky gave
me a feeling how the focused and defocused star should look like to perform
well.
Some friends who are well known testers (Wolf Hartmann) estimated some of
the good ones to be around lambda/6, that is the only figure I can give you.
I will probably be at the next ITT at the Emberger Alm, if you want remind
me shortly before once more and I can bring one along with me.
Regards Michael