Page 2 of 7 FirstFirst 1234 ... LastLast
Results 11 to 20 of 64

Thread: TMB 100mm F/8

  1. #11
    ValeryD's Avatar
    ValeryD Guest

    Default TMB 100mm F/8



    ngc7789@citynet.net (Leonard) wrote in message news:<58ee67ec.0411241127.67981bcf@posting.google. com>...



    You are mistaken. Markus can. Markus. Period. Markus has a contract
    with LZOS. Tom designed these triplets after I refused to do this
    job for Markus when he asked me.

    I can agree, that this theme is getting old. But you do not looking in the
    root. In the root you will see, that TMB constantly claims, that "his"
    apos are best of the best on the market.
    This is not true at all. They one of the best - yes. But not the best.
    Many peoples out here should remember falsification about others products
    at TMB Yahoo group. Even cooked illustration were used to prove these
    statements, that so called TMB apos are best in the world.

    I can assure you, that the design of these LZOS apos ( TK12-OK4-K8)
    can't match performance of other designs, especially fluorite triplets.
    Indeed, this or similar combinations (in LZOS objectives) is quite good,
    but not the best and 100mm F/8 objective has better color correction, than
    other objectives ONLY because it is small and has slower F/D. No another
    reasons.
    I can assure you, that if you will call to Parallax Instruments (to the owner)
    and ask him about image quality (include color correction) of ARIES 127mm F/7
    Fluorite triplet with RMS 0.012, he will tell you something. I hope, that this
    scope was not re-sold. Same with other our 127mm F/7 triplets, they, however,
    have somewhat less perfect figures - but most of them better, than RMS 0.025.

    So, you'd better advise Tom Back be more modest and not claim, that products
    he sells are best of the best.


    We will. Wait a bit more. They will be of better quality than before
    and.... wait our principally new solution of color correction in achromats
    and our new middle-level affordable APOs.




    No. I will think what need to do improving the optics!



    Due to "help" of one well known person, closely associated with these
    objectives in question, we stopped their manufacturing for a while.
    But this year we resumed their manufacturing at our own labs. Right
    now several 7" F/7.7 doublets are waiting tubes for them.
    Then we will continue with several new models doublets and triplets.

    It is easy to begin, when you have a large optical plant behind you.
    Much more difficult if you try to do this in house, in your own labs.
    This need a time and significant money investment.
    But once this will be done, we can control all in the process and play
    with prices as we wish - to make our product more competitive and more
    attractive for buyers.

    And, if you wish, drop me a letter and place an order for 7" Fluorite
    doublet. You will be impressed with it's color correction, image contrast
    and sharpness and will note how short it's cooldown time.



    He will ends badly, IMO. ;>)


    VD

  2. #12
    Leonard's Avatar
    Leonard Guest

    Default TMB 100mm F/8

    Hello Thomas ,



    Thanks , will look for it .

    Valery wrote :

    <<< Dear Mr. Back,

    Sure, your self-confidence has no limits. And as one, well known
    in optical design and manufacturing, person said, someday your head
    will explode due to your unlimited self-confidence.>>>>>>





    Thanks , And a happy Thanksgiving to you and yours .
    Leonard

  3. #13
    ValeryD's Avatar
    ValeryD Guest

    Default TMB 100mm F/8

    tedkord@excite.com (Ted Kord) wrote in message news:<7c0be594.0411241517.203e27aa@posting.google. com>...


    It is not attacking! You, perhaps, has no clue what is what.
    Constantly saying, that ONLY HIS PRODUCTS are the best is an
    indirect attacking of others.
    And I never said, that these TMB objectives are any bad in any
    aspect, they, in fact are very good, just not as good as Tom Back
    constantly saying.

    And I can assure you, that the optics we making is one of the best
    available. I can's say best, because I don't know exactly what
    other manufacturers are capable for at their limits.
    If, for example, these objectives are small, all _spherical_ and
    have warranted only 0.033 RMS, our optics with huge aspherics, much
    larger in diameter and can be ordered and made with precision of 0.02
    RMS and better, then your phrase "If Valery spent as much time
    designing
    and building scopes as he does attacking other vendors, he could
    produce a scope" looks just soap bubble, nothing more.

    I can add, that so called best of the best objectives, say, 6" F/8,
    being
    TRIPLETS has same longitudinal color aberration (within 430nm-656nm),
    as our 7" F/7.7 _doublets_ . And they have worser aberration if we
    will jump to
    175mm F/8 vs our 7" F/7.7.

    I took their longitudinal color aberration from original source.


    And wait a bit longer. Soon several firms (at least three) will come
    with their own fluorite and SD scopes of the same slow F/D, as these
    TMB objectives, they will be also air-spaced, but cheaper. Then you
    will see if one amateur user of Zemax can create a miracle or not.

    For you instance - designing of APO triplet is 10min job. Maximum.
    So, I don't need to much time for this.


    VD

  4. #14
    ValeryD's Avatar
    ValeryD Guest

    Default TMB 100mm F/8

    tmboptical@aol.com (TMBoptical) wrote in message news:<20041124180731.06574.00001088@mb-m15.aol.com>...


    Tom,

    I think you will not loss anything wasting your time here.

    And I know what the glasses do you use in these objectives.
    Due to inherent spherochromatism, it is impossible to accomplish
    the design, where all colors even from shorter range, than you
    pointed out, will have all spots within Airy disk (for each color
    it's size is different).
    Without significant space (between lenses) increasing, spherochromatism
    can't be fixed and it will be the reaason, that all spots will not
    be within Airy disk.

    This is not well known for public, but spherochromatism also
    influent on image contrast and even if an eye can't see colors,
    image still have some softness.

    I can't say, that Chromacor-II with 100mm F/10 achromat is better
    combination from practical point of view than 100mm F/8 SD triplet.
    Not. Triplet has much larger useful field for photography and does
    not require any collimation (if it's mechanics is properly made).
    Chr-II + 100mm F/10 achromat has smaller field - lateral color and
    vignetting limit it. But for visual applications, especially at high
    powers, this is not a problem at all.
    And this combination has completely fixed, spherochromatism and
    all colors within 430nm - 656nm are WELL inside Airy disk. This
    can't be accomplished with such fast triplet as 100mm F/8 is.

    As for correspondance between what Chromacor shows on Zemax screen
    and practice, then I can say one thing - all depends of who do use
    a Chromacor. Even such experienced practical observer as Ed Ting was
    mistaken in his proper use even if instructions at my Yahoo group
    was detailed enough.
    Also, there is no warranties, that chineses keep their objectives
    very consistent in color correction, because they do not re-touched
    the design according to meltings. But this variations are indeed small.
    As for Chromacor itself. Glasses refractive indexes always measured with
    about 2x10-6 precision. Not worser. This is absolutely enough to keep
    Chromacor's practical realization exactly as at the Zemax screen.

    I don't know how many of Chr-II users were able to collimate it
    properly, but thouse, who were able to perform this relatively simple
    job, reported, that they can't see any color on any object - just the
    same as through any another 6" F/8 triplet. If Tom Davis was not able
    to achieve such performance for whatever reason, this does not necessary
    mean, that his experience is absolute.
    And, of course, 100mm F/10 achromat is MUCH MUCH more forgiving for
    Chromacor collimation and color correction here is about 3+ times
    easier to reach, than in 6" F/8. If properly installed and collimated
    Chr-II shows no colors in 6" F/8, then it is worthless to say what
    the correction will be in 100mm F/10.

    From the other side, I can say, that triplets in your design also
    quite sensitive for glasses refractive indexes deviations and they
    also require redesign according to glass melt data - and they have
    the same source of errors. Period. Only idiot can argue with this.


    VD

  5. #15
    Mileva Maric's Avatar
    Mileva Maric Guest

    Default TMB 100mm F/8

    You alluded to Tom Davis' fine post ie real world -
    where of course all scope outside of the lab must perform.
    These theoretical discussions always dismiss that. Im glad you
    bring it and all readers back to the real world.

    When the Chromacor first came out and for two years we were
    beated raw by the cheerleaders/commercialists-vested and
    other 'experts' regarding this 'mirabulus fidelus'. Then the matter
    if spacing came up and there was consternation, back peddling,
    then forward sprinting to new levels of ritual.

    So the following question seems appropriate: "If I mated a
    TMB 100 f/8 to the proper Chromacor could I achieve
    5x10^6 magnification and still colour free, in time for Christmas
    at WalMart? (hee
    hee)

    Have a very nice day, and thank you for your sanity.

    Mark






    TMBoptical wrote:



  6. #16
    Mileva Maric's Avatar
    Mileva Maric Guest

    Default TMB 100mm F/8



    ValeryD wrote:


    He never said that. He never says that. That's your job!
    Mark




  7. #17
    Tom Davis's Avatar
    Tom Davis Guest

    Default TMB 100mm F/8


    "ValeryD" <aries@mercury.kherson.ua> wrote in message
    news:5c4a4ee7.0411242353.48f33b0b@posting.google.c om...
    If Tom Davis was not able

    Valery,

    I think what is a common thread here is that both you and Thomas are
    dependant on other's work to make your designs successful. In the
    case of the Chromacor, the telescope it is used on will determine how
    well it will work. In that case, the optics much be smooth, and free from
    zonal errors. The match of the spherical abberation in the telescope it
    is used upon must match the degree of opposing correction (or lack of
    it) must be matched in the Chromacor used. The mechanics (the focuser
    used) must be able ot be collimated, and hold that collimation. This is
    why early on I recommended the need for properly built achromats with
    a pre-installed Chromacor for this product to properly work. One
    issue that became clear as crystal was that when color errors were
    resolved by the use of this device, other errors became more readily
    observed. Unless those errors could be addressed, this product could
    not be successful. Sometimes a sow's ear just can't be converted into
    a silk purse. I found this to be the case with a more than half of the
    scopes I tried the Chromacor on. Either mechanical issues, improper
    matching, or optical issues such as zonal errors or turned edge prevented
    the final result from matching the performance that individuals such as
    Sol Robbins experienced. If you finally do provide your own achromats
    with a newer version of this device with better control of edge of field
    correction (I gather from past discussion the Chromacor III will do this),
    pre-installed at a factory where you control quality issues, then this
    product may reliably work. I ran proof of concept testing early on.
    I had a couple of scopes that worked with the early device, but the
    weak link was cheap mechanics, and what optical issues did exist in the
    scopes involved. The Synta 6" F/8 scopes were the most consistent in
    quality, better than the 120mm F/8.3 versions I owned, but still not as
    consistent as the LZOS production of the TMB designed lenses by a
    longshot.

    I think if we took a pole of who was more satisfied with the resulting
    product, we would find the TMB 100/800 buyers would readily say they
    were over any Chromacor buyers. Common sense dictates that there are
    fewer weak links in the LZOS built TMB lenses, with fewer variables,
    than trying to apply an aftermarket device to lower cost optics and
    mechanics. Really, control over all the needed variables is much
    simpler if everything is controlled by one manufacturer, as has been by
    Thomas and Markus in the production of the TMB scopes. Until you
    have control of the finished telescope, I really don't see how a valid
    comparison may be made. Consistency of results favor the TMB/APM
    product. It is up to you to change that by producing a total package,
    either by Aries directly, or in partnership with vendors that you have
    control of the process with.

    What needs to be understood is that the buyer generally does not care
    whose label is on their telescope, or even who makes it for that matter.
    Squables about designs and their relative merits mean little if the actual
    product does not perform to the level that the buyer expects. A fair
    design well executed in the final production product will generally be
    preferred over a poorly executed excellent design in the final product.
    Without control over any potential weak links in what your Chromacor
    is used in, success rates will be fair at best. Sol Robbins had the right
    scope and Chromacor match, others of us did not. I have no doubt I
    could have gotten Sol's scope to work, but I did not have it. If the blame
    becomes the customer's, the old saying that "the customer is always right"
    comes into play. They will reject the product, and buy what works. They
    really don't care that a product would work if they did "X Y and Z". They
    may not want to, or now how to do the needed steps, or those steps may
    not work on their equipment. I know about Ed Ting's experience, where
    he was told to use a 48mm spacer, and the meaning of the term was
    misunderstood (what was meant was a 4mm long 48mm DIAMETER
    spacer, not a 48mm LONG spacer), but many experienced partial
    success that did not meet their expectation when they properly followed
    instructions (the equipment had poor mechanics, their optics had issues,
    the Chromacor/objective match was less than ideal). Again, you need
    to provide a turnkey product. If you do that, you won't need to worry
    about TMB does. Customers want to buy turnkey solutions, where they
    know it will work right out the box. That is my recommendation. While
    we may be interested in how something is designed, whether it will work
    for us as advertised, at a price we can afford, matters most to us..

    Thanks, Tom Davis



  8. #18
    Chris.B's Avatar
    Chris.B Guest

    Default TMB 100mm F/8

    aries@mercury.kherson.ua (ValeryD) wrote in message news:<5c4a4ee7.0411242353.48f33b0b@posting.google. com>...



    Nobody has answered the question of inherent optical surface roughness
    affecting the Chinese achromat. Does the spherical aberration
    reduction of undercorrected achromat + Chromacor 01 affect the
    smoothness issue for visual and small field lunar/planetary
    photography? I'm thinking in particular of the typical slightly
    undercorrected 6" f/8 Synta achromat in combination with an 01
    Chromacor. Producing a (claimed) therorectical 1/42 wave spherical
    correction. Is the (supposed) surface roughness also reduced by the
    Chromacor? Or is this just wishful thinking? :-)

    Thanks
    Chris.B

  9. #19
    Ted Kord's Avatar
    Ted Kord Guest

    Default TMB 100mm F/8

    *sigh* Yes, Valery. Nobody knows what is what except you. All of usenet bows
    to your superiority. You make the best telescopes ever, and the best that will
    ever be made. You are all knowing.

    By the way, Tom Davis wasn't saying that Chromacor wasn't good, just not as
    good as you say...Now why does that sound familiar?

  10. #20
    Markus Ludes's Avatar
    Markus Ludes Guest

    Default TMB 100mm F/8

    >

    Valery,

    reply only to above. That what you say here is correct , but it is also
    done by LZOS, you know this people are not stupid. Each lens is
    foritself a single Masterpiece

    Markus




    --
    Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

 

 
Page 2 of 7 FirstFirst 1234 ... LastLast

Similar Threads

  1. Orion 100mm f/6 vs ED80
    By Linwood Albarado in forum Amateur Astronomy Forum
    Replies: 9
    Last Post: 08-12-2009, 11:36 PM
  2. 102 SLT vs 100mm Starseeker vs 100mm Astroview vs ??
    By Ross in forum Amateur Astronomy Forum
    Replies: 2
    Last Post: 10-07-2006, 02:03 PM
  3. Orion 100mm ED
    By Matthew D. Mills in forum Amateur Astronomy Forum
    Replies: 21
    Last Post: 04-27-2005, 07:29 AM
  4. Can the sub-$900 ED 100mm be far off???
    By Richard in forum Amateur Astronomy Forum
    Replies: 0
    Last Post: 07-31-2004, 11:38 PM
  5. Which APO 100mm Refractor to Buy?
    By Maflu in forum Amateur Astronomy Forum
    Replies: 13
    Last Post: 01-07-2004, 09:59 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin® Version 4.2.0
Powered by vBulletin®
All times are GMT. The time now is 06:43 PM.