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I put in the maximum available 600 mm-counter that it was delivered two or three months ago by Norman.
The optical bench (that would not call so, but rather ground for functionality verification and quality) It is designed to test the optical mounted in optical tubes. We are currently in progress with the pieces , Behind the advice of Norman, Optical proven experience and skills in very fast optical (f2,6-f3).
Naturalemente we use certified mirrors, and our requirement is to verify:
1) that the mirror corresponds to what is stated;
2) that the installation is not due to some defect (stapling, deformations, etc);
3) the BFL parameters etc.. are compliant with the stated, ordered and received;
4) for playing
and do various tests related to the roughness etc..This of course is feasible with all the mounted system and finished, we are choosing the various accessories required (also obviously certificates), and then complete with recording systems and recording of images for each test.
It is therefore not a bench for the process control (like that of Norman).
The control system is based on the double pass null method in which errors, obviously, doubling. We do not use the interferometer to more convictions’ that based on its inefficiency to certain corrections. The tests we perform them always full optical September, we only test that is not a primary but the whole set mounted with its obstruction and its secondary.
A very qualified laboratory which issues certification in Autocollimation of flat mirrors, è Optical Surfaces in UK, ducts in that lab tests with professional metrology systems have consistently delivered results very close to those declared by the supplier (which is what interests us), the fact that then a mirror is PtoV 1/8 and not 1/10 RMS 1/28 and not 1/35 It has a very marginal relevance. It is enough to replace some elements to the bench to change the values, Also the Double Pass Null lends itself well to the controls, but it has the advantage of playing well the final values if you do not follow to the letter all the starting elements (What much more realistic with the Hartmann method used by Airy Labs).
We are a little late with the process of urgent deliveries but they put us in difficulty. However, this is to say only as the approach of a manufacturer is different from that of an optical designer, which must forget the mechanical interference elements , and here we could talk for hours on this subject. Just to give a silly example, a client who has withdrawn a dk 230 f 12 (primary f 2,6) He challenged the product citing an optical defect unclear. The instrument had passed all tests, however, we immediately replaced the optical set with a new one (We have many sets shelf for each optical scheme, except for new models) and the customer the next day informed us that the telescope was perfect and absolutely free from defects (customer picky, meticulous and friend, not a dimwitted who do not even know what the pattern that bought….)
Suspicious of this fact we immediately thought of a mechanical problem, we identified in too hard tightening of the secondary barrel. Today Norman sends us all of the optical test set, we sent him to the bench for a control, as guaranteed by the trade. Indeed, the images of all the tests and the technical report confirms the total absence of problems of this set, ergo a normal too tight secondary support has created its own problems. This has helped us to plan the design of a secondary barrel exempt from this kind of problem (the series never stop learning).
But I could tell you about an infinite number of cases where there giugono not working telescopes, to which is singled out a poor optical quality, while in reality it is the mechanics completely wrong contour.
Ciao
MaximumVery nice and "intriguing" this hike in the professional world, a look from a window for me unusual, that offers a perspective of a very different level than amateur, and rightly so, at the bottom of the amateur must "make happy" only himself, fulfillment that as far as I, It is just not so much from the realization of the final result, but through the whole path of knowledge and experience that he has led to obtain it.
It 's the reason why I chose to "embark" on this adventure Cassegrain optics, aware that the limits of this enterprise will be just in the issues that you evidenziavi.
I believe that the optical quality is within the reach also at amateur level, However good optics is likely to remain a work's sake, as it will never be able to express its full potential if all the rest of the telescope is not up.
In my particular case, I'm realizing how complex and difficult to realize the construction of a Cassegrain system ( that works ) , with its multitude of constraints and construction parameters to be carried out with extreme precision and for their control devices.It remains amazed by observing the degree of fineness and mechanical realization of professional telescopes of sig.Massimo Boetto.
But we can also create a mechanically that Cassengrain “functions”?
It absolutely In Jean Texereau:telescopes of the kind cassengrain,in chapter
on the mechanical part it is explained in detail in the final realization phase,it is curious to observe
the leap to today's materials and mechanical techniques that when the book was written not exist, with less noble materials but respecting a greater mechanical fineness compared to a”simple” newton,you should have no problems. If you managed to achieve this amazing mirror I do not see what can stop you!
Thanks for the encouragement Mauritius ! How did you understand, are more concerned about the mechanical realization that for the optical. At the moment I'm still working on each trying to define a project that is both functional and at the same time “sustainable” even from my limited constructive means, The road is still long so, meantime, as rightly suggest, the best thing is to study in detail the various solutions that over time have been found.
Massimo are very close to this project and its development.
how do you think to realize the secondary?I think you should realize
a machine x small optical surfaces nothing in particular
a gearmotor x turn 10giri per minute a bushing x fix the diskette Maurizio, I would love, but my knowledge and skills in mechanical engineering is almost nothing, maybe when you or some other grattavetro more “engineer” release me to design a detailed, I'll do a little thought, I'd like to make at least one “miserable” rotating floor
So for now all strictly manual, “mirrors” included !
Just to say, Today the realization of motorized systems subservient to plc and various side systems, It has a fairly modest cost and functional. The hard part is the development (work processes , etc.). Electronic modern cut costs heavily, while for the mechanical part (planes of rotation, immersion systems, etc) the costs are quite high.
Ciao
MaximumThe mechanics especially for high-precision professional tools, It can get to very high costs.
For the Instead electronic (with an example of application for amateur use, of the turntable within the alias 1500watt 2 horsepower): Today the realization of a simple rotating floor (I had thought about doing but then I postponed the why for modest works that I do and I will MAYBE, I like to take this opportunity to “do gymnastics” with a little’ healthy muscle fatigue, scratching hand), Rotating table which is equivalent to the machine “fixed post” (like that of Gordon Waite), I would certainly have chosen the use of a modern vector inverter, that transforms the single-phase voltage in phase with frequency, and then the variable speed motor from zero to maximum, and a scroll control that enables a precision in the engine rotation speed contained in’ 1% and which can be supplied to the engine maximum torque even at very low revolutions, (obviously by installing an assisted ventilation for the engine that is made turn load with lower speeds to 80% of the nominal speed)……All these good things of adjustability (apart from the cost of the three-phase motor from 1 Kw, with i = 1400/30 rpm, which however it is not high), without having in their own home of a three-phase electric line, for just over a hundred euro!! When surely the mechanical part would exceed the cost.
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