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Hello everyone I'm just entered the forum name is Luigi Ruffini I'm a longtime amateur class 1969. They are amateur astronomer from 1984; i get 15 years have been very intense as visual observation that I started with a small 114/900 observing practically everything. I did a little’ homebrewing, and after ten years of break I returned to astronomy and even the processing of optical approximately 1 year and a half. I hope to exchange information in this forum I saw that there are many competent people. Currently I have a 12 jmi″ with a little’ eyepieces and are in advanced stages of polishing work of a 300 1700 focal.
I am a pure visualist; in the far 2001 I also had a call list on Yahoo discussion Visualsky, but then from 2005 I ceased trading if not occasionally for disclosure.Hello and welcome to Luigi Grattavetro! Will be a pleasure, as well as interesting, know and follow the last stages of this process your.
hello Luigi, Is’ a pleasure for me to know that you are a “insider”.
When you have time illustraci your intentions and your work.Welcome!
Well yes we say that the gim’ s Mobile at the time was a great tool, Optically perhaps still is but we visualist we do not need so short because of focal undertake to greater obstruction of the secondary and then often the eye position is really uncomfortable, for this reason I had an old Marcon lens with an edge that most replied that I flat-spotted defined… I put it under the grains and 1500 I reported to the focalle 1700 with the classic mistake to stretch it a bit’ too much. Now we are in 1770 but fair enough and therefore are at an advanced stage and polishing with the usual mistakes I was doing well in his time… then I've got a slight central hole that however I am correcting with short COC movement then I'm looking for a moment to check the usual edge retorted that it is still very contained the most difficult part was to readjust the pitch which was obviously on the curvature of a ' other perspective that I made at the time so 1500 scarce and it took me a while’ time we say to mix it and adapt it to this 1770 so it took a little’ of time. Even for preparing the tool I used the tiles of stoneware with a simple cement glue Millechiodi support and which proved to be phenomenal
Well. With racing 1 / 3D c.o.c and bring a lot of patience for sure via the central hole as well get the correction of the slight edge retorted. The only precaution with races 1 / 3D c.o.c. It is to look not beyond debodare 1 cm in right and left, why (in addition to any long runs too but are no longer 1 / 3D c.o.c,) is with the slight ooze lateale which acts on the edge by bringing out a slight edge retorted always annoying, even if the lens meets the criterion of Couder (ie all zones converge the reflection lorfo inside diffraction notch); than that of Rayleigh (maximum defect on the glass = lamda / 8 of the light 550 nm, which makes a precise reflected wave lmbda / 4).
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I did a little’ CoC alternating with mirror above and below but I think that goes with tool over slightly better.
It must be said that the disc is often 55 mm and with mirror above is a blow for how heavy.
Thanks for the tips I will try not to spill over the sidesNow, however,: If you are to have simultaneously a central hole and a countered edge, sembreresti in condition of having already passed the spherical shape (perhaps unintentionally by applying strokes with mirror above and deepens the center, and sometimes too long or wide slashing the edge).
How much would you be over, It depends on both the current depth of both (both of the hole that the degree of reduction of edge).
In these cases, you might try to return to (a nearby) sphere with many races 1/3 c.o.c hardly ooze Side.
MA…If the sphere is already gone too far (ie maybe having reached a surface towards the hyperbola), for not resorting to sub-diameter tools, should put the tool above and "overthrow" method by passing from the back forward wide strokes – left and right contained;.. Back to ..quelle contained in diameter ¼ (that is 1/8 forward and 1/8 and forth) – left and right from the edge to 70% the diameter, But exerting pressure onto the rim when you spend over 70% diameter, ie on the intermediate circular crown of the mirror that has remained "high" and is the only workable in this condition.
This is because the general rules of the game are that:
1) With the mirror above and large ran forward back, you dig in 70% D towards the center (that to you at this time would not serve);
2) With the mirror in the large forward and ran back, you dig in 70% D towards the edge, (that to you at this time would not serve); .
3) Intuitively, alternating between the two positions and with strokes 1 / 3D back and forth, and 1 / 8D right and back sinistra..si (with a little’ fatigue) the sphere.In conclusion, because I think you you can find a middle ground, I'd say you'd better do well with Ronchi and that really deformation where you stand, to see that my advice is not to be considered exaggerated.
ciaooo Louis, A warm welcome also from me…
I see that you are already in the advanced stage of the work, I follow with interest that your project…nice time…
See you soon…ciao… Well meanwhile Thank you all for your very warm welcome. I would like to be able to post some pictures I made of Ronchi but I do not know how to make a quality picture; I use a tablet 8 inch so it's not exactly the best as practical. Here on the site I can not find a button “attached” and then also the bad image that I made I can not post it and anyway I'd like to know how do you make those shots so clear your mirrors is also a great way to have a book with various jobs.
hello Luigi. To insert an image, you should load the example in http://WWW.POSTIMAGE.COM and copy one of the links that you provided vengiono, and paste it here in your mmessaggio (if the link is directed does not show the image but only the address, however, with the advantage that by clicking on the link opens a very detailed image, What less easy pasting the link to preview forum, where the image does not occasionally enlarges me,….. because I am not much experienced the differences between link).
As for the tricks and tips for shooting, the reference master is Massimo.
Kill what is complex…once before it was soo.
Anyway I hope you understand how it is put, the central hole is now more extended, but less deep than before; I should just work area 3/4 external, to remove the step before the border…
hello Luigi, try if you can, to take pictures decreasing contrast and exposure, but in any case it occurs before the slit in front of the light source is thin enough , otherwise it may happen that the Ronchi lines do not show their true aspect , but they may be altered by the excessive width of the slit.
If what you see by eye is comparable to photo( the strong light intensity that makes the dark lines rather faded) , then it is likely that the slit is too wide, Otherwise it is preferable to “to play” with the parameters of the recovery room to have less saturated images are sharper.
Anyway, from what I can see the surface it seems a good point , But my feeling is not a central hole ( rather, The center seems spherical ) but of a deeper annulus localized to 1/2 ray, but then again, serve less saturated image to better evaluate.
P.S. I am assuming that the images are in In focal
How's Louis?
If you are at a stage only the initial polishing, as it seems to understand from Ronchi, You do not worry the central hole and the flat edge, ie not worked.The two defects are physiological and disappear portanto the ball to the edge.
That would not be the edge no longer flat but turned down. And in that case it would be a sign of too ooze right-left (since it is difficult to rocking nell'avanti back that occurs with strokes well beyond the 1 / 3D c.o.c, that is too long).
hello Luigi, I too welcome! And good luck to your glass, a very similar job to my 300/1800. I'm trying to set up a foucault tester that allows me precise and repeatable measurements, then I will finish the parabolizzazione. I've been a little busy the last few weeks but I should get back to work shortly
Hello Excuse me for a while’ I did not hear but work commitments are deadly in this period. However, I am ready to return to work this weekend and I'd like to start with perfecting the image acquisition of the Ronchi and in this regard I really wanted to ask Stefanosky How do you create these images so sharp because in fact it is difficult to make a diagnosis when are so bad as my .
I tried some applications or rather I downloaded but now I have to test to see the result. I think it's important First solve this before entering into the debate on how to correct any defects in shape because at least so I can get a report of the process for future lenses.
However, the image I posted is obviously intrafocale
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