TOT and MOT

[Frankq_it]

Hi everyone,
waiting to start working on my mirror 300 f / 5 I started to re-read the primary processing posts 300 f / 6 by stefanosky. At some point he begins to mention the acronyms TOT and MOT of which I do not know the meaning, certainly referring to mirror and utensil.
You can be more specific?

Still reading, I downloaded and tried the ATMOS software mentioned by Massimo Marconi in response to Stefanosky's request regarding the arrow to reach. I have entered my mirror data but I cannot read the arrow.
This software is Freeware, it is possible and useful to buy it?

Franco

Franco

[Massimo Marconi]

hello Frank, this happens because Stefanosky doesn't trust Grattavetro and then he goes to read the American sites / forums where they have an acronym for everything.
In this case it refers, eat your intention, to the position of the mirror and tool during machining, from which MOT =”Mirror On Top” or TOT =”Tool On Top”… but in my opinion, “mirror above” e “mirror under”, works just as well

Atmos is a beautiful software created by Massimo Riccardi, one of the best Italian opticians ( designer of optical systems also for Officina Stellare ) and is available both in the Demo version ( free and more than enough for the needs of non-professional grattavetro ) than in the full version. The demo version is limited to the design and analysis of a system of up to three optical surfaces.

To obtain the arrow of a parabolic mirror, just simulate a newton using the preconfigured Atmos cards and obtain the value “Mirror Sagitta”

The most attentive and scrupulous will notice (some time ago Giulio noticed it immediately) that the value of the arrow differs by a few hundredths of a mm ( at fault ) than that calculated mathematically on the radius of the equivalent sphere.
This happens because Atmos calculates the value of the arrow referred not to the sphere but to the final Parabola, obtained by lowering the edges and leaving the center unchanged with respect to the sphere of origin.

[Frankq_it]

Thanks for the reply.
Is’ It is possible to recover the distance of the secondary mirror from the primary or from the focus?

Franco

[Massimo Marconi]

the distance between the mirrors in a Newtonian is arbitrary, it is chosen by the designer according to the extraction of the focal plane from the optical tube to be obtained.
In the example above, i set the value for “Is” (Optical Axis focal plane distance ) of 200 mm from the optical axis, to have an extraction of the focal plane of 50 mm from a hypothetical tube of 300 mm in silence. ( maybe it's a bit’ little bit )
Keep in mind that the secondary axis must be decentralized with respect to the primary ( value “Dx” in the table) , the closer you get to the primary, the greater the offset of the secondary will be.

[Frankq_it]

Ciao,
I understand that in order to draw the optical scheme of a telescope I need to know the focuser that I'm going to mount?
Franco

Franco

[Giulio TiberinI]

HELLO Frankq.
You say:I understand that in order to draw the optical scheme of a telescope I need to know the focuser that I'm going to mount?
To draw it yes. But from the practical point of view of construction, not necessarily. Because you will settle everything in the end, when as a last step, you will cut the tubes of the trellis to make sure that the eyepiece of those you have is in focus, which requires the greater insertion into the focuser.

[Author]

Posts