Making your own newt

[matt]

Hi all.

Just wondering what software you guys use for calculating tube lengths, positioning of secondary mirror...focuser etc when working on your ATM projects?

Is there good freeware available?

Cheers.

[DavidU (Dave)]

I like this one
http://www.dalekeller.net/ATM/newton...t/newtsoft.htm

[matt]

Hi David.

That looks OK, although you kind of have to mess around a bit inputting individual variables and hope for the best.

I'd like something a little simpler. Say, where you input the size of the primary and its focal length and it provides details such as ideal secondary size and positioning, and details of focuser height etc

It probably doesn't exist. but I thought I'd ask.

[DavidU (Dave)]

Hi Matt, give me your mirror diameter and F ratio and any other info and I will do it for you.

[Starkler (Geoff)]

A few design parameters you need to decide on or find out are:

focuser max and min height
Tube diameter
Desired focal plane height from focuser top (Is this scope for visual or photography?)
size of fully illuminated field ( for secondary sizing)

The wider the tube and higher the focuser, the bigger the secondary is required.

The software David linked to is the standard and works well.

[Jone5y (Steve)]

The big plus of the Newt software already mentioned is that it will highlight any design flaws in the parameters you have chosen.

This site http://www.atmsite.org/contrib/Fly/s...designie5.html gives you control over any variable you care to mention and can calculate a lot of unknowns for you, provided you know some simple facts about focal length etc.

I suppose it could also be used 'in reverse' to design a scope that has traits that you want, as opposed to newt which will tell you if what you have is going to function properly.

Also contains secondary offset and eyepiece calcs.

Hope this is of some use