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Newt Software

Announcement - March 2011

There is a new version of Newt!

Thanks to the efforts of Ken Slater, there is a new version of Newt. It's a web app, which means it will run on almost any flavor of machine: Windows, *nix, Mac, Haiku, cell phone, toaster oven, or whatever you can use to browse the web. You will need a very modern browser.

It is available at

Newt4Web Screen

Old Newt Software

Newt Screen

Newt is a newtonian telescope design program. It ray traces the telescope checking for vignetting, optimizes diagonal size, calculates baffle size and position, and a lot more. It allows you to easily and quickly change any of the design parameters of the telescope and to see the results immediately.

NEWT features:

  • Display a side view of a Newtonian telescope.
  • Modify parameters like mirror diameter, diagonal minor axis, focuser height, focuser inside diameter, tube inside diameter and thickness, and many more.
  • Use inches, centimeters, or millimeters as the unit of measure.
  • Calculate baffle size and placement.
  • Calculate diagonal offset.
  • Calculate fields of 100% and 75% illumination.
  • Load and Save files.
  • Eyepiece table includes focal length, power, exit pupil, apparent field, and true field.
  • Check for minimum useable diagonal minor axis.
  • Check for vignetting at the focuser.
  • Check for vignetting of true field by top of tube.
  • Calculate obstruction percentages for light loss and contrast reduction.
  • Cast three rays through telescope - an on-center ray, a 100% light zone ray, and a 75% light zone ray. Use these to check for vignetting at focuser, true field cutoff, etc.
  • Print specifications and dimensions to a printer (see note).

Note: There is a bug in the printer code. It will probably not print correctly on most modern printers. Sorry.

Newt Requirements:

  • Newt version 2.5 runs under Windows 3.1, 95, 98, ME, NT, 2000, or XP.

Newt 2.5 is now FREEWARE. Get it, try it, use it, share it. But please don't pay for it. It is getting quite old, but still works well (except for the printer bug). It is no longer supported.

Download NEWT25.ZIP for Windows 3.1 or later (71K).

Newt software: Copyright 1997 by Dale A. Keller 

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