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Equipment Discussions >> ATM, Optics and DIY Forum

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derangedhermit
Pooh-Bah


Reged: 10/07/09

Loc: USA
Best simple Newtonian design software? new
      #5536043 - 11/23/12 06:46 PM

Is there a better simple general Newtonian design program than Newt4Web?

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bremms
Carpal Tunnel
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Reged: 08/31/12

Loc: SC
Re: Best simple Newtonian design software? new [Re: derangedhermit]
      #5536160 - 11/23/12 07:51 PM

Piece of paper, a ruler and a calculator.

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cpr1
professor emeritus
*****

Reged: 03/24/12

Loc: Louisiana
Re: Best simple Newtonian design software? new [Re: bremms]
      #5536460 - 11/23/12 11:38 PM

I found Newt pretty simple once your had all the measurements.
Worked out good.


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derangedhermit
Pooh-Bah


Reged: 10/07/09

Loc: USA
Re: Best simple Newtonian design software? new [Re: cpr1]
      #5536778 - 11/24/12 08:18 AM

People here often say Newt isn't very good for some uses. It would seem to me that there would be a better program or interactive web page or app for overall Newtonian layout.

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Pinbout
Postmaster
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Reged: 02/22/10

Loc: nj
Re: Best simple Newtonian design software? new [Re: derangedhermit]
      #5536859 - 11/24/12 09:18 AM

Quote:

Newt isn't very good for some uses.




well that probably has to do with how do you interpret the 75% vignette if I'm recalling correctly.

in the help menu they tell you how to understand it.

so it can be a little confusing if its saying it vignetting and it really doesn't matter.

other than that it's a great schematic layout program.


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glennnnnnn
sage


Reged: 10/20/09

Loc: San Diego, CA
Re: Best simple Newtonian design software? [Re: Pinbout]
      #5536991 - 11/24/12 10:36 AM

Tinkering with different combinations of tube diameter, baffles, secondary mirror diameter and focuser height makes it easier to make the most of your primary mirror. (Newt)

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derangedhermit
Pooh-Bah


Reged: 10/07/09

Loc: USA
Re: Best simple Newtonian design software? new [Re: glennnnnnn]
      #5538390 - 11/25/12 08:47 AM

Sounds like I can just stick with WebNewt then, carefully reading the help info. I have always liked and appreciated the program myself.

Thanks for the feedback!


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Pinbout
Postmaster
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Reged: 02/22/10

Loc: nj
Re: Best simple Newtonian design software? new [Re: derangedhermit]
      #5538455 - 11/25/12 10:01 AM

did you ever play with this one?

http://www.catseyecollimation.com/designns5.html


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Crayfordjon
Vendor - Zerochromat
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Reged: 06/17/09

Loc: UK
Re: Best simple Newtonian design software? new [Re: Pinbout]
      #5540029 - 11/26/12 10:27 AM

Why do you need software to design a Newtonian, it is such a simple telescope to design that a normal knowlege of the optical principles is surely enough. Finding the diameter of the secondary is also very easy, and you do not need a computer to do this either. Is it that we cannot make any design desisions these days without a computer??

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Pinbout
Postmaster
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Reged: 02/22/10

Loc: nj
Re: Best simple Newtonian design software? new [Re: Crayfordjon]
      #5540048 - 11/26/12 10:42 AM

Quote:

Is it that we cannot make any design desisions these days without a computer??




I recently had an experience at work where I felt afterwards, wow the computers are really making the people dumb and lazy, by not letting them think outside their computers.

We had to make a 3d logo of a car company. Our production facility can silhouette cut the logo on a cnc, but how are we going to sculpt the insides to make the logo look like the branding? I couldn't believe the production manager came back with a qoute for molds and other complicated stuff from who knows what company. OMG!

the logo could have been cut on the cnc but some skilled craftsman could have used a hand held belt sander to carve out the scalloped shapes in the logo similair to the back of guitars.

Afterwards I was thinking boy what happened to challenging our craftsman all they do now is push a button and glue and staple.


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Boot
wildly diverse musical tastes
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Reged: 06/04/07

Loc: The Outernet
Re: Best simple Newtonian design software? new [Re: Crayfordjon]
      #5540071 - 11/26/12 10:51 AM

Quote:

... Is it that we cannot make any design desisions these days without a computer??




I'll get back to you on that in a minute (waiting for the hourglass to go away...).


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Jon Isaacs
Postmaster
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Best simple Newtonian design software? new [Re: Crayfordjon]
      #5541565 - 11/27/12 06:38 AM

Quote:

Why do you need software to design a Newtonian, it is such a simple telescope to design that a normal knowlege of the optical principles is surely enough. Finding the diameter of the secondary is also very easy, and you do not need a computer to do this either. Is it that we cannot make any design desisions these days without a computer??




There are several parameters that one can play with when designing/optimizing a Newtonian. A computer allows it do be done quickly.

If you wanted to show how easily it can be done without a computer, you could show the math required to determine the 100% and 75% illuminated fields for a 16 inch F/4.4 Newtonian with 3.1 inch, 3.5 inch and 4 inch secondaries with both low profile and standard profile 2 inch focusers with 17inch, 17.5 inch, 18 inch, and 18.5 inch tube diameters.

When I design, I use the computer as a tool to allow me to look at a variety of choices so I can make a decision based on a number of possible scenarios. Since generally I am designing obscure research equipment, the software does not exist so I write my own but in this case, Newtwin and now Newt for the web are readily available so I take advantage of Dale's efforts.

Jon


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cjc
sage


Reged: 10/15/10

Loc: Derbyshire, England
Re: Best simple Newtonian design software? new [Re: Jon Isaacs]
      #5541851 - 11/27/12 10:52 AM

I have found two programs to be useful. This for computing the illuminated field for a given secondary bbastrodesigns diagonal and of course Plop for determining best mirror support and particularly how large/thin you can go for three point support to be good, Plop. I do not think either of these is suited to paper and pencil calculation. Also the Oldham Optical site has some useful spreadsheets, Design page.


Edited by cjc (11/27/12 10:59 AM)


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eyepiecedropper
member


Reged: 12/31/11

Loc: aschaffenburg, germany
Re: Best simple Newtonian design software? new [Re: cjc]
      #5542107 - 11/27/12 01:15 PM

hi, you can use mynewton
http://www.softpedia.com/get/Science-CAD/myNewton.shtml

this is my favourite software. it´s translated into english. newt is very good also and the results are the same. did this a couple of times for verification of my design parameters.
there are differences regarding the input of the drawtube length.
and then...post the results/screenshot here for an evaluation and discussion.

regards, martin


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Mike I. Jones
Post Laureate
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Reged: 07/02/06

Loc: Fort Worth TX
Re: Best simple Newtonian design software? new [Re: eyepiecedropper]
      #5542227 - 11/27/12 02:21 PM

The math for doing a Newtonian is very simple and doesn't require more than a hand calculator, if that. The only benefit I see with software to design Newtonians would be to be able to individually click on every piece of hardware (tube, end rings, primary, primary cell, diagonal, diagonal holder, spider, focuser, finder, finder rings, etc.) and have links pop up to every telescope part manufacturer in existence, including pricing, availability, delivery time, and possibly CAD drawing files of each part. Finding current and reputable suppliers of telescope parts is the part that takes a while, and is where software could help. But I wouldn't want to be the person responsible for keeping the webpage updated, possibly being needed as frequently as weekly, and guarantee that all the links have correct information.

Would also be cool to be able to switch to https:// mode and actually place orders for parts to each company from the software. Now that's simplicity!

Mike


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eyepiecedropper
member


Reged: 12/31/11

Loc: aschaffenburg, germany
Re: Best simple Newtonian design software? new [Re: eyepiecedropper]
      #5542300 - 11/27/12 03:02 PM

almost every design has already been done and calculated.
perhaps someone has a design ready for you.

if you want to calculate it with software by yourself here´s a simplified walk through for -visual- purpose.

one of the basic starting points is the

-the f ratio of your mirror

-100% illuminated fov. depends on your purpose. discuss it here. there´s a tried minimum for your special purpose.

-choose your focuser, medium length to short, the shorter, the bigger the illuminated fov.

-the level of obstruction you want to achieve. the smaller the secondary the smaller the 100% fov in tendency.

-the eyepieces you will use. the height of their focal planes is different. you have to come into focus with all of them. with plössls as a rule of thumb the focal plane is where the field stop is. the shorter the focuser travel the more careful you have to be.
televue -> F
http://www.televue.com/engine/TV3_page.asp?id=28
discuss it here or look for specs.

by tendency it means that with the same 100% fov your obstruction can be smaller with a short focuser and a
small tube diameter.


then insert as starting point:

-primary mirror diameter
-focal ratio of your primary
-secondary size of a similiar commercial scope. you find it in the ads/specs.
-tube diameter=mirror diameter +50-60mm (tube currents). minimum should be what a commercial scope has.
-the parameters of the focuser
-the parameters of your eyepieces = take account of the range of different focal planes/ that you come into focus with all of them and that the drawtube doesn´t reach into the light path. of course you can shorten the drawtube if that happens.

this is your raw model.

then play with:

other available secondary mirror sizes
perhaps other focusers
perhaps your tube diameter only if necessary and if you want the lowest obstruction.

until you have the 100% fov and obstruction and perhaps the focuser you wanted. then post the result here for an evaluation. if you do it right it will work out fine and you´ll be proud of what you´ve achieved.

regards, martin

Edited by eyepiecedropper (11/27/12 04:12 PM)


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eyepiecedropper
member


Reged: 12/31/11

Loc: aschaffenburg, germany
Re: Best simple Newtonian design software? new [Re: eyepiecedropper]
      #5542316 - 11/27/12 03:16 PM

hi mike. nice idea! of course your´re right. but a great advantage of using software is the speed of optimization/approximation of the favoured parameters. you have to define the benchmark data first, with or without software. that takes some time, esp. if this is your first time.

regards, martin


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bremms
Carpal Tunnel
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Reged: 08/31/12

Loc: SC
Re: Best simple Newtonian design software? new [Re: eyepiecedropper]
      #5542346 - 11/27/12 03:34 PM

Get some paper and a ruler. Do some drawings. Use marginal rays. You will notice at shorter F ratios the diagonal offset is pretty important. Use your noggin instead of relying on a program. Programs are fine, but it's good to see the how and why of the design. Back in the stone age when I fist designed a Newt I was like... The diagonal isn't exactly centered in the light path! and it won't be when it's collimated properly either. (Something a lot people don't realize.) Secondary shadow will be offset. It can be set up so the diagonal is dead center, but in a fast scope you will have uneven field illumination.

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derangedhermit
Pooh-Bah


Reged: 10/07/09

Loc: USA
Re: Best simple Newtonian design software? new [Re: bremms]
      #5542468 - 11/27/12 04:55 PM

Thanks for all the helpful replies and pointers!

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