Mirror Making?

[Radar]

Anyone here know how to make their own telescope mirror? And how do you work out how big a secondary needs to be.

Thanks

Ray

[orion]

Yes I do. This is a link to a well known software programme Newt. You can put different diagonal sizes to determine which one is best.

http://home.att.net/~dale.keller/atm/newtonians/newtsoft/newtsoft.htm

Try this one .DIAGONAL.ZIP..http://www.bbastrodesigns.com/dnld/software.html

[Radar]

Awesome Orion. Thanks :thumbsupmate:

[AstroTasmania]

Hi Radar

Telescope making, well, surprisingly, the optics (main mirror) is the easiest part to make. Buy a ready made 1/10 wave flat.

I have made around 15 scopes over past years and it was always making the equatorial mounting that took the time and precision, for it to useful for photography. Nowadays a simple Dobsonian mount is quick & easy if you just need it for visual observing.

There are several books on the topic, which cover all you need to make the complete telescope.

Just do an ATM search in Google.

Clear skies...

[Radar]

I think it would be very rewarding to build a 200 inch telescope by yourself. :Chessy_Smile:

Seriously though, the thought of making my own scope is something that intrigues me. As I've read before, it would be very rewarding to do.

Shev, 15 scopes? that's a lot of scopes mate. You already own about 25. Have you got any pics of the ones you built. I'd love to see them sometime.

[orion]

Radar, for building your first scope you can't go past this book.http://www.obsessiontelescopes.com/publications/index.html

And here is a good site that you might have seen before for ATM's http://www.stellafane.com/

[Tenacious Del]

I've noticed that most home built scopes are Dobsonains. Why is that?

[AstroTasmania]

Hi Delio

I think it is because a Dobsonian mount is simple, quick and easy to make. It gives one a very quick way to get the homemade scope into action.

I have always maintained that making the optics is easy, making a good EQ mount is the hard part. The various mounts that I have made over the years has proved this. As the mounts get bigger, as in my 16" EQ fork, the work involved far exceeds that of the optics.

I may start posting images in the construction section to show the steps involved. Radar seems to very keen on the idea.

Clear skies...

[orion]

I believe that for a beginner the Alt Az mounts are easier to build and if you were to make say a 25" f5 mirror the EQ mount would have to be enormous and very heavy, it would also be hard to make it transportable.

[AstroTasmania]

Hi Radar,

Here are 3 links which tells you all you need to know about Newtonian secondary mirrors and a lot more.

Obviously it depends on focal ratio, the slower the scope say F/8 the diagonal will be smaller than for an F/6.

The diameter of the scope tube is a factor, as is how far from the tube wall do you want the focal point to be. For visual use it can be much nearer the outer tube wall. I guess you would be using a camera so you would need to add an extra 50mm or so to allow for prime focus use. In which case the size of the diagonal increases.

On my homebuilt 12" f/5 I have two diagonals which I can swop when I move the whole focuser unit closer to or away from the main mirror, depending if I am using a focal reducer. With a FR, my f/5 becomes f/1.7, making it a very fast wide field 12". I plan to do the same with the 16" f4.5 I am building.

http://www.tnni.net/~dustymars/misc/Newt_Sec_Mirror.htm

http://www.atmsite.org/pipermail/raytrace/2001-December/000040.html

http://www.atmsite.org/contrib/Carlin/collimation/

Clear skies...

[Radar]

Great stuff Shev. Thanks :thumbsupmate: