starting out building a telescope...

XR8beast · #1 18-02-2005, 06:48 PM

Hi ppl , a couple of months ago I got a 4" newt for a present and it's a cheap and nasty from china , but it's got me hooked on star gazing and now I want a bigger apperture (8") . I bought this book called "Build your own telescope" by Richard Berry and now I want to have a go at building one myself, but I dont know where to source the glass blanks or the abrassives to make a mirror.I know people will try and tell me it's probably not worh making it but I get great satisfaction from making my own telescope from the ground up.I live in the Sydney , Homebush area can anyone point me in the right direction and maybe give us an approx price for the 2 glass blanks ....thanks .

#2 18-02-2005, 07:04 PM

Here ya go, this guy just lives a couple of Km from me, he is the man to contact, has all the good stuff.

http://www.telescopes-astronomy.com....escopes036.htm

XR8beast · #3 18-02-2005, 07:27 PM

thanks Exfso !! , appreciate the help

iceman (Mike) · #4 18-02-2005, 07:31 PM

Hi XR8Beast!

to the forum!

How did you hear about us?

I'm not the "build your own telescope" kind, so I can't help you with the specifics, but I admire the patience and perseverence you'll need

There's a few ATM'ers on this forum (orion/cometcatcher/mhodson/vermin plus some others), so they'll no doubt be able to help you along your way.

Good luck with it, keep us posted with your progress and hope to see you back!

If you want to document (in words and pictures) your construction from start to finish, it would make a great "how-to" article on the IceInSpace site!

XR8beast · #5 18-02-2005, 08:00 PM

Quote:

Originally posted by iceman
Hi XR8Beast!

to the forum! How did you hear about us?

I'm not the "build your own telescope" kind, so I can't help you with the specifics, but I admire the patience and perseverence you'll need

There's a few ATM'ers on this forum (orion/cometcatcher/mhodson/vermin plus some others), so they'll no doubt be able to help you along your way.

Good luck with it, keep us posted with your progress and hope to see you back!

If you want to document (in words and pictures) your construction from start to finish, it would make a great "how-to" article on the IceInSpace site!

Hi Iceman !

I followed your link from a forum , I cant remember now

. Anyway I just emailed the suppliers for some prices and I'll definately show the progress I'm making .A bit worring as this is my first attempt and more than likely I'll make a "how not to polish your mirror tutorial" , but I'm patient and good with my hands so I'll definatly let you know how it goes.

RAJAH235 · #6 19-02-2005, 12:52 AM

Welcome XR8beast, You've picked a good size to start with. Have fun but take your time. One of our members ground his own 13" as his 1st project, (18 mths.in his spare time).

Just the facts m'am.

mch62 (Mark) · #7 19-02-2005, 07:32 AM

Hi XR8beast , glad to see another ATM on the forum.
The reward that you will get from doing it your self will be very satisfying .
I have ground 3 mirrors many years ago from 4"- 8"and my only advise for your first and as it is an 8" is to make it a longish focal ratio of at least f6 or more.
Even an f8 make a wonderful planetary scope and is still good for visual deep sky.
The slower light cone is also easier on cheaper eyepieces, so you don't have to go and get expensive ones starting out.
It is a lot easier to figure an f6 than say an f4.5 or 5 especially for your first.
Also if it is going to be a Dob , you will want the eyepiece at a reasonable height .
i have included a link to a very popular program for ray tracing a Newtonian's optics.
Read the Help files , mainly "notes on design".

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

Happy grinding Mark

Orion · #8 19-02-2005, 03:40 PM

Hi XR8beast, and welcome it certainly is very rewarding making the telescope your self and I would go with everything mhodson told you especially with the long focal ratio mirrors.
The hardest part of optical design would have to be the figuring of the primary mirror.
I think the best way to go for your first telescope would be the Dobsonian design with a Alt/Az axis.
Be warned you will suffer from apeture fever after your fist telescope.

In any case we are here to serve and any questions you may have we'll be glad to answer.

XR8beast · #9 20-02-2005, 02:05 PM

Hi guys , does anybody know if clubs offer courses in mirror making in Sydney ? . This is harder than it looks !

Vermin (Tom) · #10 20-02-2005, 03:06 PM

Can't help with the local clubs, but these guys have a lively discussion going on mirror grinding:

http://www.starastronomy.org/cgi-bin...Cat=&Board=atm

Orion · #11 20-02-2005, 06:05 PM

Hi XR8beast it might be an idea to buy the primary and secondary mirrors that way you don’t have to worry about figuring or coating them. BinTel in Sydney sell a range of mirrors beside other ATM stuff that you might need in building your telescope.

But if you still want to go ahead with grinding and polishing here is a web sight you’ll be interested in.

http://www.stellafane.com/atm/atm_mi...r_overview.htm

gbeal · #12 20-02-2005, 06:31 PM

I'm with Ed,
I did actually grind a 6" as a teenager, but unless it is really what you want to do, I would forget it. (just my $0.02cents worth though).
To my mind you are better off buying an optical set, perhaps an 8" or 10" and constructing the rest.
As Ed said, Bintel seem to sell them, as do a company called Antler (or whatever) Optics, they advertise on the Gecko Optical group.
Gary

Vermin (Tom) · #13 20-02-2005, 07:15 PM

If you want to buy Australian and want the best optical quality, send an email to Mark Suching:

http://deepsky.cia.com.au/optics/

XR8beast · #14 20-02-2005, 08:37 PM

Ok thanks heaps guys , you have been a big help , so I'll take the good advice and buy the optics.

rmcpb (Rob) · #15 21-02-2005, 08:32 AM

Welcome to the madness XR8beast - look forward to the photo that goes with that name.

I agree about buying the optics. I have made scopes before and found the idea of grinding the optics too much to handle. There is enough in designing and constructing the rest to keep any person going without sending them mad. One day I will have to grind a mirror just to say I have done it though.

Cheers

XR8beast · #16 21-02-2005, 09:16 PM

I got a few ideas on what materials to use in the telescope construction so far. I'm a plumber by trade so I have a fair idea on what certain material expansion rates are and what resists heat best. I'm particualrly interested in ABS pipe and fittings as it is very light and extremely strong with a low expansion rate. Any of you guys familiar with ABS ?

iceman (Mike) · #17 21-02-2005, 09:37 PM

Hey that's not too bad! Looks like a pretty good price.. Saxon aren't too bad. I'm not sure about the eyepieces and especially the barlow, looks like a 3x which will most likely be terrible.

Also the eyepieces, the 25mm will be the best.. maybe the 12 will be ok for planetary and lunar. The 4mm will be junk, I can guarantee it.

The motorised mount looks ok, the mount might be a bit wobbly when it's chugging along, especially in a bit of wind, but you could probably hang a brick off it to make it a bit sturdier.

How much is postage? For $399 + $50 postage you could've got an 8" dob which would be much better quality, and obviously a bigger mirror. But if you're planning on building your own 10" dob, then it's probably going to be quite an adequate scope to start you out and get you hooked!

You just might need to invest in a few cheapish eyepieces, like some better quality plossls or maybe the GSO SV eyepieces. The good thing about that, is you'll be able to use them in your next scope too.

Let us know how it performs when it arrives!

rmcpb (Rob) · #18 22-02-2005, 08:34 AM

Quote:

Originally posted by XR8beast
I'm particualrly interested in ABS pipe and fittings as it is very light and extremely strong with a low expansion rate. Any of you guys familiar with ABS ?

OK for us plebs, what's ABS?

Cheers

iceman (Mike) · #19 22-02-2005, 08:39 AM

doh he removed the link to the scope he bought off ebay, now my post looks out of place!

XR8beast · #20 22-02-2005, 10:17 AM

Here is some info on ABS , namely DURAFLOW. The only drawback I see is probably the bonding solvent used. It's has a very strong odour when I have used it and it's very strong aswell . We apply a cleaning fluid first (this is the strongest) , then paint on the grey solvent with a brush.The pipe is somewhat waxy but it sands easily and the wall thickness on say an 8" pipe is almost 20mm.Here is a link to some PDF files :

http://www.tycowater.com.au/water/pr...ts#ABSDuraFree

P.S. Sorry about the missing post iceman , here it is again :

http://cgi.ebay.com.au/ws/eBayISAPI....ADME:B:BN:AU:1