ATM - mirrors

[misterT]

Been an amateur astronomer for the past 17 years and only just joined the ice in space last month so there will be some questions regarding ATM stuff shortly but my first question is regarding mirror grinding and where to find tools and materials to get started? Cheers

[astro744]

Willmann Bell used to have mirror blanks but it looks like only the other bits and pieces now.

See http://www.willbell.com/ATMSupplies/ATM_Supplies.htm

[Wavytone]

Dan...

Can I ask why you want to make a mirror ? The reason I ask is that commercial ones are so cheap I wouldn't waste my time. The cost of two blanks and aluminising exceed the cost of buying one.

The only reason I'd make a small one is to show my son that such a simple process - done with skill and care - can produce something that is incredibly accurate, and for him to appreciate the effort of others to make something by hand.

[glend]

Easy to buy GSO mirrors for ATM. I used them and they are good quality for the price.

[misterT]

Yes that is correct, much cheaper to buy a commercial one but the reason why i want to grind a mirror...knowing how to, because eventually i want to build a 1-metre scope and the price for a mirror of that size exceeds 40-50K.
The only problem with that size is making the glass blank but apparently it can be done. I wont be attempting to take on a project like this unless i am able to successfully grind and shape a mirror accurately. I have looked through a 30 inch SDM telescope before at astrofest back in 2008 and the veil nebula was just...unbelievable.

[glend]

You could turn out adequate 10" mirrors for years and still not be prepared for the 1 metre mirror. Its like people who build a small boat thinking they can build a big one, its all about the scale of everything involved.

[Wavytone]

Ah... so your eyes are bigger than your wallet. If you cant afford to buy the mirror you cant afford one, period.

You have no idea what is involved, Grasshopper.

[billdan]

Dan if your really keen on making a 1 metre mirror, check out Mel Bartels website, he makes thin meniscus 42 inch mirrors, 20mm thick using the slumping technique. i.e melts a sheet of glass over a spherical mould in a kiln.

http://www.bbastrodesigns.com/slump/MoldMaking.html

Cheers
Bill

[sil]

Dan, good on you mate! Ignore the lazy nah-sayers. Your aim is going to be difficult but not impossible. As someone who was told they would live from a wheelchair and learnt to walk again after a stroke I find negativity like this rather offensive. If its what you want to do for yourself I commend you!

[misterT]

Thanks Bill that's great! Cheers

[misterT]

Thanks for the positives...I am a visionary.. cheers

[Zuts]

I agree,

I made a 6 inch then a 12 inch. I'm not saying I could make a 30 inch but i did want to. Anyway if Dan has the time and the desire then good luck to him.

[SkyWatch]

You go Dan! ATM'ers who grind their own mirrors are a dying breed, so it is great to see someone wanting to have a go! :)

If you want supplies, you might try Matthew Lovell via http://www.telescopes-astronomy.com.au

I increased two shirt sizes across the shoulders when I ground a 10" mirror, so it will be interesting to see what happens if you do a 30"!!!

All the best,

Dean

[misterT]

Thanks Dean for the link, exactly what I was looking for, cheers.