Buying a complete mirror?

[Manok101]

I've decided that since I want a normal coated mirror that the best way to complete my telescope is to just purchase a ready made mirror. I was wondering if anyone had ever done this and had any opinions for what to look for?

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[ronin]

Quite a few have done the same, about the only thing to look for is a good reputation, with you being in the US it is not easy to recommend any obvious manufacturers of mirrors.

Someone (retailer) over with you will likely be able to get hold of a "standard" mirror made by GSO, and they may be OK for what it is you want.

The problem with a mirror is that to get the basic parabolic mirror is these days fairly straight forward. To get a really good parabolic mirror means hand figuring, checking and time and then the cost goes up, and not by a small amount.

Places to look:

Stellafane:  http://stellafane.org/

Zambuto:  http://zambutomirrors.com/

Know there are others but no links to them.

[astronymonkey]

John nichol of nichol optical ships to europe..... so may send to the states.

cheers

[Manok101]

Not looking to spend a fortune just learn how to do it with this one thanks for the links will check them out. I was thinking if something between my 10" and my 4.5"

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[RAC]

This guy makes really good mirrors in the US. I have one of his 10" f4 conical mirrors in an imaging scope. You don't even need a fancy mirror cell and it will hold collimation like a refractor as long as your secondary is stable. The bad bit is the wait - about 9 months ish.

http://www.rfroyce.com/

[SkyGibbon]

If you want a standard GSO mirror, check agenaastro. They sell GSO mirror sets up to 16".

[soundwave]

How come a 12.5" zambuto mirror costs more than an entire 14" Skywatcher dobsonian?

Are the optics that much better? or is it strictly because it's hand-made?

I always assumed that buying the optics and making everything else myself would let me get more bang for the money... guess I was wrong 

[estwing]

Buying a mirror like that becomes almost an investment

[TheMightyKong]

Zambuto is considered to be the best of the best.

[crashtestdummy]

I bet an 8" zambuto mirror would work out more expensive than my 22"!!!

[quaoar]

I have a magnificent 18" f4.2 Zambuto mirror in my 18 Plettstone. All I can say is that Zambuto mirrors are worth every cent you pay over and above a commercial mass produced mirror. Invest in a top shelf mirror and secondary for your scope and you won't regret it for a second. Every time I get it out I thank myself for buying this scope. Last night in my backyard was pure joy.

Incidentally I bought this scope and mirror secondhand and have just bought another mirror,  a secondhand 20" f4 refigured by Zambuto, it is currently being recoated and then going into an ultralight. I have quite a few Dobs. Knowing what I know now, if I lost everything tomorrow and had to start again, the first thing I would do is start saving for the deposit on a Zambuto mirror.  

[Damo636]

I bet an 8" zambuto mirror would work out more expensive than my 22"!!!

Probably, but I'd still rather have your 22"!

[crashtestdummy]

Ditto fella

[mapstar]

I have a magnificent 18" f4.2 Zambuto mirror in my 18 Plettstone. All I can say is that Zambuto mirrors are worth every cent you pay over and above a commercial mass produced mirror. Invest in a top shelf mirror and secondary for your scope and you won't regret it for a second.

Or grind your own, as you just can't buy the satisfaction in that ;-)

[quaoar]

Or grind your own, as you just can't buy the satisfaction in that ;-)

Hands up all those smug [removed word] that ground out their own Zambuto equivalent mirror ;-) 

[mapstar]

Might as well add all those that also designed built and were proud of their own scope's too ;-)

[crashtestdummy]

Hands up all those smug [removed word] that ground out their own Zambuto equivalent mirror ;-)

I dont care if my mirror doesnt turn out to match a zambuto mirror as it will still be my own work.the 22" im grinding for the price of an 8" zambuto will still out perform his best 8", its simple physics!! You pay your money and im sure we will all be happy, you with your zambuto and me with my self grind.each to their own but I couldnt justify those prices for an almost indiscernible improvement over a mirror half the price

[quaoar]

I dont care if my mirror doesnt turn out to match a zambuto mirror as it will still be my own work.the 22" im grinding for the price of an 8" zambuto will still out perform his best 8", its simple physics!! You pay your money and im sure we will all be happy, you with your zambuto and me with my self grind.each to their own but I couldnt justify those prices for an almost indiscernible improvement over a mirror half the price

Fair enough.

My point is that I don't look at it as a strictly financial issue. My hobby and passion is Astronomy, for some people for example its motor bikes. If you're into bikes sooner or later you're gonna want a Harley Davidson - not a GSO Harley, not a cobbled together "I made it in my backyard" Harley lookalike I mean a real one.

Often on weekends when I drive my trailer and scope out into the bush for a good night out, I pass and am passed by, by blokes on their Harleys livin' the dream in their own little world just like I am. They could in theory be doing the same thing on bikes a third the price, they could have bought chinese knockoffs and they could have built their own -  but is it the same ?. When I get a night of excellent seeing and I point my Zambuto or Kennedy or Suchting mirror at the sky and Saturn "snaps" into focus and I let out a chuckle I'm getting the same thrill as the Harley riders I passed on the road earlier.

[mapstar]

It's not a financial thing for the majority of us as a mirror made by someone else (and there are a few names I could drop) is not out of the question.

I can see also the Harley analogy but I'm not a bike expert but some just don't like them no matter what its a personal thing.

I personally and like many others get just as much enjoyment out of making things, than I do using them and knowing that when it says hand made it is. You appreciate how much effort went into it and the sense of achievement and the respect for others that have done the same.

You have a beautifully made scope and mirror that is without a doubt but both the guys who made them who ever they may be started off the same way as every other amateur.

Going through that process is an education and can give better results especially when they are hand crafted and not just states it is on the box.

We all view the same things as you say and get the same smiles but sometimes its the journey to get there.

[crashtestdummy]

I actually find it a bit insulting that you seem to refer to amateur scopes as cobbled together.as mapster states, thats how all these big dob companies started out as proponents of john dobson, himself an amateur.

If you measure everything by price you have a pretty blinkered view of life

[quaoar]

I actually find it a bit insulting that you seem to refer to amateur scopes as cobbled together.as mapster states, thats how all these big dob companies started out as proponents of john dobson, himself an amateur.

If you measure everything by price you have a pretty blinkered view of life

Well look Mr Dummy, I don't want to upset you that was not my intention.

I thought I was advocating that quality trumps price but it looks like I'll have to polish my analogys.

Carry on, I'll be quiet now.

[jetstream]

To the OP,I would define what you want for specs in the mirror,figure,glass type,coatings,budget,wait times etc.Once you have that decided I would search what mirror makers can provide you with a product in the time frame that you want.It's surprising how many good mirror grinders have long wait times.

I personally like to have a Zygo or equivalent test report in addition to the other tests done.A minimum spec would be a true 1/4 pv with the listed specs in Royces chart/article.My minimum is a 1/6 pv and associated Strehls etc and my OOUK has 1/8 PV ,.986 Strehl and an exceptional .018 RMS.

All that said,an 8" f6 Synta/GSO mirror would be a great place to start for a scope project.I think the odds of getting a good one are high in this diameter and focal ratio-lots made and f6 not that challenging to make accurately for them.They also use a high reflectivity coating on some.

Get a high quality,high reflective and a high tested spec secondary(not that much $$$ really)-this will improve the specs of the whole scope system for you.

[crashtestdummy]

Well look Mr Dummy, I don't want to upset you that was not my intention.

I thought I was advocating that quality trumps price but it looks like I'll have to polish my analogys.

Carry on, I'll be quiet now.

you didnt upset me, its the internet and im not a child.Your narrow mindedness is irritating.quality is very important but it has to be allied to other factors like price and availability.If the op has a $1000 budgets theres no point recommending a compqny that wont supply within his budget!!

Out of respect for staying on topic I will leave this to people commenting with solutions rather than quips and banter

[jetstream]

Here is the chart.....http://www.rfroyce.com/standards.htm,good reading if ones into it.

[Mike73]

Thats a great link Gerry thanks.