£2,398 for two mirrors?

[BrendanC]

I was idly browsing just now and wondered to myself: "Does Takahashi do Newtonians?" As you do.

They do. And the very rough equivalent of my trusty Sky-Watcher 130PDS, currently retailing at £229, is this. For £2,398: https://www.firstlightoptics.com/telescopes-in-stock/takahashi-epsilon-130-ed-f3-3-newtonian-astrograph-reflector.html

Now that seems a lot of money to pay for what is essentially two mirrors!

A bit of maths-related fun: it seems to me that the primary is the same size for each, while the 130PDS has a secondary of 47mm and the Tak's is 63mm. This means that the 130PDS has a total surface area of 60,033 square mm, and the Tak's has 65,562. So, with the PDS it costs about 0.38p per square mm of mirror real estate, but the Tak is 3.66p.

I'm not being entirely serious here, but I am curious as to why/how what are essentially two mirrors could cost so very much more? I can understand that hi-tech or moving parts, or luxury items swathed in leather and Swarovsky command a premium. And yes, I'm sure the scope itself is made of better/more robust materials with more precise collimation and so on.

But they're still just... mirrors?

[CraigT82]

That's nothing. An FC100D has only 31500mm2 of figured glass coming out at a frankly ridiculous 7.9p per mm2...  All for for a little peashooter with two bits of glass! 

[andrew s]

The cost of a mirror depends on its shape (spherical,  parabolic,  hyperbolic) and how accurate its figure is.

The epsilon also has a first class corrector. The mechanics are very good to.

Regards Andrew 

 

[ollypenrice]

What you're missing are the F ratio and the corrected circle. Fast optics are very expensive to make because they are very, very difficult to make well. And then you need a mechanical installation capable of letting them work by allowing and sustaining collimation and freedom from tilt.

The Tak is a modified Newtonian astrograph, the Skywatcher a Newtonion telescope. So the Tak has a corrector which gives a 44mm corrected circle, letting it cover a large chip. I don't know the corrected circle of the Skywatcher but it won't be 44mm, I don't suppose.

I was intrigued when you said you'd found a Takahashi Newt roughly equivalent to your 130PDS but you haven't. You've found a fast astrograph for large chip cameras.

Olly

[BrendanC]

Yep, you've got me bang to rights on that one. I know nothing about Takahashis. In fairness I did say very roughly, in the same semantic sense that an elephant is very roughly a hippopotamus.

Anyway, as I said, I wasn't being entirely serious. But I do still think, even with all the fancypants optics and your hyperbolic wosnames and your correcting widgets, it's an eye-watering amount to pay for what really does amount to two mirrors.

 

Edited May 8, 2021 by BrendanC

[tooth_dr]

I actually thought the Epsilon-130 was considerably more than that!  Must be cheaper now that the 160 has been released. Dont look at the price of the 180-ed

[Mr Spock]

What is more worrying is a 6x30 finder and some tube rings costs another £600  

You'd think at least they'd have matching colours.

[BrendanC]

And Swarovski. Don't forget the Swarovski.

Edited May 8, 2021 by BrendanC

[CraigT82]

8 minutes ago, BrendanC said:

it's an eye-watering amount to pay for what really does amount to two mirrors.

Better get your tissues ready before you look at these "two mirrors"...

https://www.astroshop.eu/telescopes/asa-telescope-16n-400-1520-astrograph-ota/p,46248

[tooth_dr]

Haters gonna hate 

[ollypenrice]

8 minutes ago, BrendanC said:

And Swarovsky. Don't forget the Swarovsky.

I'm a cheapskate and put up with Leica.

lly

[Seelive]

For just 2 mirrors and a corrector, I wonder what the cost of the HST was per sq mm? 😉

[Alien 13]

As far as mirrors go the Questar 90mm scopes leave Tak in the dust for price per sguare mm.

Alan

[faulksy]

i paid 5k for just my primary 😀 and another £500 for my secondary

[BrendanC]

0.62p per square mm. Bargain!

[BrendanC]

50 minutes ago, CraigT82 said:

Better get your tissues ready before you look at these "two mirrors"...

https://www.astroshop.eu/telescopes/asa-telescope-16n-400-1520-astrograph-ota/p,46248

It's a Präzisionsokularauszug with an Okularauszug included. £1,143 per syllable.

[niallk]

4 hours ago, BrendanC said:

But they're still just... mirrors?

😂😂 Not telling ya what I paid for my mirror!

[Sunshine]

If you look at it that way, I paid 5K for a tiny sparkly stone about 4mm in diameter my wife flaunts on her finger which I still cry about today (it's a TSA 120 on a finger). Sure, it has many angles which must have been very difficult to cut but, usually the value is in the work involved.

Edited May 8, 2021 by Sunshine

[BrendanC]

Cheapskate.

[Mr Spock]

Yes, always choose a wedding ring carefully - it's the last decision you'll ever make 😜

[Roy Challen]

14 hours ago, CraigT82 said:

That's nothing. An FC100D has only 31500mm2 of figured glass coming out at a frankly ridiculous 7.9p per mm2...  All for for a little peashooter with two bits of glass! 

By that reckoning, my Tal only cost me 0.3p per mm^2. Bargain!

[newbie alert]

14 hours ago, BrendanC said:

Yep, you've got me bang to rights on that one. I know nothing about Takahashis. In fairness I did say very roughly, in the same semantic sense that an elephant is very roughly a hippopotamus.

Anyway, as I said, I wasn't being entirely serious. But I do still think, even with all the fancypants optics and your hyperbolic wosnames and your correcting widgets, it's an eye-watering amount to pay for what really does amount to two mirrors.

 

Not really,you can buy 2 mirrors from Poundland for 2 quid, will they serve in a scope? Most certainly not, and not with lambo orange livery