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I think this little fellow has to be the most beautiful telescope I've ever seen.  It's the work of the one and only Ralf Ottow, an optical engineer from the Netherlands, with some mechanical parts made by his friend Bertus Van Gemeren. I've posted examples of their scopes before. This one is a 'Kutter' telescope,  a variant of the shiefspiegler 'tilted component telescope' design. If you're not familiar with this concept you could be forgiven for thinking it was a small wind instrument with a bit missing! Light enters the shorter, wider tube where it strikes a tilted spherical primary (1) before being reflected back up into the forward end of the thinner tube where it strikes a tilted secondary (2) before being reflected down a well baffled tube (3) to a small sized Celestron Kellner eyepiece (4). Sadly we were clouded out on the one night of Ralf's flying visit but I tried the scope in the daytime and the image it gave was simply exquisite. It has only 30mm of aperture.

1451104726_LIGHTPATH.thumb.jpg.946b55fbfb5255a9e8d2979e37ee7cdc.jpg

Here's the ray diagram from Wiki: https://commons.wikimedia.org/wiki/File:Kutter.gif and below is the scope without my messy annotations:

Kutter.thumb.jpg.e47b5f192aaaa037e20b757219455f6c.jpg

The Tilted Component Telescope's original raison d'être was the removal of the central obstruction. (Herschel tilted his primaries to send their beam to an eyepiece at the front of the optical tube to avoid the catastrophic losses of his only 60% reflective speculum metal mirrors.) The Kutter design brings abberations down to acceptable levels but can only have a slow focal ratio. If this suits the observer's purposes then the design is fine.

For me there is just something unexpected and rather exhilarating about this design and its perfect execution here. Ralf will be back later in the year with this and his new big scope so I hope to be able to give an observing account from two interesting and unusual instruments.

Olly

 

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Incredible looking scope, never seen anything like that before. OK how much? 🙂

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It looks like it is the size of a pen without any scale to gauge by, interesting it is.

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Posted (edited)
53 minutes ago, Sunshine said:

It looks like it is the size of a pen without any scale to gauge by, interesting it is.

You're right. Here you have the Kutter in one hand and Ralf's 1.5cm Newtonian in the other...

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Here's Al Nagler with the Newt...

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I could read car number plates with it in the village over 200 metres away.

Olly

Edit, here's a smartphone moon image through the Kutter. 

805484211_Kuttermoon.thumb.jpg.6673e3d0817d34636a4f78dacce6c6e1.jpg

 

 

Edited by ollypenrice
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2 hours ago, JG777 said:

Incredible looking scope, never seen anything like that before. OK how much? 🙂

Sadly I don't think Ralf runs a shop! 

Olly

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OMG (hate saying that) but, i want that little newtonian!! how adorable is that little thing! where can i get one?? is it a one off? i want i want i want!!

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Hi Olly

Was it Ralf Ottow who made a pair of binoculars* out of two spare 6" SCTs?

And the same guy who collimated a scope based on the sunlight between two tree trunks on the far side of the valley?

I'm guessing it probably is. I mean - how many optical geniuses do you know?

Cheers.

Ian

* Why do we say a "pair of binoculars"? Or a "pair of trousers" come to that. Although I think the latter comes from the fact that you used to get one jacket and two trousers from one's tailor in the olden days. In return you had to ignore the tailor's bill long enough for his** grandson*** to collect.

** Very few female tailors in the olden days.

*** It took a lot longer than two generations to change that.

 

 

 

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Posted (edited)
39 minutes ago, ian_bird said:

Hi Olly

Was it Ralf Ottow who made a pair of binoculars* out of two spare 6" SCTs?

And the same guy who collimated a scope based on the sunlight between two tree trunks on the far side of the valley?

I'm guessing it probably is. I mean - how many optical geniuses do you know?

Cheers.

Ian

* Why do we say a "pair of binoculars"? Or a "pair of trousers" come to that. Although I think the latter comes from the fact that you used to get one jacket and two trousers from one's tailor in the olden days. In return you had to ignore the tailor's bill long enough for his** grandson*** to collect.

** Very few female tailors in the olden days.

*** It took a lot longer than two generations to change that.

 

 

 

You underestimate him. :D The test 'binosaur' was based on two C11s but the real one is bigger than that, I think 40cm per side. It doesn't travel (for obvious reasons) so I've never seen it.  The C11 bino was great! And yes, he does use tiny gaps in distant woodland as point sources by day.

Regarding trousers, I now wear 'un pantalon' so there is no ambiguity and I find that Decathlon, where I buy  them (sorry, it ) take a very unsporting view of deferred payment.

Olly

Edited by ollypenrice
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Ah. My mistake. I should have known better.

'binosaur'. Now there's a name and a half! Two C11s were a Test!

Blimey.

So the full sized binosauras was two 40cm OTAs? Surely a man of such talent could come up with a waist holster for them. And probably the bionic arms you would need to hand hold them. Although thinking about it, possibly outside of his field of expertise.

Glad to hear that the French at least know it's "a trouser". But, as you say, a bit unsporting of them on the payment terms. Have they no sense of history?

30 days payment terms*? A mere piffle. 30 years sounds about right to me. I'm sure my son will not object to settling up my tailor's bill as part of his duties as my executor.

People these days! It's all "Now, now, now".

Cheers.

Ian

* One rather suspects that Decathlon's payment terms are measured in seconds, not days. 

 

 

 

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Posted (edited)

Hi Olly

Two questions regarding Ralf Ottow and his binosaur.

1) How does he get enough backfocus to bring the light beams from two C11s together into your eyes? Does he re-shape the secondary? Or re-shape your head?

2) This is most important. Do you have his telephone number?

Cheers.

Ian

PS - Give my love to Monique. I still make the salad she taught me how to make. I had one last night in fact.

 

Edited by ian_bird

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Fascinating post!

I too just love that 1.5cm Newt!

Did he machine an adapter for taking a Nagler 31T5 ??

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9 hours ago, ian_bird said:

Hi Olly

Two questions regarding Ralf Ottow and his binosaur.

1) How does he get enough backfocus to bring the light beams from two C11s together into your eyes? Does he re-shape the secondary? Or re-shape your head?

2) This is most important. Do you have his telephone number?

Cheers.

Ian

PS - Give my love to Monique. I still make the salad she taught me how to make. I had one last night in fact.

 

Good thinking! Yes, he made both the corrector plates and the secondaries for the C11 binoscope. I don't know if the correctors were non standard or not because he bought the scopes with broken correctors at a good price so had to make new ones anyway. He did make new secondaries to extend the light path. Apparently it would be possible to focus with standard secondaries but the image so formed would no longer be diffraction limited.

Olly

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Fascinating design and beautifully put together little scope. 

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