You will like this. There's no doubt you will like this.

[Ben the Ignorant]

 

[John]

I don't see any Stellarvue dealers on this side of the pond on their website, which seems a shame

 

[johninderby]

Stellarvue used to have UK dealers but due to the way they treated the UK dealers the dealers gave them the boot. A UK dealer would order from Stellarvue but would have no idea when or if the order would arrive. Small wonder no UK dealer will now touch them with a bargepole.

Edited April 21, 2019 by johninderby

[Stu]

38 minutes ago, johninderby said:

Stellarvue used to have UK dealers but due to the way they treated the UK dealers the dealers gave them the boot. A UK dealer would order from Stellarvue but would have no idea when or if the order would arrive. Small wonder no UK dealer will now touch them with a bargepole.

Very true. I had a Stellarvue scope on order for getting on for 2 years before giving up!

I think the best and kindest explanation is that the owner Vic Maris is a stickler for quality and rejected optics which didn't meet his standards, causing delays to production and uncertain delivery times. Communication could certainly have been improved, but I do regret not having tried one of his scopes.

[Highburymark]

Interesting video. I really fancied that 90mm carbon apo as a travelscope but didn't want to import it myself 

[johninderby]

17 minutes ago, Stu said:

Very true. I had a Stellarvue scope on order for getting on for 2 years before giving up!

I think the best and kindest explanation is that the owner Vic Maris is a stickler for quality and rejected optics which didn't meet his standards, causing delays to production and uncertain delivery times. Communication could certainly have been improved, but I do regret not having tried one of his scopes.

I used to have a Stellarvue 80mm split tube which was a nice scope although optical performance was the same as many other scopes around. The best thing about it was that the tube screwed apart in the middle letting you break it down into a very small package for travelling..

Think Stellarvue just isn’t a big enough operation to be an interantional company. They seem barely able to supply the US market so basicly nothing left for overseas.

Edited April 21, 2019 by johninderby

[pete_l]

Interesting video. I'm surprised they haven't adopted clean room protocols in their optimisation area. If they are working down to 1/40 λ it would seem to me to be a requirement.

[Stu]

9 minutes ago, johninderby said:

I used to have a Stellarvue 80mm split tube which was a nice scope although optical performance was the same as many other scopes around. The best thing about it was that the tube screwed apart in the middle letting you break it down into a very small package for travelling..

Think Stellarvue just isn’t a big enough operation to be an interantional company. They seem barely able to supply the US market so basicly nothing left for overseas.

Me too John, was it the same one I wonder?

I've actually watched the video now, very interesting and it seems that their optics should be right up there with the best now. I think they used to source from China so suspect their quality has improved since going to in house production from blanks.

[Ben the Ignorant]

For those willing to pay such sums (not me), parting with 3000$ or 5000$ seems more justifiable when you have seen for yourself how carefully they are made. As a public relations and trust-building measure, each high-end scope maker should show its operation but I suspect some are paranoid about secrecy in their production methods. 

The only half-interesting video Vixen put on YouTube shows how they make their glass and their tubes, but skips the glass pushing and goes to show the finished scope, leaving the viewer frustrated. Not even the machining and fitting of focusers is shown, how secret could that be?

[Ben the Ignorant]

7 hours ago, johninderby said:

Stellarvue used to have UK dealers but due to the way they treated the UK dealers the dealers gave them the boot. A UK dealer would order from Stellarvue but would have no idea when or if the order would arrive.

I had never heard of that. I wondered why Stellarvue seemed to sell in Europe at a time but stopped with no explanation. After-sales service is obviously easier for an american company that sells only in the US.

[Mark at Beaufort]

Really enjoyed watching this video. I was fortunate to a use a Stellarvue frac in the United States to view the Venus Transit in 2012. Not sure of the details of the frac but the guy that owned it was telling me of its quality.

The only Stellarvue product I have owned was a 80mm finderscope which I should have kept.

After producing this thread I remember I took a photo of this Frac. It was the SV115 f/7 APO triplet. Here it is ?

[Highburymark]

Now there's a nice 4" for sale in the classifieds 

[Gabby76]

I have owned four Stellarvue refractors and they have all been excellent. 

My 80mm travel telescope is a SV/ LZOS with the split tube and is one refractor I cannot imagine parting with. 

[ollypenrice]

TEC have the worst website on earth. They don't make the worst telescopes on earth, however...

Olly

[johninderby]

Or the cheapest. ?

But as they say you get what you pay for. Now if only they would have a 75% off sale on the TEC180  ?

[gorann]

This may be sacrilege but watching the video it all seems so very old-fashioned. Surely nowadays there must be smarter robotic ways to grind perfect optical surfaces. Or what is so special about grinding glass compared to other surfaces?

[JamesF]

3 minutes ago, gorann said:

This may be sacrilege but watching the video it all seems so very old-fashioned. Surely nowadays there must be smarter robotic ways to grind perfect optical surfaces. Or what is so special about grinding glass compared to other surfaces?

I don't know, to be honest.  But I wonder what other commercial applications require grinding to the same level of accuracy.  If you said you wanted 1/10th wave accuracy, that's going to be in the region of five ten thousandths of a millimetre, isn't it?  Or have I missed something?

James

[johninderby]

You want old fashioned glass grinding and polishing. Quite interesting what little they do show.

 

Edited April 25, 2019 by johninderby

[Ben the Ignorant]

47 minutes ago, gorann said:

it all seems so very old-fashioned. Surely nowadays there must be smarter robotic ways to grind perfect optical surfaces. Or what is so special about grinding glass compared to other surfaces?

The first part of the job is indeed automatic (not necessarily computerized) but the required accuracy is too fine to be obtained like that, the surface has to be analysed and improved. So it is inspected by a person, refined, re-inspected and so on until it reaches the standards. Remember that a high-end apo of only 100mm must stand 300x and remain sharp and contrasty, so imagine how the six surfaces of the three lenses must be smooth and perfectly curved to transmit a sharp image that can be enlarged 300 times and show no defects.

Just look through a regular window at low power, only 40x or so, the image will be blurred despite the glass being apparently flat and smooth to the naked eye. It's not that glass is harder to polish finely than other materials, on the contrary, optical glass is formulated so it polishes very finely, but optics have to be smooth to a much higher degree than any large object.

[Ben the Ignorant]

12 hours ago, JamesF said:

I wonder what other commercial applications require grinding to the same level of accuracy.

None.

12 hours ago, JamesF said:

If you said you wanted 1/10th wave accuracy, that's going to be in the region of five ten thousandths of a millimetre, isn't it?  Or have I missed something?

1/10th wave is not that great, modern apos have 1/20th or 1/30th wavefronts, sometimes better, and given that the average visible wavelength is 0.5 micron, 1/10th wave is 0.05 micron. But a 130mm Vixen doublet apo tested 1/60th wave in Rohr's lab, and a TeleVue diagonal tested 1/85th wave. The crests and pits in the glass were only a few dozen molecules in height.

The current standard for high-grade scientific (and military, I suppose) optics is 1/100th wave, and is obtained by milliing the surface with an abrasive ion beam after all the bumps and pits in the glass have been mapped by a computer. A very accurate arm moves the beam across the surface and shoots ions were the bumps are known to be. Only one amateur I know of has his reflector rectified to that standard, Tony Hallas if I remember well. It must have costed him a fortune.

A science-grade 1/125th wave atmospheric dispersion corrector costs 4800€, but it's only two pairs of small prisms.

https://www.apm-telescopes.de/en/optical-accessories/flattener-reducer-correctors/gutekunst-optiksysteme-atmospheric-dispersion-corrector-compact.html

Edited April 26, 2019 by Ben the Ignorant