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ATX/STX rumor

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Old Saturday 12th September 2020, 09:58   #51
DRodrigues
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Originally Posted by horukuru View Post
Superb combo with the BTX!!!
And for digiscopy...
Less CA and more light...
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Old Saturday 12th September 2020, 10:01   #52
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...
Report has it that it can easy support 200x
...
Using 2 extenders?
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Old Saturday 12th September 2020, 10:06   #53
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As the zoom range and closest focus are the same with the 115mm and the 95mm direct comparisons will be interesting. In the meantime what advantages is such a large objective likely to show?

Better performance in low light situations = brighter?
Increased fov
Better resolution
What about depth of field?
Useable at higher magnifications (air conditions allowing)
Anything else?

Cons would include increased weight and cost - but is a larger objective inherently more difficult to “ get right” are there downsides or is bigger always better?
More light and less CA are specially welcomed by those, like me, that frequently use the 1.7x extender!...
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Old Saturday 12th September 2020, 10:21   #54
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Would it be easier to check for aberrations using two extenders?
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Old Saturday 12th September 2020, 10:52   #55
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Hi Edudiant, post 48.

115mm is small for an astro refractor, so the quality should not be a problem for skilled opticians.
But a good f/4.8 115mm needs a lot of care to get it right if one expects 200x plus performance.

10 inch or 250mm refractors begin to have problems getting perfect blanks.

A 600mm f/4 top quality camera lens or say an 800mm f/5.6 are much more expensive and probably just as difficult or more difficult to make well.

The extender or two extenders will not be perfect themselves, so may contribute to errors.

If quality control is good, hopefully these 115mm will all be a pleasure to use.

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Old Sunday 13th September 2020, 22:58   #56
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Swarovski has uploaded 5 short articles about the 115 mm objective in use
They describe the experiences of the British birder Mark Collier and the Dutch birder Nils van Duivendijk,
and can be found at: https://aa.swarovskioptik.com/birding/blog


John
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Old Monday 14th September 2020, 18:17   #57
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I wonder how big a demand there will be for this new awesome 115MM objective..? I have the 95MM ATX Kit and thought it was the bomb and now comes this beauty... I would think this may be easier to get from the get go then the 10-12 X 42 NL Pure..?
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Old Monday 14th September 2020, 19:14   #58
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What a huge beast, impressive, will make awesome seabird watching
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Old Tuesday 15th September 2020, 15:06   #59
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Originally Posted by henry link View Post
I expect the 110mm clear aperture is accurate for the BTX. I'm surprised there isn't more vignetting, including with the ATX and STX.

This thing will be hard to pull off properly. They'll certainly need to up their game for color correction. The ED glass will have to one of the types with an Abbe # around 95 and the mating glasses will have to be just right, etc.

Edit: Just saw David's post. I assumed the smaller objective modules were already using the usual fixed triplet and focusing doublet. If they want to keep the same level of spherical correction in the 115 as the 95mm that may need an upgrade, whatever that might mean.
Hi Henry,

You are right about the 110mm for the BTX.
The response of Swarovski is as follows:

The effectiveness of the lens diameter is limited in the 115 by the BTX eyepiece module, as the prims used in the BTX were ‘designed’ for a 30-70x95 system. The 115mm has a larger aperture ratio and the prism system is therefore too small for the beam in the center of the image. With the smaller lens modules (65mm, 85mm, 95mm) the BTX prisms can take up the entire beam. ATX and STX can completely get the bundles of rays with all lens modules, which is the reason for why the lens diameter is not reduced here.
Larger prisms would have the disadvantage for the 95/85/65 models, they would be too big and too heavy. The 110mm for the BTX is therefore a little “trade-off” due to our modular system.

Here goes my "wet dream" for a 150mm BTX........

Jan
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Old Tuesday 15th September 2020, 19:07   #60
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Jan,

With a slow 150mm module you might be able to have your dream.
But it would be a long telescope.

In fact the binocular module could probably be attached to any existing 150mm, 200mm or bigger telescope.

I am not sure if the binocular module is matched to Swarovski objective modules, or whether any normal long focus refractor can be used.

Regards,
B.
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Old Tuesday 15th September 2020, 19:12   #61
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Originally Posted by litebeam View Post
Congrats for being right here, JT.

I laughed out loud thinking about this posting when I saw this 115mm advertised at Europtic, thought of you thinking about deleting your 'rumor.'
Nailed it.
I was the first that responded to JT first post, but eventually deleted my post when I heard from Swarovski birdie that it was true and still under embargo. He was right on.
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Old Tuesday 15th September 2020, 19:50   #62
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Originally Posted by jan van daalen View Post
Hi Henry,

You are right about the 110mm for the BTX.
The response of Swarovski is as follows:

The effectiveness of the lens diameter is limited in the 115 by the BTX eyepiece module, as the prims used in the BTX were ‘designed’ for a 30-70x95 system. The 115mm has a larger aperture ratio and the prism system is therefore too small for the beam in the center of the image. With the smaller lens modules (65mm, 85mm, 95mm) the BTX prisms can take up the entire beam. ATX and STX can completely get the bundles of rays with all lens modules, which is the reason for why the lens diameter is not reduced here.
Larger prisms would have the disadvantage for the 95/85/65 models, they would be too big and too heavy. The 110mm for the BTX is therefore a little “trade-off” due to our modular system.

Here goes my "wet dream" for a 150mm BTX........

Jan
At first I didn't noticed the "effective objective lens diameter" and considered the 110 an error at the BTX chart. After reading Joachim and Henry's replies I went to BTX 115 web-page and the same info was available, so...
BTX users can gain all 115 potential "only" with the extender... It's when the 115mm are more needed...

With a 150mm objective module the focal length would most probably be longer, so the "effective objective lens diameter" would be >110mm...

Jan, do you ever looked through a >90º AFOV ep? As with bino-viewers, is also another dimension of birding...

As BTX aren't compatible with my CR-birding use/conditions and I still didn't found a good quality solution with a binoviewer on my X95, I will concentrate on >90º solutions...
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Old Tuesday 15th September 2020, 20:55   #63
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Originally Posted by DRodrigues View Post
At first I didn't noticed the "effective objective lens diameter" and considered the 110 an error at the BTX chart. After reading Joachim and Henry's replies I went to BTX 115 web-page and the same info was available, so...
BTX users can gain all 115 potential "only" with the extender... It's when the 115mm are more needed...

With a 150mm objective module the focal length would most probably be longer, so the "effective objective lens diameter" would be >110mm...

Jan, do you ever looked through a >90º AFOV ep? As with bino-viewers, is also another dimension of birding...

As BTX aren't compatible with my CR-birding use/conditions and I still didn't found a good quality solution with a binoviewer on my X95, I will concentrate on >90º solutions...
Hi David,

The Kowa Highlander is a beast and value for money.
The Fujinon 150 series are way out of the financial reality.
The BTX 115 and (I assume never) 150 would be in reach for a lot of people.

Jan
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Old Tuesday 15th September 2020, 23:47   #64
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Thanks for the information Jan. The thing that surprises me is that apparently right from the start Swarovski made the clear apertures of the ATX/STS prisms at least 20% wider than they needed to be to accommodate the 95mm module. It's almost like they knew a 115mm objective module with the same focal length as the 95 was coming eventually.

Henry
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Old Wednesday 16th September 2020, 06:49   #65
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Thanks for the information Jan. The thing that surprises me is that apparently right from the start Swarovski made the clear apertures of the ATX/STS prisms at least 20% wider than they needed to be to accommodate the 95mm module. It's almost like they knew a 115mm objective module with the same focal length as the 95 was coming eventually.

Henry
Sometimes, when reading between the lines, one could discover some strategic insight

Jan
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Old Wednesday 16th September 2020, 08:35   #66
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Swarovski could make a 150mm module with folded refractor optics that used the full 150mm on the BTX.

I suppose it would cost $6,000.
Weight perhaps 4.5kg.

I have the Yukon 6x to 100x Spotting scope.
It works well at 100x.
However, it is plastic, but only weighs about 1.5kg from memory.
Also it is lacking in good coatings both on the mirrors and lenses.
I don't think it is robust, but a high end robust folded refractor could be made.

There are several military folded refractor units, but these are very expensive.
Some are very large.

Regards,
B.

P.S.
On the current price for the 115mm module I make the cost of a possible 150mm module £4,850 in the U.K. at current prices.

Or £4,040 plus VAT.

I think that some would be prepared to pay this.

Last edited by Binastro : Wednesday 16th September 2020 at 11:35.
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Old Wednesday 16th September 2020, 12:26   #67
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I don't think it is robust, but a high end robust folded refractor could be made.
Hi,

some guys from the astro club have aquired a historic Zeiss AS 200 f15 doublet and are currently building a folded refractor for the planned club observatory....

Can't wait to see first light...

Joachim
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Old Wednesday 16th September 2020, 13:05   #68
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Hi Joachim,

I was offered an 8 inch folded refractor of good quality about 40 years ago, but I didn't buy it.
I suppose if it was at a lower price I might have had it, but I had Jim Hysom 10 inch and 14.5 inch Newtonians and my excellent 12.5 inch Dall Kirkham, so I really didn't need it.

There is also a British 8 inch folded refractor binocular.

I was also offered the Malta Ross 6 inch binocular, but £250 in 1968 was a lot of money.

There was a 34 inch aperture folded optic costing goodness knows what, but it vanished back into the 'doesn't exist' classified world.

Regards,
B.
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Old Wednesday 16th September 2020, 13:29   #69
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I was also offered the Malta Ross 6 inch binocular, but £250 in 1968 was a lot of money.
Ah, "the binoculars"? As in https://www.keele.ac.uk/observatory/history/binoculars/

These look indeed spectacular...

Joachim
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Old Wednesday 16th September 2020, 14:58   #70
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Thank you for that, Joachim.

Amazing you found it.

It must have been 1966, and I was offered the binocular first by Arthur Frank, owner of Charles Frank, Glasgow.
He had one of the world's finest collections of historic optics, that were sold by auction when he moved to Jersey.

A a company rep I visited Glasgow frequently.

I begged him to make an 8.5 inch Newtonian as he only made 6 inch versions.
He made me the first one, £220 retail, but he charged me £180.
It took a year to make, and I got it in 1967 and collected it by car
As it turned out the primary was faulty and Dudley Fuller gave me a first class mirror totally free of charge.
He was a jazz pianist turned telescope maker.
Lovely man.

In 1969 the 8.5 inch f/6 scope was in Helsinki observatory for a year with a brick to increase the angle by 9 degrees.
I had almost half a ton of stuff in my winterised Austin 1800 with pumped up hydrolastic suspension.
The car was fine at minus 30C.
I observed all night at minus 15C and for an hour at minus 25C.

Arthur Frank sold me a 10x70 Ross monocular from his collection.
People nowadays don't realise how difficult it was to get optics then.

The Keele observatory camera may contain a Dallmeyer 36 inch f/6.3 lens.
I had many and they varied tremendously in quality.
A few were hand aspherised, and a few coated.
They had spherical aberration that cleared at f/8.7.
Actually they weren't that good, but used yellow or red filters. Usually at f/11. there were three interchangeable shutters with different speeds.
Some of the filters contain uranium.
They were used on Williamson F52s. 8.5 inch x 7 inch film from memory.

There were also TTH 48inch f/8 and Ross 50 inch f/8 and 60 inch f/8 lenses.

The Zeiss cameras used Zeiss Telikon 75cm f/ 6.3 lenses with internal venetian blind shutters. Incredibly good quality, 30cm x 30cm format pressure backs.
Also 50cm Aero Tessar and 20cm wide angle 4 element lenses.
There are some of these survey cameras in the Science museum.
I had three of these cameras well used I gave one to a friend.

The Wray 36inch f/4 lenses were huge.
They were used for night photography.
Opticians bought these for £50 ex gov and took out the high quality 9.5 inch front lenses and reshaped them into long focus objectives.

Regards,
B.
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Old Wednesday 16th September 2020, 18:03   #71
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ok whom else is going to be picking up one of these new 115mm Swarovski Spotting Scope Objectives besides me..? Should be easier for me to find then a new 12X42NL here in the USA...
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Old Wednesday 16th September 2020, 19:23   #72
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ok whom else is going to be picking up one of these new 115mm Swarovski Spotting Scope Objectives besides me..? Should be easier for me to find then a new 12X42NL here in the USA...
Nehh, just heard that I'll get mine delivered round mid November

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Old Wednesday 16th September 2020, 21:01   #73
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Nehh, just heard that I'll get mine delivered round mid November

Jan
So October 1st is not correct..?
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Old Wednesday 16th September 2020, 21:06   #74
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So October 1st is not correct..?
Yes it is and the first batch will be delivered in the beginning of October but after that it will be mid November at the earliest (at least for The Netherlands).

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Old Wednesday 16th September 2020, 23:32   #75
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...
The Kowa Highlander is a beast and value for money.
...
Jan
Interesting you mentioned the Highlander. If the BTX 115 didn't vignetted the amount of light collected would be similar. Being "only" 110mm the BTX 115 will have about 11% less light, that should be not much noticeable on most conditions, but the BTX wins on weight, dimensions, cost and practicability for birding - focusing both eyes at the same time is a huge advantage!
To be similar to an eventual Highlander 88, there would "only" need to be a BTX130 - 125 if there would be no vignetting...

By the way, as reading my cr-telescopes page to see what I need to update due to the X115, I noticed that I asked for >=100 mm versions of the alpha producers but never thought that Swarovski would be the first and never thought would be a 115mm version. Better for all of us...

Interesting to note that my first scope was a Nikon ED60 with a 20-45x zoom... Within some time it will be a 115mm with a 30-70x wide-angled zoom, that result on 51-122x zoom with the extender! This within almost 29 years...
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