180 replies to this topic

[Sarkikos]

First Light Optics shows four in stock for approximately $380 shipped. https://www.firstlig...binoviewer.html

When I put them in the shopping basket, the shipped price is £297.05.  (No VAT.)   That's $376.35 USD.  So, yep, about $380. 

 

The Orion Linears are $529.99 shipped, after tax.  That's a difference of $153.64.  And when - if ever - will the Orions ship?   Again: 

 

I'm getting real close to ordering them from FLO.  

 

Edit:   After I started to pay through PayPal, the total price became $393.27 USD.   Looks like $16.92 was a fee for currency conversion.  

 

Mike

Edited by Sarkikos, 23 February 2024 - 04:23 PM.

[Sarkikos]

The Omegon Linear Binoviewers on Amazon cost $479 shipped, and they are shipped from Germany.

 

https://www.amazon.c...08722446&sr=8-3

 

Mike

[Sarkikos]

Well, I just now ordered the StellaLyra Linear Binoviewer from FLO.  I'll cancel the order from Orion.  

 

Mike

[betacygni]

Well, I just now ordered the StellaLyra Linear Binoviewer from FLO. I'll cancel the order from Orion.

Mike

Let us know how you like them. I have a pair in my Germany shopping cart, but still can’t quite bring myself to push the button. Curiosity might get the better of me eventually.

[Sarkikos]

Soon after I sent an email to Orion cancelling my order, I received a reply back saying:

We don't like disappointing you.  Unfortunately, we find that we are unable to ship the following item(s) that you have ordered.  We apologize for any disappointment this may cause.

Order Number: 2205495

Item Number  Description                                   Reason
52054              Premium Linear Binoviewer            Backorder

Maybe this is just boilerplate copy that Orion sends to anyone cancelling an order that is currently backordered.  Maybe I'm reading too much into it.  But it sure seems to imply that they'll probably never be able to have them available again.  

 

On Amazon, Orion lists the Linear Binoviewers as "discontinued."

 

Maybe anyone who wants a linear should buy them now while they are still in stock here and there.  

 

Mike

Edited by Sarkikos, 23 February 2024 - 08:22 PM.

[Sarkikos]

Let us know how you like them. I have a pair in my Germany shopping cart, but still can’t quite bring myself to push the button. Curiosity might get the better of me eventually.

Which German company?  The one on Amazon, or another?   Link?

 

Mike

Edited by Sarkikos, 23 February 2024 - 08:23 PM.

[betacygni]

Which German company? The one on Amazon, or another? Link?

Mike

https://www.teleskop-express.de/

Have bought a lot from them over the years, very good company (will often have items in stock sold out stateside).

[Sarkikos]

https://www.teleskop-express.de/

Have bought a lot from them over the years, very good company (will often have items in stock sold out stateside).

Yep.  I've bought several things from them.  

 

Here's the linear binoviewer at their website:  https://www.teleskop...ect-image-10297

 

Mike

[Sarkikos]

The linear binoviewer from FLO arrived either early today or yesterday evening.  My daughter found it on the porch this morning.  

 

Here are some pics:

 

Mike

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Edited by Sarkikos, 29 February 2024 - 11:59 AM.

[Sarkikos]

The "Owner's Manual."

 

Mike

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Edited by Sarkikos, 29 February 2024 - 11:58 AM.

[Bintang13]

Congratulations on getting them. Be fascinated to read your impressions especially in combination with all the different scopes that you have. Kasai offers a .66 reducer that is worth trying, it’s less than $60. I don’t have a lot of experience using reducers so had a mixed experience using different eyepieces but got good results with the 18.2mm Delites in a 10” Dob.

Edited by Bintang13, 29 February 2024 - 12:57 PM.

[Sarkikos]

Congratulations on getting them. Be fascinated to read your impressions especially in combination with all the different scopes that you have. Kasai offers a .66 reducer that is worth trying, it’s less than $60. I don’t have a lot of experience using reducers so had a mixed experience using different eyepieces but got good results with the 18.2mm Delites in a 10” Dob.

Thanks.

 

What would be the advantage to the 0.66 reducer, specifically in the linear binoviewers?  Wouldn't a 0.66 reducer - or any reducer - increase possible vignetting even more?   Were you using the 0.66 reducer and 18.2mm DeLites in linear binoviewers in the 10" Dob?  The 18.2mm DeLites have a 19.1mm field stop.  Wouldn't the 0.66 reducer increase the effective size of the field stop to 31.7mm?  That's way above the 17mm aperture of the linear binoviewers.  Or am I thinking about this incorrectly?

 

Would you post a link to a source for the Kasai 0.66 reducer?  

 

Mike

Edited by Sarkikos, 29 February 2024 - 01:33 PM.

[Bintang13]

Yes I was using the .66 reducer and 18.2 Delites in the linear binoviewers in a 10” Dob. The 18.2 Delites are as far as I can go without reducer where I can’t perceive the vignetting. I get the same ( non vignetting ) result with the reducer added to the Delites. The only advantage is as with barlows which is providing additional magnifications with little cost. I use the 15 and 18 Delites as well as APM 15mm 65 degree with and without reducer. ES16mm 68 degree work well for me without the reducer but not as well with reducer.

I don’t want to mess up the link so I’m referring you to jprideaux 09 Feb 2022 and 06 Sept 2022 posting re: Orion linear vs standard binoviewers, use comparison discussion.

 

Jim

Edited by Bintang13, 29 February 2024 - 04:33 PM.

[TOMDEY]

Soon after I sent an email to Orion cancelling my order, I received a reply back saying:

Maybe this is just boilerplate copy that Orion sends to anyone cancelling an order that is currently backordered.  Maybe I'm reading too much into it.  But it sure seems to imply that they'll probably never be able to have them available again. 

On Amazon, Orion lists the Linear Binoviewers as "discontinued."

Maybe anyone who wants a linear should buy them now while they are still in stock here and there.  

Mike

It might mean they will never have it available to you again! A friend who worked in marketing said some mail-order/on-line vendors discover the shelves are bare... specifically to customers who waffle, complain, cancel, or return stuff too often... even sharing ~lists~ with their associates. But when a customer with good history, rarely a complaint, asks for the same item --- it arrives at his house a couple days later. It's similar to customers who frequently submit (even minor) insurance claims... then go to renew and find the premium shot up, or they won't even offer a contract to him anymore. One agent (chatting) told me that it's not the magnitude of the claim, but the frequency of the claims that downgrades customers' scores. I know we rate/score vendors --- but many fail to realize that vendors also rate/score customers. With purchases being so visible now-a-days... I (reasonably) assume that each of us has earned some sort of shared rating out there in the ether. So one guy eventually finds that the stuff he wants somehow is habitually sold out or delayed, whereas the neighbor next door seems delighted with his orders stocked and always arriving within a few days. My rating is so good that what I want arrives... the day before I order it! They know me that well.  Tom

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[Eddgie]

 

 

Or am I thinking about this incorrectly?

 

I think you are indeed thinking about in incorrectly. 

 

The Linear Bioviewer is made using a collimator and a relay lenses. In essence, it it is a light pipe that simply relays the image at the entry to the focal plane. If the reducer causes more vignetting from the telescope (as it would with an SCT for example) then whatever the vignetting is when it enters will be exactly  what it is when it exits, meaning that the binoviewer itself does not vignette at all, other than when the field stop of the eyepiece is too big for the system.

 

This is why you can use the linear in any speed telescope. If you think about it, people use the in fast reflectors and they work fine even at f/4.5 and in theory, they should work down to f/1. Whatever arrives at the entry lens is collimated down, where it passes though the relay lenses and the gets re-constructed by the last elements in the collimator and the mirrors. 

 

 

 

 

This design is kind of a reverse to the US PVS-7 Night Vision goggle.  It uses a surprisingly similar system and it too works at f/1. The image is formed on the rear of the image intensifier, and the collimator and mirrors relay the image to the focal plane of the eyepiece, but here, the collimator and mirrors are used to add light path. 

 

 

Note: These systems are conceptually similar, but in the case of the PVS-7, the image is formed by the tube and is displayed on the rear window of the tube. The rays emanate from the rear window of the tube as parallel rays. With the Linear, the rays are converging until they  reach the front window of the collimator lens at entrance to the collimator, at which time they are converged by the collimator (in essence they are shrunk down for the trip through the system) and then re-expanded as they leave the collimator and travel to the mirror and on to the lens.  In the PVS-7, the focal plane is actually at the rear of the tube, and the collimator in the PVS-7 simply makes the 27mm eyepiece have a non-magnifying distance so that there is enough light to get the eyepieces far enough apart to accommodate the average user.  In other words, in the PVS-7, you are adding distance between the field stop of the eyepiece (which is actually the rear the window of the tube where the image is formed) and the eyepiece lenses, but preserving the 27mm focal length. and the exit pupil of the eyepiece.  With the Linear, you are eliminating light path.  A collimator can work either way.  You can make a light path shorter, or you can make it longer, without adding any vignetting. 

Edited by Eddgie, 29 February 2024 - 05:16 PM.

[Bintang13]

Thanks Eddgie I was getting way over my head that does corroborate my observations with the reducer. One of the biggest advantages of course is the reduced magnification and increased TFOV with eyepieces that you already enjoy using.

 

Jim

[Sarkikos]

It might mean they will never have it available to you again! A friend who worked in marketing said some mail-order/on-line vendors discover the shelves are bare... specifically to customers who waffle, complain, cancel, or return stuff too often... even sharing ~lists~ with their associates. But when a customer with good history, rarely a complaint, asks for the same item --- it arrives at his house a couple days later. It's similar to customers who frequently submit (even minor) insurance claims... then go to renew and find the premium shot up, or they won't even offer a contract to him anymore. One agent (chatting) told me that it's not the magnitude of the claim, but the frequency of the claims that downgrades customers' scores. I know we rate/score vendors --- but many fail to realize that vendors also rate/score customers. With purchases being so visible now-a-days... I (reasonably) assume that each of us has earned some sort of shared rating out there in the ether. So one guy eventually finds that the stuff he wants somehow is habitually sold out or delayed, whereas the neighbor next door seems delighted with his orders stocked and always arriving within a few days. My rating is so good that what I want arrives... the day before I order it! They know me that well.  Tom

I seldom return anything.  I can't remember the last time I did.   As long as it works as advertised, and it's not damaged or defective, I'll keep it.  Maybe this is a reflection of the general reliability of the products I buy and the vendors I buy them from more than anything else.  

 

I don't expect perfection.  I accept that everything is a compromise.  If the product fulfills the criteria I expected for it, I'm satisfied.  

 

But if I order something and the shipping date is continuously delayed, often I will cancel the order.   When I buy something, I'm buying it for my present self, not for some future self who will have lost interest in the product, found a vendor who actually has one in stock, or decided to buy a near equivalent instead.  

 

Mike

Edited by Sarkikos, 29 February 2024 - 06:36 PM.

[Sarkikos]

I think you are indeed thinking about in incorrectly. 

 

The Linear Bioviewer is made using a collimator and a relay lenses. In essence, it it is a light pipe that simply relays the image at the entry to the focal plane. If the reducer causes more vignetting from the telescope (as it would with an SCT for example) then whatever the vignetting is when it enters will be exactly  what it is when it exits, meaning that the binoviewer itself does not vignette at all, other than when the field stop of the eyepiece is too big for the system.

 

This is why you can use the linear in any speed telescope. If you think about it, people use the in fast reflectors and they work fine even at f/4.5 and in theory, they should work down to f/1. Whatever arrives at the entry lens is collimated down, where it passes though the relay lenses and the gets re-constructed by the last elements in the collimator and the mirrors. 

 

 

post-260649-0-73668400-1604102103.png

 

 

This design is kind of a reverse to the US PVS-7 Night Vision goggle.  It uses a surprisingly similar system and it too works at f/1. The image is formed on the rear of the image intensifier, and the collimator and mirrors relay the image to the focal plane of the eyepiece, but here, the collimator and mirrors are used to add light path. 

 

Screenshot 2024-02-29 155620.png

 

Note: These systems are conceptually similar, but in the case of the PVS-7, the image is formed by the tube and is displayed on the rear window of the tube. The rays emanate from the rear window of the tube as parallel rays. With the Linear, the rays are converging until they  reach the front window of the collimator lens at entrance to the collimator, at which time they are converged by the collimator (in essence they are shrunk down for the trip through the system) and then re-expanded as they leave the collimator and travel to the mirror and on to the lens.  In the PVS-7, the focal plane is actually at the rear of the tube, and the collimator in the PVS-7 simply makes the 27mm eyepiece have a non-magnifying distance so that there is enough light to get the eyepieces far enough apart to accommodate the average user.  In other words, in the PVS-7, you are adding distance between the field stop of the eyepiece (which is actually the rear the window of the tube where the image is formed) and the eyepiece lenses, but preserving the 27mm focal length. and the exit pupil of the eyepiece.  With the Linear, you are eliminating light path.  A collimator can work either way.  You can make a light path shorter, or you can make it longer, without adding any vignetting. 

the binoviewer itself does not vignette at all, other than when the field stop of the eyepiece is too big for the system.

 

Let's remove the reducer for a moment.  I'll accept that a reducer doesn't change whatever impact the binoviewer has on light throughput.  

 

The largest field stop in a 1.25" eyepiece is 27mm.  If I insert a 27mm field stop 1.25" eyepiece into the focuser of my 10" f/5 Dob, the eyepiece won't vignette.  But if I insert the same eyepieces into a binoviewer with a 17mm clear aperture, won't there be vignetting?  Or else, what is the advantage of a binoviewer like the 27 Binotron which has a 27mm clear aperture? 

 

Maybe "vignetting" is not the correct terminology.  What I mean to ask is, "Won't a binoviewer with a 17mm clear aperture not fully illuminate an eyepiece which has a 27mm field stop?"   

 

Mike

Edited by Sarkikos, 29 February 2024 - 06:37 PM.

[Bintang13]

This is way way over my head and I can’t find the popcorn eating emoji. It is a very good question because the reducer seams to defeat the 17mm clear aperture restriction.

 

Jim

[Sarkikos]

This is way way over my head and I can’t find the popcorn eating emoji. It is a very good question because the reducer seams to defeat the 17mm clear aperture restriction.

 

Jim

Here you go:  

 

Here's mine: 

 

Mike

[TOMDEY]

There's a point where the easiest route to enlightenment is --- buy, try, and react. I buy lots of things, especially uncertain or even questionable products, just to find out for myself hands-on. Often they are way better and interesting than the armchair experts are asserting. And that is worth the modest price of admission. If confirmed as cheap worthless junk --- I take it to the town dump, often with a smirk on my face, and not particularly miffed that I dropped a C-note or more on it. Junkiness is an acquired taste, even addictive.    Tom

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[Bintang13]

Hi Mike,

 

l love that emoji. After some thought, and I use that word lightly, I will give it a stab. I believe nothing is happening to the binoviewer but the scope has had its f ratio reduced. Basically a different scope feeding the binoviewers. As an aside I only have and use stock focusers so I’ve always chosen eyepieces that are lighter in weight. It would be very interesting to hear from those that have a linear and can use them with heavier eyepieces.

 

Jim

[jprideaux]

the binoviewer itself does not vignette at all, other than when the field stop of the eyepiece is too big for the system.

 

Let's remove the reducer for a moment.  I'll accept that a reducer doesn't change whatever impact the binoviewer has on light throughput.  

 

The largest field stop in a 1.25" eyepiece is 27mm.  If I insert a 27mm field stop 1.25" eyepiece into the focuser of my 10" f/5 Dob, the eyepiece won't vignette.  But if I insert the same eyepieces into a binoviewer with a 17mm clear aperture, won't there be vignetting?  Or else, what is the advantage of a binoviewer like the 27 Binotron which has a 27mm clear aperture? 

 

Maybe "vignetting" is not the correct terminology.  What I mean to ask is, "Won't a binoviewer with a 17mm clear aperture not fully illuminate an eyepiece which has a 27mm field stop?"   

 

Mike

Those of us that have the linear tend to choose (less-expensive) eyepieces that have smaller field-stops of around 17.4mm (+/- a bit).  If you have an eyepiece with the 27mm field-stop, you won't be able to fully take advantage of the potential of that eyepiece if what feeds it has less than 27mm diameter light-path.  

Adding a reduce before the linear does not let you better use a 27mm field-stop eyepiece.  You will still be limited by the 17.4mm field-stop of the linear itself.  The reducer, though, will make the wider field "reduced" down to a smaller area so it will fit through the more narrow 17.4mm field-stop of the linear - thus you can see a wider field of view relative to not using the reducer.  For example, I have Baader 18mm orthoscopic (16.8mm field-stop) eyepieces and I can say from personal experience that the FOV is increased  when using the linear when I use a .66 reducer.  

[betacygni]

My experience with reducers, at least the one I use as part my daystar quark/binoviewer system, is it creates a hard vignette (basically I see a new much smaller fuzzy field stop in view). I’m able to drop the magnification with the reducer, but I don’t get a larger TFOV. It’s like using a 40mm instead of 32mm plossl, same FOV, smaller AFOV. I of course don’t know if this would apply to the linear, but I’m suspicious of somehow getting a larger TFOV through the same sized hole essentially.

Edited by betacygni, 29 February 2024 - 09:52 PM.

[Sarkikos]

My experience with reducers, at least the one I use as part my daystar quark/binoviewer system, is it creates a hard vignette (basically I see a new much smaller fuzzy field stop in view). I’m able to drop the magnification with the reducer, but I don’t get a larger TFOV. It’s like using a 40mm instead of 32mm plossl, same FOV, smaller AFOV. I of course don’t know if this would apply to the linear, but I’m suspicious of somehow getting a larger TFOV through the same sized hole essentially.

About 15 years ago, I briefly experimented with screwing reducers onto eyepieces.  My thinking was, "Barlows decrease the effective focal length of an eyepiece.  Reducers increase the effective focal length.  Let's see what happens."  In some instances, this did cause obvious vignetting.  

 

I also saw definite vignetting when using a 0.63x R/C on a C90 Mak with some eyepieces.  The 35 Ultrascopic was probably the worst case.  

 

Mike

Edited by Sarkikos, 01 March 2024 - 10:30 AM.