Astreya other products

[ghartke]

Originally Posted by astreya

Hi Jim,
Astreya main plan is to realize ALL mine APO-projects. There're a lot of, so I hope that we'll offer one of them in 2008. It will be a lens with aperture of 130mm or even more (I hope 152 or 180 F/7.5). All depends on glass price/quality we'll can get.
About telescopes. Yes, we offer 130 and 152 SAPO telescopes and now we don't plan to produce 102 and 180 scopes. In general, 102 lenses are intended, basically for the internal, Russian market. As for 180mm scopes, we're searching a partner to produce the tubes for them.

Hi, Andrey,

That sure got my attention! If a 180 mm f/7.5 scope became available, I might think very seriously about replacing my 152 mm SAPO. Serious imagers will want a field flattener and a large 2-speed focuser. Have you considered producing FFs for your refractors? A well balanced OTA would also help. This is often overlooked in an effort to keep the weight down but I simply wouldn't buy an OTA that doesn't balance properly. My personal preference is to ignore the frills like a sliding dew shield. This is already a large scope and saving a little length probably won't make much difference to serious users.

Do you see any hope for better distribution in North America? I know Dave Dearing (MPI astronomy) was gearing up for it but his unfortunate accident probably put a stop to those plans. We'd love to see you over here!

Regards,

Greg Hartke
Sykesville, MD USA

[astreya]

Originally Posted by Jim Fusco

The process is very extensive, and more so for a high performance lens. Is there a final test for the lens and if so how is it performed and how should it understood by the owner. Because some makers seem to point out one thing and hide the other also not offering glass type. I see with Astreya makes no secret of glass type or other information about the lens.
I see now, that the process of making of the lens is the lens is the difficult part and method is most important.

Thanks,

Jim

Of course, the final test of any lens should be. It should be first of all for the manufacturer to be sure that the lens corresponds to all requirements.
Is it necessary to show this report to owner of a lens in any case? I'm not sure.
If a customer wants to get it, we give. What about other companies? Not all companies do it. Why? I think there are a lot of reasons. And it is not necessarily connected with the desire to hide something from the client.
The fact is that not every client can interpret this test. More over, no one test-report can give to the owner of a lens absolutely complete info about it. I think that the best testing for an customer is his own testing of his lens.
And it has nothing to do with interferogram or something of the sort.
In most cases, his own eyes for an amateur is more important tester than interferogram or something else.
Why some companies make secret of glass types and others? Maybe they are afraid of competitors. I don't know... In fact, the design of a lens which is on sale can't be of any secret for experts or for somebody who wants to know what is what. But design is not the main thing. The main thing is technology and a skill to realize in practice this or that design. There are only few companies all over the world which CAN do this. A secret is HOW they do it.

[Jim Fusco]

Andrey, this is very intersting and the process is extensive. Appears custom tooling is a requirement to make custom lenses.
I understand that you were involve with designing Maksutov Cass and Newts than we see today. I was wondering if you could tell us the history, and also the advantage for the newer design improvements. If someone is looking for a Andrey Strakhov design Mak what model can we find this.

Thanks,

Jim

[astreya]

Originally Posted by ghartke

Hi, Andrey,

That sure got my attention! If a 180 mm f/7.5 scope became available, I might think very seriously about replacing my 152 mm SAPO. Serious imagers will want a field flattener and a large 2-speed focuser. Have you considered producing FFs for your refractors? A well balanced OTA would also help. This is often overlooked in an effort to keep the weight down but I simply wouldn't buy an OTA that doesn't balance properly. My personal preference is to ignore the frills like a sliding dew shield. This is already a large scope and saving a little length probably won't make much difference to serious users.

Do you see any hope for better distribution in North America? I know Dave Dearing (MPI astronomy) was gearing up for it but his unfortunate accident probably put a stop to those plans. We'd love to see you over here!

Regards,

Greg Hartke
Sykesville, MD USA

Hi Greg,
I quite understand your interest for 180 F/7.5. Really, it's very powerfull instrument for imagers. I can say that we have even shorter design but this one is more balanced.
About field flattener. You see, each APO design generally speaking needs its own individual flattener because it has unique correction of aberration. And optical design of such FF is not a simple one. Of course, one can use some standard FF but the result can't be optimal.
In this way we should make different correctors for each lens model. But it's impossible for our small company. So we plan to make only one flattener model and only for one lens - our top model, which will intended aspecially for imaging. I think it should be 180 F/7.5, but now it's only a project. As for focusers and other mechanics, I believe that there are some companies who make it very well and there is no any reason for us to try surpass them in it (our business is optics), we should just cooperate with them and we try to. Yes, we was in contact with Dave, but the accident stopped those plans. Now we're searching another possibilities.
I wish you sucsess in imaging and hope to see a lot of new pictures.

[astreya]

Originally Posted by Jim Fusco

...I understand that you were involve with designing Maksutov Cass and Newts than we see today. I was wondering if you could tell us the history, and also the advantage for the newer design improvements. If someone is looking for a Andrey Strakhov design Mak what model can we find this.

Thanks,

Jim

Hi Jim,
yes, some years ago I worked on designing Maks. It's rather conservative optical design and it difficult to improve some principal characteristics in it.
It's just possible to vary such points as central obstruction, back focus and F/number a bit. My job was to optimize this parameters and make two variants of Maks-Cass: with focuser and with moving primary.
So, now we can offer 6", 7" and 9" Maks F/10- F/13 as standard set and up to 20" optical sets to order.

[ghartke]

Originally Posted by astreya

Hi Greg,
I quite understand your interest for 180 F/7.5. Really, it's very powerfull instrument for imagers. I can say that we have even shorter design but this one is more balanced.
About field flattener. You see, each APO design generally speaking needs its own individual flattener because it has unique correction of aberration. And optical design of such FF is not a simple one. Of course, one can use some standard FF but the result can't be optimal.
In this way we should make different correctors for each lens model. But it's impossible for our small company. So we plan to make only one flattener model and only for one lens - our top model, which will intended aspecially for imaging. I think it should be 180 F/7.5, but now it's only a project. As for focusers and other mechanics, I believe that there are some companies who make it very well and there is no any reason for us to try surpass them in it (our business is optics), we should just cooperate with them and we try to. Yes, we was in contact with Dave, but the accident stopped those plans. Now we're searching another possibilities.
I wish you sucsess in imaging and hope to see a lot of new pictures.

Hi, Andrey,

Of course you're not going to get into building full scopes! What was I thinking? Anyway, Jim and I are already conspiring to keep an eye out for a 180 f/7.5. Here's an interesting question: What's the best way to mount a refractor lens cell in a tube? I would think that for optimal performance, the collimated lens-in-cell would have to be placed on the tube, then the cell-to-tube mounting would be adjusted to collimate the optical assembly on the optical axis of the tube. Thereafter, the lens collimation would be adjusted as necessary. How else would you be assured of perfect collimation? I'm sure you see my point. If the lens were mounted on the tube in less than a perfect position, the user would wind up tweaking the collimation to minimize the errors. The problem is that the imperfect optical alignment would mean you could never properly collimate the lens. What's the best way to proceed? I'd love to hear how this should be done!

Thanks for the help!

Regards,

Greg

[Jim Fusco]

Hi Greg,

I seen it both ways, collimation ring inside the tube (mounted to tube by adapter) or a outside collimation ring to a outside adapter. I'm not sure how Astreya adapts there collimation ring to the tube though. However these are basically the options, besides a highly machine shim tube. However collimation has a greater impact on flatness with a longer F# scope.

[Jim Fusco]

Hi Andrey,

The design and history of the SAPO. What made you select this design and advantages. I understand when a Master designer selects a design it's for a primary reason, like contrast, color, sharpness ect.
I see Zeiss had the N type formula a 4 lens design and Lichenknecker 4 lens VAS design. Wolfgang mentions here http://www.astro-foren.de/showthread.php?t=7214, yours should be the SRQ (Strakhov Russian Quadruplet)

[astreya]

Originally Posted by ghartke

Hi, Andrey,

...Here's an interesting question: What's the best way to mount a refractor lens cell in a tube? I would think that for optimal performance, the collimated lens-in-cell would have to be placed on the tube, then the cell-to-tube mounting would be adjusted to collimate the optical assembly on the optical axis of the tube. Thereafter, the lens collimation would be adjusted as necessary. How else would you be assured of perfect collimation? I'm sure you see my point. If the lens were mounted on the tube in less than a perfect position, the user would wind up tweaking the collimation to minimize the errors. The problem is that the imperfect optical alignment would mean you could never properly collimate the lens. What's the best way to proceed? I'd love to hear how this should be done!

Thanks for the help!

Regards,

Greg

The basic purpose of adjusting a lens on a tube is to overlap lens optical axis with a geometrical axis of a tube. For this purpose apply a flange with push-pull screws. Such design also allows to compensate an error of manufacturing of some mechanical details. I think it's the better way to collimate cell-to-tube mounting especially for large telescopes.

[astreya]

Originally Posted by Jim Fusco

Hi Andrey,

The design and history of the SAPO. What made you select this design and advantages. I understand when a Master designer selects a design it's for a primary reason, like contrast, color, sharpness ect.
I see Zeiss had the N type formula a 4 lens design and Lichenknecker 4 lens VAS design. Wolfgang mentions here http://www.astro-foren.de/showthread.php?t=7214, yours should be the SRQ (Strakhov Russian Quadruplet)

Hi Jim,
this history is very simple: we wanted to make the best APO all over the world. The main purpose was to achieve high level of color correction and do F number of the lens as fast as possible. And I think we managed to do it. Zeiss and Lichtenknecker do F/15 or smth of the sort, but we do F/7. This is a very big difference. Of course, it's original design but without any name at the moment.