Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

Vixen HR 3.4mm


Franklin

Recommended Posts

8 hours ago, jetstream said:

Whats the bottom of these EP's look like? In my quest to eliminate scatter Ive even painted the bottom of the EP adapters flat black. What do you mean by back scatter? reflected light off the eyepiece bottom?

 

20230407_102041.thumb.jpg.43a1b531ee97e3ff97a8f1891e2d09b3.jpg

  • Like 3
Link to comment
Share on other sites

11 hours ago, Louis D said:

I wonder if that lower "TOE" image used to accompany the following Vixen comparison of the HR line to the 2.5mm LV:

hr_770.jpg

They basically threw the LV under the HR bus.  Those Vixen pages seem to mostly be gone now that the HR line is discontinued.

However, it might be the 2.5mm Vixen LV internal diagram despite the odd lens and group count.

Could be Louis.
It’s definitely not a TOE though - obviously the eye lens is nothing like that size, as well as the wrong number of lenses and groups.

  • Like 2
Link to comment
Share on other sites

15 hours ago, Don Pensack said:

It looks like an SSW, to me--8 elements.  Nope.  The SSW is 7 elements.

TOE is 6 elements.  The LV didn't have 8 elements.  Some (but not all) of the focal lengths of LVWs did.

It's a mystery.

 

By the way, HR stands for High Resolution.  That pretty much says it all.

The baffle at the bottom makes a difference.  Try removing it when looking at something bright.

A bottom baffle like that is the reason I always use the Apollo 11 as a 2" eyepiece.  Remove the 2" adapter and the bottom baffle disappears,

and it makes a visible difference in the image.

I wish the bottom baffles were an accessory you could buy.  Unfortunately, what is under the Vixen HR's bottom baffle is not a filter thread, so if you use a planetary filter of some kind, it has to be attached elsewhere.

I rest my colour filters in the rubber eye-cup of the HR's. Not ideal but it works as long as the eyepiece isn't horizontal or below!

  • Like 1
Link to comment
Share on other sites

3 hours ago, Highburymark said:

Could be Louis.
It’s definitely not a TOE though - obviously the eye lens is nothing like that size, as well as the wrong number of lenses and groups.

I edited that image out Mark. Although it did have a footnote on the original pic which I cropped, it certainly wasn't six elements in four groups. Unfortunately I haven't been able to find a diagram for the TOE so far.

Link to comment
Share on other sites

13 hours ago, jetstream said:

What's the bottom of these EP's look like? In my quest to eliminate scatter I've even painted the bottom of the EP adapters flat black. What do you mean by back scatter? reflected light off the eyepiece bottom?

As light passes through an eyepiece, some of the light is reflected back toward the source.

If that reflected light encounters another optical surface, it can reflect forward again, albeit at a significantly reduced intensity.

Still, it will be out of focus and mostly adding to the sky brightness background in the eyepiece.

 

If there is a little dust on the optical surface, the reflection/scatter is increased.  It has the same effect as a rough optical surface.

This was noticed on some production runs of some Takahashi eyepieces.

The eyepieces could, of course, be dismantled and internally cleaned, but most people buying a new eyepiece won't want to do that.

  • Like 1
Link to comment
Share on other sites

2 minutes ago, Don Pensack said:

If that reflected light encounters another optical surface, it can reflect forward again, albeit at a significantly reduced intensity.

Thanks Don, I wonder if an objectives coatings play a role in this assuming the back side of the lens in a refractor is coated at all? Could placing a barlow ahead of the diag potentially make  this type of scatter worse?

Ive had one serious problem with scatter-many years ago- from a bad diag, massively bad actually. Ive always wondered if the light cone through a refractor would make it all through the diag, espc at fast f ratios? Thoughts? ie the fully illuminated field idea.

Link to comment
Share on other sites

1 hour ago, mikeDnight said:

I edited that image out Mark. Although it did have a footnote on the original pic which I cropped, it certainly wasn't six elements in four groups. Unfortunately I haven't been able to find a diagram for the TOE so far.

No worries Mike. That second diagram was indeed an LV as Louis suggested - at shorter lengths the LVs did apparently use a pseudo-Masuyama design with an added field group. There are no TOE diagrams as far as I’m aware.     
Back onto the main theme of the thread, I wonder if it would be feasible for Vixen to make further HR batches in future, or whether the tooling/materials are no longer attainable? I’m sure they could sell a lot of 3.4s if they were made available tomorrow. 

  • Like 3
Link to comment
Share on other sites

8 minutes ago, Highburymark said:

Back onto the main theme of the thread, I wonder if it would be feasible for Vixen to make further HR batches in future, or whether the tooling/materials are no longer attainable? I’m sure they could sell a lot of 3.4s if they were made available tomorrow. 

For sure. I’d buy a 2.4 without a doubt. I’m lucky enough to have the 3.4. Maybe some emails to Vixen suggesting that might put the idea in their minds :) 

Link to comment
Share on other sites

If Vixen did offer a second batch, I'm sure many would buy them. They are quite specialised however, and perhaps a new run of HR's would be limited as the first were. I also imagine that a few who missed out on the first run would snap them up. How much this would cost Vixen and what profit they would make may hold a second run back, unless prices were high. I have a feeling that Vixen knew from the start where they were going with this eyepiece, and that it was an experiment designed for their pleasure as much as for the amateur observer.

Edited by mikeDnight
  • Like 3
Link to comment
Share on other sites

Just now, mikeDnight said:

If Vixen did offer a second batch, I'm sure many would buy them. They are quite specialised however, and perhaps a new run of HR's would be limited as the first were. I also imagine that a few who missed out on the first run would snap them up. How much this would cost Vixen and what profit they would make may hold a second run back, unless prices were high. I have a feeling that Vixen knew from the start where they were going with this eyepiece from the start, and that it was an experiment designed for their pleasure as much as for the amateur observer.

You may well be right, Mike. I sent them a mail just to see what they say :D I’m sure they’ll say no in a much nicer way than my dear wife would…

  • Haha 2
Link to comment
Share on other sites

Just now, Littleguy80 said:

I did try dropping your name in the email to them to aid the cause!

Perfect! there are few eyepieces that have ever reached this level and I hope to complete the set, and use them. They are bizarrely good IMHO. I wonder what their minimum number of units would be needed to get them interested in another run?

  • Like 4
Link to comment
Share on other sites

22 minutes ago, mikeDnight said:

If Vixen did offer a second batch, I'm sure many would buy them. They are quite specialised however, and perhaps a new run of HR's would be limited as the first were. I also imagine that a few who missed out on the first run would snap them up. How much this would cost Vixen and what profit they would make may hold a second run back, unless prices were high. I have a feeling that Vixen knew from the start where they were going with this eyepiece, and that it was an experiment designed for their pleasure as much as for the amateur observer.

I certainly would buy a 3.4mm..:smiley:

  • Like 5
Link to comment
Share on other sites

14 minutes ago, Alan White said:

I would purchase a 3.4 if I had the funds and sell a Kidney if I did not, it was / is a super Lunar eyepiece.

Who's kidney are you thinking of selling Alan, anyone particular in mind?

Edited by mikeDnight
  • Haha 4
Link to comment
Share on other sites

The main reason for the HR range being discontinued is Vixen was not happy with the QA they could do on the EP’s. 
Having said that APM have ordered a new run of Doctor EP’s, maybe Marcus could be convinced he could do the same for the HR line?

  • Like 4
Link to comment
Share on other sites

If that’s the case, it sounds like they underpriced the product in the first place. Clearly they are difficult and intricate eyepieces to make. But at £220, or whatever the UK retail price was, they were very cheap compared with other class leading planetaries. 

  • Like 3
Link to comment
Share on other sites

4 hours ago, mikeDnight said:

I'm guessing a hundred thousand would be a healthy order. You're at least on your way with the three of you dusting your wallets off.:laugh2:

I know that is tongue-in-cheek,  I'd be surprised if they even made a thousand.

  • Like 3
Link to comment
Share on other sites

6 hours ago, jetstream said:

Thanks Don, I wonder if an objectives coatings play a role in this assuming the back side of the lens in a refractor is coated at all? Could placing a barlow ahead of the diag potentially make  this type of scatter worse?

Ive had one serious problem with scatter-many years ago- from a bad diag, massively bad actually. Ive always wondered if the light cone through a refractor would make it all through the diag, espc at fast f ratios? Thoughts? ie the fully illuminated field idea.

The likelihood is high that a refractor objective is fully coated, or fully multi coated.  I've dismantle cheap plastic telescopes and found fully coated lenses.

One thing is for sure--a Barlow in front of the star diagonal would magnify so much that any scope cheap enough to have an uncoated lens would be being pushed WAY beyond its maximum usable magnification.

Star diagonals all vignette the image plane, but on refractors, the focuser drawtube does too, before the image even makes it to the diagonal.

It only matters if the vignetting is severe enough to be visible and if the eyepiece's field stop is large enough that it matters.

If done right, though, a VISUAL scope is fine with a 70% illumination at the edge of the largest field stop used.

A PHOTOGRAPHIC scope will need 100% illumination over the field of the chip if designed for that chip.  In practice, flat fields can eliminate a small amount of vignetting.

Most refractors these days (except the cheapest ones) are being built for photography.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.