New EP delivered today!

[25585]

[Louis D]

I've got a 20 year old 9mm Vixen LV that I still use occasionally.  Very comfortable and sharp to the edge.  I'm sure you'll enjoy your 15mm version.  They're vastly undervalued on the used market, often going for $50 to $70 here in the states.  Mine was $90+ when new 20 years ago.

[25585]

36 minutes ago, Louis D said:

I've got a 20 year old 9mm Vixen LV that I still use occasionally.  Very comfortable and sharp to the edge.  I'm sure you'll enjoy your 15mm version.  They're vastly undervalued on the used market, often going for $50 to $70 here in the states.  Mine was $90+ when new 20 years ago.

This cost about £35 on ebay. I have a 10mm and 6mm already. 20mm in the mail. With my 32mm TV Plossl, they are my travel kit, all good eye relief and fit in a flak vest's pockets. 

[Highburymark]

Very nice - congrats

[25585]

20mm also arrived

[Louis D]

Impressive they still had the original box and caps all these years later.

[25585]

4 hours ago, Louis D said:

Impressive they still had the original box and caps all these years later.

Looks little used. More expensive than my 15mm was. Had I not got a TV 32mm Plossl, I would buy a 30 LV too. 

[Louis D]

1 hour ago, 25585 said:

Had I not got a TV 32mm Plossl, I would buy a 30 LV too. 

You do realize the 30mm LV is a 2" eyepiece with a 60 degree field so not really comparable to a 32mm 1.25" plossl with a 50 degree field?

[25585]

19 hours ago, Louis D said:

You do realize the 30mm LV is a 2" eyepiece with a 60 degree field so not really comparable to a 32mm 1.25" plossl with a 50 degree field?

Didn't. But as I also have a 35mm Panoptic, surely that must be better?!

I would like to try a 31mm Nagler as it's eye relief is 19mm. Need a store with it in stock. 

Edited October 6, 2017 by 25585

[Louis D]

3 hours ago, 25585 said:

Didn't. But as I also have a 35mm Panoptic, surely that must be better?!

I would like to try a 31mm Nagler as it's eye relief is 19mm. Need a store with it in stock. 

I'm sure the Panoptic is better.  However, if you were trying to complete a set, that would be a reason to buy it.  The 50mm LV is even more rare.

I have yet to try the 31mm Nagler for eye relief, but the original style 30mm ES-82 with the mushroom eyeguard is just usable with eyeglasses.  It's also sold as the Meade UWA and Celestron Axiom.  It's a little tight, but still doable to get a reasonably well corrected 82 degree field.

[25585]

I have a TV 55mm Plossl as finder ep mainly. Did not know a 50LV made. Considering the 41 though. 

[Louis D]

6 minutes ago, 25585 said:

I have a TV 55mm Plossl as finder ep mainly. Did not know a 50LV made. Considering the 41 though. 

I have the 40mm Meade SWA 5000 and find it to be basically perfectly corrected across the flat field with pinpoint stars from axis to edge, much better than the 30mm ES-82.  It also has sharp field stop.  Multiple reporters have agreed that the 41mm Panoptic is also sharp across the field but has a fuzzy field stop.  You might still be able to find the 40mm Maxvision equivalent new for much less than the Panoptic.  Its weight can be reduced significantly by decloaking it.

I was interested in picking up a 35mm Panoptic until I read that it has a curved field like the 14mm and 20mm Pentax XLs/XWs.  Have you noticed it having a curved field?

[25585]

Not noticed a curved field as such. I notice effects on smaller objects more than viewscapes though. 

Is a curved field most apparent when panning?

[John]

Here is the definition:

Field Curvature

If star images near the field’s center are in focus when those near the edge are not, and vice versa, then the eyepiece suffers from field curvature. This is a familiar effect for owners of Schmidt–Cassegrain telescopes, because the focal plane of such telescopes is not flat but strongly curved.

I guess this also shows why field curvature in eyepieces can actually improve the performance of the scope, as long as it is the opposite type to that which the scope itself delivers. If the eyepiece is delivering FC that adds to that which the scope delivers than things are not likely to be as satisfactory.

Edited October 7, 2017 by John

[Louis D]

4 hours ago, 25585 said:

Not noticed a curved field as such. I notice effects on smaller objects more than viewscapes though. 

Is a curved field most apparent when panning?

The curved field effect when panning is known as pincushion distortion.  It's also known as the rolling ball or globe effect.  Basically, the image is magnified more in the center than the edge.  It's still sharp and in focus everywhere, so it's not considered an aberration.

The curved field issue, as John did such a good job of defining and explaining, is when you can't bring the entire image into focus at once.  Young folks may not even be able to perceive it because of focus accommodation in their eyes.  I never noticed it in my 14mm Pentax XL 20 years ago, but I sure notice it now that I have presbyopia.  Basically, an object goes out of focus as it is moved from center to edge.  The image has to be refocused to make it sharp at the edge.  This assumes it's possible to do this.  An eyepiece with astigmatism at the edge may not be able to bring any object to a sharp focus at the edge no matter what position the focuser is set at.

[25585]

I notice curved field effect in binoculars a lot. In fact it (with eye relief) is deal maker or breaker when looking at new ones. With cyclops using my good eye, it's not bothered me. 

[25585]

SLV 25mm. 

Compared to the LV20mm, the SLV25mm has slightly less effective eye relief as the cup and more recessed eye lens make a difference, though marginal. With spectacles neither gives whole FOV, without both do - the SLV still needing it's cup at lowest position but avoids eyelash smear which LV does not. 

SLV is slightly heavier but easier to hold. 

Waiting for a decent night to test both out on the night sky now. 

[Louis D]

6 hours ago, 25585 said:

SLV 25mm. 

Compared to the LV20mm, the SLV25mm has slightly less effective eye relief as the cup and more recessed eye lens make a difference, though marginal. With spectacles neither gives whole FOV, without both do - the SLV still needing it's cup at lowest position but avoids eyelash smear which LV does not. 

SLV is slightly heavier but easier to hold. 

Waiting for a decent night to test both out on the night sky now. 

The LV eyecup can be rolled all the way down flush with the top of the eyepiece.  You're giving up 3mm to 5mm with it part of the way down as in your top photo.  I've measure my 9mm LV to have 18mm of usable eye relief with the cup rolled all of the way down.  It's very comfortable with eyeglasses to see the entire field.

[25585]

Bottom photo the LV's eye cup is rolled all the way down. Thankfully it still has a rubber rim that protects my spectacle lenses. Annoyingly the eye cup rolled down is too wide for its cap!

Have another 20 on the way from an ebay purchase for when I buy a bino viewer (model to be decided yet). 

Sadly it seems Vixen have decided that astronomy eps sell more profitably on AFOV width than eye relief - TV apart. This makes me wonder about the continuation of their SLV range. 

[25585]

13mm LVW & another 20 LV (for a future bino viewer). 

The LVW takes over from my Nagler 1 13mm. Former is way more comfortable to use, much lighter in weight & no kidney beaning. The eye cup pulls of, but doing so does not increase eye relief - but the cup rolls down. Eye relief is actually a better "20mm" than LV & (more definitely) SLV eps. More LVWs on search & buy list!

One minor irk is that the LVW's cap, as for LV range, is too narrow to go over a rolled down eye cup. Not a problem on the SLV. 

 

[John]

Nice Japanese glass

The Vixen rep at the astro show last month confirmed to me that the LVW's are definitely out of production now so pick them up while you can !

I asked if they had a successor planned and he pointed to the SSW's but I had to point out that they did not really fill the same niche. 

 

[25585]

No 22s as far as I can find, though there are a couple of 30s, but I prefer XW on read reputation.

I would swap my Nagler 13mm T1 for a LVW 22mm, but unlikely to happen......

[Louis D]

16 hours ago, 25585 said:

The eye cup pulls of, but doing so does not increase eye relief - but the cup rolls down. Eye relief is actually a better "20mm" than LV & (more definitely) SLV eps.

Yeah, I was really annoyed by having to roll down the stiff rubber eyecup of the LV series everytime I wanted to use it.  Occasionally, I'd slip and put a fingerprint on the eyelens.  The Pentax XL line (competitor at the time) could be stored cup down, so no issues using it straight out of the case.  That, and it screws up and down, so much easier to set the height than rolling.

FYI, can you measure the diameter of the eye lens?  The contemporary Pentax XLs (also 65 degrees) have 30mm eye lenses.  The XWs (70 degrees) have 35mm eye lenses by comparison.  The 9mm LV (50 degrees) has a 23mm eyelens.

16 hours ago, 25585 said:

One minor irk is that the LVW's cap, as for LV range, is too narrow to go over a rolled down eye cup.

Yep, my finding as well.  Thus, 20 years ago I went with Pentax.  Yes, the 14mm and 20mm have field curvature, but back then, I could accomodate it.  Even today, it's not bad because stars are pinpoint at the edge once refocused.

 

14 hours ago, 25585 said:

I would swap my Nagler 13mm T1 for a LVW 22mm, but unlikely to happen.....

I just picked up a smooth side Meade 14mm 4000 UWA recently.  With its 33mm eye lens, it is relatively easy to take in the entire 80 (measured) degree AFOV with eyeglasses.  Certainly much easier than with either a 12mm or 17mm Nagler T4.  I measured 17mm of usable eye relief and no SAEP (kidney beaning).  Stars are short, thin lines pointing back to center at the edge, but astigmatism seems well controlled, so it's just a function of the design.  It is also flat of field as far as I could discern.  Overall, not bad for a 30 year old design.

[25585]

LVW 42mm 2 inch. Penultimate of the LVWs I have bought. 

This will be interesting to compare with my TV 55mm Plossl & older Vixen 32mm 36.4 Erfle. Not too heavy, lighter than my 35mm Panoptic, which will also be tested alongside, on a suitable night. 

Need some 2 inch filters now!

Photo is with cup rolled down. 

 

Edited November 1, 2017 by 25585

[25585]

6 hours ago, Louis D said:

Yeah, I was really annoyed by having to roll down the stiff rubber eyecup of the LV series everytime I wanted to use it.  Occasionally, I'd slip and put a fingerprint on the eyelens.  The Pentax XL line (competitor at the time) could be stored cup down, so no issues using it straight out of the case.  That, and it screws up and down, so much easier to set the height than rolling.

FYI, can you measure the diameter of the eye lens?  The contemporary Pentax XLs (also 65 degrees) have 30mm eye lenses.  The XWs (70 degrees) have 35mm eye lenses by comparison.  The 9mm LV (50 degrees) has a 23mm eyelens.

Yep, my finding as well.  Thus, 20 years ago I went with Pentax.  Yes, the 14mm and 20mm have field curvature, but back then, I could accomodate it.  Even today, it's not bad because stars are pinpoint at the edge once refocused.

 

I just picked up a smooth side Meade 14mm 4000 UWA recently.  With its 33mm eye lens, it is relatively easy to take in the entire 80 (measured) degree AFOV with eyeglasses.  Certainly much easier than with either a 12mm or 17mm Nagler T4.  I measured 17mm of usable eye relief and no SAEP (kidney beaning).  Stars are short, thin lines pointing back to center at the edge, but astigmatism seems well controlled, so it's just a function of the design.  It is also flat of field as far as I could discern.  Overall, not bad for a 30 year old design.

Eye lens diameter is 27mm (just noticed cup fold is torn & lens has prev owners finger print)

The Nagler T1 eld is 25mm. Holding this venerable ep to my un-bespectacled eye, rigidly, I can see about 70 degs. Twitch my nose & less!