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Vixen 37mm Terrestrial adaptor

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#1 KennyJ

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Posted 11 April 2015 - 07:44 AM

Following many internet searches and queries over several years, my attempts to find any useful information or reviews on this item drew a complete blank.

 

I therefore believe this may be the first ever / only available mini-review of this item that has ever existed.

 

In keeping with the mystery and apparent secrecy surrounding the item, I chose to post this historic review right here, in a forum where these days I'll be surprised if anyone even bothers to read it!

 

Three years ago, the somewhat reluctant sale of my Zeiss 85mm Diascope left a gap in my options for daytime terrestrial viewing, with only my TeleVue 76 scope to replace it. I rate the optics of the TeleVue slightly higher than the Zeiss spotter, but have never really come to terms with either reversed images, or using a 45 degree erecting prism for terrestrial use. I've always prefered STRAIGHT THROUGH scopes, going back to my first ever drawtube 35x60 spotter from 50 years ago.

 

How much I missed the straight - through Zeiss scope was highlighted throughout a 2 week holiday last summer, at a rented elevated beach-side house on the mid Wales coast. The stunning views took in the entire panorama of Cardigan Bay, stretching from the high peaks of the Llyn Peninsular in the north west to Pembrokeshire in the south west. I spent many hours looking through my Nikon 10x42 SE and taking photos of perfect sunsets after 9.30pm.

 

The veranda overlooking the bay lends itself perfectly for a tripod mounted straight-through scope, with the front protective railing/ windshield terminating at around chin-height from a sitting position. We re-booked the holiday home for the last fortnight in June of this year, so a few weeks ago I decided to make definite attempt at purchasing a straight-through image erecting prism to use with the TeleVue 76, in spite of the continuing absence of any kind of review of any such product. Even an appeal in the Cloudy Nights refractors forum led to not a single response.

 

I could only find two suppliers of the Vixen Erecting prism in the UK, so after receiving confirmation the item was in stock, two weeks ago, I ordered and immediately paid for one ( via paypal ) from one of the two suppliers. When nothing arrived after 5 days I sent an email asking why, but received no reply. Alarm bells began ringing when after 9 days and still no delivery, a further two emails remained unanswered. I then contacted paypal to try to cancel the transaction, which to my delight was carried out within a couple of hours, with the paid fee returned into my account. Three days later I received an apologetic letter through the regular post. By a remarkable co-incidence, the company had ceased business on the very day I ordered the item. At least the company had the decency to apologise in writing and provide a full refund.

 

I then re-ordered the item from a company called The Astronomy Centre, and what difference in service!

 

The item arrived within 2 days, very securely packed, accompanied by a letter from the manager, thanking us for our business, his telephone number attached should we have any further queries.

 

I felt quite excited opening the package to find the item so carefully wrapped and in perfect condition.

 

However, as soon as I fitted it to the TeleVue 76 scope, one of my fears were confirmed. With it attached and my favourite TeleVue 18mm Radian eyepiece fitted, the scope wouldn't come to focus on anything closer than infinity, and probably not even then.

 

Carefully holding and moving the eyepiece closer to my eye, I realised the shortfall in tube length was around 6 inches.

Luckily, I have both a 2x and a 3x TeleVue Barlow lens, so by removing the actual lenses, I found the two empty tubes stacked provided just enough extra out-travel to provide crisp focus from around 15 feet close focus to infinity.

 

As shown in the attached photo, the resulting configuration DOES appear a little ungamely, to say the least, but in a way I quite like the unique, eccentric looks of it, reminiscent of the old drawtube scopes.

 

 

 

I'm also quite impressed with clarity of the image, which is every bit as sharp and pleasing to the eye as any I recall through the Zeiss Diascope. The focusser also allows for very precise, very slow focus.

 

Hopefully, come June, I will able to post some actual observing reports.

 

Kenny

 

 

 

 

 

Attached Thumbnails

  • TV 76 with Vixen TEP.jpg


#2 maugi88

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Posted 11 April 2015 - 08:51 AM

Nice. I prefer binos for terrestrial viewing but to each their own.



#3 KennyJ

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Posted 11 April 2015 - 09:09 AM

I also prefer binos for terrestrial use, generally speaking, but sometimes I like to take a "closer" look at things at magnifications greater than around 25x.

 

Binoculars with that level of magnification require PERFECT collimation, and to provide images of similar quality to the TeleVue scope, VERY fine optics indeed.

 

I can't really think of any STRAIGHT THROUGH binoculars that satisfy such criteria, and even if they do exist, I'm sure they would cost several thousand pounds!

 

By the way, I just measured the distance between the fully extended anti-glare / dew shield and the eyepiece and it's just short of 31 inches!

 

Kenny



#4 maugi88

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Posted 11 April 2015 - 09:26 AM

That is true.

 

That is one long spotter!

 

I have actually been pondering one of these. The price is keeping me away for now.

 

http://telescopes.ne...binoculars.html



#5 KennyJ

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Posted 11 April 2015 - 02:30 PM

Just to give a idea of the location, a couple of photos of the area, taken during last year's stay.

 

 

Attached Thumbnails

  • coastal path (600 x 400).jpg


#6 KennyJ

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Posted 11 April 2015 - 02:31 PM

Typical sunset:

 

 

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  • sunset from Holiday Cottage.jpg


#7 NGC704

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Posted 11 April 2015 - 06:49 PM

Curious: why the strong preference for straight-thru? I am very fond of the 45 degree erecting prism, which seems like it solves several problems at once, such as required tripod height, tube length, and that sort of thing.

 

Lovely veranda vista there - mind if I come with you? Ha ha, just kidding, but I am serious when I say I absolutely love lingering over good scenery with telescopes in daytime, and covet your Televue refractor a great deal!



#8 KennyJ

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Posted 12 April 2015 - 01:59 AM

NGC704

 

Thanks for your interest, comments and question.

 

Although I'm still a regularly active full time employee, with a job that requires a fair amount of physical effort, and am also a guitarist/ lead singer in a rock band that plays regular gigs, one stance/ posture that has long caused me problems with pain is what I call " the washing-up position", -- such as one engages whilst slightly leaning over a sink to wash up plates and cutlery following a meal.

 

I only need to adopt that position for around 30 seconds and I suffer for about 30 minutes immediately afterwards.

 

I've no idea what the cause of the problem is, but it's been with me for at least 30 years or so now.

 

It is almost exactly the same posture that needs to be engaged whilst leaning over and looking down into an angled ocular on a telescope during daytime use.

 

In addition to that, in the case of the veranda at this holiday accomodation, the height of the front "rail guards", which actually have clear, toughened plastic panels all the way along them, to protect against the wind and to prevent a small child or pet  from falling through the railings, is such that a straight- through scope can be horizontally aligned so as to be aimed right above it, and used from a comfortable sitting position, with the back remaining straight, whilst panning the entire panorama as required.

 

True, a 45 degree erecting prism "could" be used, from a seated position, with it effectively angled at 135 degrees from the true "line of sight", but I much prefer to be facing the same way as I'm looking, not least because I also often have binoculars attached to the same tripod, so as to alternate between views without having to move a limb.

 

It really is surprising how much activity is taking place in an area of sea that stretches for around 50 miles wide and as far as the visible horizon out towards Ireland. There are times when it appears to the naked eye that there isn't a single object to be seen, yet even through 10x binoculars, half a dozen small fishing boats can be seen along with frantic activity of sea birds etc.

 

Then there are the larger boats and more distant ships, with names that are much more easily read and their movements much more easily followed with a CORRECT image, as seen through binoculars, rather than via a reversed image.

 

I suppose one could simply say it's just MY preference!

 

Kenny



#9 KennyJ

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Posted 12 April 2015 - 09:34 AM

One thing I've noticed by adding the necessary extension tubes to achieve focus is the exit-pupil has decreased with the TeleVue Radian 18mm eyepiece, from just over 2.8mm to noticeably below 2.5mm.

 

This equates to a magnification increase from around 26.6x to around 32x, which I consider to be a little bonus.

 

This just about what I consider to be "optimum magnification" for a 76mm refractor in medium to bright daylight over water on warm days. Experience has shown me that much higher than this is more or less "wasted" due to the increased effects of heat haze etc. while 32x magnification is just enough to provide that "wow" factor so difficult to describe by words alone.

 

Also, I'm presuming the extension tubes have also increased effective focal ratio, from f6.3 to something around f8.

 

Of course, my interpretations of the basic optics theory I've understood could be some way off the mark, but led me to base this on the fact that I've increased the focal length by around 140mm, which added to the 480mm standard spec. of the scope, gives a focal length of 620mm. This divided by the objective diameter of 76mm. gives a figure just above 8.1.

 

This may explain why any degrading of image quality suffered as a result of the erecting prism appears to be countered, at least to some extent, by the less noticeable aberrations resulting from the increased focal ratio.

 

Thus far, I've certainly not seen the slightest hint of CA, at least not at around 32x magnification, and of course this is a true APO objective lens, after all.

 

Kenny



#10 maugi88

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Posted 12 April 2015 - 09:41 AM

Gorgeous vistas.



#11 maugi88

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Posted 12 April 2015 - 09:49 AM

NGC704

 

Thanks for your interest, comments and question.

 

Although I'm still a regularly active full time employee, with a job that requires a fair amount of physical effort, and am also a guitarist/ lead singer in a rock band that plays regular gigs, one stance/ posture that has long caused me problems with pain is what I call " the washing-up position", -- such as one engages whilst slightly leaning over a sink to wash up plates and cutlery following a meal.

 

I only need to adopt that position for around 30 seconds and I suffer for about 30 minutes immediately afterwards.

 

I've no idea what the cause of the problem is, but it's been with me for at least 30 years or so now.

 

It is almost exactly the same posture that needs to be engaged whilst leaning over and looking down into an angled ocular on a telescope during daytime use.

 

In addition to that, in the case of the veranda at this holiday accomodation, the height of the front "rail guards", which actually have clear, toughened plastic panels all the way along them, to protect against the wind and to prevent a small child or pet  from falling through the railings, is such that a straight- through scope can be horizontally aligned so as to be aimed right above it, and used from a comfortable sitting position, with the back remaining straight, whilst panning the entire panorama as required.

 

True, a 45 degree erecting prism "could" be used, from a seated position, with it effectively angled at 135 degrees from the true "line of sight", but I much prefer to be facing the same way as I'm looking, not least because I also often have binoculars attached to the same tripod, so as to alternate between views without having to move a limb.

 

It really is surprising how much activity is taking place in an area of sea that stretches for around 50 miles wide and as far as the visible horizon out towards Ireland. There are times when it appears to the naked eye that there isn't a single object to be seen, yet even through 10x binoculars, half a dozen small fishing boats can be seen along with frantic activity of sea birds etc.

 

Then there are the larger boats and more distant ships, with names that are much more easily read and their movements much more easily followed with a CORRECT image, as seen through binoculars, rather than via a reversed image.

 

I suppose one could simply say it's just MY preference!

 

Kenny

I have the same problem. A slightly forward leaning position very quickly puts my back muscles into spasm and intense pain. Mine is all muscular but once started it takes hours to get them to relax again. I have had it last for days, and then I have to go to the doc to get muscle relaxers.

 

Much better to avoid the situations that start that roller coaster in motion.



#12 NGC704

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Posted 12 April 2015 - 10:20 AM

You certainly make good points. From a posture standpoint I can see the charm of straight-thru viewing. I actually very much prefer to keep a spine straight, chest out, shoulders back posture that both Mother and Chiropractor would approve of to the greatest extent possible. I don't have any undue back/spine issues, but have always been keen to avoid them just the same.

 

32X is actually quite a lot of magnification for terrestrial 'scoping. Not saying too much, just that any higher would be pretty low on my own priority list. While it's always fun to jack up the power for play, for general use I'd say you have quite an enviable set up.

 

I definitely insist upon correct images for terrestrial viewing, and any reversal is intolerable. I also believe in correct-image views in finder scopes, keep a cheap 80mm ST refractor with 45 degree prism and 20X Erfl on my 16" f/5 dobby. I find the 45 prism "priceless" in that role, and correct image makes using it for star hopping a breeze. I have an identical ST 80 outfit for terrestrial use, and use it often. Optical quality may not be the best, but certainly beats having no easily portable 20X80 scope.



#13 KennyJ

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Posted 12 April 2015 - 02:34 PM

Another of my favourite sunset snapshots from last year.

 

I can hardly wait to get there again, now!

 

 

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  • sunset 2.jpg


#14 mooreorless

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Posted 12 April 2015 - 06:28 PM

Hi Kenny,  I am really glad you found what you need for your TeleVue 76 telescope. I never even knew about this Vixen erecting straight thru prism. I found this on a site, I did look to see if our host had the same thing with no luck.

http://www.bhphotovi...rect_Image.html

 

I am not bothered by the reverse image and sadly not bothered by washing dishes. I have not needed to read anything so far using both of my ED refractors and find them excellent for land use.  I would like to get the TeleVue 60° erecting diagonal. The 45° diagonal does sort of bother me sometimes. Excellent view there and Kenny and pictures! I do have  the Nikon 50ED, soon to be put up for sale Nikon 60ED Fieldscope and a Brunton Icon 20-60x80 ED spotter if need be.


Edited by mooreorless, 12 April 2015 - 06:31 PM.


#15 KennyJ

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Posted 13 April 2015 - 12:44 AM

Hi Steve,

 

I'm pleased you happened to stumble upon this thread.

 

Your declaration of not being bothered by reverse images did surprise me a little bit. No wonder you struggled to read vehicle registration plates from a distance of 5 miles! :grin:

 

I've decided that for this to qualify for truly eccentric - looking scope status, it requires a further extension to the front end by way of home-made dew shield, 12 inches long, to result in a 42 inch end to end finished product! :lol:

 

Kenny



#16 mooreorless

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Posted 13 April 2015 - 08:38 AM

Hi Kenny,

 

I always check Cloudy Days on here and saw your post of course!!  I guess I am ok with reversed image with my 100ED and 80ED refractors because I am used to being able to use them I guess and both of these have excellent images. I sort of hate to go back to the spotters. I  can see an overlook from my place that is 2.8 miles away  and have pictures of that. I have never been able to read license plates , I just see the sides of vehicles. I will send a picture of one to you when I get time. I found this again and hope you don't mind!  ;)

 

http://www.cloudynig...-at-five-miles/

 

Yes, by all means make up a home-made dew shield and take a picture!



#17 KennyJ

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Posted 13 April 2015 - 02:18 PM

Thanks for providing that instant link, Steve.

 

Believe it or not, I've just spent a wonderful hour re-reading the entire thread, and with the benefit of hindsight, now consider it to be truly one of the greatest optics discussions of modern times! ;)

 

Whatever happened to all those great participants in such debates? :bawling:

 

Kenny



#18 mooreorless

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Posted 13 April 2015 - 08:06 PM

Kenny,  I reread some of that thread tonight and agree with you. It is sad we don't have the participants like before.I forgot about  the fellow Wolf and his post on there.  Although I don't miss that awful picture I posted.



#19 mooreorless

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Posted 14 April 2015 - 03:51 AM

Here is a picture I took of that overlook 2.8 miles away ,  I don't think I could read license plate at that distance. I didn't try an eyepiece.

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  • doe and overlook site 014crop (Large) cloak.jpg


#20 mayidunk

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Posted 14 April 2015 - 08:52 AM

Excellent photos, Kenney!  I love that you were able to get enough back-focus on that scope, and was curious if the increased focal length might have negatively affected the lens' performance.  Good to know that it actually improved its performance by decreasing the exit pupil diameter, which definitely helps Sunlight constricted pupils.

 

That's a nicely written review, thanks for posting it!  :grin:



#21 mooreorless

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Posted 18 April 2015 - 04:05 AM

I don't quite understand what you are saying.  I can not speak for Kenny,  but I am talking about anything posted on Cloudy Days about using spotting scopes, astro scopes, binoculars etc. for daytime use and there were a lot more people that posted about that on Cloudy Days. Sorry if you were offended by any of this. I guess a lot of people have never read this part of Cloudy Days. It is sad that Mike left the site.

 

http://www.cloudynig...to-cloudy-days/



#22 maugi88

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Posted 18 April 2015 - 09:32 AM

Alright, I misunderstood. Deleted it.



#23 KennyJ

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Posted 18 April 2015 - 02:38 PM

Steve,

 

I think that is quite a remarkable photo, considering it was taken from 2.8 miles away.

 

A bit more magnifcation and a touch better resolution and I reckon that vehicle's license plate could just about be read.

 

Mind you, there IS a big difference between 2.8 miles and 5 miles, across land.

 

I never got to see maugi's deleted post, by the way.

 

Yes, it is sad that Mike left.

 

I wonder what he's up to these days?

 

I recall he went to start living a completely different lifestyle, in some kind of commune, didn't he?

 

Kenny



#24 mooreorless

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Posted 18 April 2015 - 05:35 PM

Kenny,

 

Thanks for the compliment! 

 

I think you are right about a commune or different lifestyle that Mike said something about. I am afraid I can find no posts on here by Mike or that other site, non by you as well on that other site. I used to be able to see some. I have used an eyepiece in the Orion 100ED and was able to see a group of people good enough that I might recognize them if I saw them shortly after this. The road that goes up to that look out either comes down to a road about 200 yds. away from my place or 2 other places no where else. I thought to put a license plate up there but thought better of it, esp. if one of my old ones. There is a Hawk Watching site up there, it is a rough walk from the parking area, lots of rocks, big and small. I have info on that if you are interested with pictures of my son when he was a little younger. This is on another site.

 

Maugi I sort of understand why you posted the way you did.  We just miss the old days and friends that used to post .  I think you would of liked it as well.



#25 KennyJ

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Posted 21 April 2015 - 04:25 PM

We've been blessed with two or three crackingly clear, warm sunny days here, but I've been so busy catching up with much needed outdoor D.I.Y projects that until this evening found no time to take even a quick look through the TV 76 with this prism fitted.

 

I probably wouldn't have bothered even then had it not been for the fact that I spotted a very colourful low-flying leisure balloon hovering about 200 feet high, around half a mile north of our house.

 

I quickly dragged out the tripod with scope attached, and within two minutes was trying to make out if I recognised any of the faces of the three people stood in the basket.

 

I must report though that on more careful judgment, I think my initial comment on how good this prism is was misleading.

No way, I thought, was the image anything like so clear as it would have been using the standard TeleVue diagonal.

 

Then suddenly I thought to myself " That balloon is going nowhere fast, so why not compare the two -- right now?"

 

Within five minutes my suspicion was confirmed --  the convenience and relative physical comfort of straight through viewing is coming at a considerable price in terms of loss of optical quality. Through the straight through prism, there appears to be a darkening and fuzziness of the image on axis.

 

A few minutes later, the balloon had drifted much closer to our house, but to the north east, so I quickly grabbed the Nikon 10x42SE and immediately thought to myself "now THAT is SO much better"!

 

Granted the balloon now was probably no more than 300 yards from me, so roughly a third the distance it was when looking at it through the scope, and it was a bit lower too, but I could see more detail through the 10x binoculars than I did even through the scope with the diagnonal fitted.

 

On such a clear evening, it's hard to put the difference down to just the nearer distance negating atmospheric conditions, but I'm already well aware that shorter distances always bring out the best in any optical instrument.

 

 I wonder if this is why MICROSCOPES appear to be so in vogue on this forum these days? :)

 

Kenny




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