Rate Tele Vue T4 17mm

circumpolar (Matt) · #1 20-06-2007, 08:23 PM

I'm interested in comments regarding this EP. I have read that it is one of the jewels in the Nagler series. As the T4's are not Scaled, it is difficult to compare to the others in the series. I believe the eye relief is close to that of Radians.

This just might be my first Nagler purchase so I need some feedback. The 17mm focal length is what I need.

Please give your thoughts regarding any aspect of the EP, including the weight, size and that click stop insta-adjust eye guard which some people seem to hate with passion.

Thoughts...

Satchmo · #2 20-06-2007, 11:20 PM

Matt, from past experience I'd rate this EP as my favorite as it seems to hit a sweet spot with F5 scopes and you can just leave it in for so many different kind of objects. The 82 degree field gives it a true field equal to a lower power, and exit pupil is still big enough to give a very rich field. The eyerelief is great. The 'instaguard' is easily dealt with...unscrew it and stick it in the draw! Makes the EP a lot more compact too.

Sentinel · #3 21-06-2007, 08:12 AM

Quote:

Originally Posted by Satchmo

Matt, from past experience I'd rate this EP as my favorite as it seems to hit a sweet spot with F5 scopes and you can just leave it in for so many different kind of objects. The 82 degree field gives it a true field equal to a lower power, and exit pupil is still big enough to give a very rich field. The eyerelief is great. The 'instaguard' is easily dealt with...unscrew it and stick it in the draw! Makes the EP a lot more compact too.

I have a 17mm T4 and a f5 scope. This eyepiece spends 80% of time in my scope. With Paracorr I get 114x.

This is a great eyepiece.

Paul Kemp
13.1" Reflector
Auckland, New Zealand
36° 55' 09" South, 174° 43' 30" East

-- The Southern Sentinel --

Website http://homepages.ihug.co.nz/~michellekemp

Rodstar (Rod) · #4 21-06-2007, 08:24 AM

Hey Paul, Welcome to IIS! I notice that you have just posted for the first time.

I had a look at your website....very cool. I laughed when I saw you have a penchant for observing lists (just like me).

I notice you do a lot of your observing at about 115x. I find that to be an excellent magnification as well, although with my recent increase in aperture to 20", I am planning to get a 17mm Nagler + Paracorr, which should give me about 170x. AT the moment I use a 22 Panoptic as my workhorse, and it gives about the same mag as you seem to enjoy.

astropolak (Joe) · #5 21-06-2007, 08:30 AM

I use one in F10 SCT, great eyepiece. Actually great in every scope I tested it in. Very heavy. Takes time to learn to look through it to get the whole 82Deg. I like it so much I just bought a 22mm T4.

One thing I do not like in them is the distance of the field lens from the outer rim of the barrel - way to close to the edge making accidental damage a real possibility.

Joe

janoskiss (Steve H) · #6 21-06-2007, 11:21 AM

Very nice EP. Only complaints are that it's very heavy indeed, and there is some aberration of the exit pupil, which for me means that I can only get about 75 degrees of FOV. If I get my eye close enough to the lens to see the edge of field, the centre of field starts to go dark. The T5s and T6s are much better in this regard. Many other users don't have this problem though, so try for yourself.

xstream (John) · #7 21-06-2007, 12:30 PM

17mm T4 in my opinion is one of Al's best, It's excellent!

As for the Inst-adjust I happen to like that feature in the T4's, I find it makes for nice and easy eye placement.

I can say you won't regret buying it.

circumpolar (Matt) · #8 21-06-2007, 06:27 PM

Great feedback guys. Keep it coming.

Tamtarn · #9 21-06-2007, 07:21 PM

Quote:

Originally Posted by xstream

As for the Inst-adjust I happen to like that feature in the T4's, I find it makes for nice and easy eye placement.

We totally agree with John, using the Inst-adjust stopped out at 5 stops we find it is perfect for our eye placement.

It is our most used eyepiece giving stunning views on all DSO's and when used
with our Orion Deluxe 2" Barlow it becomes a super high power ep.

casstony · #10 21-06-2007, 08:12 PM

I think insta-adjust shifted to easily on the early eyepieces and got a bad reputation at that time, but it's been stiffened on more recent eyepieces. I can pick up my 22 Nagler without the housing shifting, unless I give it a slight shake. I keep the insta-adjust in the home position and could even use another mm or 2 of eye relief; I guess the preferred setting depends on whether you've got a face shaped like an owl or a face shaped like a witch

AstroJunk (Jonathan) · #11 21-06-2007, 09:59 PM

Like others, My fave! Paracorr makes it even better.

Instaguard is a must because the eye relief is way too much for us non-spectacle wearers.

It works very well with the big barlow too, so you get a superb 9(ish)mm thrown in as well - what a bargain.

circumpolar (Matt) · #12 22-06-2007, 06:50 AM

Quote:

Originally Posted by Tamtarn

It is our most used eyepiece giving stunning views on all DSO's and when used
with our Orion Deluxe 2" Barlow it becomes a super high power ep.

How do you counter balance when using your Dob?

Quote:

Originally Posted by AstroJunk

It works very well with the big barlow too, so you get a superb 9(ish)mm thrown in as well - what a bargain.

Exactly!
I was aiming on using my TV big barlow when needing around X176 mag but now have to setup a counter weight system. This why I'm choosing this focal length as my first Nagler.

Sentinel · #13 22-06-2007, 09:41 AM

Quote:

Originally Posted by Rodstar

Hey Paul, Welcome to IIS! I notice that you have just posted for the first time.

I had a look at your website....very cool. I laughed when I saw you have a penchant for observing lists (just like me).

I notice you do a lot of your observing at about 115x. I find that to be an excellent magnification as well, although with my recent increase in aperture to 20", I am planning to get a 17mm Nagler + Paracorr, which should give me about 170x. AT the moment I use a 22 Panoptic as my workhorse, and it gives about the same mag as you seem to enjoy.

Thanks for looking.

There has been a lot of people from Ice in Space joining my Yahoo Group NZ Astronomers fin recent weeks, so I thought I better have a look. What an excellent community.

I still think that if you can get a combination of about 100x to 120x with your new scope, you will use this combination more, than 170x. This is mainly to do seeing and preference though.

The seeing here in NZ is regularly average to poor and I like the steadier views of the lower power and FOV.

Paul Kemp
13.1" Reflector
Auckland, New Zealand
36° 55' 09" South, 174° 43' 30" East

-- The Southern Sentinel --

Website http://homepages.ihug.co.nz/~michellekemp

Tamtarn · #14 22-06-2007, 09:52 AM

Matt we have a 120mm cooling fan mounted on a ply wood base so that gives us our counterbalance.

The easiest way to counterbalance is to use old sound speaker magnets they certainly do the job.

MarkN · #15 22-06-2007, 11:53 PM

Have to say that I don't like the 17T4 in my 8" LX90. The outer 15 percent or so is just not sharp and clear. I much prefer the 18 mm Radian because of its more compact dimensions and lighter weight. A very agreeable and fully useable 60 deg. AFOV.

In a Newtonian it's a different story. Stunning, immersive! You just run out of superlatives. Put an OIII filter on your 17 and line up the "Tarantula" in the LMC. If Hell exists at all I'm sure it must be there! It looks like something out of Dante's "Inferno".

Mark.

ausastronomer (John Bambury) · #16 23-06-2007, 06:33 PM

Quote:

Originally Posted by AstroJunk

Like others, My fave! Paracorr makes it even better.

I agree with your comments re the Paracorr. This eyepiece really benefits being combined with a paracorr in any newtonian faster than F5. In the 18"/F4.5 Obsession it works beautifully when combined with the paracorr.

CS-John B

circumpolar (Matt) · #17 23-06-2007, 09:05 PM

Bintel sell this one for$499.
Televue PCV-2000 Paracorr coma corrector visual.

There is no mention of it's weight. Just wondering if any knows if it's weight is similar to the TV Big Barlow which I have? Also what is the magnification effect? X0.3 maybe

AstroJunk (Jonathan) · #18 23-06-2007, 09:15 PM

Quote:

Originally Posted by circumpolar

Bintel sell this one for$499.
Televue PCV-2000 Paracorr coma corrector visual.

There is no mention of it's weight. Just wondering if any knows if it's weight is similar to the TV Big Barlow which I have? Also what is the magnification effect? X0.3 maybe

It's magnification is 1.15x which is purely to push the focus out so you 'shouldnt' have to alter your optics (I had to shorten my trusses by 2cm).

It is heavier than the BB by about 75g at 450g (ish!)

circumpolar (Matt) · #19 23-06-2007, 09:17 PM

I suspect that my Big Barlow will tighten up the edges of the image, but with added mag though.

anj026 · #20 27-06-2007, 03:27 PM

I have just purchased this eyepiece and only had it for a couple of days. I bought it for the 2.5mm exit pupil and wide field in a 90mm f6.9 refractor. I have read great reviews of this eyepiece used in a Televue 85.

First impressions;
It is heavy and the field lens is close to the edge of the barrel but no worse than a camera just different to other eyepieces.
Quality is first class. The instadjust seems to serve a purpose especially for those not used to such a wide field of view (me!). It takes time to get used to placing the eye correctly.

Last night I used it for the first time in the dark and was very impressed. Sharp to edge in the 90mm f6.9 and a nice dark field viewing from my back yard in suburbia with a bright moon. I tried it in the 6"f15 (137x and 1.1mm exit pupil) and was impressed with the contrast. The wide field and great eye relief make it more comfortable to use than a 15mm plossl. I observed great detail on the moon and a Jovian moon shadow in transit. Ultimately I would expect the plossl to be a better planetary eyepiece but only when the seeing is better than average. I look forward to using this eyepiece more.