Nagler 2.5mm

[Stussy76]

Hi all.

I'm quite new here and also new to serious visual observation. 

I recently bought a 8" dobsonian with starsense, I've bought a few eyepieces, a Luminos 23mm, tv De-lite 9mm and a tv 2" barlow. 

I saw a tv Nagler 2.5mm on ebay and offered 180 for it when he had it up for 250.

He accepted much to my surprise but then I also started reading about the difficulties I will probably encounter with this eyepiece. 

Have I just wasted my money or will I be able to use it or just cut my losses and resell it.

Thank you. 

[Ags]

The reputation of the Naglers speak for themselves. I am not sure what difficulties you are referring to, but I think the eyepiece will be useful on some nights of good seeing. It should be fabulous on the Moon on the right night. In any case you should be able to sell it for what you paid, so no harm trying it out for a few sessions!

[Stussy76]

3 minutes ago, Ags said:

The reputation of the Naglers speak for themselves. I am not sure what difficulties you are referring to, but I think the eyepiece will be useful on some nights of good seeing. It should be fabulous on the Moon on the right night. In any case you should be able to sell it for what you paid, so no harm trying it out for a few sessions!

Thank you, I'm hoping for the same.

It's only the fact that I read a few posts on here and cloudy nights that has put doubt in my mind.

I'm very exited to try it!

[Coolhand1988]

3 hours ago, Stussy76 said:

I saw a tv Nagler 2.5mm on ebay and offered 180 for it when he had it up for 250.

He accepted much to my surprise but then I also started reading about the difficulties I will probably encounter with this eyepiece. 

 

Hi

I have this seller on my watchlist.

Some of the items are fairly low in price, others items are over the top.

I might make an offer on something small the seller has!

The only downside to Naglers for me is their short eye relief. Only the 22mm and 31mm has the highest ER of 19mm. Which is probably on the lowest border for observing with glasses.

However, it's a Televue, they will always sell at reasonable price.

Thanks

 

Edited November 22 by Coolhand1988
added extra Eyepiece

[Mr Spock]

You won't get much use with an 8". x480 is too much.

When seeing is perfect I've used x461 (3.3mm TOE) on my 12" and it was sharp. I wouldn't go higher though, and mine is a very good 12"!

If you are going Nagler then the 5mm T6 would be ideal. 

[Louis D]

The biggest problem I run into using a 2.5mm eyepiece with most scopes is the resultant tiny exit pupil.  My prodigious floaters get in the way of the tiny beam of light making it to my retina.  This gets annoying in a hurry.

[Oldfort]

Look at it as an investment for the future.  If you take to this hobby, then you will probably buy at least one more scope, and if you then want something more portable, it will be quitte a bit smaller than an 8" dob.  That's when the 2.5mm Nagler will shine.

OTOH, if you don't pursue astronomy, you will probably sell up everything so no hame done.

[Stussy76]

12 hours ago, Coolhand1988 said:

Hi

I have this seller on my watchlist.

Some of the items are fairly low in price, others items are over the top.

I might make an offer on something small the seller has!

The only downside to Naglers for me is their short eye relief. Only the 22mm and 31mm has the highest ER of 19mm. Which is probably on the lowest border for observing with glasses.

However, it's a Televue, they will always sell at reasonable price.

Thanks

 

Yes I was worried about the eye relief too.

I had been watching a few of this guy's eyepieces, had made an offer on a barlow which they refused, I was a little worried about their feedback but they posted it within the hour and communication was good.

I'll let you know what it's like when it arrives. 

[Coolhand1988]

22 hours ago, Stussy76 said:

Yes I was worried about the eye relief too.

I'll let you know what it's like when it arrives. 

Hi

Yes, Televue advertise distance of eye relief should by exact. I have read some manufactures exaggerate more ER than the claimed distance.

Please let us know about your upcoming Nagler eyepiece and your experience with the seller.

Thanks

 

[Mircea]

Stussy76

I have and use a TMB Planetary 2.5mm eyepiece when the seeing is good enough.

The usefulness of any 2.5mm eyepiece depends on your observational interests, the possible uses being however quite narrow.

I gathered some experience with the 2.5mm eyepiece on my 200mm and 250mm Dobsonian telescopes.

For subarc double stars, planetary nebulae and immersive views of globular clusters, the said eyepiece is, sometime, useful.

The easiest use is on globular clusters where it can be used quite often.

On some planetary nebula even this eyepiece could be not strong enough. Anyway, forget about combining this eyepiece with UHC- like filters. It can be used only alone ... ''dry, on rocks''.

The most demanding use is on subarc double stars where the seeing is the King.

If the reflector  is a Dobsonian, to be able to use a 2.5mm eyepiece, one should know very well all the idiosyncrasies of that telescope. It should be used in pair with a ''finder'' eyepiece of 4mm or 5mm. If you will use longer ''finder'' eyepieces, probably you will lose often the targets. So, also the finder of the telescope should be spot on.

Good luck, Mircea

[Stussy76]

20 hours ago, Coolhand1988 said:

Hi

Yes, Televue advertise distance of eye relief should by exact. I have read some manufactures exaggerate more ER than the claimed distance.

Please let us know about your upcoming Nagler eyepiece and your experience with the seller.

Thanks

 

I most definitely will. I'll hopefully be receiving it tomorrow and accuweather says viewing conditions will be good.

[Stussy76]

19 hours ago, Mircea said:

Stussy76

I have and use a TMB Planetary 2.5mm eyepiece when the seeing is good enough.

The usefulness of any 2.5mm eyepiece depends on your observational interests, the possible uses being however quite narrow.

I gathered some experience with the 2.5mm eyepiece on my 200mm and 250mm Dobsonian telescopes.

For subarc double stars, planetary nebulae and immersive views of globular clusters, the said eyepiece is, sometime, useful.

The easiest use is on globular clusters where it can be used quite often.

On some planetary nebula even this eyepiece could be not strong enough. Anyway, forget about combining this eyepiece with UHC- like filters. It can be used only alone ... ''dry, on rocks''.

The most demanding use is on subarc double stars where the seeing is the King.

If the reflector  is a Dobsonian, to be able to use a 2.5mm eyepiece, one should know very well all the idiosyncrasies of that telescope. It should be used in pair with a ''finder'' eyepiece of 4mm or 5mm. If you will use longer ''finder'' eyepieces, probably you will lose often the targets. So, also the finder of the telescope should be spot on.

Good luck, Mircea

I'd had no inkling that I'd be able to use the 2.5mm for nebula and clusters.

I definitely don't know all the idiosyncrasies of my scope yet but hopefully with a few clear nights the learning will be quick.

Many thanks.

[Stussy76]

On 22/11/2024 at 02:25, Louis D said:

The biggest problem I run into using a 2.5mm eyepiece with most scopes is the resultant tiny exit pupil.  My prodigious floaters get in the way of the tiny beam of light making it to my retina.  This gets annoying in a hurry.

Mmm, yes I also struggle with floaters, they're that bad I've contemplated having laser treatment on them but it says that the risk outweighs the benefit. So from what your saying it's not looking to promising. 

Thanks. 

[Mircea]

I have also troubles with floaters. But I haven't seen any more difficulties with the 2.5mm eyepiece than with any other strong eyepiece.

The seeing is the decisive factor. If the seeing is good, to use the 2.5mm eyepiece is like the 3mm Radian or 3.2mm TS Planetary.

I was referring only to planetary nebula, not diffuse nebula. 

 

Good luck, Mircea

[Louis D]

12 hours ago, Stussy76 said:

I'd had no inkling that I'd be able to use the 2.5mm for nebula and clusters.

Small, bright things.  Planetary nebula, globular clusters, and close doubles are all good targets for highest power eyepieces.

[Louis D]

12 hours ago, Stussy76 said:

Mmm, yes I also struggle with floaters, they're that bad I've contemplated having laser treatment on them but it says that the risk outweighs the benefit. So from what your saying it's not looking to promising. 

Thanks. 

Binoviewers are your friend then.  I use them for high power viewing of bright objects like the full moon and Mars at opposition.  Instead of being washed out and lacking detail, they come alive with detail and don't overwhelm with brightness.  And, the brain's visual processing center will do a decent job of filtering out floaters, combining the best of the two views into a single, much better view.  It's still not perfect if floaters are interfering in the same region in both eyes, but it is much improved.

[Coolhand1988]

The last few posts reminded me of a thread I started last year.

I have yet to find out, what eyepieces become unsuitable when my floaters will become a problem. I have a large one, in no other than my right eye.

I was also advised about binoviewing.

And I was also advised from the eye doctor about the risk of getting them removed, not by laser though.

Looking forward to hearing your overall thoughts on the 2.5 Nagler.

Thanks

 

 

 

 

 

 

[Stussy76]

Hello all.

Just an update on the 2.5mm eyepiece. 

I got it the day before yesterday, the seeing was very good, I'd been getting some amazing views with my 9mm de-lite so I tried the 2.5.

The view of Jupiter was so dull and I was unable to get it anywhere near focused.

I was thinking that it must've been dirty but after a clean with some lens cleaner but it was just the same.

I messaged the seller and they said to just return it for a full refund.

So to make myself feel better I've just bought a es 82° 30mm off Aliexpress after reading some good things on here and cloudynights about the Aliexpress ones.

Thanks for all your advice. 

[Louis D]

30 minutes ago, Stussy76 said:

The view of Jupiter was so dull and I was unable to get it anywhere near focused.

I was thinking that it must've been dirty but after a clean with some lens cleaner but it was just the same.

Without something like a known good 2x Barlowed 5mm combination to compare against, you really can't make any sort of final judgement call.  More than likely it is just to much magnification for the scope and/or seeing conditions.  Try it indoors with a high contrast target like graph paper or a ruler.  Also, star test it against a medium bright start.  Bad seeing conditions will show up as an unstable image, possibly boiling looking.

[Stussy76]

It wasn't really the inability to focus that was the main problem it was the dullness of a very bright Jupiter that had me thinking there was something amiss, it was blinding in 9mm     de-lite.

Anyway it's been returned now and I'll get a 5mm Nagler when I can afford it after buying the es 30mm.

Thanks.

[John]

Jupiter's features do get washed out if too much magnification is used. 

I'm finding 120x - 180x gives the best views of the giant planet currently. The 9mm Morpheus would be "just right" with your 8" F/6 dob I would think. 

Saturn or Mars might have been more receptive although 400x plus is pushing things even under excellent seeing conditions.

[Coolhand1988]

Thanks for the testing of the 2.5mm Nagler.

480x with an exit pupil of 0.42mm, the view would of been much dimmer, compared to your 9mm delite( 133x exit pupil 1.5mm).  It was probably the high magnification, the smaller exit pupil and Jupiter.

I have to ask, how was your eye floaters at that exit pupil and magnification using the 2.5mm Nagler?

The 5mm Nagler should be much better and comfortable for Jupiter.

I await your verdict on that one.

Cheers.

 

[Ags]

I don’t think Jupiter was the right target to test the 2.5. In my experience it doesn’t benefit greatly from increased magnification, and the subtle shadings become invisible if the view is too dim. The Moon would be a better target, or tight doubles.

[Mr Spock]

x180 is ideal for Jupiter. x480 is way too high which is why you saw what you saw. I only go to x180 on Jupiter in my 12". 

I do use a variable polariser though. If you don't get the brightness right it will wash away all the fine detail.

[Stussy76]

8 hours ago, Coolhand1988 said:

Thanks for the testing of the 2.5mm Nagler.

480x with an exit pupil of 0.42mm, the view would of been much dimmer, compared to your 9mm delite( 133x exit pupil 1.5mm).  It was probably the high magnification, the smaller exit pupil and Jupiter.

I have to ask, how was your eye floaters at that exit pupil and magnification using the 2.5mm Nagler?

The 5mm Nagler should be much better and comfortable for Jupiter.

I await your verdict on that one.

Cheers.

 

Hi, surprisingly they were no more noticeable than any of my other eyepieces.