Televue Nagler 2.5mm

[DRT]

Does anyone have any experience of using one of these?

I am considering one for high power through my 120ED but am concerned that the eye relief might be tight. I also don't get on well with eyepieces with small eye lenses so would be interested to see what one of these looks like from the top if anyone can post a picture please.

Thanks

Derek

[miguel87]

Barlow a 5mm? Keeps much better eye relief and larger eye lense.

My eyepiece collection is based on using a barlow to achieve more comfortable high magnification views.

A decent 5mm is also generally cheaper than a decent 2.5mm.

Mike

[DRT]

Thanks, Mike.

I have based my EP collection on not using barlows or Powermates so was looking for something really high powered. Having just checked the eyepiece calculator on the TV website the 2.5mm would be floater-tastic in my scopes with a sub 0.4mm exit pupil. I'll be leaving this one alone

[Stu]

I've used one of these but with shorter focal length fracs so the mag was not so insane. To be honest I think they are designed for the Genesis/TV101 type scopes which are 4" apos with short focal lengths (500 or 540mm). 2.5mm in these gives a very manageable x200 or x216, so the exit pupil remains useable.

As I recall, the eye relief is fine, and the exit lens quite large given the focal length. I agree though, not something which would suit your scopes.

[John]

I've owned the 2.5mm T6 Nagler. I bought it to complete the set a while back. It's just as nice as the other T6 Naglers of course but I found that the floaters in my observing eye were just too distracting to enjoy using it. It was also too much power for the scopes I had back then. The ED120 is a great scope and I do use my 3mm Radian (300x) quite often on tight double stars but I'm really not sure that 360x would be useful with the scope.

Along with the 2mm-4mm Nagler zoom, I reckon the 2.5mm Nagler was aimed at TV's short focal length refractors as Stu says.

[Piero]

I haven't used it directly, but with my TV60 F6 (FL:360mm) I used:

- PM2.5x + Nagler 7mm (=>2.8mm, e.p. 0.6mm, 129x)

- Bresser SA 2x + Vixen 5mm (=> 2.5mm, e.p. 0.4mm, 144x)

- PM2.5x + Vixen 5mm (=>2mm, ~0.3mm, 180x)

- Bresser SA 2x + Nagler3.5mm (=>1.75mm, ~0.3mm, 206x)

I could use them all with some success. However, floaters do not cause me problems and as you can see all those magnifications are within 'seeing permitting'. 

I think the highest magnifications at exit pupils of 0.3mm are still usable for splitting bright doubles of different colour. Of course this under excellent sky conditions. 

Although I have a short telescope, I would not buy a 2.5mm. I think it is too specific and I doubt it would sell easily in the SH market. 

Just an opinion of course. 

Piero

[DRT]

Thanks guys - you have confirmed my suspicions. Even in my TV Pronto the exit pupil would be 0.37mm and it would give a true FOV of less than half the Ethos 3.7mm so not even worth it for the smallest scope I have.

[alan potts]

I tried a 2.5mm some time back but not a TV and I got on with it fairly well, it is very much a personal thing and I do agree it may be hard to shift one if bought.

Alan

[rl]

I bought mine for use with an 80mm f/6 triplet and a 72mm f/5 ED doublet but found it virtually useless most nights. I was glad to move it on in spite of its pedigree. Eye relief for a 2.5mm was excellent but just too much magnification.

RL

[swamp thing]

Barlow a 5mm? Keeps much better eye relief and larger eye lense.

My eyepiece collection is based on using a barlow to achieve more comfortable high magnification views.

A decent 5mm is also generally cheaper than a decent 2.5mm.

Mike

And, if you find you don't really use the mag provided at least you can actually sell a barlow or powermate because people want them.