Nagler 5

[jeanlg 2]

Bonjour,

Que pensez-vous de cet oculaire ?
C'est pour un Dobson 380, F/D 4.5.

Merci

jeanlg

[Gordon 0]

Je l'utilise sur un Dobson 200/1200 et sur une TV76 et j'en suis plutôt content....
Piqué, grand champ et image OK jusqu'au bord, c'est beau.

[jeanlg 2]

Merci Gordon pour ta réponse
Donc sur F/D 6 c'est "beau", avec pupille de sortie de 0.8. Je me pose la question car un ami a testé le Nagler 4.8 avec le même instrument que le mien, l'adjectif qualificatif qu'il a utilisé pour décrire la capacité de cet oculaire sur le planétaire était éloigné de "beau" . D'ou ma question pour le Nagler 5...
jeanlg

[PierreJL 191]

Effectivement j'ai le Nagler 4.8mm.
Même si c'est trés agréable de regarder la Lune en grand champ j'ai trouvé qu'il manquait de contraste sur Jupiter notamment par rapport à un plossl clavé.

Est-ce que quelqu'un a comparé le Nagler 5 avec le 4.8 ?

[Ce message a été modifié par PierreJL (Édité le 07-02-2005).]

[Gordon 0]

Ouais, faudrait pouvoir comparer....

Y avait ça sur le site Company7 (http://www.company7.com/library/televue/orrtv5mmN.html) :

"Telescopes used for this comparison:

1. TeleVue 85mm F7 Apochromatic Refractor: 120x magnification
2. Astro-Physics 155 F7 Starfire Apochromatic Refractor: 218x magnification

Left: TeleVue 5mm Nagler Type 6 eyepiece (at right) next to original design 4.8mm Nagler eyepiece. (87,208 bytes)

The night is clear, clean, and dark. V-aquilae is a delight to behold. It is so red. Not the orange-color that forms from the low surface temperatures of so called red giant stars like Betelgeuse, Antares, and Aldebaran but the intense deep red of the tainted atmosphere of a carbon star. In a well corrected apochromatic refractor such as the 155mm AP at high power this star appears as a brilliant point of blood fixed against the black face of eternity itself. So what is wrong with me? Instead of enjoying this wonderful star as any normal amateur astronomer would -- here I am looking at it out of focus, barlowed absurdly at nearly 100x/inch of aperture, looking for the most subtle of differences between two, as near perfect eyepieces as you are ever going to find -- the 5mm Nagler and the 5mm Radian. This reviewer has got to get a life; whatever I am doing with an out-of-focused v-aquilae, it is not astronomy. This is not the best use of my time under a dark sky.

I enjoyed the 4.8mm Nagler for years. In its day, it set a new standard for short focal length eyepieces under 6mm. But times change. Radians dealt it a near fatal blow when they entered the market and I believe the 5mm Nagler type 6 will finished the job. Unlike the old and new 7mm Naglers, which when compared were at least close in testing, the cleaner image and much improved eye-relief of the 5mm Nagler sets it way apart from the old 4.8mm. The 4.8mm Nagler's main draw back was that the 7mm eye-relief (always seemed shorter to me) robbed me of the Nagler space walk feeling that I enjoyed with his other 82 degree F.o.V. eyepieces. I have heard it said that the 4.8mm is a lower cost alternative to the 5mm Nagler. It is not. With the 5mm Radian and the 5mm Nagler both currently available I can see no reason (including cost) for anyone to purchase a 4.8mm Nagler new.

[jeanlg 2]

Merci Gordon.