Lunette pentax 75 SDHF

[STOF 0]

Bonjour,
Je cherche des avis objectfs sur les qualités et défauts de cette lunette.
Cordialement.

[frédogoto 2 006]

connais pas... t'a un lien ?

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Frédéric T | | AVEX
Parc régional du Vexin
C9'1/4 EQ6 - mak 127
AVEX • Astronomie du Vexin

[HAlfie 2 078]

Salut ,

c'est celle-là:

Objectif: 75mm de diametre
focale: 500mm
f/6.7,
Objectif triplet: SMC 3-element SD APO (correcteur de champs inclu).
Diamètre du tube 75mm
Longueur du tube: 480mm length
Weight: 2.2 kg

J'ai des photos mais c'est avec la version 100mm de la même marque avec un design optimisé pour la photo ça donne ça avec une ST10: http://www.astro-image.com/images/ngc6992hargb.htm http://www.astro-image.com/images/vdb-142_3nm.htm

En argentique avec une 75 SDHF: http://www.ianking.darkhorizons.org/northamerican.htm

Ca se défend .

Tu auras du mal à trouver des avis d'utilisateurs, c'est une lunette vraiment pas répandue. Essaye de demander sur des forums allemands, américains aussi, avec de la chance tu trouveras peut-être un utilisateur .

Amicalement

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Chacun fait sa vie, ses choix, chacun découvre à son rythme

[albireo84 0]

bonjour
voilà quelques tests en allemand:
http://www.zumstein-foto.ch/PDF/tpf.pdf http://www.zumstein-foto.ch/PDF/tpr.pdf

et ev.
http://www.zumstein-foto.ch/PDF/tpsdp.pdf

[Tony 2]

J'ai pu discuter avec des proprios de cet engin : superbe astrographe, 0 en visuel (trop de verre, coulant pour oculaire parfois batard et demande des bidouilles/adaptations pour etre bien utilisable). Mais le but c'est la photo avec un engin pareil : et la le resultat est vraiment tres bon.

[scc 147]

http://www.scopereviews.com/page1l.html

"3) Pentax 75 SDHF 8/7/00
(75 mm f/ 6.7 air-spaced doublet with field flattener lens, OTA only, about $1450 street)

Pentax refractors are not officially available in the US, but they do show up from time to time on the used market. They appear to be very popular in Japan. This cutie offers some really nice performance for such a small, light instrument.

All of the Pentax refractors in this line (the 75, the 105, and the 125) employ an unusual design - there's a doublet up front, and a single-lens field flattener near the focuser. It's like 3/4 of a TeleVue 101. These field-flatteners usually screw up the image a bit, but this one star tests really well - just a little spherical aberration, and some very slight false color. The contrast is impressive also, with very little glare (I tried to induce some while looking at the moon.)

You'd swear you were looking through a well-baffled apochromatic doublet.

Optically, the scope is much better than a Ranger/Pronto, but it falls a tad
behind the Takahashi FC76/FS78. We spent an enjoyable evening looking at the summer Messier objects. One nice highlight was looking at M8 and M20 in a 19 mm Panoptic with an OIII filter attached. Aggressive filters like the
OIII aren't usually recommended on small-aperture scopes like this one, but the Pentax look it in stride, and revealed impressive extension on the nebulae.

Low contrast objects like M33 and M101 were easily seen, an indication that the field flattener was relatively benign. The Double Cluster was an impressive sight.

Mechanically, the scope is better built than the Vixen units, but not quite to the artful level of a Takahashi. Like many Japanese telescopes, this one came equipped for .965" eyepieces. Luckily though, there was a 2" adapter
included. You may have trouble finding focus with a 2" diagonal in place unless you have a low-profile 2"-1.25" adapter like the Astro-Physics or the JMI (hint: the TeleVue is too high, and the Orion unit is just barely so.)

The dew shield is retractable and has a rubberized ring at its tip - nice touches. The scope is really light, around 4.5 lbs. The tube ring is tapped for 1/4" X 20, which means you can mount it on a photo tripod. The (Japanese-only) manual suggests that you could really go to town on accessories if you had a mind to.

The only kicker with this nice little telescope is that, here in the US, there seem to be plenty of Takahashi FC76s floating around in the used market, for roughly the same amount of money. The Taks are slightly superior, both mechanically and optically. But they are also a lot larger. The Pentax may be the telescope you want if you travel with your equipment a lot.

Recommended for devotees of the Pentax marque, or for gap-filling in larger collections."