SpaceWalk 2" EP

ariefm71 · Post by **ariefm71** » Wed Feb 21, 2007 11:28 am

Thanks Weehan. You can just bring the EP to one of our observation sessions (Dempsey, Tampines, Mersing!). There will be quite a few EP experts there elton, cheechien, yangbeng, rlow, vinsnr that will gladly do the comparo with the XLs, XWs, and Pans. i would like to compare it to my 34mm siebert observatory.

cheers,
arief

rlow · Post by **rlow** » Wed Feb 21, 2007 3:26 pm

I do not know the exact physics behind it but briefly, at longer FLs, the light cone in the eyepiece is so fat that a 2" barrel/focuser cannot accomodate a 82 deg FOV. Maybe the optical experts can chime in

I don't qualify as an expert, but a potential 40mm eyepiece with 82 deg AFOV would have require a barrel bigger than 2". Thats why the limit for a 40mm eyepiece with 2" barrel is a 46mm fieldstop, which limits the max. AFOV to about 70 deg.

Also, the larger apparent field of view eyepieces are more immersive because of the larger 'field stop' seen when you look through them.

To me, certain eyepieces like the Nagler T2, 4, & 5 gives a more immersive or 'spacewalk' feeling because of the larger eyelens and ultrawide field of 82 deg AFOV. This is not apparent with the T6s.

weehan · Post by **weehan** » Sat Feb 24, 2007 2:46 pm

Thanks alot Arief and Richard!

Cheers

WeeHan

alvinsclee · Post by **alvinsclee** » Sat Feb 24, 2007 4:17 pm

Yes, watch out for that slippery slope.

After hearing about 2" ep and the benefits of spacewalk ep from Richard when we met recently for a buy/sell transaction, I am mouth-watering for these things. That's why I'm getting wife to tag along for the coming Mersing trip... while I drool at the beauties, she will pay watchful attention at my wallet...

mrngbss · Post by **mrngbss** » Sat Feb 24, 2007 8:15 pm

Yes alvin, You are right!! Hahahaha!!!

rlow · Post by **rlow** » Sat Feb 24, 2007 10:58 pm

Btw guys, the Pentax 40XL is still available! It is good premium ep, and the lightest 2" 40mm ep to boot!

alvinsclee · Post by **alvinsclee** » Sun Feb 25, 2007 8:13 am

Arrrghhh... don't poison me further... I am an ardent Pentax fan! Go and poison Airconvent... he is the other Pentax regular at CS ;)

Let's see... I think my widest ep is 32mm... 40mm would be nice... dreaming on...

weehan · Post by **weehan** » Sun Feb 25, 2007 8:38 am

Haha! Thanks Alvin! Fortunately, I do not have a Finance Minister in my life yet. Well aware of the slippery slope which once bit me bad in photography but have eased down over the years. That said, I better get all that I want now coz the wallet wun be mine anymore when the FM enters my life! :oops: