UO Ortho 5mm Ortho or Vixen LANTHANUM 5mm or Antares LE 5mm

bodoh · Post by **bodoh** » Wed Jun 16, 2004 8:57 pm

Looking for a high power eye piece to use with my nighthawk ... once Sam and I collimate it. Intend to use it with a barlow.

So far I like the contrast and resolution of the ortho but eye relief is gonna be bad. As it is, my 9mm ortho is quite bad, can imagine my eyeball being squashed to the 5mm!!!

The LANTHANUM is about $50 more expensive and I'm not sure in terms of performance how it compares to the ortho. Anyone has any experience using the 2?

The other would be the Antares LE 5mm. How does this compare with the ortho?

Post by **VinSnr** » Thu Jun 17, 2004 5:30 pm

bodoh wrote:Looking for a high power eye piece to use with my nighthawk ... once Sam and I collimate it. Intend to use it with a barlow.

So far I like the contrast and resolution of the ortho but eye relief is gonna be bad. As it is, my 9mm ortho is quite bad, can imagine my eyeball being squashed to the 5mm!!!

The LANTHANUM is about $50 more expensive and I'm not sure in terms of performance how it compares to the ortho. Anyone has any experience using the 2?

The other would be the Antares LE 5mm. How does this compare with the ortho?

Get the Antares WA 5.2 mm. Pretty good eyepiece for the money.

Forget about the Lanthanum la.....unless you get the superwide version. Yes, the lanthanum has 20mm eye relief, but only about 45 degrees fov. what's the point?

The best if you can afford, is the Pentex 5.2XL

bodoh · Post by **bodoh** » Thu Jun 17, 2004 6:46 pm

Hmmm that was something I'd not considered....

But I am beginning to appreciate eye relief more and more. You should see the amount of essential oils my eye lashes impart on my eye pieces after each observation session.

Grin! And I knew someone would bring the Pentax XL up eventually. But being my first month, have decided to have some kind of stop gap high power eyepiece like the ortho rather then send my wife to any early grave by buying a $300-400 eye piece.

Unless someone is willing to loan me a high power eyepiece until I gather enough 'credits' to buy a Pentax of a Radian!

MooEy · Post by **MooEy** » Thu Jun 17, 2004 8:13 pm

if i were to buy the lanthanum, i would get the 2.5mm version and dump the barlow. since u get 20mm of eye relief with either combi, might as well use without a barlow.

ortho gd choice too, sharp but lacking eye relief. i wouldn't care too much about eye relief, can always take off my specs and squirt my eye.

but till now i have used anything more than a 4.8mm nagler on my scope. the 410 head is nice, but doesn't take high power that well. neither does the scope take high power well.

most of the time a 7mm nagler stay on my scope, just about the sweet spot for this scope.

~MooEy~

bodoh · Post by **bodoh** » Thu Jun 17, 2004 9:39 pm

Thanks...

7mm barlowed or non-barlowed? Was hoping to try and touch 200x for planetary work...

harlequin2902 · Post by **harlequin2902** » Thu Jun 17, 2004 10:12 pm

Was hoping to try and touch 200x for planetary work...

Hi,

Wide field achromat refractors under 4" usually max out at 120-150x. Any higher and the image starts to become 'soft' and a little unpleasant to view (i.e planetary features begin to get blurry and you'll find that it becomes more and more difficult to get a clean focus).

There are some exceptions of course, but this is still generally the case with most of them.

kayheem · Post by **kayheem** » Thu Jun 17, 2004 10:20 pm

VinSnr wrote: Get the Antares WA 5.2 mm. Pretty good eyepiece for the money.

Vin, are you referring to the WA 6mm or the W70 5.2mm? If I am not mistaken, the Antares W70 5.2mm already has a built-in barlow and I read that it is not advisable to use another barlow with it.

The rest of you guys reading this, please correct me if I am wrong.

Kay Heem

Post by **weixing** » Thu Jun 17, 2004 10:21 pm

Hi,
Wow.. You really push your scope to the limit..

7mm Orth with 3x barlow should give you enough eye relief and a magnification of 205x. But I think 9mm with 3x barlow(160x) may be a better choice in singapore sky condition.

Have a nice day.

bodoh · Post by **bodoh** » Thu Jun 17, 2004 10:57 pm

Think I may end up with a Vixen 6mm barlowed 2x. Eye relief is prefered...

But I think the Vixens are supposed to be poorer in terms of performance compared to the orthos. Rather not use 3x barlow because there isn't a reasonably priced good one out there. Using a 2x barlow before the diagonol give 3x but also supposedly introduces quite a bit of CA, so will only do that if I have to.

Post by **VinSnr** » Thu Jun 17, 2004 11:25 pm

bodoh wrote:Think I may end up with a Vixen 6mm barlowed 2x. Eye relief is prefered...

But I think the Vixens are supposed to be poorer in terms of performance compared to the orthos. Rather not use 3x barlow because there isn't a reasonably priced good one out there. Using a 2x barlow before the diagonol give 3x but also supposedly introduces quite a bit of CA, so will only do that if I have to.

Let me tell you something. whichever eyepiece you choose, make sure it is wide angle at high power. Ortho or Lanthanum at 200X will have you pushing the scope more than you view through it if you are using a alt-azi mount.

The moment you push the mount to track it, it will vibrate. When the vibration stop, you reliased that the object is out of the eyepiece again. Then you push again......vibration again.....in the end, you see nothing.

So get a wide angle eyepiece if you want high power at 200X. A 7mm Nagler would be the best choice here, but the EF is only 10mm.

SingAstro

UO Ortho 5mm Ortho or Vixen LANTHANUM 5mm or Antares LE 5mm

UO Ortho 5mm Ortho or Vixen LANTHANUM 5mm or Antares LE 5mm

Re: UO Ortho 5mm Ortho or Vixen LANTHANUM 5mm or Antares LE

Re: UO Ortho 5mm Ortho or Vixen LANTHANUM 5mm or Antares LE