Hello everyone, I'm looking for information from anyone who star tested either the Orion 80ED or the Celestron 80ED. (Same objective lens for both.) I just got the Celestron version on Friday and gave it a star test Saturday night. I'm not very pleased with the result I saw with mine. Very good collimation on mine, but outside of focus no diffraction rings visible (just nice round glow). Inside of focus I see the typical ring pattern fairly clearly. It's doubtfull the lens has turned edge which could explain the result I'm seeing. Of course I allowed plenty of cool down time and I'm using only very high quality diagonal and eyepieces. (TeleVue diagonal and Celestron Ultima 2x Barlow with 8mm Brandon eyepiece.) I'd like to know basically from anyone with this scope if they can see diffraction rings outside of focus unlike with mine. Ideally, one should see similar patterns on either side of focus. If others are getting similar patterns on both sides of focus through their samples, then it might be warrented for me to return mine for refund or exchange. The seeing conditions really didn't allow me to make a call on the quality of the image in focus. It wasn't the best nor the worst seeing that night and thats usually something that can't be determined on the first night out with a brand new scope. All I know is that the star test doesn't lie - so I'm a little concerned about the optical quality of this scope. Thanks to anyone who owns this scope ahead of time who might be able to tell me how goes the star test from their sample. Thanks, Dave
Star testing the 80ED
Started by Dave Sewell, 02/19/2006 07:10AM
Posted 02/19/2006 07:10AM
Opening Post
Posted 02/19/2006 08:05AM
| Edited 02/19/2006 08:05AM
#1
Dave,
have you tried it without the diagonal to get a true test of just the scope?
have you tried it without the diagonal to get a true test of just the scope?
[SIZE="Large"][/SIZE][COLOR="Blue"][/COLOR] Floyd Blue
Amateur Imager
Posted 02/22/2006 05:21PM
#3
Hello Dave!
I have the C80ed since 6 months.
Startest shows me very similar pictures as you see; sharp round rings inside focus, fuzzy outside, but the outermost rings are sharp and well defined on both sides.160X with WO 2" diagonal, Intes Barlow 2,4X + 9mm Antares Ortho eyp.
According to what I have red on "the net" this is normal for a scope of this design.Mind you Iam not an expert
Anyway,I do not worry too much. The "at focus" image ( and that`s what matter, isn`t it?!)is just fine.
Pinpoint stars that snap into focus at 160X (Iam sure the scope can handle a bit higher mag. with a good 3X barlow!)
1.5" binaries split or elongate depending on seeing.
I can`t ask for much more with 80mm aperture I think!?
Cheers,
Magnus
I have the C80ed since 6 months.
Startest shows me very similar pictures as you see; sharp round rings inside focus, fuzzy outside, but the outermost rings are sharp and well defined on both sides.160X with WO 2" diagonal, Intes Barlow 2,4X + 9mm Antares Ortho eyp.
According to what I have red on "the net" this is normal for a scope of this design.Mind you Iam not an expert
Anyway,I do not worry too much. The "at focus" image ( and that`s what matter, isn`t it?!)is just fine.
Pinpoint stars that snap into focus at 160X (Iam sure the scope can handle a bit higher mag. with a good 3X barlow!)
1.5" binaries split or elongate depending on seeing.
I can`t ask for much more with 80mm aperture I think!?
Cheers,
Magnus
Funding Member
