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UO Orthos: filling a EP gap on a budget

Started by toml, 10/18/2002 03:02PM
Posted 10/18/2002 03:02PM Opening Post
I have a chance to buy 12.5, 9, and/or 6mm UO Orthos locally and each are $35.

I'm still a beginner but I understand these are really good on planets for some reason.

I am DYING to see the GRS which I haven't been able to truly say I have yet, or maybe I have, but didn't really know it, even though I do concentrate on looking for it each time I see Jupiter.

Part of that is surely that a dob isn't as good on planets as a refractor, but still...here's my equipment list with some comments.

I have: Orion XT8 (love it), Celestron Ultima 30mm (REALLY enjoy looking into this clear and crisp EP -- wonder if I should just get more and more ultimas over time and forget other orthos/plossls altogether), Stock orion sirius 25 and 9mm plossl (25 is fine, 9 is so so) and Celestron silver type Plossl 6mm (pretty good..tolerable relief, i think clearer than the orion 9, but not as clear/crisp as the ultima) and on top of all this i have a TV 2.5x barlow (very nice, but can't really use it with the 6 now can I?!)

Since I already have a 9 and 6mm plossl I was thinking about the 12.5 (the orion 9 is not too hot, the celestron 6 is actually okay but only gives me 200 power and can't really be 2.5x with my TV barlow as 500x is really not usable) and barlowing it to get me to 240x (more power than the 6mm, and possibly better contrast and eye relief). I'm wondering if this will be best for planets and or if I should replace one of the two plossls of the same f/l 6 or 9 with the 6 or 9 ortho instead?

my XT8 focal length is 1200mm...so currently i get:
ultima 30: 40 and 100x
sirius 25: 48 and 120x
[uo ortho 12.5? 96 and 240x]
sirius 9: 133 and 333x
celestron plossl 6: 200 (and 500x -- not)

so, should I get just the 12.5? or another F/L? I'm on a budget, but I also want some great planetary views this winter (and for mars next year)...what to do? one or two?

thanks for any opinions!!
Tom.
Posted 10/18/2002 04:12PM #1
For what it's worth Tom, here's what I would do . . .

If you are going to be using the higher powers primarily for the planets and moon, buy all three UO orthos - the 12.5, 9 and 6 - and sell your sirius 9 and celestron 6 plossls on Astromart for $35 each. That way, you will have a perfect low to mid power set with your 30mm, 25mm and 12.5mm, and a perfect high power set for the planets with your three UO orthos. I know a lot of folks who would kill to get three UO orthos so cheaply.

I have experimented with a lot of different plossls on planets, and with the exceptions of the Celestron Ultimas and Televue plossls, nothing beats the University optics orthos in the under $100 range. The orthoscopic design is superior for planets because of its excellent optical and color correction. The only drawback is that it has a narrower field of view than a plossl (45 degrees instead of 50).

Best of luck in seenig the GRS!

Posted 10/18/2002 05:34PM #2
The UO orthos are worth more than $35 used. They are much better than the plossls you own. They do have about a 10% to 15% narrower field of view. I own the 30mm, 5mm and 7.5mm ultimas. I also own almost all the UO's. The 7.5 Ultima is pretty good. The 5 Ultima is not so good. The UO's resolve fainter objects better and are sharpest right to the edge. The UO Konigs have a wider field of view, but are not as sharp toward the edge as the orthos, especially the 16mm Konig. The 12mm Konig is a better choice, sharper total field of view than the 16 and it has longer eye relief. I would buy all the orthos, you will be amazed at the difference in the view thru the orthos as compared to the average plossls. edz
Posted 10/18/2002 05:37PM #3
Hello Tom!

I have the whole set of UO orthos... and I love them! they are probably the best planetary eyepieces... (yes, their only shortcoming is the tight FOV)

Anyhow, if planets is what you want to look at, you might want to get an extra Ortho or two to complete your set... but you already are on the right track... the 12.5 and the 9 are definitely some of the best... the 6 will be good, but somewhat tight...

Good luck!


Clear skies to you all!
smile


Ivan

Ivan Gastaldo 8)
Coconut Creek, FL

Ivan's Observatory
Lat 26N 16' 48" Long 80W 10' 48"
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CCD Imaging and Processing/Deep Sky - Moderator
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Posted 10/18/2002 07:12PM #4
Hi Tom the ortho's at 2 times the price will still be better than the Ultima's. They have so much better sharpnes over the Ultima's on Planet and lunar views, contast is far better and there sharp right to the edge, buy those as fast as you can and keep em.
Posted 10/18/2002 11:57PM #5
I have similar eyepiece brands as you do, Tom, only in differnt focal lengths:
(1500mm 6" MakCas)
26mm Sirius Plossl
17mm Sirius Plossl
12.5mm Ultima
10mm Sirius Plossl
5mm UO

My experience is that the UO has great clarity and sharpnes but REALLY tight eye-relief (don't blink or you'll get eye-lash oil on the optics!)

My favorite is the 12.5mm Ultima - yes, I agree that it may give up a *tiny* amount to the UO's, but is more comfortable and easier to use with the additional FOV, IMHO.

I really believe that the Sirius plossl's are substandard but, like you, I am working on my eyepiece collection on a budget. They may not be fancy, but they get the job done.

I think that unless you are REALLY discriminating about that last 2-3% the UO's would give you, the wider FOV and more comfortable eye-relief of the Ultima series is worth the money.

That being said, BUY THE UO's!!!!!

The price is right, the opportunity is here and you can still replace them slowly when you find more comfortable (read: more expensive) eyepieces. There will ALWAYS be a market for the UO's as they are great little eyepieces for a price too hard to pass up.

So what are my eyepiece plans? Well, I just bought (on astromart) a 35mm Ultima plossl, and ordered a 16mm Konig, and a 40mm Konig from UO. I am looking for a 7.5-8mm ultima and maybe a ~25mm ultima.

Hope this helps!

James