Click here if you are having trouble logging into the forums
Privacy Policy |
Please read our Terms
of Service | Signup and
Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User
simon123
member
Reged: 06/29/08
|
Orion 80mmED f/7.5 versus Orion 120mm f/8.3 achro
#2514797 - 07/12/08 01:14 PM
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
This is probably a dumb question, but....
I'm a central city apartment dweller, without much observing experience, looking for a portable set-up, and I love refractors (crisp views, pinpoint stars, no collimation hassles). Last night I attended a small suburban star party and was allowed to observe unhindered for about 30 minutes with another guy's Orion 80mm ED scope. I really liked the 80mm, though it seemed a bit aperture-challenged. No doubt the 80mm would have performed better absent the gibbous Moon last night.
Anyway, for about the same cost, I can buy either an Orion 80mm ED and Skyview Pro mount, or an Orion 120mm achro (plus Baader Semi-Apo filter) and Skyview Pro mount. I've never looked through an Orion 120mm achro. With a Baader filter, would the 120mm achro give me as good a view of open clusters, star fields, and doubles as the 80mm did? What about the Moon and planets?
I have found that I really like observing star clusters and just roaming around the Milky Way looking for interesting star patterns. A wide field of view is very nice.... 
Comments, anyone?
The Orion 100ED is a possibility, although it cost more than I want to spend (gotta save money for diagonal, eyepieces, etc.), and at f/9, I'm wondering whether it might have too-limited of a field of view???
Thank you.
Simon
|
tony4563
super member
Reged: 10/12/04
Loc: Bradford, West Yorkshire, UK
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: simon123]
#2514841 - 07/12/08 01:33 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
" I have found that I really like observing star clusters and just roaming around the Milky Way looking for interesting star patterns. A wide field of view is very nice.... "
You have just answered your own question... ED80 all the way.
The ED80 has the widest colour free views of all the scopes you mentioned. Very portable too.
|
pferendzo
super member
Reged: 02/10/08
Loc: St Louis
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: tony4563]
#2514959 - 07/12/08 02:11 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
If you're not too interested in looking at the planets you might also want to consider the Orion 120 f5 achromat. It has the same focal length and therefore presumably the same field as the ED80. You likely wouldn't use it above 100x - the ED80 can easily go to 180+, but I find the view on dim objects is better than that provided by the ED80. CA is bothersome on bright objects and can be mitigated with a fringe killer or semi-apo filter.
FYI... I have both the Orion 120 f5 and ED80, as well as the ED 100. I use an Orion SVP and Celestron CG5 for equatorial mounting, and Astro-Tech Voyager for alta-azimuth. I'm anticipating the combintation of the 120 f5 and voyager mount will become my 'grab and go' system
|
mathteacher
Carpal Tunnel
Reged: 05/13/07
Loc: Oakland, CA
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: pferendzo]
#2515102 - 07/12/08 03:49 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Welcome to CN! Simon, a few questions:
Do you need tracking (EQ) or prefer lighter weight (altaz)?
Will this be your only scope?
Edited by mathteacher (07/12/08 03:54 PM)
|
simon123
member
Reged: 06/29/08
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: mathteacher]
#2515331 - 07/12/08 06:20 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Hi, Mr. Wang,
Yes, I prefer an equatorial mount with a clock drive. And, yes, this will be my only scope for the next few years.
Simon
Quote:
Welcome to CN! Simon, a few questions:
Do you need tracking (EQ) or prefer lighter weight (altaz)?
Will this be your only scope?
|
mathteacher
Carpal Tunnel
Reged: 05/13/07
Loc: Oakland, CA
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: simon123]
#2515644 - 07/12/08 09:48 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Well, per your reply I would say get the 120 f/8.3. It will be a more versatile scope. With 120mm you will get very nice planetary and lunar views. You also have enough aperture to complete the Messier list, although you may have to leave the city for dimmer objects (galaxies). Your scope will also be more adept at splitting double due to its greater resolution power. The 120 has a 1000mm focal length will yield approx. 1.7 degree FOV with 1.25" eyepieces, which is almost big enough to fit the double cluster. With 2" EPs you can see even more sky. Yes, you are giving up wide views of the pleiades, Andromeda galaxy, but you are gaining more all around performance. In a city, the light pollution takes some of the fun out of wide field viewing anyway.
An 80mm makes a nice second scope for grab n' go/travel. If it was your only scope, I think you'd be wishing for more after a short time. If you had dark skies I'd say differently, but we share the curse of urban light pollution. Good luck making your choice!
|
jason_milani
Carpal Tunnel
Reged: 09/03/04
Loc: Northeast Ohio
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: mathteacher]
#2515799 - 07/12/08 11:40 PM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
I have the Celestron 80ED (same as the Orion) and had a few ST120 f/5 scopes. In fact i had both side by side on a grab and go for awhile. If you're interested in wide field views the ST120 is a nice scope and goes deeper than the 80mm but i was always bothered by the chromatic abberation on the moon and planets and the fringe killer filter gave everything a yellowish hue i didn't care for. I'm sure the 120mm f/8.3 scope would do much better in this regard although it's one of the few scopes i have not looked through so i can't comment on its performance. There are a few 100-102mm f/6 - f/7 achromats out there that perform quite well overall also. If it was to be my only scope i would not opt for the 80mm. I would go larger. That being said i will hold onto my 80mm for quick views since i have a larger scope for viewing dimmer objects.
Welcome to cloudy nights 
|
simon123
member
Reged: 06/29/08
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: mathteacher]
#2515815 - 07/13/08 12:02 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Okay, I've decided to go with the 100ED and SkyView Pro mount (non-goto), with dual tracking motors. Anyone have any tips for me regarding accessories or what to look for when the scope arrives?
Thank you.
Simon
|
Mr. Mike
scholastic sledgehammer
Reged: 11/08/05
Loc: Churchville, NY
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: simon123]
#2515836 - 07/13/08 12:25 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Quote:
Okay, I've decided to go with the 100ED and SkyView Pro mount (non-goto), with dual tracking motors. Anyone have any tips for me regarding accessories or what to look for when the scope arrives?
Thank you.
Simon
Congrats on the scope! When you get it, just give it a good look over and try out the focuser and other mechanical operations. Then, take a look through it ASAP! Thats about it. Get yourself some decent eyepieces too, really makes a difference in viewing quality.
Enjoy. 
|
stevecoe
"Astronomical Tourist"
Reged: 04/24/04
Loc: Arizona, USA
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: Mr. Mike]
#2515976 - 07/13/08 03:39 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Simon;
I think you have made an excellent choice. I would recommend a couple or three of the Ultrascopic eyepices from Orion. Not wide field, but sharp views and a 20mm, 12mm and 8mm will give you a wide variety of magnification for lots of targets.
Enjoy;
Steve Coe
|
mathteacher
Carpal Tunnel
Reged: 05/13/07
Loc: Oakland, CA
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: stevecoe]
#2515997 - 07/13/08 04:49 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
You just couldn't resist the lure of the apo, huh?  Anyway, welcome to the club. A 4" is a versatile scope. I would listen to Steve Coe's advice and get at least one ultrascopic. They are very sharp and constrasty. At f/9, the scope will be very forgiving of many EP designs and it will be easy to find focus. The tube feels long at times, especially with all these fast scopes coming out, but 900mm allows for a wide range of magnifications. Open clusters will look great through the 100ED. It will also do an excellent job of busting doubles. I just came in from the best view of Jupiter I've ever had... You will enjoy this scope for Lunar/Planetary. For DSO in the city, you may feel a little aperture challenged, but it will force you to get the most out of what you have. I'm thinking about a 6" refractor, but I really haven't seen all I could with the 4" yet. Congrats on your decision.
|
pferendzo
super member
Reged: 02/10/08
Loc: St Louis
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: mathteacher]
#2516050 - 07/13/08 07:45 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
The Orion 100ED is my most used scope - mainly for planets though. Optically both the 80ED and 100ED give very pleasing views to my eyes - good contrast, no CA, and sharp images. My single complaint about the scopes is the focuser, I replaced the focuser on both scopes with a GSO dual speed crayford from ScopeStuff. I wasn't that the supplied focuser wasn't adequate, but the replacement GSO is much better mechanically and the fine focus adjustment just makes using the scope that much more enjoyable - theory being the more I 'like' the scope the more it will get used.
I use a mix of 1.25 eyepieces with excellent results, mainly Nagler T6 and UO HD Ortho's - the Ortho's seem to have the edge at the higher magnifications. Both are excellent with the 100ED's longer focal ratio.
I've used both aluminum coated and dialectric coated diagonals (WO, TeleVue, and Astro-Tech) with good results. However, the dialectrics (teleVue and Astro-tech) seem to provide a sharper more constrasty view - surprisingly with the Astro-Tech being pretty much equal to the TeleVue, but much less costly.
One of the first SVP accessories I bought was a set of anti-vibration pads - they work very well. Later I ended up putting the SVP on an 8 inch extension and mounting the combination on a Meade field tripod (the one provided with their LX200 line) - solid as a rock, but no longer quite in the 'grab and go' category, but maneageable.
Of all the modifications and upgrades that I've made to my equipment, those that enhance ease of use and enjoyment have the greatest value.
All my comments need to be qualified as my personal experience and observation under typically marginal seeing conditions (when I go camping I find there are too many stars and it's difficult to find things because there's so much). My eyes seem to be degrading faster than the rest of my body so I'm sure I don't see things quite the same as anyone else - I also don't wear glasses when I observe, though it's difficult to navigate about the house without them. But, in spite of my environmental and physical limitations I do enjoy the hobby and observe as often as I can.
|
Doug76
Long Achro Junkie
Reged: 12/05/07
Loc: Refractor Heaven
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: pferendzo]
#2516262 - 07/13/08 11:01 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
I believe you made the correct choice. Congrats and enjoy!
Doug
|
simon123
member
Reged: 06/29/08
|
Re: Orion 80mmED f/7.5 versus Orion 120mm f/8.3 ac
[Re: mathteacher]
#2516287 - 07/13/08 11:14 AM
|
|
Edit
|
Reply
|
Quote |
Quick Reply
|
|
|
Quote:
You just couldn't resist the lure of the apo, huh?
Well, ya know, the 100ED on the SkyView Pro mount really doesn't cost that much more than the 80ED on the same mount, and I figure the 4" will keep me happy for years. My first accessories will be an AP Maxbright diagonal and a 35mm Panoptic. I'll also get a good mid-to-high power eyepiece, but I don't know which one yet. All that should keep me broke for a while.
I've already picked up a Mercury Support Systems SFA2 compression-ring visual back that should fit the 100ED's focuser.
Simon
Edited by simon123 (07/13/08 11:18 AM)
|
|
37 registered and 24 anonymous users are browsing this forum.
Moderator: Scott in NC, Bowmoreman, KWB
Print Thread
|
Forum Permissions
You cannot start new topics
You cannot reply to topics
HTML is disabled
UBBCode is enabled
|
Thread views: 630
|
|
|
|
|
|
|
Previous
Index
Next
Threaded
