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Should I buy the Orion 120mm f/8.3 refractor

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#1 Guest_**DONOTDELETE**_*

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Posted 01 November 2003 - 03:07 PM

I already have the astroview 6" f/5 reflector, so I could
just get the OTA and some tube rings and use the same mount
right? So tell me, Yeah buy it, you will love the views of
the planets over the reflector, or tell me no don't buy it.
You have allready spent enough money on astronomy stuff.
Besides it's too cold to go outside to play with a
telescope now anyway.


#2 Blair

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Posted 01 November 2003 - 04:44 PM

I had a 6" f/5 Discovery Dob and Orion's 120mm f/8 scope at the same time. I liked the look of Jupiter better in the Dob but then I never used a Violet filter with the refractor. I sold both. The Dob because I did not like the position I had to sit in to use it. The 120mm because it was heavier (on an equatorial mount) than what I wanted to deal with on a regular basis. I now have a 100mm f/6 rich field scope on a AZ-3 mount and am really happy with it. I can go from 15X to 120X which is a good power range. The 120mm OTA will work on the Astroview mount but when looking at the apex of the sky the eyepiece will be very close to the ground (below sitting in a chair to view) if the scope is balanced and there will be a vibration issue at high powers. Hope this helps.

#3 Stacy

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Posted 01 November 2003 - 05:11 PM

I have been eyeballing those for awhile. But the mount is a serious consideration. I have my 5” f/9.3 on a CG-5A, which I believe extends a little farther than the Astroview, and still find myself on the ground when looking near zenith. Since it seems planets and the moon are rarely directly overhead, that may not be an issue.

OTOH, I love the views out of the refractor! Not better or worse than a reflector, but different in a good way. I love my reflector as well, but the contrast is better with the unobstructed reflector. At $319 + it’s hard to go wrong.

Since the clouds don’t appear to be going anywhere soon, you may want to hold out for a sale from Orion (although their sales usually apply to their package deals) or check their 2nd’s. Or better yet, check out Astromart. Great deals on refractors appear there often. Don’t waffle though … you gotta be quick! I got my Meade 5” almost new with rings, finder, diagonal & EP for $275. Missed out on a Skywatcher 6” for $250 though.

Good luck!

Stacy

#4 Guest_**DONOTDELETE**_*

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Posted 01 November 2003 - 07:38 PM

Thanks for the feedback you guys. I think I will stick with
just my reflector for now. After I read a few reviews of
the 120mm refractor, it seems that there are qc issues with
them. People are saying it is hit or miss wheather you get
one with good optics or not. Plus I don't like the idea of
lying on the ground to look through the thing. That is one
thing I like about the eq reflector is the comfortable
viewing position while sitting on the observing chair I
bought. I think i will keep an eye on the astromart ads
though.


#5 Guest_**DONOTDELETE**_*

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Posted 01 November 2003 - 08:57 PM

If it is a miss, send it back and get a hit. I agree about lying on the soggy, Portland ground, though...yuk! I refuse to venture off my deck in fear of being swallowed whole by the bog in my back yard.

#6 Guest_**DONOTDELETE**_*

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Posted 01 November 2003 - 10:19 PM

Let's not kid ourselves about quality achromatic refractors. My Synta 120mm will easily match and out-perform an 8" f/6 dob on Moon and planets. I use a V-Block filter with my refractor of the same manufacturer in China, which almost nullifies chromatic abberation. Not too many refractor lovers here it seems. Everything said really doesn't give the Synta refractor(Orion, Sky-Watcher, Celestron, etc.) credit where credit is due assuming one has a good mount- I have an HEQ5. Using a quality minus violet filter takes care of most of the lingering problem most people complain about. For certain purposes such as mostly lunar, planetary, solar, terrestrial, quite frankly, a reflector (especially a Dobsonian-mounted reflector), makes a mediocre choice for serious observing. I also hear many say how relfectors are "more versatile".. Really? With my refractor I have done solar astronomy during the day, night time astronomy, guided astrophotography day and night, sketched some pretty sharp views in absolute comfort (don't let everyone fool you about the claims about zenith viewing with a refractor), and day/ nighttime terrestrial observing and photography. To add, my refractor is more transportable than those large dobs out there. Using a diagonal, one also reaps the benefit of additional magnification options with a barlow lens. I'll be honest: of the achro refractors of this size I've tested now, they all kick the hell out of my 10" f/5 dob (Orion) for Solar System observation for the most part. It's up to the individual, however, and what their intentions are with a new scope. Light buckets become really important for deepsky..there's no debate- its pretty redundant...dobs are cheap for their aperture, but this kind of optical system has its rightful, optimal uses. So that's my input. There are quantitative reasons behind my convictions. Go for the 120mm with a good mount and enjoy! If deepsky is more your intention, keep the dob and sacrifice the other benefits.

Clear Skies,
Michael

#7 Guest_**DONOTDELETE**_*

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Posted 01 November 2003 - 11:11 PM

I don't think I would put that refractor on the astroview mount. That mount holds my 127 Mak just fine, but a much longer tube would give too much jiggle at high power. I was looking at refractors and called Orion to see how they thought the Mak and refractor compared, they said the refractor was better, but they felt the difference was not that great on planets. Given the size difference, the need for a bigger mount, and my happiness with the Mak, I decided not to buy.

#8 Trever

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Posted 02 November 2003 - 04:27 AM

Well since in the last 2 months I have owned an 8 inch Dob and a 6 inch refractor, I can say that it is somewhat easier to carry the refractor tube on my shoulder. It also seems to me that the images are brighter through the refractor. Especially the DSO's....

#9 SAL

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Posted 02 November 2003 - 11:52 AM

Kileak: I'm going to weigh in on this discussion because I have owned two versions of the Orion 120mm f8.3, one on the AstroView mount and aluminum tripod, and a second on the SkyView Pro mount and steel tripod. First let’s address quality control issues. Mt first 120 OTA arrived from Orion with fantastic optical performance, (once I collimated the scope). My second version arrived with terrible performance even after collimation (greatly increased false color, color spiking, and distortions near the edge of the field of view). Orion customer service was terrific, and offered to either replace or repair the OTA immediately. I let their repair department test my OTA, and they found there were problems with the focuser. However, it had better Ronchi and star test results than three “new” versions they tested it against, so I elected to keep this OTA with a repaired focuser. The end result is a 120mm f8.3 that actually outperforms my original Orion, which I really loved.

So, why did I upgrade my original AstroView 120 for the SkyView Pro 120? The short answer is the AstroView mount and tripod system. By Orion’s own service tech’s admission, this OTA pushes the AstroView to the edge of its capabilities. I found the AstroView system was usable with this OTA, but focusing at higher magnifications was quite difficult due to mount movement and tripod vibration. There was a large amount of “slop” and free play in the mount. Tightening the adjustment screws reduced this condition, but did not eliminate it. Placing the tripod on grass helped, and I’m told the anti-vibration pads also help a bit. There are web sites that provide suggested tweaks to further decrease AstroView vibration, but this OTA is simply asking a lot from the AstroView system due to its weight. The SkyView Pro mount and steel tripod on the other hand, are a completely different story. This OTA is rock steady on the SkyView Pro system. If I had to assign a numerical comparison, I would say the SkyView Pro is three to four times steadier than then the AstroView for the 120 f8.3 OTA

I have no real experience with reflector telescopes (I’m a refractor enthusiast), so take this into consideration when reading my comments. It is true that at zenith the viewing position is low, but I don’t find it impossible. (The SkyView Pro tripod does give you additional height that helps with this issue). The views are sharp, stars are nice bright pinpoints, and a 120mm worth of aperture is a good amount to see many DSO’s beyond the planets. Fellow astronomer friends of mine have commented on how ridiculously good the views are from the OTA for the price. Is false color evident? Yes, but when properly collimated it is relatively little, and then only shows itself mostly on bright stars like Vega. I do not use a minus violet filter at this point. (Admittedly CA false color does not bother me like it does some folks. I’m sure that if I became accustomed to high-end APO views, it would be more noticeable to me). I have very little cool down time, which is important to me during cold Midwest winters.

My point is that I consider this OTA a fantastic bargain for the price. You certainly can use it with your AstroView system, but will probably need to tweak the tripod and mount to get optimum performance. I wouldn’t let Synta quality control issues scare you away as Orion is one of the most dedicated companies I’ve found when it comes to insuring their customers satisfaction. If you get a bad sample, they will make it right. Hope this post helps make your decision a little easier… (Scott)


#10 Guest_**DONOTDELETE**_*

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Posted 03 November 2003 - 01:37 AM

Good feedback btw! Try one of the minus violet filters..I have the Orion V-Block, it works great. Sirius Optics makes a good one as well. Goodbye chromatic abberation. :)

No apologies needed for loving the refractor. This is a refractor forum, afterall. We mean no disrespect to reflectors or any other type of proven optical system. Let reflector owners try and tell me I don't sport a terrific and versatile scope. I'm always glad to elaborate for those who want to know the absolute pleasure of owning a relatively inexpensive, well-performing 4.7 " achro on a decent mount.

I have a Pacific Instruments Sky-Watcher (Synta) 120mm- pretty much the same in many ways as the Orion or Celestron version. The HEQ5 is one great mount for the price; similar in performance to the Vixen Great Polaris, I heard.

Thanks again,
Michael

#11 RGM

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Posted 03 November 2003 - 04:45 PM

I just have to add my 2 cents worth. The mount makes all the difference. I have a Vixen SP eq head on a 4 inch diameter pier. This set up will take any magnification with no vibration. If you use a tripod, modify it the best you can. The only things I have done to the OTA is to take the focuser apart and clean it, and collimate the objective. I use a Lumicon MV filter and just keep it on for everything. I am glad to see all the interest in this telescope. This is a great telscope for the money. Leaves you enough money for eyepieces and filters. Bob


#12 Guest_**DONOTDELETE**_*

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Posted 03 November 2003 - 06:22 PM

You won't be sacrificing much DSO observing by choosing the 6" refractor. The images are bright and sharp. As for viewing at the zenith, there are several small manufacturers that make extension tubes for different makes that will raise your scope a foot or more off of the tripod. AstroSky is one such manufacturer.

Stability and rigidity of the tripod becomes critical with the added height, but you can sit Indian style fairly comfortably while viewing at the zenith depending upon how bigga boy ya are.

Mine is on a 48" pier and with the added height of the mount to the OTA, a small beer cooler is what I sit on while the tube is pointed straight up.

When mine was on the factory tripod, I used all manner of contortions to view at the zenith. The diagonal/eyepiece was practically scraping the driveway...well not that close, but it was pretty far down to the ground.


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