Mike Loffland
Web Guru (Astronomics)
Reged: 09/03/04
Posts: 2080
Loc: Norman, Oklahoma
|
|
Orion 120 mm F5 Short Tube Achromatic Refractor
|
Mike Lynch
member
Reged: 04/07/06
Posts: 52
|
|
How many baffles are in the tube of this scope? (Orion describes it as "well-baffled.")
Mike Lynch
Frankfort KY USA
|
revans
Carpal Tunnel
Reged: 09/26/05
Posts: 1514
Loc: Fitchburg, MA
|
|
I'm not sure about the number of baffles. But, I wanted to added to the review that post-processing of images with this scope often also has to deal with the problem of bloated stars (the bloated appearance of brighter stars is worst of all in the blue channel, and only moderately severe in the green channel, when the red channel is sharply focused). It is sometimes possible to improve the appearance of star bloat in post-processing as shown in the attached re-processing of the M27 image shown in the review. Alternatively, it might also be approached with use of filters during imaging or by focusing on blue stars.
Rick
--------------------
Rick Evans
http://www.freewebs.com/revans_01420/
"The universe is there for us to see, but it cannot be understood without learning its language -- mathematics." Galileo Galilei
|
Rat
super member
Reged: 10/13/06
Posts: 146
Loc: USA
|
|
A nice report!
|
PAW
sage
Reged: 10/12/06
Posts: 251
|
|
Thanks for the review - I have been considering buying one of these as a rich field refractor. What that holds me back is that I'm not sure how this refractor would perform when compared to my 130mm f/5 Newt reflector. I suspect the images would be very similar.
|
revans
Carpal Tunnel
Reged: 09/26/05
Posts: 1514
Loc: Fitchburg, MA
|
|
Well... I sort of suspect that the images in your 130mm F5 Newtonian might actually be better... especially for imaging. You won't have star bloat in the green and blue channels to worry about although its true you'll have a little central obstruction and maybe a touch of coma in the Newtonian. I like the achromat mostly because it is light, rugged, portable and doesn't need collimation but I don't think it is going to win any contests with your Newtonian...
--------------------
Rick Evans
http://www.freewebs.com/revans_01420/
"The universe is there for us to see, but it cannot be understood without learning its language -- mathematics." Galileo Galilei
|
StarStuff1
scholastic sledgehammer
Reged: 04/01/07
Posts: 976
Loc: South of the Mason-Dixon Line
|
|
Nice review. Have you checked to make sure the front end of the focuser tube doesn't cut off part of the light cone when it is racked in for photography?
--------------------
Tools that make objects very far away appear much closer than they actually are.
|
revans
Carpal Tunnel
Reged: 09/26/05
Posts: 1514
Loc: Fitchburg, MA
|
|
I haven't had this problem with the focuser so far either with various eyepieces or in the TTL viewfinder of my Canon Rebel DSLR... but I have seen this issue discussed in other threads. There are several very similar versions of this scope under slightly different names etc. and I had assumed the issue applied to one of these improved "clones" of the original older OTA that I have (and probably put out by the same factory in China). They seem to have fancier paintjobs and an improved external appearance, so maybe something was also done to modify the innards as well in these newer versions??
--------------------
Rick Evans
http://www.freewebs.com/revans_01420/
"The universe is there for us to see, but it cannot be understood without learning its language -- mathematics." Galileo Galilei
|
highfnum
super member
Reged: 09/06/06
Posts: 232
Loc: NY
|
|
I was thinking of getting one of these also or some other like it
|
StarStuff1
scholastic sledgehammer
Reged: 04/01/07
Posts: 976
Loc: South of the Mason-Dixon Line
|
|
An easy way to check without taking anything apart is to measure the exit pupil. Say you use a 30mm ep for 20x the exit pupil should be 6mm. If it noticeably smaller that that then either there is focuser tube intrusion or a mis-sized/mis-placed baffle. This is not uncommon.
The ST 120 is a great scope for its' price and size. The only reason I sold mine was because I got a great deal on a 127 f/6.5 achro and couldn't see keeping the smaller scope too. It turned out the 127 also had the same focuser intrusion. A vendor told me once that this particular manufacturer only had one 2-inch focuser tube and used in both long focus as well as short focus refractors. Kinda wish I had still kept the 120 it as it was so compact.
--------------------
Tools that make objects very far away appear much closer than they actually are.
|
John Zimmerman
member
Reged: 10/05/09
Posts: 15
Loc: California
|
|
I've had one of these for the past 3 years mounted on an Orion Alt-Azimuth mount with slow motion controls. It is a wonderful grab and go scope. And in additional to good wide field views, I find with a barlow lens it does a decent job on the moon and planets at higher powers.
--------------------
John Zimmerman
Celestron NexStar 11GPS
Celestron Nexstar 8SE
Orion Astroview 120ST
Celestron NexStar 4
Meade ETX 90PE
|
Rob E
Pierrot
Reged: 05/20/09
Posts: 1126
Loc: Eastern Virginia
|
|
It's the only refractor I own. It's a great scope. I did change the focuser to a GSO Crayford.
--------------------
Rob E.
Some of us are actually paid to be funny.
------
Zhumell 16"
Orion 120ST
Orion Starmax 127
Baader Planetarium Hyperions
Zhumell SWA EP's
There's two ways to do anything...right and twice
|
star drop
Guilty as Charged
Reged: 02/02/08
Posts: 16224
Loc: Snow Plop, WNY
|
|
Quote:
I've had one of these for the past 3 years mounted on an Orion Alt-Azimuth mount with slow motion controls. It is a wonderful grab and go scope. And in additional to good wide field views, I find with a barlow lens it does a decent job on the moon and planets at higher powers.
Hi John and welcome to Cloudy Nights. This past spring I had a chance to try one of these on a few deep sky objects before the clouds moved in. Very nice views when using a 26mm Nagler eyepiece.
--------------------
Ted
|
RonBurgundy
sage
Reged: 06/16/09
Posts: 252
Loc: Philadelphia
|
|
I got it for widefield views without giving up the world in the aperture department. Great telescope.
--------------------
Kipp Ginsburg
8" LX200-ACF
Orion 120mm F/5.0 Piggybacked Refractor
Meade UWA Set [4.7mm-30mm]
DSI-II
|
eric_zeiner
Pooh-Bah
Reged: 12/09/06
Posts: 1377
Loc: Georgia USA 34 31'57.18N 83 53...
|
|
Out of all the scopes I ever owned the 120ST was my favorite!
|
DLB242
professor emeritus
Reged: 07/29/08
Posts: 545
Loc: Pen Argyl, PA
|
|
Quote:
Thanks for the review - I have been considering buying one of these as a rich field refractor. What that holds me back is that I'm not sure how this refractor would perform when compared to my 130mm f/5 Newt reflector. I suspect the images would be very similar.
I have one of the Orion 130ST Newts. I don't think you will gain anything going to a 120mm f/5 Achromat. My 130ST will go a bit deeper than my 102mm APO I would say about as deep an my friend's 115mm APO triplet so that would put it in about the same range as the 120mm f/5 Achro for deep sky and the views are quite good through the little Newt. Where the Newt fall down compared to even my SV90T is when pushed to higher power for planetary viewing which is to be expected. I think the same would be true when pushing the 120mm f/5 achro plus the CA starts to intrude with the Achro. So I think over all the edge would go to the 130mm f/5 Newt vs the 120mm f/5 Achro because there is no CA with the Newt. You would be better off holding out for a 6" achro as an addition to the 5" Newt. I have both and the jump from the 130mm Newt to the 152mm f/6.5 Achro is noticeable when going deep.
--------------------
David B
10" f/5 DOB
6" f/8 DOB
Celestron C8
Antares 1529 6" f/6.5 MoonLite Focuser
Orion ShortTube 130mm f/5 Reflector
Stellarvue SV102BV f/8.7 LOMO Doublet APO
Stellarvue SV90T f/7 Fluorite
Synta ShortTube 80
Stellarvue SV70ED
|
Previous
Index
Next
Threaded
Edit
Reply
Quote
[Re: 