Orion ShortTube 90mm


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Brand and Model:Orion ShortTube 90mm
Price ($USD):$329.00
Type:Achromatic Refractor
Attributes: un-checked Go-To un-checked PEC
Aperture:90mm (3.5")
f Ratio:f/5.6
Focal Length:500mm
Finder:6x30
Electric Power:n/a
Mount:EQ-2
Tripod:adjustable aluminum
Weight (lbs):5 lbs. OTA
Dimensions (w/h/d):18" long
Description:Includes 1.25" star diagonal and 26mm Sirius Plossl eyepiece.


Orion's ShortTube 90mm Page

Affordable Astronomy's Review
Cloudy Nights' Review

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Orion ShortTube 90mm
I purchased my scope as a tube assembly and mounted it on a russian alt-az pedestal from a Tal Alcor newtonian.
After star testing I was disapointed, but soon discovered the cause. The lens retaining ring was loose causing the scope to be badly out of collimation. After tightening it performed really well, giving a nice set of diffraction rings on both sides of focus.
With the suplied 26mm plossl giving 19x magnifcation it gives breathtaking views. I have tried up to 166x on Jupiter and Saturn and it performs quite well for such a fast scope.
There is quite a bit of false colour when viewing the moon, but this can be overcome by stopping the scope down to f11 by drilling a 45mm hole in a suitably sized sweet jar lid and placing it over the lens hood. The blue fringe around the moon then all but disappears.
I use a good mirror diagonal and a Tele Vue 11mm plossl and have just tried a Baader contrast boosting filter which eliminates most of the false colour found in most budget priced achromats.
I have removed the original finder as I found it very difficult to use and fitted a Celestron Star Finder, but really a finder is not needed on a scope of this type as it is easier to use a low magnification to find your subject and then change eyepieces for a better view.
I think this is a brilliant little scope for the money and it has given me many hours of pleasure.

Overall Rating: 9
Optics:8 Ease of Use:9 Value:10
Weight: 5 (Veritable Vote)
Date:
By: Bilgewater
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=179039


Orion ShortTube 90mm
I have a ball with this little tube. I use a MV1 filter with it to cut down on the purple at higher mags and have mounted it on an eq3 mount and tripod. Solid as a rock. I like to see how far the seeing will let me push it as well as the fantastic views of open clusters. With a barlow, it does fairly well on Jupiter too.

Overall Rating: 8
Optics:7 Ease of Use:10 Value:8
Weight: 3 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.223.35)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=83169


Orion ShortTube 90mm
After having to make a slight adjustment in collimation of the optics, the scope has a nearly textbook perfect star test at high mags. The optics in this scope are extremely impressive with acceptable color. Did I get lucky? The optics alone are worthy of the 10 rating considering the price.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.32.20)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39618

>After having to make a slight adjustment in collimation of the optics, the scope has a nearly textbook perfect star test at high mags.  The optics in this scope are extremely impressive with acceptable color.  Did I get lucky?  The optics alone are worthy of the 10 rating considering the price.


How did you collimate it?

Orion ShortTube 90mm
THIS LITTLE SCOPE REALLY SURPRIZED ME. I HAVE A 8" SCT THAT RESOLVES FAINTER OBJECTS BUT THE EASE OF USE HAS ME GRABING FOR THE SHORTUBE A LOT MORE THAN I THOUGHT I WOULD. IT'S NOT AN APO BUT FOR THE PRICE, I REALLY THINK IT IS A FANTASTIC SCOPE. I RATE IT HIGH BECAUSE IT OUT-PERFORMS IT'S PRICE TAG AND IS VERY SO EASY TO TRANSPORT AND SETUP. I USE A MIRROR DIAGONAL AND MEADE 4000 PLOSSLS. IT STAR TESTS WELL AS LONG AS I DON'T PUSH THE MAGNIFICATION TO FAR. THERE IS A HALO AROUND BRIGHTER OBJECTS BUT IT ISN'T BAD ENOUGH TO BOTHER ME MUCH. WOULD RECOMEND IT AS A GREAT BEGINNER SCOPE.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.205.165)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39609


Orion ShortTube 90mm
Always in the back of my car! Truely transportable! (The cheap diagonal replaced with a high quality one.)

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.72.130)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39606


Orion ShortTube 90mm
Simply put, this scope delivers. Because it is a short-focue achromat, it is not very good with planets. It IS good with the Moon (as most well made scopes are)

However it shines as a womderful wide-field scope. If you do get this scope in dark skies, you will love the views it gives.

In short, at low power a wonderful scope for the money.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.151.210)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39601


Orion ShortTube 90mm
Not bad. I bought this for my son about a couple of years ago.
I just wanted to see what he could do without Televues and Vixens and low aperture (He's 14 now). A test you could say. Nice travel scope. I placed a
piece of ED glass on top of the dew cap with some of that ultra-strong glue
(the one they put aircraft pieces together with!), so it corrected some of
the enormous color flaw. I give it an 8 for portability and reasonable optics.

daSentinel

Overall Rating: 8
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.253.104)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39619


Orion ShortTube 90mm
Very small with a larger objective than the 80mm.

Seemed pretty well put together and had nice crisp images, however the secondary colour on bright objects was very annoying on high powers. With an 8mm Radian the view was distinctly coloured, however on the 18mm it was fine.

If you want a portable rich field scope this should fit the bill, just go easy on the power and avoid bright objects like the planets and moon. Of course you could stop it down to 60mm ;-)

Overall Rating: 7
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.77.5)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39616


Orion ShortTube 90mm
I hope you like color abberations. I found bright objects show purple halos - Moon & Jupiter mostly. Stars were pinpoints and contrast was medium. Most offensive was the Orion Alt-Az tripod. Tracking any celestial object was frustrating. Some hint of internal reflection. On the plus side, it is small and portable. It works well for terestrial viewing and birding given the price. But forget these Chinese Achros for night time viewing. I did not invest in a mirror diagonal upgrade. It would probably help. Pushing the ST90 to 192X the contrast fell off dramatically. That is 52X per inch of aperature. Jupiter revealed banding but not impressive. Wide field is OK in the darkest skies. Solar viewing is decent with a solar filter. I gave it to a child as a starter scope. She loves it. I would suggest buying an Orion 6" to 8" Dob for Celestial viewing. For the same price you will get a true rich field scope that can reach out to DSO's and the mount is perfect for manual tracking. They are just not as portable. For birding, the ST90 is fine.

Overall Rating: 6
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.182.249)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39615


Orion ShortTube 90mm
Nicely packaged but optics exhibit too much color for me on bright objects. Good only as a rich field telescope. Forget the planets.

Overall Rating: 6
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.207.196)
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=39614

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