Comment on Orion Short Tube 80mm Refractor Telescope

jimmyleong · Post by **jimmyleong** » Wed May 18, 2011 4:07 pm

Hi I would like to ask if anyone has experience using the above mentioned refractor telescope. There are pretty good review online, but I would like to hear from users in Singapore.

Presently I am a newbie who like to get a decent telescope that is not too expensive or heavy. I might also be using this telescope as a telephoto 400mm lens with my nikon dslr.

All comments and suggestions are welcome. Thanks.

wucheeyiun · Post by **wucheeyiun** » Wed May 18, 2011 4:13 pm

Hi , i have tried the Orion Short tube ( Achromatic lens assembly by design ), it is a very light and bright telecope. However, it has a lot of colour aberration. Not suitable as a DSLR zoom lens.
You will need a ApoChromatic telescope for short focal length scope. If you need to get a achromatic type telescope ( for economical reason ) , try celestron c4r and the focal length is 1000mm. It has better for colour correction and cheaper than APO scope.

jimmyleong · Post by **jimmyleong** » Wed May 18, 2011 6:40 pm

reason i asked was because i read a review by one user and it seems ok:

http://www.cloudynights.com/item.php?item_id=1777

orly_andico · Post by **orly_andico** » Thu May 19, 2011 1:08 am

The ST80 may have been grand 10 years ago. But today it's just another cheap fast achro.

You're better off finding something like a Megrez 72 or Megrez 80. At least those are APO, and the price isn't too horrible. example

http://www.williamoptics.com/wo_shop/ca ... cts_id=534

This is $400 USD shipped. So you just need to add the 7% GST. I think it's money far better spent than on an ST80.

kayheem · Post by **kayheem** » Thu May 19, 2011 8:45 am

Perhaps if you send out a 'Want To Buy' (WTB) post in our Buy/Sell forum, you may be able to get a good small apo at a good price.

jimmyleong · Post by **jimmyleong** » Thu May 19, 2011 9:33 am

Thanks for the replies. I am practically new to astronomy and I also do not want to spend too much in it yet. I am just looking around for now. I may even get a scoping telescope first to start with.

Meanwhile I am waiting for the books I purchased online to arrive so that I could start reading and get myself more informed.

vil · Post by **vil** » Thu May 19, 2011 1:07 pm

i bought 1 months ago but yet to use it for night viewing, only did some terrestrial viewing in the daytime and the images were sharp and clear. it is currently underutilized now but I think i will be bz with it when I move over to my new place with superb unblock views in Jul 11.

cloud_cover · Post by **cloud_cover** » Thu May 19, 2011 9:17 pm

The orion 80 ST is a fast achromat. Generally most modern achromats demonstrate moderate to little CA apart from bright objects like the brightest stars, jupiter, the moon for visual use, unless you are very CA sensitive.
However, when doing photography, especially with longer exposures, the CA will become evident as blue, bloated stars
Also, with a faster telescope you need better eyepieces to deal with the steeper light cone or the edges of your FOV will look terrible.
So in summary, as a telephoto lens for terrestrial objects, probably acceptable IF you can accept manual focus and don't intend to shoot subjects with fairly high contrast and don't mind some purple fringing. As an astronomical lens, you have to be prepared for blue, bloated stars. A reasonable way to work around this is to either use a minus-violet filter, narrowband filters or LRGB filters

Hope it helps!
I suggest for the price you intend to bring it in, consider the Celestron 80EDF that is going for a bit more, or for even a little bit more, consider Tim's Megrez 88. These are ED scopes that suffer from far less CA which means that component of light that is dispersed is now concentrated into your eyes as the image proper

jimmyleong · Post by **jimmyleong** » Thu May 19, 2011 10:35 pm

hi it seems that celestron 80edf is out of production and i am not sure if the megrez 88 you are referring to william optics megrez 88 fd which is also not available anymore...