Jump to content


- - - - -

Orion Skyquest XT4.5

My first telescope purchase was in 1993. After a great deal of research I had decided on a Celestron SPC-8. It was not my first experience with a telescope but it represented my decision to get serious with astronomy as a hobby. Since then I have added to my telescope stable. Each telescope had been acquired to compliment the original SPC-8. I added a Celestron 102HD refractor and an Orion ST-80. The C102HD was purchased as a second main scope with the primary purpose of giving sharp views the moon, planets, and double stars. The ST-80 was obtained via trade on Astromart. I obtained it to serve as a travel scope, a scope for solar observation, and as a grab and go scope. I wanted a scope that would allow me to walk out my front door and start observing. It served that purpose but I wanted a scope that would show me more but still have a weight light enough for me to move around with ease.

With that in my mind I decided to purchase another telescope. Price was a factor. My spending limit would be $600. After some research and thought I narrowed the field to two telescopes. All had good reviews. The Televue Ranger represented the high end of my price range. I considered it because of its image sharpness and quality. In a middle position I considered the Stellarvue AT1010. It costs less than the Ranger and has a greater aperture

I was still uncertain about purchasing either the Ranger or the AT1010. Both would be excellent scopes but they still lacked a feature I wanted which was a larger aperture. They were also similar to the ST-80 I already had. With the idea of increased aperture combined with light weight in mind I started to think differently and looked at an Orion Skyquest XT4.5. It had the larger aperture as well as the light weight that I wanted. It weighs around 17 pounds including its base. The price the final deciding factor. At $199 I could not overlook this scope. After reading reviews of the scope I decided to go for it. I could keep my ST-80 and with the money I had left over I decided to get a Kendrick baader solar filter for it. I called Highpoint Scientific to order the XT. I could pick it up at their shop and they would put it together for me as well as collimate it.

I picked up the scope. The base and tube easily came apart for transport in my trunk. All I had to do was release the tension springs. Orion made this easy to do since each spring has a cord attached specifically for that purpose. Once I got the scope home I placed the tube in the base and pulled the tension springs over their corresponding posts on the base. The mount is very stable and the tube moves easily in it. The tension springs work well as far as holding the position of the tube and allow easy altitude adjustment. After putting the tube in the base I attached an Orion EZ Finder that I had laying around to the tube with double sided tape. The scope comes with a correct image 6X26 finder on it already. The EZ Finder compliments the stock finder. A combination of both will make finding objects in the sky much easier.

Fortunately the weather on the day I brought the scope home was clear so I could use it that night. I live in a fairly large town that creates moderate light pollution. Fortunately I live on the edge of town so my view of the eastern sky is actually not too bad. The moon was almost at first quarter. After aligning the finders that was my first target. In the finder scope there was a distinct double ghost image of the moon. I guess I can overlook this since the finder is used sparingly. I have an extra 6x30 finder so I might slip that into the bracket instead. I didn’t notice any double images for other bright objects. The scope came with two eyepieces, 25 and 10mm Orion plossls. They worked well with the scope. My view of the moon was crisp through both eyepieces although the part of the sky that it was in was starting to cloud up and since it was my first object of the evening the scope had not cooled down enough yet. The next target was Albireo. It also was crisp and clean. I decided to wait a bit for the sky to darken and the scope to cool down more. Some high clouds were starting to move into the southern part of the sky.

After about 30 minutes I started to observe again. The next target was M13. I easily found it in the 6X26 finder after using the EZ Finder to point the scope to that part of the sky. The view was great through the 25mm eyepiece. I could make out a granulated texture easily. I put the 10mm eyepiece in and that texture stood out even more. The sky was not totally dark yet.

Next I tried for M92. I used a 40mm Orion plossl to help find it. After a bit of hunting I picked it up in the field of view and switched to the 25mm eyepiece. Again the view was great. I saw a pronounced granulated texture. The 10mm eyepiece showed more of this.

Throughout the night I viewed a number of deep sky objects that included M15, M31, M27, M56, M11, M 57, and the Double Cluster. Each view was crisp and clean. I also viewed a number for double stars that included Mizar, Nu Draconis, Almach, Eta Cassiopiea, and Gamma Delphinis. Again each view was crisp and clean. I tried to split Epsilon Lyrae but by that time the sky was deteriorating and I could only split one of the doubles cleanly with the 10mm eyepiece.

After a couple of days of rain I observed with the XT again. The moon was in first gibbous. The craters Tyco and Copernicus were clearly seen. I again observed M27, M13, M15, and M57. This time I used my Televue 7.4 mm plossl to cleanly split both pairs of Epsilon Lyrae at 121x. I decided to get up early to observe the morning sky. After letting the scope cool I started a mini observation session before I was off to work. The views of M42, M35, M1, M36, and M38 were all remarkable. I easily saw four stars in the Trapezium at 121x. Jupiter looked great. The cloud bands were easily seen with a slight amount of detail. Saturn was also great. Saturn's cloud bands and Cassini Division were easily seen at 121x. I tried my Orion shorty barlow with a Televue 7.4 mm plossl. The view of the planets was good but I felt it was better at a lower magnification.

I observed with the XT a number of times over the next week. Each time I became more and more impressed with the scope. I decided to modify a small plastic lawn table to act as a base to hold the scope up to a more acceptable eye level. I attached a set of three old lens caps from binoculars to the table to help hold the three feet on the scope’s base from slipping off the table. The setup seemed to work well.

The time came to bring the scope to one of my club’s monthly observing sessions. This was the first time the XT would be used at a truly dark site. I brought my Celestron SPC-8 as well. The skies that night were clear and steady. I observed many of the same objects through both scopes. The views of the Double cluster in Perseus and M34 were actually better in the smaller scope due to it’s wider field of view. I used a Sirius 25 mm plossl with the XT. It created a wider field of view for the XT allowing it to frame M34 and the Double Cluster better than the larger scope. Both clusters of the Double cluster were easily seen in the XT. I used an Ultima 30 mm eyepiece with the SPC-8. The field of view created was not wide enough to allow both clusters of the Double Cluster to fit in it. If I used my focal reducer with the SPC-8 I can fit both clusters in the same field of view. It changes the scope from f/10 to f6/3. The XT is f/8. Of course the larger scope allowed me to see fainter stars and therefore more stars in these clusters. I later turned the SPC-8 to the faint galaxy NGC 7331. The mirror of the XT just wasn’t large enough to let me see it. The same goes for M110. The XT showed M31 and M32 nicely but showed no hint of M110. It was just too faint for the XT. The larger scope showed M110 easily. M27 also looked quite nice in the XT. It was very bright with good contrast and a distinct shape. Anyone who looked through the XT that night was impressed with the views through it. It showed many of the showcase Messier objects very well.

The optics on this scope seemed to be very good. The views of all the objects were clean and crisp after the scope cooled down and the sky got dark. The mount moved easily and was very stable. The only problem I’ve encountered so far were the double ghost image of the moon in the finder and the small size of the scope. In order to use it you must kneel on the ground. Sometimes I found myself sitting on the ground looking through the eyepiece. This is why I modified one of my plastic lawn tables to act as a base to hold the scope up higher. It is an excellent size for children. Both my daughters want to give it a try.

The 25 mm Sirius eyepiece gives very nice views. I’m not so sure about the 10 mm. Maybe I’m spoiled by my Televue 7.4 mm plossl. The images just don’t seem to be as sharp as they could be through the 10 mm eyepiece.

After moving in and out of my house many times the collimation is still right on. The manual that came with the scope shows how to collimate the scope. It gives a nice set of instructions and pictures that show how to do this. The procedure looks easy. The primary mirror has a set of three thumbscrews that adjust the tilt of the mirror. There is also a set of three thumbscrews that lock the mirror in place. A 2 mm Allen wrench is used to adjust the secondary mirror. A collimation cap is also provided. I’m not sure how well this will work but the only way to know for sure is to use it. I may have to pick up a laser collimator or a chesire eyepiece if it does not work well. There is also a section in the manual concerning cleaning the optics and how to put the scope together. It also has a section on how to use the scope.

So far I think this scope is great. It is easy to use and offers clean, crisp views. At the end of an observing session all I do is pick it up by its carrying handle and walk through the front door of my house to put it away. I would recommend this scope to anyone who is looking for a small grab and go scope. It offers a greater aperture than many short tube refractors. It may weigh slightly more though but not by much especially if you are using a heavier duty tripod. The only aspect of using the scope that may turn some people off to it is kneeling to use it, but at a price of $199 this could be overlooked if you make some sort of base to put the scope on.

The April 2001 edition of Sky and Telescope offers another suggestion on this as well as ways to modify the optics to make them even better. Some may suggest going for a XT 6 instead of the 4.5. I considered this but even though it has a larger aperture it weighs 37 pounds. For me that would be a bit too much. I would recommend this scope to anyone. I could be a great beginner scope for adults or children. It is also an excellent choice as a grab and go scope or second scope for more experienced observers. It gives excellent views for a bargain price.

Addendum (10/06/02)

After posting this review a reader emailed me and told me I should be able to see M110 and NGC 7331 with the XT. I brought the scope to my club observing session and tried for the two objects again. I found both easily. I'm not sure why I couldn't find M110 before. It could be the sky was a bit too bright to see it. I can see how I missed NGC 7331 though. It is quite small and if I was not in the right area of the sky I could easily miss it. This time NGC 7331 appeared as a small faint oval smudge. M110 was very faint and really could only be seen with averted vision. I was able to frame M31, M32, and M110 in the same filed of view with an Orion 40 mm Sirius plossl. All objects were much fainter than they would appear in my SPC-8. Again all those who looked through the XT were quite impressed. The view of the three galaxies especially impressed them. The more I use this scope the more impressed I am with it. The only other problem I encountered was that it takes extra effort to pull the tension springs over the pegs on the base to seat the tube. I'm not sure a child could do this without help.


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics