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Home / Celestron 70mm Travel Scope Review
by Ed De Mateo 11/28/10

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CELESTRON 70MM TRAVEL SCOPE REVIEW

By Ed De Mateo

BACKGROUND

I have an Orion XT6 Classic that I enjoy a lot, along with a modest eyepiece collection. One of those eyepieces is a 40mm Plossl for viewing wide expanses of sky at low power. Seeing the double cluster in Perseus or the Pleiades within the eyepiece is breathtaking. Eventually I realized that I wanted a short-focus, wide-field telescope which would serve double duty as a spotting scope. It had to be something I could easily pack up and take on a car trip to a tournament, and be able to do double duty for night sky observing. Finally, it had to be of reasonably good quality and inexpensive. After scouring the internet and looking at a lot of options I found the Celestron 70mm Travel Scope at Amazon for around $55 shipped. The scope package seemed to be just what I was looking for and the price was right. Out came the credit card and all the anticipation of waiting that follows.

TRAVELSCOPE

The box finally arrived. Everything was stored inside the backpack, which is well made and of good quality. Included are the scope, a 45 degree correct image diagonal, one 20mm and one 10mm eyepiece, a finder scope, a tripod, a lens cleaning cloth and an excellent instruction manual. Everything fits inside the backpack with plenty of room for various necessary items, such as a red flashlight. There are additional storage pockets in the backpack and a zippered pocket inside the lid that can hold a small sky atlas and other papers.


Figure 1. View of the backpack (left) with the scope and other items inside (right).

The supplied ownerís manual is well written and very detailed, and is translated in several different languages. It can be downloaded from Celestronís website in PDF format. The manual does a good job of covering the telescope assembly and basic operation, as well as having sections covering astronomy basics and celestial observation. Maintenance and specifications are found in the last pages.

The scope is a refractor with a 70mm (2.8Ē) aperture and fully coated glass lenses. It has a short focal length of 400mm, enabling lower magnification for a given eyepiece and more expansive views. Up front the objective lenses are housed in a plastic lens cell with a fixed dew shield. The lens cap is actually two pieces. With the center piece removed it can be used as an aperture stop, helping to tone down and enhance the view of bright objects, such as the moon or Venus. The scope tube is made from aluminum and has an aluminum bracket with standard ľ-20 threads for mounting on most camera tripods. The focuser assembly is mostly made from plastic, keeping weight and cost down.


Figure 2. Celestron Travel Scope mounted on my photo tripod.

The included diagonal is a 45 degree correct image prism in an all plastic housing. This diagonal design is primarily intended for terrestrial observation. It can get uncomfortable when observing targets with the scope near vertical. For daytime viewing the diagonal is actually good, but at night there is noticeable green and purple fringe coloring on the bright objects, especially with higher magnification. This is to be expected when combining a correct image prism with a fast focal ratio. Using the lens cap as an aperture stop helps considerably.

Two eyepieces are supplied in nice storage containers. The lenses appear to be glass and the chromed barrels metallic, presumably aluminum. The eyepiece bodies appear to be plastic, keeping weight and cost down. The 20mm gives 20x magnification in this scope, the 10mm giving 40x. Like the diagonal, I found that the eyepieces perform well for daytime viewing and are acceptable for casual night observation. Other than brand name and focal length, there are no evident markings denoting design type.


Figure 3. The supplied 20mm and 10mm eyepieces (left) and prism diagonal (right).

I canít say much about the finderscope except that I donít use it. It reminded me of the toy pirate scopes sold at dollar stores. I have never had any trouble finding a target with the 20mm eyepiece.

The included tripod is a simple and compact photo tripod that fits nicely in the backpack. When fully retracted it is a very usable and stable unit. It has served me well on the shooting bench at the rifle range, as well as on a table top for back yard astronomy. Fully extend the legs and neck and it becomes totally useless. It is spindly and seems like it will never stop shaking, and even a slight breeze will make it dance. Itís also not quite tall enough for viewing standing.

DAYTIME PERFORMANCE

During the day the performance of this scope is very good. The images are sharp and clear, and the scope can focus from very close to infinity. My favorite eyepiece is the 20mm and is the one I almost exclusively use. It gives me a good wide field of view with sufficient magnification to see detail. The 10mm eyepiece feels more restrictive to me and does not give me the wide field of view that I like. Also, it does show some purple fringe color, and if you are looking for it you will definitely see it.


Figure 4. Transmission tower seen in background from parking lot is 1.34 miles distant (left). View through scope with 20mm eyepiece is good even though there was a lot of haze and mirage (right).

At the shooting ranges, both gun and archery, I exclusively use the 20mm eyepiece. At the archery range I can see the full FITA target (the big colorful one familiar to most) all the way out to 90 meters. The view is clear and sharp, allowing me to see my arrows in the target. At the shorter distances, down to 30 meters and less, the view is expansive enough to be useful. I also use the scope as a spotter at the rifle range, either on the bench with the tripod that comes with it, or on the ground using my photo tripod. At 100 yards even the .22 caliber bullet holes can be seen. At 500 meters I can clearly spot targets as small as clay birds on the ground, and I am able to ascertain hits. At 1,000 yards I also like the 20mm eyepiece. I can see the target area and the steel swingers, 10Ē and smaller, and observe hits. One negative is that this scope is not sealed and water can possibly enter if it should start to pour. But then again, it isnít a high end scope and you can dry it out.

Viewing birds and other flora and fauna is a treat with this scope. I was surprised by the level of clarity and detail that can be seen. Iím not a birder or nature observer but for casual viewing this scope will give a more than satisfactory view.


Figure 5. I photographed these two birds in my back yard at an approximate distance of 20 feet.

ASTRONOMY

The manual that comes with this scope states that it ďÖis ideal for terrestrial as well as very casual astronomical observation.Ē I couldnít agree more with that statement. When using the scope with the supplied 45 degree diagonal it can start to get awkward or uncomfortable as the targets get closer to vertical. Itís no different than other scopes using a 45 degree diagonal. The diagonal itself uses a correct image prism that allows you to see the image as you would with your naked eyes. The complexity of the prism and short focal length combine to introduce false color in the fringe of bright objects and some image and brightness degradation. The view is actually quite good, just donít expect it to rival fine refractor scopes. The eyepieces are also not the finest in quality but are usable and give a good view of objects in the night sky. The 20mm gives a more expansive view and is my preferred eyepiece of the two. The 10mm gives a slightly wavy image that is a bit on the dim side. Itís OK, but I really prefer the 20mm eyepiece.

LUNAR AND PLANETARY

The moon is a big brilliant target that many people enjoy observing. This scope does a good job on the lunar surface with either of the two eyepieces. Views are reasonably sharp and clear, showing good surface detail. Some false coloring is evident, but not so bad that it spoils the view. Using the scope cap as an aperture mask almost totally eliminates the coloring while taming the image brightness.


Figure 6. Lunar photos taken through the eyepiece with a digital pocket camera.

Venus is another brilliant target that benefits from stopping down the aperture. The green and purple fringe coloring can be very pronounced without the aperture mask. With the 10mm eyepiece the planetary phase becomes evident, Venus looking like a small and bright half moon.


Figure 7. Venus through the eyepiece, showing fringe coloring on both sides of focus.

The scope also does a decent job on the two naked eye gas giants. Viewing Saturn with the 20mm eyepiece reveals a small disk with the rings appearing as a line through it. Increasing the magnification to 40x with the 10mm eyepiece gives a surprisingly good view. Jupiter is also a good target with either eyepiece. The four large moons are visible, and with good seeing and the 10mm eyepiece one of the bands can be seen.

STAR CLUSTERS

Open clusters are one area where this little scope performs well. The lower magnification of the 20mm eyepiece is great for taking in wide views of the night sky. NGC6231 is a small open cluster in Scorpius that looks like a pile of diamonds shining in the night sky. M7 and M6 are more spread out than NGC6231, but can still be observed well in the eyepiece. Views of the open clusters through the 20mm eyepiece are bright and sharp. I tried the 10mm eyepiece out of curiosity but the view was dim and not very sharp. With the higher magnification, the 10mm is not the eyepiece of choice for open clusters.

Globular clusters, as well as galaxies, are too dim for this little scope. I tried looking at globular cluster M22 in Sagittarius but it appeared as a very faint, almost ghostly image. Maybe in a dark sky site, but in my backyard I was pushing the little scope way beyond what it was intended for.

DOUBLE STARS

This is another area where the scope performed well with the 20mm eyepiece. Albireo separates nicely at 20x and the yellow and blue colors of the stars were beautiful. The image is bright and sharp, even in my light polluted environment. Viewing the double double in Lyra through the 20mm eyepiece also gave a sharp and bright image, although at 20x the tighter doubles are not going to be resolved. The 10mm eyepiece was again a big disappointment with a dim and fuzzy view, and itís not powerful enough to resolve tight doubles anyway.

SUMMARY

The Celestron 70mm Travel Scope is a reasonably good low cost unit intended for daytime viewing and casual astronomical observation. The package is light and compact, primarily designed for travel. All components can be stored in the backpack, which has enough room for accessories. It serves well as a spotting scope at the rifle or archery range, and for impromptu views of flora and fauna. At night the scope will give reasonable performance on a variety of astronomy targets should the urge strike. Plastics are used extensively, especially in the focuser assembly, but it helps to keep weight and cost down.

Performance of the scope is surprisingly good. I was impressed with the views using the supplied 20mm eyepiece, which are reasonably sharp and bright. I find that it is the only eyepiece I use at the gun and archery ranges, as well as at night for astronomy. The 10mm eyepiece was a disappointment with its dim and not so sharp views. Good thing I donít find much use for it. The supplied tripod, if extended, can be a source of frustration. Keep in mind it was meant to fit in the backpack.

This scope is a good option for someone who wants an inexpensive scope that can be stored on a closet shelf in a tiny apartment or efficiency, or kept in a car or pickup truck for spur of the moment views. Traveling to tournaments is a breeze with everything stored in the backpack. Finally, a couple of inexpensive Plossl eyepieces and a prism star diagonal will really make this scope shine, improving performance exponentially.

Clear skies to all,

Ed D

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