The Optical Tube
The Celestron TravelScope 50 is a 50mm f/7.22 achromat. At this size and focal ratio, there should be fairly little chromatic aberration. The aperture, while tiny, is sufficient to show you details of the Moon, planets, and the brightest deep-sky targets. Unfortunately, for whatever reason, there is poorly designed internal baffling, which is usually there to control light scatter and internal reflections. This actually stops the telescope down to 20mm, making it essentially unable to deliver an image much better than the naked eye – your eye dilates to around 7-8mm under good conditions. With only 20mm of aperture available, the telescope becomes an f/18 and provides ridiculously dim images of even the Moon. You are using a telescope that is about on par with what Galileo had.
The TravelScope 50 also has a 0.965” plastic rack-and-pinion focuser, so using a quality diagonal besides the provided one is going to be tricky, if not costly and impractical. The entire tube, focuser, and lens cell are plastic, making for a ridiculously lightweight instrument – only around 300 grams (less than ½ a pound).
The TravelScope 50 includes two Huygenian eyepieces, 1.25” units with focal lengths of 20mm and 8mm, providing 18x and 45x, respectively. These are extremely bad eyepieces made almost entirely out of plastic (including the lens), and they provide fuzzy views that require jamming your eyeball into them to even see. They also have narrow apparent fields of view, and the resulting effect feels like staring down a soda straw.
For a star diagonal, the TravelScope 50 includes a 45-degree erecting prism that adapts the focuser to fit 1.25” eyepieces and flips images to be correct left-right. It’s of quite low quality, and the 45-degree angle makes it less-than-ideal for pointing the scope high in the sky.
For a finderscope, Celestron includes the same 5×24 finder supplied with many of their low-quality entry-level scopes, like the PowerSeekers. Not only is this finder nearly impossible to align with the main telescope, but it also provides extremely dim and fuzzy images thanks to its single-element plastic objective lens. It’s also, thankfully, completely unnecessary with the TravelScope 50, which itself is only a little bigger than some finderscopes and can easily be aimed by sighting along the tube with a low-power eyepiece in the focuser.
The included backpack is of low quality but functional. Everything fits nicely inside.
The tripod included with the TravelScope 50 is pretty low quality; basically, it’s just a cheap camera tripod like the kind you can order on Amazon for around $10. The good news is that the TravelScope 50 is so absurdly small and lightweight that it basically does not matter. For once, Celestron has managed to supply a mount adequate for the scope it’s sold with, though the TravelScope 50 is so bad that this essentially doesn’t matter.
What can you see with the Celestron TravelScope 50?
As a daytime spotting scope, the TravelScope 50 produces a fairly dim image with a cloudy edge around the field of view using the included H20 mm eyepiece, which provides 18X. As long as you are not too fussy about colour and clarity, this arrangement is at least usable in bright sunlight. The central 50% of the image can be brought into fairly sharp focus.
When fitted with the 8 mm eyepiece, 45X, the image is just awful. It is dark, difficult to focus, and has significant colour aberration, even in bright sunlight. We consider this eyepiece unusable for spotting scope service. So, as a spotting scope, we would give it 2 out of 5 stars based on the package, but the optics are not great and the included eyepieces are very low quality.
As an astronomical telescope, this package fails in so many ways. I give it 1 star out of 5 as an astronomical telescope. The 45-degree correct image diagonal does not work well for astronomy in this or in any scope. To view a target that is more than 40 degrees above the horizon, you have to get into a very awkward position. You could buy a 90-degree star diagonal, but we would not recommend investing in that with this scope. With the included eyepieces, you could view the Moon, but typically bright star clusters are very dim and the image is not clean anywhere outside of the centre 50% of the field of view with the included eyepieces.