Celestron’s FirstScope is probably the only usable telescope that I’ve ever seen that ever retails for under fifty dollars. However, usable does not necessarily mean good, and that’s what we’ll focus on in this review.
The Optical Tube
The FirstScope is a 76mm (3”) f/3.95 Newtonian reflector with a focal length of 300mm, and a spherical primary mirror. If you have done some basic research about telescopes you probably know that a spherical mirror won’t focus light correctly like a parabolic one does, and that is indeed the case with the FirstScope.
Telescope's Rank - 6
Optical Tube Rating - 3
Accessories Rating - 1
Mount Rating - 3
Visibility Score - 2.5
Funny enough, if the FirstScope were f/6 or so, thanks to its small size and shallow curve it’d actually have a mirror close enough to parabolic as to work quite well. Even an f/5 would be passable. But an f/3.95 sphere simply doesn’t work well. The spherical aberration with the FirstScope is about 550 nanometers (1 wave), or 4-8 times the maximum tolerance for a decent telescope depending on who you ask. If you’re wondering why Celestron didn’t just make the scope longer, it’s because the material cost would go up, and the increased box size and weight alone would make it impossible to market the FIrstScope at the price it is sold for.
At f/3.95, precise collimation is critical with a Newtonian. Unfortunately for FirstScope users, the primary mirror sits on a plastic plate that doesn’t allow for any kind of collimation. You have an approximately 50/50 chance of the scope coming in decent enough collimation to render a remotely usable image (well, as usable as can be with a 1-wave aberrated mirror). Thankfully, Celestron’s customer service is fantastic and they’re more than happy to exchange your scope for a better one.
You can sort of collimate the scope yourself if you enlarge the holes for the screws attaching the mirror cell but it can be a little difficult to do this correctly. I struggled with mine, and I have owned hundreds of scopes. Oddly enough, the secondary mirror on the FirstScope is collimatable, but you’ll probably never need to adjust it.
The focuser on the FirstScope is actually more or less the same thing you see supplied on most cheap small Newtonians even four times its price – a plastic 1.25” rack and pinion. I’m impressed that Celestron was able to put something this usable on such an inexpensive scope.
The FirstScope has no finder – you’re supposed to simply sight along the tube. With the mere 15x supplied by the included low-power 20mm eyepiece, this is easy enough but may take some practice.
The FirstScope’s tube is wrapped in vinyl adorned with the names of famous opticians, astronomers, and physicists throughout history – a nice touch. This was originally done when the FirstScope was brought out for the International Year of Astronomy in 2009 to celebrate the 400th anniversary of Galileo’s first discoveries with the telescope, and Celestron has kept it in the decade since.
The FirstScope comes with two eyepieces: A 20mm Huygens giving 15x and a 4mm Ramsden (“SR”) giving 75x.
The 20mm Huygens…. functions. The apparent field of view is extremely narrow (30 degrees), and the view is fuzzier than it already would be with a good eyepiece in the FirstScope. The Huygens design adds some chromatic aberration (something one should never see in a Newtonian) and the edge of the field of view contains aberrations I don’t even know how to describe.
The 4mm Ramsden is useless, being the same hated eyepiece supplied with Celestron’s Powerseeker line. It provides too much power for the scope (75x), the eye lens is tiny, it has zero eye relief, it doesn’t perform well with a fast focal ratio telescope like the FirstScope, and the field is slightly narrower than the 20mm Huygens. It also has an annoying tendency to get stuck in the focuser, the solution to which is to turn the scope upside down, loosen the screws, and shake it – preferably while above a garbage can, where it belongs.
You can buy an “accessory kit” for the FirstScope. All the kit contains is some more garbage Huygenian eyepieces, a useless 5×24 finderscope, and a cheap Moon filter which you plain don’t need and doesn’t work well anyways.
Celestron offers a “Cometron” variant of the FirstScope which is exactly the same, except with passable Kellner eyepieces and the same godawful 5×24 finderscope attached. If that’s all you can afford I would recommend it over the base FirstScope, but really I would strongly caution you about both.
The FirstScope comes on a simple tabletop Dobsonian mount to which it is semi-permanently attached. Altitude tensioning can be adjusted with a hand knob while azimuth can be adjusted by tightening or loosening the nut in the middle with a wrench or pliers.
As to the smoothness of the mount’s motions, they’re pretty good, but it’s more or less irrelevant for a scope that is probably not able to handle more than 40x.
How Useful Is Celestron Firstscope, Really?
So, all that being said, what can you really see with the FirstScope?
Venus’ phases are visible (forget Mercury being anything but mush if you can even find it). The Moon shows its craters and a fair amount of detail. Mars is a fuzzy, small red dot at best, and at worst nothing more than a star. Jupiter’s moons are visible and Jupiter itself is a small cream-colored ball – with a higher magnification than the 20mm eyepiece you could maybe make out the equatorial band(s), but the Great Red Spot is probably invisible as are any other features. Saturn’s rings are visible at 15x as “ears” sticking out from the planet similar to how Galileo saw them, and higher power might show you the rings in their true form if you’re lucky. Saturn’s moon Titan is also visible nearby.
Forget finding Uranus or Neptune, because they look like nothing more than a star and you’ll be lucky to get in the general vicinity by sighting down the tube.
As for stuff outside the solar system, it’s a little challenging to locate stuff and of course you can’t use high magnification at all – however, the Orion Nebula and many open and globular star clusters are visible and look surprisingly decent. Provided you are able to locate them, there are plenty of interesting things to look at all year round with the FirstScope.
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All in all, do I recommend the Celestron FirstScope?
While a pair of binoculars is better, period, the FirstScope has a certain allure, perhaps charm to it that I can’t seem to get past. It may not be the best, but for the money it’s a surprisingly fun little scope that is a great jumping-off point for better things.