Optical Tube Assembly of AstroMaster 114EQ
The Celestron AstroMaster 114EQ is supposedly a 114 mm Newtonian reflector with a focal length of 1,000 mm. This should immediately raise some eyebrows, as the optical tube of the telescope is obviously way too short to accommodate such a focal length.
So what’s going on? Well, the AstroMaster 114EQ isn’t actually a Newtonian. It’s a Bird-Jones (or Jones-Bird, depending on who you ask).
As originally designed by Bird and Jones, this catadioptric design uses a spherical primary mirror with a corrector lens just before the secondary mirror. This design allows for the secondary mirror to be shrunk down, the primary take the shape of a sphere that is easy to make (cheap), and allows for a stout and stubby telescope that has a long focal ratio and next to no coma. At the time the Bird-Jones was designed, eyepieces were simple and coma correctors were nonexistent, so focal ratios tended to be on the long side to achieve sharp images.
The Bird-Jones design is outdated and no longer needed. The cheap Kellner eyepieces supplied with many entry-level telescopes today would’ve amazed a 1950s amateur with their quality and work well enough with even a relatively fast focal ratio telescope. Furthermore, Celestron didn’t even bother to execute the design correctly. Celestron’s Bird-Jones design places the corrector lens inside the focuser. This causes two problems.
First, it can’t easily be removed, which is basically required to collimate the telescope precisely and achieve sharp images. Second, it means that the spacing between the corrector and the primary mirror is not fixed, but instead varies depending on what eyepiece you’re using and also whether you’re nearsighted or farsighted. So the correction is constantly varying depending on what eyepiece is used or even who is looking through the telescope.
The problems don’t end here, though. The correctors in these scopes are incredibly cheaply made and aren’t remotely close to the right shape, being glorified cheap Barlow lenses. As a result, the 114EQ cannot achieve decent images even when well-collimated, which itself is hard to do.
Moving on to the mechanical aspects of the OTA, we come to another problem: the plastic castings. The giant casting with the AstroMaster logo that protrudes nearly halfway along the tube, as well as the area around the focuser, means that you cannot slide the tube in its rings to achieve balance on the declination axis in most situations. This strains the mount and is a nuisance while observing, as you will always have to tighten the declination axis.
The focuser on the AstroMaster 114EQ is a modest and functional 1.25” rack-and-pinion, mostly made of plastic, apart from the knobs. The finderscope is a standard StarPointer red-dot finder, though until recently, most AstroMaster scopes had an obnoxious and often-faulty built-in red-dot finder.
The Celestron AstroMaster 114EQ comes with standard tube rings and a very short Vixen dovetail, which would allow you to put the scope on a different mount, although this is the equivalent of putting premium dipping sauce on McNuggets—the prime ingredient is still cheap and the secondary ingredient is never going to compensate for that. One of the rings has a captive ¼ 20 knob, so you can piggyback a DSLR camera on top, but this will further wreck the balance, and is too much for the mount to handle anyway.
Eyepieces with AstroMaster 114EQ
The AstroMaster “Newtonians” all come with a 20 mm “erecting” eyepiece just like the PowerSeekers for low power. The eyepiece is almost entirely plastic, has a narrow field of view, and isn’t sharp in the slightest. Celestron includes this eyepiece solely so they can sell it at nature and science stores under the premise of it being capable of terrestrial viewing.
The other eyepiece included with all AstroMaster telescopes is a 10 mm Kellner. It works fine in most other telescopes, though the 114EQ is, of course, incapable of delivering a sharp image with it.
The CG3 Mount
The mount Celestron supplies with the AstroMaster EQ telescope is known as the CG-3, though some literature refers to it as a CG-2. Celestron’s CG numbering system is confusing; they should ditch it and stick with the EQ1-8 system that other companies use.
The CG-3/CG-2 is of the run-of-the-mill, cheap, and German equatorial design, with tiny, useless setting circles that are little more than decoration. It has 1.25” tubular steel legs and lots of plastic castings on the tripod. The mount also has a Vixen saddle, so it can accept other optical tubes interchangeably with no tools needed.
The CG-3 has flexible slow-motion cables for both axes and fine adjustments in altitude, and has an azimuth for accurate polar alignment. You can also equip the mount with Celestron’s logic drive for hands-free tracking.
German equatorial mounts can often place the eyepiece of a Newtonian in an awkward position, and you must rotate the tube in its rings to reposition it somewhere more comfortable.
Normally when doing this you’d have to worry about accidentally sliding the tube forward or backward when the rings are loosened, and thus possibly ruining the declination axis balance, but since the optical tube can’t really slide far in either direction and the balance is so messed up anyway, this is a non-issue.
Were it not for the balance issues, the CG-3 would actually make a fairly adequate mount for the Celestron Astromaster 114EQ. However, given that the telescope cannot actually balance on the declination axis, it is nearly impossible to aim accurately.
At the same price as the AstroMaster 114EQ, there are a lot of good scopes. A few we’ve selected include:
- The Zhumell Z130, with significantly more aperture, better optics, better accessories and an easy-to-use Dobsonian mount.
- The Sky-Watcher Heritage 130P, essentially the same telescope as the Z130 but with a collapsible tube.
- The Orion StarBlast II 4.5 EQ offers everything the AstroMaster 114EQ promises but with significantly better optics and accessories.
- For a bit less money, the Zhumell Z114 offers a 114mm telescope like the AstroMaster or StarBlast but with great accessories, great optics and a simple, lightweight and affordable Dobsonian mount.
The optics in the AstroMaster 114EQ are so bad that you can completely forget about taking decent pictures with it. Even if this were not the case, a camera, whether directly coupled or piggybacked, would ruin the balance and strain the CG-3 mount too much.
What can you see with the Celestron Astromaster 114EQ?
If you manage to get it collimated, the AstroMaster 114EQ can give you fairly nice views of the Moon. Venus’ phases can be seen, while Mercury’s might be a little more difficult. A dark spot or two on Mars, along with an ice cap, is possible when the planet is close to Earth. Jupiter’s moons and cloud belts are easy, while the polar zones and Great Red Spot will probably elude you. Saturn’s rings and a few moons can be spotted. Uranus and Neptune are fuzzy star-like dots, assuming you manage to locate them in the first place.
Deep-sky objects are a little more forgiving, though the included 20mm eyepiece will make it feel a bit claustrophobic when viewing them. Open star clusters like the Double Cluster are easy, while globular clusters are unresolvable fuzzy smudges. You might have difficulty distinguishing many of the smaller planetary nebulae from stars, though the Ring and Dumbbell are easy. Galaxies will have detail-less smudges even from dark skies, apart from perhaps M82 and its dust lanes, and a few emission nebulae like Orion and the Lagoon are mildly intriguing, if washed out easily by light pollution. There is more to see with a good 4.5” with more resolving power and good eyepieces, for sure.