Optical Tube Assembly of AstroMaster 114EQ
The 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 shrunken down, the primary take the shape of a sphere that is easy to make (cheap), and allows for a stout and stubby telescope which has a long focal ratio and next to no coma. At the time the Bird-Jones was designed, eyepieces were simple and coma correctors 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The Bird-Jones design is outdated and no longer needed.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 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 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.
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 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 awkward positions, 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 anyways, this is a non-issue.
The optics in the AstroMaster 114EQ are so bad 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.
The AstroMaster 114EQ may be slightly better than its cousin, the PowerSeeker 127EQ, but not by much.
In short, please don’t buy this telescope, and if you already did so and are reading this review for reassurance, I would recommend canceling your order or returning it.