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Celestron Astromaster 130 EQ
by Revier
I cut my astronomical teeth on Celestron's refractors and as such the company is synonymous with nostalgic fondness in my mind, however, that was a long time ago and the world of astronomy has moved on since then. Have Celestron managed to keep up with the curve with their low cost reflector, the Astromaster? Well, the answer is ... yes...and no.
The Astromaster's strength undoubtedly lies in it's affordability and all of its attributes should be judged primarily against this criteria. Are there better optical performers out there? Yes! Are there sturdier and more solid mounts out there, without question! But few scopes manage to provide these things at such an alluringly low price.
The optics are solid and perform competently whether you're viewing the lunar surface or taking in those wispy and ethereal 'faint fuzzies' comprised of distant galaxies and nebulae. At F5, the larger more diffuse galaxies stand out well and are beautifully framed in lower powers, as are the myriad open clusters that dot the northern hemisphere but with a focal length of 650mm the use of higher powers will be needed to discern fine detail on planetary discs.
The scope is relatively light at around 24lbs and setup is quick and straightforward , it's always a relief lifting a tube this light when compared to my main 12" Dob which weighs almost as much as I do!
The CG-3 mount is adequate but does suffer from vibration issues and is too wobbly to be considered excellent. It does serve its purpose though and when you're only parting with £150 it's hard to be overly critical.
It even comes with an erecting eyepiece (though very cheap and plasticy) which means you can indulge in a little twitching (if you're that way inclined). The job of the erecting EP is to orient images the 'right' way up so when looking through the eyepiece, the object appears as it would through the naked eye rather than upside down or turned about.
All in all a plucky scope that is ideal for the frugal Astronomer and beginner alike. It provides those on a budget with a basic (but functional) tool with which to view the heavens and as such must come highly recommended.
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Celestron 6mm Omni Plossl 1.25" Eyepiece
by Revier
The Celestron Omni 6mm is a Plossl design. Traditionally, Plossl eyepieces contain 4 or 5 lenses, the Omni is typical in this regard containing 4 lenses. The lenses are arranged in a symmetrical fashion, 2 goups of 2 lenses closely spaced.
The plossls main selling point is the low amount of glass used in their design. The ... fewest number of lenses (otherwise known as elements) used in an optical system the clearer and more pristine an image will be. It's a different story when talking about premium eyepieces but as the Omni costs only £30 the rule less is more holds true.
On the down side, as a result of the positioning of the lenses, the field of view isn't enormous at 52 degrees. As the 6mm provides relatively high magnification (making it best suited for lunar and planetary observation) the field of view may seem frustratingly small especially on an undriven mount. At high magnifications objects such as the moon and planets appear to move rapidly through the eyepiece, this is caused by the Earth's rotation and can be the source of much frustration in smaller fields of view. A small field means more regular adjustment of the telescope to keep the object centred. This is not only annoying but can actually make it harder to pull out faint details as part of your brain is being held back by having to concentrate on keeping the image centred.
The Omni has 5mm of eye relief which can become uncomfortable, this eyepiece is absolutely not recommended for spectacle wearers. The field stop is very tight and can make it feel like looking through a pin prick, this can cause eye strain and headaches making for an uncomfortable viewing session.
Optically this eyepiece is reasonable for the price, contrast is fair, light scatter is minimal. Practically it's an absolute nightmare to use. Short eye relief and a small field stop conspire together to make for an unpleasant viewing experience. Though the optics are of a quality in keeping with the eyepieces price, its prohibitive physical traits make it one to avoid.
For a similar price why not check out the Skywatcher range of Plossls, far superior to the Omni and far more comfortable to look through.
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Celestron NexImage
by Revier
Everybody has to start somewhere in a new hobby and Celestron would like you to start with them and their entry level planetary imager the Neximage. Exclusively a lunar/planetary camera, the Neximage is marketed at the beginner interested in shooting objects within the solar system.
First, the facts...The neximage uses a 3.6mm ... x 2.7mm CCD colour chip with 640x480 resolution, with a pixel size of 5.6 microns giving a sensitivity of <1 lux. It's USB 2 and is capable of a maximum of 30fps (although we'll look at that in a bit more detail later). It comes with a CD Rom that's got processing software and camera control software on it. A Pc with a 333mhz pentium 2 and 128mb of ram is required as a minimum to run the camera.
On the surface all that sounds great to the budding astrophotographer until we look at the pricetag, £116. Celestron are hoping that their potential customers will be sufficiently unconfident and uncertain enough in starting their new hobby that they'll pay over the odds for a "comprehensive and complete start up package". A little unfair perhaps to place the blame squarely on Celestron, all of us (this writer included) have been guilty of paying for convenience and for someone else to do the work for us but in this instance, significantly better cameras with better (and free) softwares can be found with only a minimal effort.
The software found on the CD rom is outdated and basic with better image processing tools as well as camera operating softwares being easily obtained on the net, they are widely distributed, absolutely free (and legal).
The cameras claim to 30fps is slightly misleading, while technically the camera can produce 30 frames per second you can only effectively use 10 before data compression dramatically reduces image quality.
These days there are so many simple webcams out there that outperform the neximage, using the logitech fusion webcam that I started out with as an example. The Fusion has a max resolution of 1280x960 and will capture 20 fps at 640x480 with a pixel size of 3.5 microns. The most amazing part is, all that cost me just over a quarter of what Celestron is asking for the Neximage, £30.
I cannot recommend the Neximage for the simple reason that it is overpriced by about 400%, it is a highly standard camera with a hugely inflated pricetag that is targeted at the newcomer who might be attracted by a certain style of advertising.
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