When I was first made aware of this refractor from Vixen Japan, I was naturally curious given all the competing products in the market place. In particular I was thinking of the highly improved ED doublets coming out of Japan, now China and Taiwan. I was indeed very impressed by the Sky-Watcher 100mm ED both in the old gold tube and now Black Diamond series. But, like most it was a dream to own a true multi-element apochromatic 4 inch refractor (not a rushed mass market model) that was reasonably affordable and I certainly didn't want to pay the often super high price for a Takahashi or be put on a 2 to 5 year waiting list for an even more expensive oil filled objective model. Having owned over 20 telescopes over the years (each for a specific purpose) I'd often heard it said by critical lovers of refractors, "there's something to be said for owning a great 4-inch refractor to bring a lifetime of satisfaction"... and let's face it, with the highly sensitive CCD cameras available today, exposure times are greatly minimised so one can achieve pictures in seconds that took 30 minutes or more with fast films using larger apertures in the old days.

As a personal owner of this scope now (yes, I found what I was looking for), I was quite simply blown away at how well this treasure performs.. not just visually, but in the pursuit astrophotography also.  Flat field views, perfect colour correction and camera ready, the Vixen AX103S refractor is a true winner. Absolutely no need for colour masking filters (still required for most doublets and some triplet designs) or expensive add-on field flatteners. With a triplet ED objective and integral field flattener correcting lens (similar in concept or utilisation within the famous VC200L modified catadioptric reflectors), this superb 4 element design boasts top of the pile performance at a far better price point in its class over the other leading Japanese manufactured scopes. Not only does it perform well optically but is has a sleek finish, with threaded locking retractable dew shield and perhaps the finest steady movement rack & pinion reduction focuser (as smooth as any dual Crayford yet without the slippage issues). First thought to mind was... why do Takahashi, Vixen and other superb telescope manufactures from Japan continue to fit rack and pinion focusers given all the Crayford focuser hype. Well, as I first came to know with my earliest Vixen, not all R&P focusers are made the same. It's an unfortunate development that they get a bad rap due to the poorly made Chinese versions out there however when made properly, they are as steady as any Crayford design. More importantly, they lock / hold on to considerably more weight so you can use heavy bino viewers, eyepieces, or mount a moderate size CCD camera without worry of shifting when pointed at zenith. Another feature of this scope I like is the option to fit another optional Vixen finderscope shoe aside from the existing one it comes with. This provided the opportunity to fit a larger finderscope if needed that could be used for auto-guiding.

With a convenient carry handle, slip safety lightweight tube rings, the OTA rides beautifully on the SXD or HEQ5 Pro GEM mounts with plenty of load baring to spare for a guide scope etc. If you don't want to lug super heavy refractors or reflectors into the field and want something you can move around quickly for visual or set-up easily for astrophotography at home or in the field, the AX103S is the answer.

When I looked at Jupiter and Saturn at high powers the colours were excellent and images razor sharp. I'd forgotten how enjoyable the planets can be just visually with an excellent 4-inch refractor. In fact when refractor optics are as well corrected as the Vixen is, one can push the magnification beyond the rule of thumb theoretical limits and with a primary focal length of F/8 it is well suited to the task. For astrophotography only, the AX103S  0.7X focal reducer takes the scope down to a nice f/5.6 for brighter images (less exposure time needed) and wider field of view. What I was half expecting was that the reducer might create edge distortions however it has clearly been designed to perform uniquely with this refractor in conjunction with the in-build field flattener so as to maintain optimal correction. So using only short exposures of 10 seconds with the Moravian G2-8300 CCD camera on the HEQ5 Pro (no autoguiding) it was easy to achieve a nice wide field shot of Omega Centauri.

 
Above: NGC5139 (a simple unguided exposure using the optional AX103S (37228) focal reducer) and the excellent G2-8300FW mon CCD camera.
The image is comprised of 3 x 10 second exposures and even with the focal reducer, the telescopes built-in field flattener yields pinpoint stars right
 to the edge of the field of view.

Left: We mounted the AX103S optical tube on a Sky-Watcher HEQ5 Pro mount fitted with Farpoint Astro side-by-side guiding scope mount and 80mm ProStar achromat refractor as the guiding scope.

A Vixen F/5.6 focal reducer and Moravian G2-8300 one shot colour CCD camera can be seen fitted to the AX103S refractor. The Vixen visual back adaptor #5971 provides the perfect spacing to the cameras CCD for a great flat field image even with the focal reducer fitted.

The guide scope is fitted with the easy-to-use LVI Smart Guider system which takes all the hard tedious work out of finding a good guide star and calibrating the mount errors etc with external PC connections and softwares.

We were deeply impressed at how sharply produced across the entire field of view, the images taken from the AX103S are both with and without the focal reducer simply because Vixen have thought out and designed the optics so well to cover all needs in a classic, highly corrected 4-inch refractor that you'll want to keep and use for years. One thing that really is special (just as Takahashi and other leading edge scope manufacturers still use) is Vixen's brilliantly engineered helical cut R&P focuser that boasts the 7:1 smoothness and zero shift accuracy of a well made Crayford style focuser but unlike a Crayford (and very important when imaging near Zenith) can hold the weight of heavier cameras without slippage.

If you would like to calculate the field of view using this or any other telescope with your CCD camera or a Moravian Instruments model you can visit use our AstroShop online eyepiece and CCD calculator.

Above: The lovely M42 Great Orion nebula with Vixen AX103S refractor with f/5.6 focal reducer fitted using Moravian G2-8300 colour camera.
10 minute exposures stacked in DeepSky Stacker.

If you genuinely are seeking a true, optically corrected refractor for both astro-photography and visual work that can be easily transported into the field
without struggling with an over heavy beast, a scope that can hold a heavy cameras weight at Zenith without slipping and that will yield beautiful images both at f/8 and f/5.6 then this may be the scope for you. At around the $3K AUD mark, you won't be disappointed and it may well be all you ever need. Only AstroShop (as an Australian leading Vixen importer and specialist can talk to you first hand (from an amateur astronomer perspective) about this excellent refractor.

Copyright: AstroShop 2011