Dear Reader,
taking notice of the special interest in my report about the new Stratus eyepieces and the poor translation results of translation machines made me write an English version of the article. However this was the first time I wrote such a report in English. I believe its much more readable than the automatic translation but of course far from a perfect translation.
The Orion Stratus eyepiece series
- chinese Vixen Lanthanum View clones -
In April 2005 Orion offered a new line of wide angle eyepieces called 'Stratus'. In June 2005 these eyepieces were available in Germany and I was lucky to receive four specimens for testing with one of the first shipments from Teleskop Service Ransburg.
If you have an eye on the eyepiece market you'll notice that Orion's Stratus are delivered with the same focal length as the well known Vixen Lanthanums (LVW). The only exception is the 21mm Stratus while Vixen delivers a 22mm Lanthanum. There are more matching features between these two lines of eyepieces. 68° AFOV of the Stratus are quite close to the 65° of the Lanthanums. An eye relief of 20mm and an 8 lens design are the next common features. Comparing size and appearance of the eyepieces you notice that they are very similar, too. The only difference is again between the 21mm Stratus and the 22mm Lanthanum with the Stratus clearly larger.
Within short after the Orion Stratus were announced Baader introduced their new 'Hyperion 68' series covering the same focal length that were known from the Stratus. The first photos indicate that the Hyperions are basically the same eyepieces as the Stratus except for a different body with a thread to attach camera equipment. Other features of the Hyperion like 8 lenses / 5 groups and 68° AFOV underline that. Baader announced however that their Hyperions will be equipped with their new phantom group coating. They should be available in autumn 2005. Both Stratus and Hyperion will be priced at about or below €150,- which is quite low priced when you look at the optical parameters. It's possible because of chinese production.
Each Stratus eyepiece comes in a small leather bag for protection. This is quite a new idea considering eyepieces but might be interesting for people who transport their eyepieces in a photobag or similar. But while observing one would hardly like to fumble around with getting the eyepieces into or out of the bag. The outer appearance of the eyepiece is nice on the first view. Looking more closely I found a few stains like from dried water on the anodized parts of the eyepiece. As these spots disappeared after the eyepiece had been handled for some time I assume they were nothing but water stains that remained from the anodizing process. While the focal length is printed in huge digits some marketing guy also had the brilliant idea to print the apparent field of view with almost the same size. So if you are looking for one particular focal length in the dark you will find quite a lot of 68mm eyepieces before you notice that the number you are looking for is just on the other side...
The eypiece handles nicely because of a soft grid of silicone rubber. The eyecap is made of the same material. Personally I like the soft silicone rubber better than rubber eyecaps because its much softer. The eyecap can be folded back to use the eyepiece with glasses. The safety groove was cut quite deep into the 1,25" barrel which caused some trouble when switching between eyepieces. On most occasions it caused me to readjust the fastening screw twice before the eyepiece finally came out. The Vixen Lanthanum have a much smaller groove and handle much better. With that I'm already starting to compare the two eyepiece designs. Like the Lanthanums the Stratus can also be used in a 2" holder but on second view you'll notice that the eypiece would slide less than half an inch into the holder which may lead to a very loose and insufficient fit. 13mm Stratus and 13mm Lanthanum are almost exactly of the same size. On the first look the eye lense of the Stratus seems to be much larger but after the eyecaps are removed the size difference was no more than about 3 millimeters. While the Vixen eyepiece showed no lense edges they were quite obviously visible on the Stratus. If someone tried to blacken them he did very poor work. In addition the Stratus have a bright reflective edge of the polished surface which looks like it was caused by the coating process.
The Stratus wear a mostly green multi coating with some violett and yellow areas. "Fully Multi-Coated" is printed on the barrel. The Lanthanum shows a mostly red or orange multi coating. The Stratus' coating doesn't look bad compared to the Lanthanums'. Looking into the Stratus one of the bright lense edges is clearly visible similar to the of the eyelense noted before. The Vixen eyepiece shows no such flaws with a clearly better blackening of the inner tube.
Looking into the 1,25" barrel clearly points out the better workmanship of the Lanthanum. Its filter-thread and lense frame are blackened very well while the Stratus has it's lense frame of shimmering black plastic and a clearly less effective paint on the filter thread.
Looking at the many similarities between both eyepiece designs it's hard to resist the thought that the stratus are a chinese clone of the Lanthanum design. Only the 21mm seems to be an exception. How far the chinese producer went cloning the Lanthanums can be easily viewed on two pictures made from the 13mm Stratus and the 13mm LVW. The pictures had been made to compare the black paint on the inside of the eyepiece barrels. For a fair comparison two photos were made with the eyepieces in switched positions. The surprising result were virtually the same patterns of reflections of the differently coloured coatings. The Stratus obviously uses the same lense positions and surfaces. Only the type of Glas used might be different. The different apparent field of view might be caused by different measurements or calculations. Comparing the AFOV with a Stratus on one eye and a Lanthanum on the other showed that both showed virtually the same AFOV. So the Stratus deserves to be called a clone of the Lanthanum. How well the design had been copied should be found out during the following observations.
The first observation took place in a warm summer night around solstice on a 300/1200 Newtonian along with the coma corrector from a Vixen R200SS. I observed M3 and M13 which allowed to compare transmission and contrast when looking at stars at the edge as well as on axis sharpness by looking at the center of the globular clusters. The first comparison was between 21mm Stratus and 22mm LVW. First of all I want to mention that the Stratus performed well. Fine stars on axis and a good eye relief without kidney beaning. The edge of the field looked acceptable, too. Comparing it to the Lanthanum showed that the original delivered much sharper stars on the edge of the field. The Stratus showed them of twice or tripple size. Looking close the Stratus could be noted to show enlarged stars much farther from the edge of the field than the LVW. Transmission seemed to be similar. At least there were no stars found visible in the LVW that remained invisible with the Stratus. On axis performance was well with both eyepieces. But because of the different focal length the eyepieces were not easy to compare as for example M13 was very close to dissolving into stars so the slightly different magnification (54x and 57x) caused a clearly visible difference. Both eyepieces were close to being parfocal.
The 13mm Stratus and 13mm Lanthanum could be compared without such difficulties. Looking at the edge of the field showed slightly less sharpness with the Stratus but the advantage of the Lanthanum was clearly smaller than between 21mm and 22mm. On axis the Lanthanum showed a slightly better transmission as the brighter stars in the center of both clusters appeared somewhat more brilliant. Besides that I couldn't note any differences. The focal position different more than between 21mm and 22mm, maybe one millimeter.
The Stratus 5mm showed virtually no loff of sharpness towards the edge of field. I compared it with my Speers Waler Zoom 5-8mm at 5mm (of course). This comparison showed that the Speers delivers sharper stars even at the center of the field. The Speers might also have slightly less transmission. The Stratus however performed well enough to be called a top notch eyepiece.
The 3.5mm Stratus had the hard task to perform against my 3.5mm Nagler Type 6. Despite failing to compare to this one concerning transmission and on axis sharpness the Stratus still had a fine performance. The sharpness was good on the edge and in the center of the field. After comparing the Lanthanum 3.5 with the Nagler 3.5 and the Pentax XW 3.5 more than a year ago its hard to compare it to the Vixen and the Pentax. Still I think that the Stratus 3.5mm performs much the same like the Lanthanum 3.5mm did concerning sharpness. Transmission however can not be compared after such a long time.
So I conclude that the chinese Stratus are cloned Vixen Lanthanum eypieces and sold about € 100,- to € 150,- cheaper than the original. Differences are obviouis in workmanship. In their optical performance the Stratus of longer focal length are slightly inferior to the Lanthanums. Still every Stratus is well recommended even for faster scopes around f/5 to f/4. The 5mm and 3.5mm performed so well that I doubt Vixen can explain the different prices to their customers.
However it is neccessary to loose a word on cloning because Orion and their chinese manufacturer make their money with the work of other people who put hard work into developing the Lanthanum eypiece design. Of course the Vixen design is more then ten years old now and sales should have well payed the costs for developing the eyepiece.
So if you are looking for an eyepiece with the specifications of a Vixen Lanthanum, wich are
- wide apparent field of view (65°)
- comfortable eye position or observing with eyeglasses
- good edge sharpness even with fast f/4 scopes
- relatively slim form to work with a binoclular
you should also think about buying a Stratus as an alternative. Baader's Hyperion will also become an interesting option if their coatings work significantly better than those of the Stratus or even those of the Lanthanums. |
显身卡
