下面是引用 aa 於 2012-04-09 18:48 發表的 : 
我不是很確定也，你可以看一下 opt 上的規格
http://www.optcorp.com/product.as...&kw=F/6.3&st=2
meade 有他自己的減焦鏡啊
http://www.optcorp.com/product....kw=F/6.3&st=2
謝謝您..
看資料好像是 Antares 的減焦鏡比 Meade 好用..
http://www.optcorp.com/prod...d=8580&tb=8Antares vs Meade comparison
I recently had the opportunity to compare the Antares f/6.3 SCT Reducer/Corrector with the Meade f/6.3 Series 4000 Focal Reducer/Field Flattener.
The Antares focal reducer comes in a small box. Unlike the Meade f/6.3 Series 4000 Focal Reducer/Field Flattener, the Antares has only one cover, which surprised me. You attach the focal reducer to the rear port on a SCT and can keep it covered. But when not in the box or on the telescope, there is no cover for the other end. I wish there was.
With a 2000mm focal length f/10 telescope like a 8 SC or 8 ACF, both the Antares reducer and the Meade reducer should yield a 1260mm focal length f/6.3 telescope. This makes the telescope a faster system with a wider field-of-view and brighter objects, requiring shorter exposure times when doing astrophotography.
Unlike a problem I had with the Meade focal reducer, I had no problems focusing eyepieces or my Nikon D70 DSLR camera on either an 8 LX90-ACF or an 8 LX200-ACF with the Antares focal reducer. I did notice an image size difference between the Meade and Antares focal reducers when using the same setup. When I attached an Off-Axis Guider, the guide eyepiece field-of-view was not restricted, unlike what occurred with the Meade reducer.For visual work, the Antares reducer worked fine with all the eyepieces (both 1.25 and 2 I tested on both the LX90 and LX200. The expanded field-of-view and the increased brightness of objects really added some enjoyment to the viewing. Depending on the telescope/eyepiece combination, there was no distortion or minimal distortion at the edge of the field-of-view. When distortion was visible, it was not distracting.
I was very pleased in the images I was able to capture with my DSLR when using the Antares reducer. The increased speed of the system made a considerable difference in what could be photographed in the 3-5 minutes that the exposures could be made when mounted in Altitude/Azimuth, without experiencing field rotation.
One thing to keep in mind when using a focal reducer with an Alt/Az fork-mounted telescope is the eyepiece/camera clearance from the base. I found that the maximum elevation on the LX90 and LX200 can vary from 90 degrees to less than 65 degrees, depending on the accessories used.
Based on my photographic and visual tests, I prefer the Antares focal reducer over the Meade focal reducer. The Antares focused in all my test scenarios whereas the Meade reducer had problems reaching a focus with most of my accessories. The physical and optical quality seemed to be essentially identical for both but the Antares model is somewhat less costly.
