回复 13# fshjj30
因为我们大多数使用的是102折射。我在最近看的一本英文书里找到一段关于Omni 102XLT和BK1021EQ3-2使用感受，虽说是英文的，楼主可以凑合着看一下。102和120的差别应该不大。
Celestron, for example, has maintained its interest in making and selling
its own version of the Vixen 102 M. The original Celestron C-4R enjoyed a
very loyal following due to its nice views. Recently, however, the company
has revamped its 4-in. F/10 refractor in the form of the Celestron Omni
102 XLT. You get a lot of gear for the asking price ($499). The optical
tube is one of the lightest in the industry – just 9.5 pounds. The objective
features the excellent StarBright XLT multicoatings for maximum light
transmission. The telescope also comes with a nice 25 mm Plossl eyepiece
and a good 1.25-in. mirror diagonal giving 40× and 1.25° field of view.
The 102 XLT also comes with a fairly sturdy CG-4 German equatorial
mount, with setting circles and slow motion controls. The telescope andmount sit on a heavy-duty pre-assembled stainless steel tripod featuring
1.75" legs for extra stability.
Owner reports are generally very good and speak of their well-cor-
rected optics and sharp views at low and high power. These telescopes are
often touted as a good telescope for a discerning beginner. That’s certainly
true. You can do a lot with this size instrument. A case in point comes
from one enthusiastic Celestron 102 XLT owner who said: “I had the old
version, the C-4R,” he said, “but you’ve got to remember that the Japanese
(Vixen) version of this achromat used to go for nearly $2,000. This is the
refractor that resurrected my interest in astronomy. It is optically sound
and with the improved tripod and aesthetics I couldn’t say enough good
things about it. It could keep a lunar/planetary enthusiast happy for a
long time and is no slouch on the brighter deep sky objects, either.”
Sky-Watcher has also marketed a few incarnations of this telescope
over the years. Bizarrely named the BK1021EQ3-2, this telescope ($355)
appears to gaining a well-respected reputation among owners. Like the
Celestron Omni XLT, it comes as a nicely finished optical tube atop awell-designed equatorial mount and a fully collimatible lens cell so the
user can tweak optimum sharpness. Ted Moran, an amateur based in
the American Midwest described his experiences with this instrument:
“Overall, I’m very, very happy with the Sky-Watcher 102,” he said. “My
harshest criticism would be that the telescope does produce some chro-
matic aberration, most annoyingly in the form of a very faint, pale blue
color tone cast to large scale, bright images – notably those of the Moon.
It’s made somewhat worse by eyepieces that have “warm” color tones of
their own. But even in worst case scenarios, to me the overall negative
effect is more than acceptable. I do a lot of lunar observing, and the
effect doesn’t trouble me very much at all. Venus shows distinct violet
fringing, as well – but it is fairly minimal and well controlled for a tel-
escope of this aperture.”
Ted is also impressed with the Sky-Watcher’s resolution. “I’m not really
a double star chaser,” he added, “but the telescope appears to have excel-
lent resolving power. I have no trouble seeing details down to 3 miles and
less on the Moon under even poor conditions. Saturn’s rings are dramati-
cally presented, even with the planet’s rings edge-on, as they are now.Jupiter’s north and south equatorial belts are well shown, perfectly
separated, and even showing hints of detail. On good nights I’ve seen three
or four other northern belts and two or three southern belts.” And Ted has
also praised the Sky-Watcher’s wide field views. “I remain impressed with
the telescope’s performance on brighter deep sky objects and open clusters.
Its decent light grasp and low-power, wide-angle performance continue to
impress me. Nebulosity is visually apparent, even striking on many deep sky
objects. I wasn’t expecting this from a long focal length, non-APO refractor,
and it continues to surprise me. I purchased a 40 mm 2-in. eyepiece for this
application. The supplied draw tube didn’t have enough extension length
to come to focus with this eyepiece, but I have since obtained a high-quality
2-in. mirror type star diagonal, and this has cured all my focus problems.”
Ted’s comments are typical of those heard about this versatile telescope.
And at a typical street price of $355, the Sky-Watcher 102 looks like a very
good bargain indeed. |
置顶卡
变色卡
千斤顶
显身卡
长焦好，夜视无敌，爽死你。。星星看不了几次的，主要还是夜视。