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Celestron 150mm |
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REVIEW ARCHIVES Refractors Barlow
Lenses LINKS FAVORITE LINKS NASA
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The Review I acquired this telescope as a loaner to test some filters I was developing to reduce the intrusion of chromatic aberration. Rules are being broken here. A 6 inch refractor should be f/18-f/20 to decrease the chromatic aberration to acceptability and f/8 is too short. Of course a f/18 6 inch refractor would require an extremely sturdy mount which translates to high price. The mount and tripod proved to be very wobbly. A good portion of the fault goes to the light aluminum legs. Replacing the aluminum tripod with oak removed most of the problem. To make the telescope comfortable you should have the equatorial head that is 6 feet or slightly higher. This makes it an enormous telescope. Optically, this telescope is good not great. Globular star cluster are viewed in glory. Planets and high definition objects suffer as a result the chromatic aberration. As an optical engineer I developed a filter that maintains high transmission in most of the visible spectrum and still maintains some natural color rendition by permitting some of the blue through. In a direct comparison to my 5 inch Intes Micro MakNewt the CR150 took second place except light gathering power. The MN56 has world class optics and is difficult to overcome. The CR150 is a surprisingly good telescope for viewing globular star cluster and in this regard more enjoyable than the MN56. For lunar, planetary, and double stars it is the MN56 all the way. As an aside, the MN56 is on the order of 2 to 3 times more expensive when properly equipped. With the chromacor from Aries the CR150 could be elevated to a much better performing telescope. In some ways I regard the CR150 as somewhat inferior to its little brother the C102HD. As a conclusion the CR150 is not a perfect scope, but it has its place. It handles deep sky objects well. If you can't handle blue halos around bright objects then go to something else Submitted by Al Misiuk - AlMisiuk@email.msn.com - Seattle, Washington The Review Being a user of
6" and 9" APO scopes, I had the use of a CR 150 Refractor for a
month. With no full Moon a good test for false
color on the outer edges would have to wait. The next best object would have
to be Jupiter and some bright stars. With the reviews that I’ve read it’s
been said that this scope starts to breakdown somewhere between 300 and 350
power so I knew that the planetary observers would not be too happy. I had
each observer write down what they had seen as far as sharpness and contrast
went, and their thoughts on the amount of false color. John was the youngest
with an eye for contrast so he would be the first to use the scope. He was
very surprised at the contrast and sharpness of detail that could be seen at a
power range of between 171x to 425x using ortho’s and Siebert Optics 7mm and
10mm eyepieces. As for the issue of the amount of false color,
he wrote in his observations that it was not as bad as most of the
reviews that he had read on this scope. He had seen more of a faint yellow at
low power My turn on the scope would come two days later. Using the
scope in my backyard with no one around is the why I like to test eyepieces and
telescopes. I had set the scope on my G11 mount. I wanted a good stabilized
platform to work with, and I must say that with an 80mm Burgess scope sitting on
top of the 6", this setup was
no lightweight, being somewhere around 24lb. The first thing that I did was to
take off the focuser and place a custom made 2" B&D focuser ( available
through burgessoptical.com ) on the scope. The stock focuser on this scope was
very smooth, but I’m spoiled on using nothing but the best focusers and they
get no better than a B&D focuser. Jupiter was going to be my first object,
and I wanted to compere my views to Johns to see how close my observation would
be to his. I must say that I was very amazed at the contrast and sharpness that
I could see. At 240x six belts and some festoons could be seen. At 350x more
belts and zones with greater festooning could be observed with ease. As for
false color I was amazed to see that it was not bad at all and must say that the
view was the same as what John had seen. On the limb of the full Moon, there is
more of a yellow than violet color. Even though there was color to be seen, it
was not taking away from the sharpness or contrast in the view. Either this scope has great optics compered to others that have gotten bad reviews, or the reviewers are one sided to comparing this scope to APO’s ( which is not the thing to do ), or there are a lot of bad CR150's out there. If you buy from a dealer that you know has a good return policy if you get a bad one, then these scopes are worth looking into. The one that I’ve tested is a very good sample that I was able to do some serious observing with. Yes there is false color, but if your use to seeing no color at all, then the smallest amount of color can turn some totally off and give bad review rating’s to this scope. I’ve seen two other CR150's and they both had very good optics. The scope in this review I ended up buying and will use it a lot, and I’m an APO user. As for the amount of useable power, 425x is great for a classical refractor working at f/8. Review by Don Regan Director of the Deep Sky Observatory located in upstate New York. Using 6" f/8 custom made Refractors for Planetary observing, and a 12"SCT for super novae research. Submitted by Don Regan - deepsky@scsinter.net - New York
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