Re: Orion 150mm Mak
- From: "David Nakamoto" <res07oeg@xxxxxxxxxxx>
- Date: Fri, 02 Sep 2005 07:28:47 GMT
My own experience is not as towards the other side of the coin as your report
is, but I have to mildly disagree with your "results". We had more than one guy
look through all three telescopes and came up with the same general assessment.
Granted the C-8 might not have been in strict collimation, but the member who
owned it did not think so or express this view. On the other hand, the general
experience in the LA Astronomical Society with the members I've talked to seem
to agree that well-made Maks general perform better than SCTs of the same
aperture, and often match larger SCTs (up to around 3 to 4 inches or so) well.
In looking at my original words, I expressed myself a little badly there. I
didn't mean to say that both Maks were outstandingly better than the SCT. The
difference in sharpness and clarity of image was there, enough to write home
about at least, but I'm talking in the range of percentages better, not 2x or 3x
or more better.
I think both Maks would make a very good case for themselves for people thinking
of a C-8, but not a larger SCT. At least one experienced observer tested his
127mm Orion Mak against his old C-8, and I believe he was certainly astute
enough to make sure optics were clean and collimated. On deep sky objects the
127mm Mak didn't quite come up to the C-8 in terms of image brightness, as one
would expect, but the sharpness and contrast improvement of the Mak allowed my
friend to see almost as many and as much of deep sky objects as with his old
C-8, or so he claimed.
I think that if you're looking into a lighter cheaper alternative to an 8-inch
SCT and don't mind forgoing GOTO, then look at the Orion 127mm and 150mm Maks.
I'm not saying they'll replace a C-8 in all respects, but they do offer a very
good optical package for the buck. Now, hopefully the tracking problem on the
150mm was an anomaly of lack of proper adjustment.
Sincerely,
--- Dave
--
----------------------------------------------------------------------
Pinprick holes in a colorless sky
Let inspired figures of light pass by
The Mighty Light of ten thousand suns
Challenges infinity, and is soon gone
david.nakamoto@xxxxxxxxxxx
"Stephen Paul" <smarshallpaul@xxxxxxxxx> wrote in message
news:UOmdnfkk2pf7R4reRVn-vg@xxxxxxxxxxxxxx
>
> "David Nakamoto" <res07oeg@xxxxxxxxxxx> wrote in message
> news:u%JRe.32279$Uz2.19709@xxxxxxxxxxx
>> Hello fellow amateur astronomers !
>>
>> One first quarter moon ago, an informal side-by-side-by-side test was
>> inadvertently arranged during a public star party, all telescopes within 5
>> meters of each other, looking at the first quarter moon.
>>
>> In one corner, the new 150mm Mak from Orion. A slightly beefed-up version of
>> the EQ-3 mount (an EQ-6?) was used and came with the scope.
>>
>> In another, Orion's 127mm Mak, mounted on the EQ-3 type mount it came with.
>>
>> In the third, relatively new (last 5 years?) Celestron C-8. Dual arm fork
>> mount.
>>
>> We didn't use the same eyepiece through all three. Need to remember to do
>> that next time. I'll try and stick to what I saw. The eyepieces used gave
>> similar magnifications; the entire moon was visible through all three.
>>
>> Images:
>> The Maks had consistently higher contrast and sharpness over the C-8, and
>> both consequently showed more details. The Moon with its wealth of find
>> details allowed for good comparisons of this. The C-8 was significantly
>> brighter, but not overwhelmingly so. If the 150 was brighter than the 127, I
>> couldn't see the difference. The 127mm Mak seemed to me to have SLIGHTLY
>> better sharpness than the 150m.
>
> Should we assume that the C8 was not critically collimated?
>
> I had a StarMax 127 and a C8. My results were completely different. At 250x,
> the 127 Mak simply didn't hold up to the critically collimated C8 in good
> seeing.
>
> I sold the StarMax 127 shortly after picking it up in a trade. Later I sold
> the C8. I decided after a few years that I just didn't like the FM/Wedge
> combination of my C8, so I sold it to a school teacher at a private Vermont
> high school. He's now collected three Ultima 8-PECs to teach imaging to his
> astronomy class.
>
> Some time ago I started to regret losing the versatility of the C8 OTA for
> general purpose astronomy. Being in need of a decent planet scope for this
> years Mars opposition, yesterday I picked up a used Celestron Advanced Series
> C9.25S, and added the GoTo to make it a full blown AS-C9.25GT. What a pleasure
> to have GoTo in a reasonable aperture again, and the C9.25 lives up to its
> reputation. I give it 1/6th wave undercorrection at the eyepiece after
> assuring that it was critically collimated. The C8 that I had (the Ultima-PEC
> model) also had excellent optics for an SCT.
>
> I'm sorry, I just don't see the 127mm Synta Mak competing well with the
> Celestron SCTs of 3" additional aperture. It just doesn't seem credible to me
> that a 5" scope is going to best an 8" scope, unless there are conditions
> around that particular test case that are inducing extraneous errors in the
> C8's optics.
>
> This is just as hard to take as reading how Joe Blow's 4" apo refractor
> outperformed an 8" F6 reflector on planets. Well, I've been there and done
> that test. My results were different. The 4" apo is an absolute dream scope
> optically, FOR IT'S APERTURE, but there's no way in hell it's going to provide
> more resolution than a scope of twice its aperture on the moon, Saturn,
> Jupiter, or Mars, given decent seeing, and someone experienced at collimation.
>
> Never mind using the same eyepiece in all three scopes, use eyepieces of the
> same design, with focal lengths that make each scope operate at the same
> magnification. Try to get all three scopes as close as you can to 100x, 150x,
> 200x, 250x, and 300x.
>
> Above 150x, the 8" SCT should steal the show. If it doesn't, then check the
> collimation at 400x or more.
>
.
- References:
- Orion 150mm Mak
- From: David Nakamoto
- Re: Orion 150mm Mak
- From: Stephen Paul
- Orion 150mm Mak
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