vahe352 wrote:
>> I suggest getting the second edition of Suiter. If the inside and
>> outside patterns are different, the scope is not perfect. The star test
>> is very sensitive, so it may be close enough.
>>
>
> In certain scopes you will see a difference between inside/outside focus
patterns, all spherical Maksutovs, fast apo's are just some of the examples, I
do not consider that an indication that these scopes are not perfect but rather
this is the nature of the beast,
Vahe, in the case to which I refer on the Tak group, the one owner had a
scope which had /dramatically/ different patterns on each side, he
showed them, and all that responded said theirs did the same thing
(including many older fluorite Taks of longer focus), and that it was
normal, not to worry about it, his scope was fine.
... In the case of all spherical Maksutovs they have higher order spherical aberration, so in that sense they are not optically perfect. They may, however, be...
... Vahe, in the case to which I refer on the Tak group, the one owner had a scope which had /dramatically/ different patterns on each side, he showed them,...
... You're confusing me Tony, on the one hand you say your Tak star tests perfect, but OTOH all these other people on the Tak group say theirs does not, and...
You didn't read the post very carefully, Bud. I said near perfect... "all but eliminated". Don't be confused, Bud. This isn't brain surgery, this is fun. Have...
... What I was referring to was the fact that your star test was no where near as skewed (or wasn't even considered off enough to be consider skewed at all!)...
A 5" at $9,000? Hell, I'd get the TOA 150 and pocket a couple hundred in change. But it makes the FS128 or the Pentax 125 look like an even better deal....
While I feel that Vic makes great scopes - based on the posts from his group, I don't consider his pricing or products - leading edge in either price or...
All I know... is that at the last 3 public gatherings I was at... there were an assortment of bigger and more expensive scopes including a 12 foot long D&G -...
Hey, Not to argue the point, but the ES website describes that 127's objective as containing a Hoya ED element and call the scope "...an air-spaced triplet ED...
Terminology is a source of mystery to me. My Vixen f/6.5 SS102 I am content to call an ED doublet. And it proclaims itself ED in big letters on the dew...
... Many refractors were sold as APO fifteen years ago that probably wouldn't be so labeled if sold today. My FS-128 is one, and my 178ED is another. Early...
As you probably know, ED stands for Extra-low Dispersion. Any modern apochromat almost certainly uses an ED element, either fluorite or a fluorcrown. Some...
... Does anyone know what kind of glass that Hoya element equates to in the Schott catalog? ... There are all kinds of "apos" out there, just throw 3 lenses in...
Most likley because they are not experienced enough to know what is going on? On one side of focus you are looking through turbulent air and the other side...
... That's what I thought Chris, but you sure could fool them! Many reported really skewed star tests and ain't the least bit phased by it all. I think Rod...
I agree there are all kinds of "apos" out there. As you know though they can and most likely will fail to meet the debated definition of an apo though. The...
Hey, Didn't the Tak Sky 90 II have problems holding collimation? Or were those folks just lyin'? Or was I jus hallooseinatin' from hittin' the coolaide? ...
Warp: While your comments are interesting, I have to say that comparing a SV or TV with "Explore Scientific" is not fair - I highly doubt that many of these...
If I think it through when I say an 8" apo is not cost effective it is a purely personal declaration of what size apertures I would like to have and what I'm...
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