Hi Dennis
I bought one of them when I first returned to astronomy 2 years ago. On paper, it looked good.
It was very well made mechanically, but optically it was a disaster!
The figure of the lens was not too bad but the chromatic aberration was much worse than ANY achromat I have ever looked through. The colour error was at both ends of the spectrum, with any bright object being deluged with both red and violet.
I returned the first scope and tried a second one, and it was just as bad.
My advice is run, don't walk away from it-by far the worst refractor I have ever used.
Thanks Gentlemen, strange company the make product for Williams Optics and dam good products, yet can't seem to do it with their own brand.
cheers
A short f/5.5 scope with only FPL-51 glass is probably a poor design choice rather than necessarily a bad implementation of that choice. Their other products may or may not be better, but they did themselves no favours with this model.
Of course, there is always the possibility that quality control is stricter on the products branded for other companies such as William Optics, or that WO themselves carry out additional testing before selling.
I had one of these once as well and it was the first one sold here .
Mine had very good build quality , nice fit and finish with a great focuser , very sharp optics but as said at f 5.5 the CA was there , not as good as my ( now sadly sold ED80 ) , way better than ( also sold C102 f5 achro ) so I think I got the best one sold here in OZ .
I sold all 3 of these short refractors and now have the best 90mm f5.5 doublet made , my beautiful Takahashi SKY90 fluorite APO , I have never see any CA in this scope on any object at any powers , up to 300x plus .
Yes that 92mm signature is the best , but its a triplet and it should be , but there is something about Takahashi Fluorite's that's magical , not to mention the best build quality there is ,, nice , but as said also this comes at a price . .
On that for $800 the LP was a great scope , if used within its limits and its sad that LP's QC let them down on these scopes .
Its a shame because the build screams for better optics , if they had only used say , FPL53 ( or equalivant ) instead of FPL51 they would have had a real winner here . .
You made a good choice on the Orion 80T , these have virtually perfect colour correction with good smooth optics and nice build quality to boot , you will love it .
You made a good choice on the Orion 80T , these have virtually perfect colour correction with good smooth optics and nice build quality to boot , you will love it .
Brian.
Yeah Brian, I had the Orion 80ED, although I did upgrade the mechanical side of that scope, nevertheless, I have to concur that the optics are fantastic in those, considering the price bracket, but as you know, a certain person, kept asking me to sell it, so I did, but only after getting the AT65ED Quad, and I think that that is the best value grab-n-go scope I have ever owned, particularly considering it only cost $579. I will never part with it, but then, maybe I shouldn't say that, as I said that about the 80ED, so I will add a qualifier, I will never part with it, unless , I can afford to go all Tak!
Your Tak Sky 90, is superb, indeed! And, so compact.
I have used my LP90 for 4 years and find no problems with it for imaging as a doublet. Visually it is good and crisp (except for expected CA obviously), I know its not a TAK but I didn't pay for that. The build quality is great and although it is 51 glass good results can still be obtained. I also use the Orion ED80T CF for imaging so I have the best of both worlds. I'm just wondering if the comments relating to bad optics relate to a drop in quality in recent years due to mass production of this short style instrument being pumped out and maybe mine was built to a better standard due to its age. As I say I wouldn't write these off, see if you can try one and make up your own mind. I love mine and even prefer some aspects (focusing, camera attachment, ease of use etc) over the ED80.
I love this aspect of astronomy, you work with what you have and If the skies are clear!!!
I had essentially the same scope in William Optics guise (Megrez 88) and it had very good optical performance. Centering of the elements is critical in such a fast doublet and I wonder if that was the issue in the poorly performing scopes?
There have been problems in the past with WO scopes (made by LP)having incorrect spacing of elements leading to severe spherical aberration - nicely ground/polished lenses, nice tubes, but poorly put together, though easily rectified by the manufacturer.
The build quality is great and although it is 51 glass good results can still be obtained.
I agree. I have an ED80 with something other than FPL53 and it's colour correction is quite good.
My LP90 didn't just have bad CA, the contrast was poor, so much so that with daytime viewing everything looked smokey, which shouldn't be considering how well the tube of the LP90 is baffled.
I sat my Long Perng 90 next to a Skywatcher 120mm F5 achromat and the SW120 outperformed it by a wide margin. See the attached comparison pic. Definitely something wrong here.
I notice also that there is no reference to "ED" or "APO" on the front lens ring, even though they are advertised as such.
Broke my heart to send it back considering how well it was constructed but the lens is all important.
I had essentially the same scope in William Optics guise (Megrez 88) and it had very good optical performance. Centering of the elements is critical in such a fast doublet and I wonder if that was the issue in the poorly performing scopes?
There have been problems in the past with WO scopes (made by LP)having incorrect spacing of elements leading to severe spherical aberration - nicely ground/polished lenses, nice tubes, but poorly put together, though easily rectified by the manufacturer.
Tony, what you say has much merit, for a lot of the problems can be related to quality control. I have seen this in many, run of the mill, products and it isn't until you get into the very high quality products that you get consistency between the units. Take a Takahashi, for instance, you would be very hard pressed to find any noticeable difference between scopes, of the same model, but the price is commensurate with that level of quality.
Quality control comes at a cost, you simply can't have high volume manufacture with consistent high quality at a low cost, it simply can't be done. Yes, you will get some good units and some bad units, it is, essentially, unavoidable. But, that said, it is what warranty is all about.
We often take pot luck with quality when we pay a modest price, and this accounts for the varying comments about any particular product.
I was lucky, I got a great example of the WO FLT 110, and I did know that I was taking a risk buying this scope, at the price of $2300. I know I would have been better off with a Tak 106ED or a 130NFB, however, I simply couldn't justify the 5.5k and 8.5k respectively, never mind all other Takahashi specific accessories.
It is all a matter of cost. Yet, we are seeing a lot of examples of well priced quality scopes, fortunately. If this wasn't the case, we would all have Takahashi's or its like.....or nothing. Back to grinding our own mirrors, we would be!
Cheers Pete
Last edited by Stardrifter_WA; 20-04-2014 at 02:27 PM.
I had one of these once as well and it was the first one sold here .
.
Thanks Peter , yes the Tak is perfect .
