On page 35 of the Feb. 2021 edition of Sky & Telescope, Dennis di Cicco writes about the SW Evostar 150ED: "It is a very fine instrument for serious visual observers and delivers everything I expect from a 150-mm-aperture telescope." He writes further: "If owning a high-quality, large-aperture refractor is on your bucket list, I can highly recommend the Evostar 150 APO. Its optical performance for visual observing is on par with some of the finest refractors I’ve ever used, including ones costing three and four times the price of the Evostar."
These magazine reviews are purposely worded very carefully and sound like they say more than they actually do. They are meant to position products favorably in the reader’s mind.
I don’t get S & T anymore (after 40 years of subscribing) but if that’s what he said, let’s analyze it.
It’s a very fine instrument for the serious observer. And what does “serious” really mean? And what would you call someone who spends $10,000 for a 6” Apo – super duper serious? And what about the poor person with an 8” Dobsonian is he or she not serious. Using the word “serious” gives the reader a feeling that this is a “scientific research” instrument. It’s the same approach that Meade used when Meade dressed models in lap coats for their ads in S & T.
What I (di Cicco) expects. What does that mean? And how is that helping me with what I expect? Maybe his expectations are below mine.
Optical performance is "on par" with some of the finest… “On par”, what does that mean? Using “on par” is completely vague but still sounds like it might be “equal to” the high-priced spread as to not show any difference. A Mustang GT and a Ferrari Superfast will both do 60 MPH and get you to the 7-Eleven. Does that mean the $44,000 Mustang is “on par” with the $300,000 Ferrari Superfast?
What exactly were these refractors costing 3 and 4 times as much? AP guarantees optical quality at 98% Strehl. What was the Evostar 150 Strehl? What’s SW’s optical Guarantee – diffraction-limited I believe.
A Tak TOA triplet uses 2 ED elements in the TOA 150 for perfect color correction. What’s the glass in the Evostar 150 doublet? Was there a color crossing or spot diagram in the review? And if “on par” let’s see a bench test. I can point to amateur reviews that include spot diagrams.
The wording in these magazine reviews (and I’m not just talking about the Evostar) is flattering and sounds purposeful without being precise for a reason.
Anyone could write the copy used in the review. The copy works with “any” telescope. Just give it a try, its kind of fun…
"It is a very fine instrument for serious visual observers and delivers everything I expect from a 180mm Maksutov telescope. If owning a high-quality, large-aperture Maksutov is on your bucket list, I can highly recommend the Sky Watcher 180mm Maksutov. Its optical performance for visual observing is on par with some of the finest Maksutovs I’ve ever used, including ones costing three and four times the price of the Sky Watcher." (With that last sentence, the reader now congers up the image of a SW 180mm Maksutov being the equal of a Questar 7 – mission accomplished)
I’m not picking on the Evostar 150 just pointing out the "purposeful vagueness" in the statement posted from the S &T review.
To answer your question directly: if "on par" means equal to, then it is not a fair statement. If "on par" means the Evostar is a nice 150mm ED refractor but is 3, 4, 5 performance and mechanical ticks behind the high-priced spread, then the statement is more true. That's how using vague terminology can carry different meanings.