PDA

View Full Version here: : Eye opener Telescope Tests


Bobbyoutback
11-12-2019, 11:00 PM
This is a German site that's tested many scope brands , I was shocked to see so many poor results !

As you scroll down around three/quarters there is a test of a TS Photoline 102/700mm FPL53 Triplet APO , Wow :eyepop: I want that one .

http://teleskop-spezialisten.blogspot.com/2015/09/testaufnahmen-verschiedener-teleskope.html

Have a look .
Bobby .

Bobbyoutback
12-12-2019, 12:09 AM
Up to date contact -
https://www.teleskop-spezialisten.de/shop/index.php

Wavytone
12-12-2019, 08:39 AM
Nooo... these are the fringes you really want http://fidgor.narod.ru/Observers/Test/test_84.html

The Russian site published DPAC test results of a lot of scopes - but be careful - it serves up a lot of nasty malware aimed at PC users... Their tests were done properly and used the same setup and method consistently. The results are indeed interesting. http://fidgor.narod.ru/Observers/test.html

Bobbyoutback
12-12-2019, 06:46 PM
Your right about that second site ' bad news !

Hemi
12-12-2019, 06:53 PM
hmmm.....Russian testing?:question:

CeratodusDuck
12-12-2019, 08:23 PM
The Explore Scientific 127 is exactly as my example was - terrible, pathetic and downright junk. I couldn't dispose of it fast enough.

Yet people keep buying them.

Wavytone
12-12-2019, 10:07 PM
Hemi, buried in that lot of Russian test results are some scopes that had test certificates from the manufacturer - notably the maksutovs from Intes and Santel which are sold with a test sheet with the scope serial number, the P-V and RMS test results, and usually a DPAC interferogram. The lab results are similar to those from the manufacturer which suggests to me the lab tests are valid.

The sample is also large enough to do some statistics on well-known products - for example the Celestron SCT's average ⅓ wave P-V while Meade SCTs average ½ wave P-V. There are some really awful dogs as well as a few quite good ones, typical of the statistical variations to be expected from a mass-produced product that has no quantitative cutoff for quality (below which they would be rejected).

George, The astronomy market is a classic example of a market where the vast majority of buyers are ignorant of the qualities of the product that actually matter (vs those that don't), and unable to measure optical quality in quantified terms, with the result being the vast majority of buyers are poorly-informed and choose products based primarily by lowest price.

Rather like the real-estate market in Sydney.

Buyers are hence easily swayed by trivial things that don't really matter such as a pretty paint job. Nice packaging and boxes cost little but can heavily influence sales and customer loyalty (as Apple demonstrated beautifully). Or a new-fangled hi-tech idea (carbon fibre OTA's) that sounds good to the uninitiated, but actually might be worse than a traditional solution.

The reason is that very very few users have the means or the skills to measure the quality of their optics accurately. Manufacturers also are able to avoid offering any sort of guarantee of optical quality for a whole host of reasons - starting with poor collimation.

The result being a market dominated by low-quality products that barely do what is expected but don't excel, and most are not built to last long.

The exceptions to this situation are the "craftsman" manufacturers who make high-quality products in small numbers, and a small number of knowledgable buyers are prepared to buy these, for whom quality comes first - and the price is almost irrelevant.

Peter Ward
13-12-2019, 12:35 AM
There was a time when the likes of Celestron did indeed QC test their optics.
I spent quite some time in their Torrance factory, met and chatted with their
Testing and Figuring guys.

While they could not spend a inordinate time figuring a good optical null, they did reject the dud optical sets that could not be saved.

I'd even go so far as to say if you can source a circa 1990 to 2000 Celestron optic you will be rewarded with excellent value for money performance.

That said, there are some manufacturers that deserve kudos: Astro-Physics, Takahashi, TEC, CFF and Alluna to name names....but this is hardly a revelation...and given many of the former will have a price tag you'd normally
associate with buying a motor vehicle, are aspirational purchases at best for many.

Rare birds however do come up from time to time in the used market.....and are often snapped up by savvy buyers that "shock/horror" are prepared to pay more more an excellent (albeit pre-owned) instrument, than an shiny new piece of rubbish.

Hemi
13-12-2019, 12:52 AM
Hi Wavy, I shouldn’t have posted my response, it was just a flippant, pithy remark meant light heartedly in the wake of the recent WADA stuff:eyepop:

Hemi

Wavytone
13-12-2019, 07:53 AM
No problem ... this has been done to death before.

Outcast
13-12-2019, 08:00 AM
Interesting... I had a look, with considerable caution after Wavy's warning but, I didn't have any issues with malware, none of my protection went off... & nothing has infected my computer (I've run several scans using multiple software)

What problems did you have mate, genuine question?

Bobbyoutback
13-12-2019, 10:30 AM
I run good security but that didn't go off when I tried to open it But a Telstra page popped up saying they had banned that site as dangerous .

:confused2:

Wavytone
13-12-2019, 12:42 PM
I'm using a mac with Safari in private mode, adblockers and Intego malware software ... some pages opened well enough, but others did trigger malware alerts. Previously I trawled it to make a table listing all the catadioptric scopes with make, model and results.