New GSO classic cassegrain.

[doug mc]

Well, here it is.

[Wavytone]

Interesting... so what are the specs ?

[Merlin66]

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p10753_TS-Optics-8--f-12-Cassegrain-Teleskop-203-2436-mm-OTA.html

Rebadged TS version.....

[pmrid]

I see that GSO also make a 6" Cassegrain F12 version which are selling for 599 (in Sydney).

Might be a good choice for lighter mounts like the HEQ5Pro and similar.

The 8" is also not expensive at 1199.

Peter

[glend]

Actually TS rebadge the GSO, they are all made by GSO. Astro-tech has one as well. There is a CN thread on the Astro-Techs but I gather we are getting the GSO ones first.
The price seems reasonable, from Andrews. Visual only at f12 i would think, perhaps planetary, and hopefully it does not share any of the devil's that that their small RCs harbour; although that focuser looks identical to the RC version. The whole scope looks like it was built from the RC parts bin.

[gregbradley]

Could make a nice little visual scope.

Looking forward to some reviews.

Greg.

[doug mc]

The unit i have has a steel tube. It surely has been made from the rc parts bin. Nevertheless, i have only had it out once, and i find it is as enjoyable as a C8 i used to own. With one major improvement. No corrector plate to dew up.
It was not the best of seeing, but i believe it will deliver very good views, as diffraction patterns of stars in good moments were looking good. I am sure these scopes will work well within their design capabilities.

[Saturnine]

That seems to be a short tube for an classical cassegrain, the focal ratio of the primary must only be about F 2.5. A bit faster than is normally associated with C.C. which leads to larger central obstruction, quoted at 33%, not ideal if wanted for visual planetary observing.
Would love to have a look through one all the same and would also love to see comparisons with 8" Schmidt Cass. and 180mm Skywatcher Maks. Waiting with bated breath.

[casstony]

One thing to be aware of when cleaning these scopes is that they are no longer dielectric coated (RC & classic cass) so more care is needed. Astronomics is the only website I'm aware of that has updated their information - others still claim dielectric coatings.

[glend]

Why is that? Trying to keep costs down?

[casstony]

The Rep from Astronomics wasn't sure but suggested it was to contain costs.

[Wavytone]

IMHO its attempt to pull market share from Celestron/Meade 8" SCTs aimed at those who are motived by lowest cost first and foremost with no idea about quality.

... these scopes are cheap, for a reason.

These have 33% central obstruction meaning they will be soft like SCTs, compared to premium maks that have a much smaller secondary.
The open tubes mean the coatings wont last long*.
They have 4-vane spiders with overly thick arms - no thought was given to optimising these for diffraction.
The parts are basically those for an RC.

Note * longevity of the coatings doesn't matter because on average these will see a half dozen outings before most owners figure its all too hard, too complicated and put it in storage for the next 20 years - because surfing the internet is a lot easier - starting with APOD. I've seen the sales figures for Celestron 8's... there are a staggering number "out there" that have been forgotten, and simply never get used.

Hence overcoating is an unnecessary cost as these aren't built to last.

FWIW I'd bet my MN86 will slay these. And never mind the MK91, no contest.

[Kunama]

Obviously it is not going to be a match for a TEC Mak but nor is the price. Not sure that I agree with a lot of these assumptions, certainly not until I get a chance to see or use one....:shrug:

[Wavytone]

Interesting to see what happens. Brave move by GSO, frankly.

Bear in mind astronomy is not a viable hobby in China so GSO is purely a financial operation manufacturing stuff responding to what they think is a market opportunity in the west. As is Synta.

[Atmos]

As someone that has not done a lot of comparisons and possibly doesn’t have the eye sight to do them anyway, my Mewlon 250 has a CO around the 33% mark and yet pretty much everyone seems to agree that they have “refractor like views” even with the CO anchor.

Matt commented a while back that his 8” mal performed better than a M210 but I do wonder if the extra aperture (M250 vs 8” mak) is enough to push the MTF over?

[billdan]

The GSO range is manufactured on the island of Taiwan (protected by the USA) and has no affiliation with mainland China.

[brian nordstrom]

:thumbsup: We had an old 12.5 inch CC at the Whakatane astro society ( North island NZ ) and while it was a bugger to collimate , most gave up but I persisted for weeks , back and forth between the primary and secondary but once it was on ,,, WOAW :eyepop: this was a better planetary scope than the C14 in the main observatory .

Cant wait for a detailed viewing report , and thank's :shrug: that's all I need ,,,, a new Classical Cassegrain ;) 8 inch in the scope room .. but then again the 6 inch is quite the bargain :lol: .

Brian.

[doug mc]

Due to the fact that i have not read Suiters book on optics, i will leave star testing to someone who knows what they're talking about. I will be happy counting craterlets on the floor of Plato when seeing allows.

[doug mc]

Attaching a handle to the top rail is a must do to carefully manage this ota. I can reach focus with both my William Optics 1.6x OCS and a Siebert 1.25x OCS that i bought for the dob I had. You can use a blower to remove dust from the primary and secondary. I can get my hand past the secondary, and it's not a dainty one ( the hand that is ). The secondary has a spot mark for collimation if needed.