8" SCT vs 15" Truss

ariefm71 · Post by **ariefm71** » Wed Mar 01, 2006 6:07 pm

The 15"Obsession has 4 times the light gathering power of the popular 8" SCT yet costs about the same.

Maybe 8" SCT on EM-200 mount

neoterryjoe · Post by **neoterryjoe** » Wed Mar 01, 2006 6:36 pm

Hey Yang Beng,
Mind if i pay you a visit once your big one comes? Might just be afraid that the extraordinarily long thunderstorms will be the only barrier i need to overcome to go to your place!!!

But one thing for sure is that you will need to consider the portability issue esp in Singapore. That reminds me, if one is going to get a dob here, portability is certainly not an issue as he would have a high tolerance than 'normal' people! Truss tube is still not significantly lighter than a tube one.

Canopus Lim · Post by **Canopus Lim** » Wed Mar 01, 2006 8:37 pm

Ha. Truss tube dob is about half the weight and half the physical volume of a conventional tube dob (of the same aperture). Anyway, wait till I get the scope first then maybe have a firstlight in some dark place in Singapore. Lim Chu kang?

Post by **weixing** » Wed Mar 01, 2006 8:51 pm

Hi,

Umm...how come nobody points out this : I don't think that 15" Obsession cost the same as that 8" SCT.

>>The 15"Obsession has 4 times the light gathering power of the popular 8" SCT yet costs about the same.

If it cost about the same, I would have bought one long ago.

I was wondering too... Celestron Advanced Series Computerized Go-To 8" Schmidt-Cassegrain C8 S-GT with StarBright XLT Coatings cost US$1514 and an Obsession 15" cost US$3995... I don't think the different of US$2481 is consider as "costs about the same"... I basically can buy two C8 S-GT XLT with the cost of an Obsession 15"... Just wonder which 8" SCT is he refering to???

May be you can ask them to sell you at the price of an 8" SCT...

Have a nice day.

PS: It is obvious which (8" SCT vs 15"Obsession) telescope is better if portability is not an issue and you are not doing Astrophotography.

jermng · Post by **jermng** » Wed Mar 01, 2006 10:53 pm

HAHA ... what i was thinking also (I just copy and paste), but would this statement be accurate 5-8 years ago? What about comparing with LX200? (I'm not home now so can't check) ....

Well, a 12.5/15 seems pretty tempting, but at least the C8 can still be used to travel on flights if the need arises. Travelling with a 12.5" mirror would be very worrisome ... and I love the tracking too ...

neoterryjoe · Post by **neoterryjoe** » Wed Mar 01, 2006 11:17 pm

yes, good, good.. the argo navis dsc is a tracking device is it? something like the intelliscope scope dob from orion right? maybe someone wants to enlighten?

Post by **weixing** » Wed Mar 01, 2006 11:33 pm

Hi,

What about comparing with LX200? (I'm not home now so can't check) ....

I think the most expensive LX200 (LX200GPS-SMT with UTHC) is still less than US$2500.

Hmm... the only 8" SCT that cost as much as an 15" Obsession is the Celestron CGE 800 8" Schmidt-Cassegrain with GoTo Equatorial Mount with StarBright XLT coatings... US$3752... but IMHO it'll be a bit misleading and unfair to use this type of setup as an example...

Anyway, a 8" SCT will cost hundred millions of $$ if I mount it in a satellite... ha ha ha

Have as nice day.

Post by **weixing** » Wed Mar 01, 2006 11:44 pm

Hi,

yes, good, good.. the argo navis dsc is a tracking device is it? something like the intelliscope scope dob from orion right? maybe someone wants to enlighten?

Err... argo navis dsc is a Digital Setting Circle... it help you to find object and it doesn't track unless you coupled with the SERVOCAT GOTO system.

By the way, please try to stayed in topics...

Thanks and have a nice day.

Canopus Lim · Post by **Canopus Lim** » Wed Mar 01, 2006 11:45 pm

The Argo Navis is the DSC (Digital Setting Circle) or object locator. It cannot track but helps to find objects by displaying a counter in degrees (altitude and azimuth). When you move the scope in the correct direction, the numbers will count down. When it is at zero, the object should be in the field of view of the eyepiece and that depends on how well the scope was aligned (2 star alignment and which stars were chosen prefarably far apart in both altitude and azimuth). I have not used it yet but that is what I read from the manual. The Argo Navis has a fast processor and it can give 'real time' information on whatever object (which can be defined in magnitude or type eg. globular, galaxies, stars etc) the scope is pointing at or is near to.

neoterryjoe · Post by **neoterryjoe** » Thu Mar 02, 2006 12:10 am

oh.. ok. Interesting...Something like the Skyscout ah?
okok, back to the topic..