Initial Review: Vixen R200SS 8" F4

Post by **weixing** » Thu Mar 27, 2008 12:56 pm

Hi,
Finally, able to bring the Vixen R200SS OTA home... [smilie=victory.gif]

First impression is the weight... it's a lot lighter compare to the Celestron 8" F5 Newtonian... I think around the weight of C8. The Vixen R200SS is slightly shorter than Vixen R135SS. Below is the photo of Vixen R200SS (left) and his little brother Vixen R135SS (right):

The focuser is a rack and pinion focuser. Look exactly the same as Sky-Watcher/Celestron/Orion rack and pinion focuser, but the feel is a lot smoother and seem less play.

The vixen R200SS cover is very lose and will easily drop out if not careful. When I open the cover and to my surprise, the primary mirror cell had no mirror clips. I think the old version got the mirror clips as shown in the old manual. This is good as the mirror clips will cause some "artifact" on the star in astro photo.

The secondary spider are very, very thick and sure to cause bright diffraction spike...

The secondary collimation screw is hide behind the Vixen R200SS logo sticker.

The back of the primary mirror is cover by a piece of metal plate and the collimation screws are not stainless steel type and will rust if expose to water... should not a big problem as it should be able to prevent it by applied some WD-40 on the screws.

The Vixen R200SS Coma Corrector2 is quite big and bigger than 2" size. It's screw in behind the attachment plate and insert inself in the focuser. The coating on the Vixen R200SS Coma Corrector2 (left) is very obvious compare to my MPCC (right).

Will give more review on the visual performance when I'm free and the sky is clear!!

Have a nice day.

codenamejag · Post by **codenamejag** » Thu Mar 27, 2008 1:24 pm

wow.....nice..... how much did u pay for it?

kingkong · Post by **kingkong** » Thu Mar 27, 2008 1:37 pm

waseh! you sure that tripod is up to the job kah...?

Post by **weixing** » Thu Mar 27, 2008 1:38 pm

Hi,

wow.....nice..... how much did u pay for it?wow.....nice..... how much did u pay for it?

Both Vixen R200SS and Vixen R135SS were from Meng Lee... Thanks to him... He sell the Vixen R200SS OTA to me at a very low price of S$1100 and the Vixen R135SS OTA also at a very low price of S$450... which I'm also selling at this price, so to pass the good deal to someone else.

Anyway, I think the usual price for a new Vixen R200SS OTA is around S$2400.

Have a nice day.

Post by **weixing** » Thu Mar 27, 2008 1:44 pm

Hi,

waseh! you sure that tripod is up to the job kah...?

Should not be a problem as manfrotto 475B which is rated at 12kg load.

Anyway, if it can carry my Celestron 8" F5 setup (which is near to 9kg) whithout any problem, I think the Vixen R200SS setup should not be a problem... I guess the above setup is at around 7kg.

Have a nice day.

Post by **acc** » Thu Mar 27, 2008 3:03 pm

Nice deal! Weixing, have you tried the celestron coma corrector for visual use (understand that additional spacers are needed)?

Post by **weixing** » Thu Mar 27, 2008 4:33 pm

Hi,
I try using all the adapters I had, but can't get the correct spacing.

MPCC need to be positioned approximately 55mm (+/- 3mm) from the rear mounting face of the MPCC housing to the eyepiece's field stop. The problem is if you got a lots of different brand or different type of eyepieces, you'll need different spacing as the field stop position for various brand/type eyepiece might be different... not a very practical solution. But if you use only single brand or type of eyepiece, you migth be able to use only a single set of adapters. Below are the link to MPCC visual adapters:
http://www.alpineastro.com/optical_acce ... visual.htm

The TeleVue solution is to use a tunable top on their paracorr, but you might not be able to use a barlow when you use paracorr as the barlow might hit the paracorr rear elements.

By the way, some users in cloudynights comment that the MPCC is no good at high magnification viewing as it's add a lots of spherical aberration. But I think this should be ok as coma is usually not a problem at high magnification, so just don't use it at high magnification lor.

Have a nice day.

wucheeyiun · Post by **wucheeyiun** » Thu Mar 27, 2008 4:46 pm

Nice scope weixing...
looks really impressive.
Can you integrate your GSO focuser into the scope?
it will be better

Post by **VinSnr** » Thu Mar 27, 2008 6:19 pm

acc wrote:Nice deal! Weixing, have you tried the celestron coma corrector for visual use (understand that additional spacers are needed)?

actually the coma is not so bad if you use some good eyepieces. I do not really notice coma using Pentax XL eyepieces with my 8" f/4, but obviously I didn't purposely go look for it. If it doesn't distract me, then I just ignore it.

Weixing, try to invest in some good collimation tools for this scope because at f/4 it's freaking sensitive to collimation. A laser is not good enough.

The MPCC, IMO, need a same set of eyepieces to work with. if not very troublesome to change spacers all the time.

Post by **acc** » Thu Mar 27, 2008 8:01 pm

Thanks WX for the inputs.

VinSnr, ya u are right... I guess the MPCC is more suited to be permanently attached to an eyepiece. I am considering getting one for my 28mm UWAN primarily because its lighter and cheaper than a parracor and I find coma rather intrusive at lower power. Coma is not obvious to me at higher powers > 100 or in small fov eps like the pentax xl.