TS-Optics 200 / 1000 / F5

[LouisJB]

Hi, Just wondering, has anyone got any experience on this tube:

TS-Optics 200/1000 f/5 Newtonian Parabolic - 2" Dual Speed Crayford, GSN2001OTA

It basically looks like the same mirror setup as a Skywatcher 200PDS, but actually with a few extras and a bit cheaper.

I'm looking for a new tube for imaging, most likely it will be a 150PDS but I did wonder about the 200PDS and then found the above as an alternative 200mm OTA

Probably I'll stick with the 150PDS but if it's for the sake of a little bit more money I should get the bigger tube I'll get it, in which case which one, the Skywatcher or this TS Optics one?

However, I'm using an HEQ5 pro synscan and will be doing some imaging so probably a 200mm tube will be too big/long/heavy for imaging on this setup and should wait for when I eventually get an NEQ6 - I guess, or maybe it would work ok?

[emadmoussa]

TS reflectors are basically GSO (Revelation) and they're pretty good.

I've got the 250mm version and it's excellent both physically and optically. I previously had the SW 200P and optically I can see there's no difference..

The 200mm is slightly cheaper than its Sky-watcher equivalent and you have a dual focuser as a plus..I think there's a cooling fan as well?

[Zuben Elgenubi]

Compared to the 150PDS the 200mm tube would give you a narrower field of view/larger image (not sure if my terminology is accurate here?) which would be useful for some targets but it might have some disadvantages.

It is larger and heavier so that places greater demands on your mount, plus the increased size will make it more affected by wind. The longer focal length may also make guiding more tricky.

As they are both f/5, perhaps the 150PDS has fewer disadvantages? Having said that, there are plenty of people imaging successfully with the HEQ5/200mm reflector combination.

[emadmoussa]

200mm will give you 65% more light collection than a 150mm - which will make the difference in resolving finer details on certain objects or seeing particular objects at all.

While the 200mm is heavier and bulkier - it's still fairly manageable - not really heavy..8Kg I think -and your mount will certainly handle it comfortably.

 if your aim is imaging only - then a small ED refractor will do just the job - even do it better. But if you juggle imaging and visual then a bigger aperture will do the trick for you.

A point here: bigger aperture doesn't only mean more magnification - more importantly it's the ability to resolve more details (resolution) and collect more light allowing fainter objects to be within reach.

[LouisJB]

Thanks everyone.

Problem is I can't decide what focal length I need, guess it comes back to there is no single tube that suites all purposes. I tend to like to image galaxies and planetary nebula (and nebula). I'll probably end up with more than one (but I don't want more than one covering the same job) - also I have camera lenses around F5 up to 300mm for really wide stuff.

Since I have the 130P I'm now thinking maybe a 150PDS would be too similar (not that that's necessarily a bad thing as such) - but a 200 F5 would be significantly different and allow better visual use (which of course I would do a little of as well). 

It's a question whether that size would compromise my guided astrophotography.

I guess an ED80 and 200 F5 could complement each other, whereas a 130P and 150PDS or ED80 and 130/150 are going to be more similar...

I'm not sure, the main issue I have with the 130P (now that I moved the mirror up for prime focus) is that the cheap focuser doesn't take 2" filters for the coma corrector, and the price of a better focuser is a large chunk of a new tube!

So, maybe the TS tube is a contender against the 200PDS. It does seem to have a fan in the back, that maybe is useful. GSO stuff is generally quite well regarded it seems?

[LouisJB]

I do quite like the look of this 200 - 1000mm F5 GSO / TS-optics OTA - does anyone know how they fair on back-focus for DSLRs? I've been told it will be fine so long as the coma corrector is the type in the draw tube. Can anyone confirm? That means the Baader MPCC presumably.

Still torn between 150PDS/200PDS or 200 GSO F5s to be honest. The 8" is massive compared to the 5/6" and that does worry me, but onto an APS-C the shorter focal lengths seem make for very small images of galaxies etc which is pushing me towards the 1000mm focal length area.

[laser_jock99]

GSO scopes are similar in quality to Skywatcher- both are budget but capable brands. The GSO has a better focuser and the mirror cells lend themselves to easier modification (in case you want to upgrade springs in the future). 

If you want to image only galaxies then the longer focal length of the 200mm/F5 might be a bonus, if you want fast imaging (and aren't put off by collimation scaremongering) then consider the 200mm/F4 scopes? You'll get the benefit of a wider FOV and shorter exposures.

These scopes are designed to be used with a DSLR and a coma corrector so you should have no problems achieving focus. Problems might arise if use accessories like filter wheels but even then it's possible to shift the main mirror up the tube a few mm if needed. I wouldn't put anything bigger than a 200mm scope on the EQ5 though.

[LouisJB]

thank you. Yes 200mm was my limit on the current mount, it is an HEQ5 (not an EQ5) but even so I think this is my maximum for imaging so it would appear.

I've been put off of F4, after reading some views saying with a steel tube the collmination goes out even per viewing and really it has to be carbon. Although I've no experience of either so I don't know 1st hand, just reading as much as possible to make the right next purchase.

I've set up Stellarium with my APS-C chip size, I could most likely live with either 750mm or 1000mm but I think 1000mm is better for single galaxies I'd like to image, also better visually of course - would be a significant upgrade from 130P for visual observations. It still seems odd aperture doesn't matter for imaging, but if that's the way it is...

So sounds like this OTA could be a good choice potentially. As you say, an improved focuser and also a mirror cell fan (no idea how well they work but guess it's better than none). Also cheaper than 200PDS, and doesn't come with a generic 25mm plossl (I don't need a 3rd one!).

[emadmoussa]

So sounds like this OTA could be a good choice potentially. As you say, an improved focuser and also a mirror cell fan (no idea how well they work but guess it's better than none). Also cheaper than 200PDS, and doesn't come with a generic 25mm plossl (I don't need a 3rd one!).

Exactly.

[LouisJB]

I'm very likely going to get one of these, unless I get nervous about the size / weight of it on the HEQ5 pro.

It's made by GSO and the people at http://www.teleskop-express.de/ seem very helpful about. 

While Googling around researching it, I found this great review of what you get here:

http://stargazerslounge.com/topic/196116-first-look-gso-200-f5-reflector-14-images/

just in case anyone else is in a similar boat to me...