dawson Posted April 2, 2013 Share Posted April 2, 2013 Does anyone have any experience or comments about this 8" scope: http://www.vixenoptics.com/reflectors/vmc200l.htm A second hand one has been offered to me. I was going to be looking for a 180mm mak-cassegrain eventually as i am currently interested in solar system objects, but this looks appealing; shorter focal length than the mak, but much lighter in weight and slighly larger aperture. Any thoughts? James Link to comment Share on other sites More sharing options...
Brantuk Posted April 2, 2013 Share Posted April 2, 2013 Is it OTA only or does it come with a mount and tripod? I've no experience of it but on paper it looks very good. Have you any pics or a link to pics or advert? Link to comment Share on other sites More sharing options...
dawson Posted April 2, 2013 Author Share Posted April 2, 2013 It's just the OTA and some bits, no tripod or mount so that would need to be factored into the equation. It's not advertised, someone approached me following a wanted request i put on ASB. I'll get some pictures of it. It appeals as it would give me more scope to look at DSOs. But as you say, i'd need to get a mount for it, unless Graham can help me modify my current one James Link to comment Share on other sites More sharing options...
Brantuk Posted April 2, 2013 Share Posted April 2, 2013 The mount is the most important thing James and it is primarily a planetary scope - so factor in a reducer as well if you intend to view/image dso's. But beware it won't have as wide a field as most dso scopes - though the aperture is good for gathering faint light. I'd want at very least an HEQ5 Pro or CG5GT Goto. Link to comment Share on other sites More sharing options...
dawson Posted April 2, 2013 Author Share Posted April 2, 2013 It does include: OTA,9x50 finder Vixen 2" and 1.25 " adapters dedicated Vixen 0.6 x photographic reducer and T adapter 60mm extension Vixen fit Baader 2" clicklock adapter Would it require much care in terms of collimation? I know nothing about "Mak-Newts". Part of me thinks it is mid way between a really long focal length good for planetary stuff, and a much faster scope for DSO stuff; and as such might not be ideal for one or the other, just middle of the road. James Link to comment Share on other sites More sharing options...
Brantuk Posted April 2, 2013 Share Posted April 2, 2013 Yep you got it - I had the CPC800 and it was very nice for both planetary and dso but it excelled on planets. It's good that the reducer is included (mines a .6x as well). Collimation is usually pretty stable on Maks and Sct's and rarely needs doing unless the scope gets a big knock. But it's good to know how to do it just in case. The secondary is pretty fixed on the meniscus so doesn't move much at all. In a slow scope like this dso subs are a little longer at f-6. Bear in mind this will impact on which camera you choose, chip heat, cooling time between subs, and amount of noise. But many folks have dealt with it well and been very successful - I actually love these scopes but they do need thinking through. The package looks good - hope you get it for a good price - start thinking seriously about the mount if you go for it lol Link to comment Share on other sites More sharing options...
dawson Posted April 2, 2013 Author Share Posted April 2, 2013 I think the mount i've been drawn to for some time is the NEQ6 pro; if sheila says she can cope with the weight then i think i should be able to (no disrespect to sheila's back or her strength meant there). Also, having seen them in the flesh, they are not as large as i had feared. We'll see. I'm still thinking. Thanks for the info though kim. James Link to comment Share on other sites More sharing options...
Brantuk Posted April 2, 2013 Share Posted April 2, 2013 Next time we're both at a dark site you can help me set up the NEQ6 and test the weight of each bit for yourself. If I handle it ok with my back problems then I'm sure you'll be ok. As always it's just a question of being careful to keep ones back straight and lift properly. Link to comment Share on other sites More sharing options...
BAZ Posted April 2, 2013 Share Posted April 2, 2013 Hi James, I have the 95mm version of this and it's a cracking scope. Collimation is not something I would not yet attempt, and it states in the literature that it should be sent back to Vixen. That said it is a belting scope, and really delivers very sharp and clear views. The contrast is also good. The other good thing with it is, it doesn't have a a corrector plate, so with just a dew shield, it goes all night. It doesn't take long to cool down either for the same reason. As you would expect from Vixen the build quality is good too. Link to comment Share on other sites More sharing options...
dawson Posted April 2, 2013 Author Share Posted April 2, 2013 Ok. I'm a bit cautious about the collination issue. Especially with it being second hand. He is looking for about £550 for the lot. James Link to comment Share on other sites More sharing options...
BAZ Posted April 2, 2013 Share Posted April 2, 2013 I paid £95 for this, it came with a Vixen RDF that's worth £70. I have star tested mine and it's bang on. Ask him if it is collimated, if he says yes, it might be worth a punt. But if he says it needs collimating, don't go near it. Link to comment Share on other sites More sharing options...
dawson Posted April 2, 2013 Author Share Posted April 2, 2013 I aksed him soe cifically about collimation, this is what he said: The primary,secondary and focuser can all be collimated on this scope which sounds a bit scary! In practice the secondary and focuser seem well centred on my scope so I have left them well alone. You will have to tweak the primary from time to time, especially if you are transporting the tube. It took me a while to get the hang of it but now I can do it in a few moments. Some of the descriptions make it seem harder than it is. It would be more difficult if it ever got way out but in practice if it's set up ok then collimation is just tweaking the primary mirror push pull screws by tiny amounts. Basically you find a bright star and defocus. If the central section of the defocussed image is off centre then you use your mount controls to move the star in the same direction as the offset and then use the collimation screws to bring it back to the centre of the field. This will improve the alignment of the central section of the defocussed star. You can repeat this until the defocussed star is symmetrical. You can do this using an eyepiece or looking at an image from a webcam on a screen. If you buy the scope I can show you which screws to use and what to leave well alone. I also read some of the posts on the web. I think a lot of the problems arose with people misunderstanding the collimation instructions and also making too big an adjustment of the screws. Link to comment Share on other sites More sharing options...
dawson Posted April 2, 2013 Author Share Posted April 2, 2013 The whole concept of collimation scares me. This is one of the reasons i'm drawn towards the mak-cassegrain as i'm led to believe they don't need it. James Link to comment Share on other sites More sharing options...
Brantuk Posted April 2, 2013 Share Posted April 2, 2013 The Maks have a lens at the front, rather than the Sct's meniscus. So it tends to make the scope heavier and longer to cool down. However it does hold the secondary convex mirror in place more firmly and doesn't move at all. The primary may still need collimation - but it's really not a big thing - collimation scares everyone who's never done it - once they understand and master it they wonder what all their fuss was about lol. Link to comment Share on other sites More sharing options...
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