In the Blue corner SW150PL. In the Black corner SW200P

[stargazerlily]

Hi everyone,

I'm going round and round, chasing my tail about which of the above scope would be better and why.

I currently have a SW150PL (1200mm focal length) and am toying with getting a SW200P (1000mm focal length). I can't really go any bigger than a 200 as I have a HEQ5 pro mount (a SW250 is probably too much for this mount).

Taking into account the size of the primary mirrors, the potential magnification of both scopes is about the same.

My main interest at the moment is imaging of planets (with a web cam, not yet with a DSLR) but I'd like to move onto DSO imaging at some time in the not-so distant future (with DSLR).

So I'm wondering ... which of these two scopes would be the 'best' for my current interests (and why).

Many thanks

Pete

[Peter Drew]

Hello Pete. My vote would be for the 200, planetary imaging relies heavily on resolution and the 200 would offer more than the 150. Either scope would need significant eyepiece projection or Barlow use to provide a large enough image scale. The 200 would also be "faster" if DSO's are to be targeted in the future.

[rfdesigner]

I'll vote for the 200 as well.

I'd vote for a 2000 if it was on offer:D

Focal length can be 'bought' with a barlow. Focal reducing is harder, as focal reducers to some extent are field reducers too, unless you look beyond 2" focussers.

IMHO, best is: Fast scope + barlows + lot's of aperture.

Are you sure you can't look at the 250?

Derek

[JB80]

Here is something I learnt just yesterday (thanks spaceboy ), when imaging say Jupiter it is best to have an f ratio of f/25-30 which would mean you have to add a barlow like x4 or x5 and maybe even an extension tube. Now a 200P is f/5 so presumable a x5 would work well but and 150PL is f/8 so it would require less magnification to reach the higher ratio.

I'm not certain what the practical implications of that mean but it's always said that the longer focal length is better on planets.

Plus 150PL will probably be better suited on the HEQ5 if it's lighter especially if wanting to do DSO's in the future but then people will probably say get the 200P.

I'm going to vote for the 150pl 'coz no one else will

[stargazerlily]

Thank you Derek and Peter for your comments. To be honest I hadn't really considered resolution. That is a very good point. Assuming all things are equal, would greater resolution equate to sharper focusing? On my 150, I feel that I can't quite get the focus spot on (ok ... putting my hands up here ... I haven't collimated the scope recently so that might be the reason).

Regarding the 250, I've read on various threads here that a 250 plus camera etc would be pushing the weight limits on the HEQ5 Pro mount a bit too much. I can't afford to upgrade the mount.

Thanks Pibbles ... one + for the 150PL

Pete

[rfdesigner]

resolution wise see what Damien Peach says:

Courses in Astrophotography

[nightfisher]

coming at this from a different aproach, how about keep the 150 and get a small ED for imaging

[stargazerlily]

coming at this from a different aproach, how about keep the 150 and get a small ED for imaging

Sorry ... I'm not sure what a small ED is :o

Pete

EDIT ... Must be Friday ... I do know what a small ED is. That is an interesting idea ... worth following up, thanks.

[nightfisher]

Sorry ... I'm not sure what a small ED is :o

Pete

a small Ed refractor like a skywatcher 80ED, they are prefered for dso imaging with dslr`s and ccd camera`s

[jkwhinfrey]

An 80ED is a good wide field scope, but how good for high resolution planetary stuff?

As for focusing, resolution/aperture isn't necessarily the issue.

Generally a fast scope will be harder to get into sharp focus than a slow one. I use an f5 scope - like the 200, but smaller - and I'd love a dual speed focuser

The 150PL being slower that the 200 should be easier to focus.

[nicnac]

of the various things i have read over the 250, the HEQ5 and the CG5 will take it and perform well for visual use but when you start adding cams and guide scopes, well, it is said that neither will cut the mustard, you are entering EQ 6 territory

[b_kassabov]

Are you sure you can't look at the 250?

Do you think a EQ6 Pro mount would handle a SW 250 decently -with all additional equipment, guiding scope etc and you'll be able to get good results for photography?

[pritc]

SW200P on a HEQ5, vote from me

Great package, across the range

I have it

Wayne

[stargazerlily]

An update to this thread

The fight has been won ... and the winner is ...

...

...

...

A brand spanking new SW200P !!!!

Can't wait to give it a go ... when all this blinking fog has moved elsewhere.

Thanks everyone for all of your comments.

Pete

[Gina]

SW200P on a HEQ5, vote from me

Great package, across the range

I have it

Wayne

I'm going for the next step up I already have the NEQ6 Pro SynScan and will soon be buying the SW250P DS OTA. I'll report back when I've got it set up. I'm going for the DS version for both the superior focuser and shorter tube for DSLR imaging. I shall be using it for both visual and imaging.

[michael.h.f.wilkinson]

An update to this thread

The fight has been won ... and the winner is ...

...

...

...

A brand spanking new SW200P !!!!

Can't wait to give it a go ... when all this blinking fog has moved elsewhere.

Thanks everyone for all of your comments.

Pete

Wise decision! I upgraded years ago from a home-made 6" F/8 (very good scope indeed) to a C8. Though at a given exit (but higher magnification) pupil the contrast is perhaps a shade lower, the C8 shows more planetary detail. An F/5 scope needs a 4x to 5x barlow, and the demands on quality will be higher (try the Meade TeleXtender 5x, now sold under the Bresser brand) than in a slower scope.