Imaging newtonian question

[beamer3.6m]

I have a 200p and a 130p. Both are great for visual use but the 130p cannot take a dslr due to focus problems and the 200p can be quite unwieldy to guide even on the HEQ5. It is prone to wind shake etc.

I like newtonians and am happy with collimation etc and have managed to flock my 130p recently. I also like the price of them.

My question is:

If I were to go for a PDS version of a skywatcher newtonian what size would you get. I do NOT intend to use it for visual.

I understand that as all the skywatcher PDS are f5 and it will be used for imaging only the aperture makes no difference. In other words I believe that the 130p will give the same results in terms of imaging as the 200p. Is that correct?

If so my next question is why would I want the larger size? It may be due to the 130p giving a widerwent field of view but for dso imaging the wider field the better - ie the fov with an ed80 is quite wide.

I do not want a mak as an alternative etc and an ed80 is way outside my budget so that won't be helpful responses. I have also owned a c80ed in the paSt and a 127 mak and found they overall uninteresting scopes. I just like newtonians.

I appreciate that a coma corrector may be required in due course.

Awaiting the response.

[laser_jock99]

The 130p and the 200p could be modified into a 130pds/200pds by moving the main up the tube by 10mm or so. AFAIK that is the main difference between the two scopes- it brings the focus point further out.

I have modified all of Newtonians in this way merely by installing longer (and stronger) springs

http://stargazerslounge.com/topic/217170-10-gso-newtonian-mirror-cell-mods/?hl=%2Bsix+%2Bspring

The extra back focus gained is useful when using filters and other accessories. The stronger springs make your collimation more stable.

[D4N]

You're right that bigger isn't always better in AP, they are just different.

The longer focal length gives smaller FOV hence larger image scale but at the cost of being harder to guide. That's no good if you want to image something big of course.

TSED70Q, iOptron Smart EQ pro, ASI-120MM, Finepix S5 pro.

[nightfisher]

Simple answer is keep the 200 for visual, sell the 130p and get a 130p ds for imaging

[Uranium235]

I concur with that

Its probably not worth modding the old 130p becuase the cost of the tools and a replacement focuser (of which there are no third party replacements) makes it uneconomical. Best to just go with the 130pds from scratch.

As mentioned above, both the 200 and the 130 are exactly the same speed - the only difference is the FOV and resolution, and that one will be much harder to guide for long periods than the other.

Keep the 200 for small stuff (ie: galaxy season, Feb-May), then let the 130pds cover the big stuff available at any other time of the year.