moving secondary for photography

[Bungielad]

Hi all,

I am wanting to use my 130p skywatcher for AP but know I need to move the secondary mrror, i haven't a clue how to do it and am hoping someone could help me out with advice on how its done.

many thanks in advance

Bungielad.

[Moonshane]

Why would you need to move your secondary ?

[Bungielad]

Because I cant reach focus with dslr and iv heard the moving your secondary up or down the tube will resolve the problem, I have the 130p not the 130pds

Bungielad

[Charic]

I would have thought the primary mirror is the one to modify, or the use of extension tubes for the camera to reach focus. If its inward travel to get to focus maybe a low profile focuser would help.  

[Moonshane]

Yes it could be easier to move the primary as moving the secondary would involve resisting the focused and spider.

[Stu]

Yep, it would definitely be the primary to move, not the secondary.

Sent from my iPhone using Tapatalk

[happy-kat]

http://stargazerslounge.com/topic/10503-going-to-mod-my-skywatcher-130p/ might be a related read

[Bungielad]

Oh......thought it was secondary mirror that had to be moved? Ok in that case....how do I move the primary and where to?

Also what are nose collers, how do these work and where do I get them from?

Apologies for all the questions, just eager to know.

Bungielad.

[Charic]

I've edited since?.........Extension tubes?  On my Skywatcher the 2" to 1.25" adaptor can be used as your first extension tube, connected to a  camera specific T-Ring. 

[Bungielad]

It is inward travel that is the problem! What is low profile focuser?

Bungielad

[Charic]

one that is shorter than you have now, a replacement?

How much extension is added to the camera by way of tubes. I'm just developing an image for you. the three components are the T-ring, the 2-1.25" adaptor without extension tube, and the 2" eyepiece adaptor.

All three fitted gives you more outward focus, just using the middle adaptor  with the T-ring should reduce the focal length.

[Bungielad]

I use the t ring and t ring nose adapter, I have tried not using the nose adapter to get further inn but no luck, in the end what I did was chop off about 5mm off the focus tube as so to reach focus. ....and it did but, unfortunately, now to try to collimate the scope is a nightmare due to the focus tube is to lose.

I am getting a new focuser for the 130p due to me messing up the other one but dont want to go down the same route again.

This is why I want to find out about moving the mirror. If I could get a focuser that fits the 130p without doing much modding then I would....know of any? That dont cost more than the scope!

I have the 200p coming soon on eq5 but wanted to use the 130p on the eq5 mount for AP.

Bungielad.

[Charic]

.........so not too drastic a modification then? there's gotta be something to say about that   but whats done is done, to your loss at present   Don't be  chopping any more bits or adding anything just yet. let someone else take a look at your signature setup, and hopefully provide you a better solution. Unfortunately, I know of no second hand focusers for sale, but you never know, one may turn up. 

[Thalestris24]

Hi

You might be better off just getting a 130pds ota (£165 from FLO) rather than messing about so much. Failing that you could try a low-profile t-ring. I'm not sure you can get a low-profile focuser for the 130p. In any case, not worth the extra expense.

Hth

Louise

[Bungielad]

Yeah I think I might just do that louise, alot less bother.

Bungielad

[Father Jack]

I've been lurking around this forum for months taking good advice and having nothing to contribute until now. So thank you Bungielad!

Anyway I have a 130p and had the same problem with inwards travel (tis quite common I've heard). I too cut a section of the focsuer off. I even had to go a step further and extend the primary mirror down the tube before I was able to reach prime focus.

I also had a problem with collimation after cutting the focuser tube. All I did to rectify this is put a couple of layers of electrical tape around the focuser tube, made a line where my DSLR reached focus and collimated at that line. It sounds silly but it worked and has continued doing so without modification for about 9 months.

I have some pictures of the focsuer and mirror mod somewhere if you're intersted? I can't post them at the moment though as I'm at work and their at home.

[laser_jock99]

It's fairly straightforward to install longer/stronger springs in most Newtonian primary mirror cells. I have modded all my Newts in this way.

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