Sony A350 focusing issues on a SW200p

[SCOOB_81]

Hi All,

I was hoping someone could offer some advice with a similar setup to mine, please?

I have a sw200p on an EQ5 and have just picked up my first dslr, which is a sony a350. I'd have much prefered a canon of some sort, but got mates rates on the above-beggars can't be choosers! :-)

I have a t-ring, but the issue I have is there is not enough outward travel with the focuser to focus clearly. I've tried the camera with the t-ring screwed directly onto the focuser, using the sw 'deluxe' barlow as both an extension tube and as the barlow itself, but it's still some way off.

Can I ask if anyone has any suggestions, please?

Many thanks!

Sean.

[Chris]

I had an old blue tube 200p which wouldn't focus with a DSLR but It would with a 2xBarlow. The new Black diamond series 200p has rectified this problem and many people on here image with it using DSLR and T-ring. I find focusing is good with the new black diamond 150p and T-ring.

Therefore, if you have the Black diamond 200p you should be able to focus so there must be some other reson why you're having trouble? If you have the old blue tube you can try moving the primary mirror a little up the tube by maxing out the three primary mirror adjustment screws. If this doesn't work try buying some slightly longer screws, or you can get a lower profile focuser, there is more than one way to skin a cat:) Can you give us some more info about which 200p you have and your focussing precedure so we can help you further:)

HTH,

Chris

[SCOOB_81]

Hi Chris,

Thanks for taking the time to reply.

I do have the Black Diamond version of the 200p, but I’m a little embarrassed to admit that the problem is a little closer to home than the scope – me……

The weather wasn’t the best when I picked up the camera, and like a kid at Christmas, couldn’t wait to get it stuck to the scope. I was using a terrestrial target, which would seem to have been far too close to achieve focus.

Decent weather, a target at a decent distance and voila, focus.

Thanks!!

Sean.

[Chris]

your not the first and you won't be the last Sean:) one thing I wish I'd been told early on is the importance of a focusing mask as perfect focus will make a massive difference to your images, you can tweeek many things but if your focus is out your images will be unsalvigable.

here is a demo of how focus looks with the Bahtinov mask, its perfectly focused when all the spikes are equidistant and symmetrical.

You can buy them here: http://www.firstlightoptics.com/bahtinov-focus-masks/starsharp-bahtinov-focus-masks.html

or a simple vesion can be made, its called a Y-mask and its simply a Y-shape that sits at the front of the telescope, A friend on here recently forgot to take his mask with him when imaging away from home at a dark site, so he just picked up a Y-shaped twig of the floor and it gave him perfect focus:)

hth

Chris

[SCOOB_81]

Hi Chris,

Haha, nope, I bet I'm not the last, either!

Thanks again for the information, especially having recently picked up a Bahtinov mask myself from FLO. With our current monsoon season I've only had the chance to try it out the once, and so the video is very useful. Hopefully, it will be as good at helping achieve focus with the webcam as with the DSLR.

Thats a great story about the twig!

Cheers!

Sean.