Skywatcher BD-252 and HEQ5PRO - Infocus for DLSR

[DRCORTEX (Lance)]

Hi People,

Well, have my new scope, as per the thread title. Having some issues here. Firstly, the mount grinds like a meatgrinder when in operation ( from what I have been able to find this is normal ).

But the real deal, connecting my Canon EOS-450D with T-RIng to the scope and obtaining sufficient infocus.

Even with the focuser wound down to it's limit, I can not quite manage focus on the moon.

I had a GSO 10" prior to this, and cut it down 50mm or so. Gave me what I needed for astrophotography, but wasn't impressed with having to cut the scope. It was never the same afterwards, and don't want to do that again.

Realisitically, do I have any other choices with my new scope ? Am I better off getting rid of this scope while new, and grabbing something else ? Perhaps a SCT, etc, which don't seem to have these hassles.

It is only JUST out of focus, so longer collimation screws would probably do the job, but then to increase magnification using a barlow, I would probably be in the same boat again ( is this correct ) ?

Looking to get some shots of the planets to start, and move on from there.

Perhaps I should look at a CCD imager ? then again, they have issues as well - and man, I want an enjoyable part-time hobby, not an obsession. Money goes in lots of directions, many of them, not my choice

ANyway, if sone kind person, that has had the same issues, could give me some advice, great.

Looked in many forums, but there dosn't seem to be any clear cut solution.

Cheers

Doc

[bmitchell82 (Brendan)]

grab your 1 1/4 adaptor, unscrew the 1 1/4 nose from it and then screw that into your Tring. happy days untill you add a MPCC

[that_guy (Tony)]

i heard somewhere that you can get more in focus with a low profile focuser while i was reasearching for astrophotography with my dob

[adman (Adam)]

go with the longer collimation bolts. Very cheap, very easy, totally reversible, no holes drilled in tube or cutting down required. You will need extension piece for visual use though. While you are at it - get some stronger springs for the collimation bolts - less mirror shift when moving the OTA.

Adam

[cybereye (Mario)]

Brendan's solution is the best - it's how I attach my DSLR to my Skywatcher. You don't have to make any modifications to your scope!!

Cheers,
Mario

[DRCORTEX (Lance)]

Thanks for the info people. I think I have already tried removing the nose piece. In fact, by removing the 1 1/4 adaptor completely, the camera fits straight on, but even so, I cannot manage infocus.

Anyway, there are 2 or 3 suggestions there, so I will try them one at a time, and see how I go.

The absolute myriad of telescopes, with the hundreds if not thousands of variations, make it difficult when you want to move into astrophotography.

Lucky cars are not designed and manufactured in the same way or we would all be walking.

Cheers

DOC

[bartman (Bart)]

I unscrewed the lens part of my 2x barlow and screwed it to my t-ring.
Seemed to do the trick.
bartman

[bmitchell82 (Brendan)]

Thats extremely odd that it doesn't attain focus as mine did with about 10 mm to spare once i did it.

Can you take some photos of how your connecting it all together because i have seen people with BD 8" scopes do this and it works.

[jjjnettie (Jeanette)]

My 8" BD newt, the exact same model that RobF has, wouldn't achieve focus either, whereas his would. I believe the optical tubes were cut to a different length.
Near enough isn't good enough when you're building scientific instruments.

[RobF (Rob)]

It is very frustrating Skywatcher hasn't addressed this by now. So many people want to at least dabble in AP at some point. Surely it wouldn't be that hard to make the focuser more 2" friendly and ensure prime focus is reasonably accessible

They're such a great value for money proposition its a shame this part is hit and miss. I still haven't been willing to bring myself to cutting down the OTA, so I routinely image with an inch or two of drawtube obstructing the lightpath.

[bmitchell82 (Brendan)]

I think what everybody forgets at some point is that they are not made for astrophotography. And hence why should they change their design when it isn't designed for that in the first place. The ED 80 from skywatcher is made for AP and hence you need almost 100+mm of back focus to gain focus for eye pieces.

Visual and Astrophotography are 2 completely different things. They require different aspects, Visual requires a low Central obstruction, AP anywhere up to 50% i have seen and just little things like that. If you go out to do AP first up the scope you will get will more than likely be none of the Skywatcher dobsonian range for a start irrespective of how good value for money they are.

That being said sometimes you need to modify to do what you want it to do, I have done this to my Skywatcher 10" Dobsonian, enough not to call it a Skywatcher Dobsonian any more. Accept what it is that you have and make it work from there. if you don't like to modify. purchase something already made for the job at hand its easier that way!

There is so much knowledge in this forum that a quick question will land you a answer if not within a day within the week to what would best suit.

Just my 2 cents worth