DSRL to Telescope Adapters

Chrissyo (Chris) · #1 15-09-2007, 04:56 PM

OK, I know this is like the third topic I've made about camera adapters. Please forgive me, for some reason I just don't understand them that well!

OK, here's the situation. My dad has been interested in getting into amateur photography for a while. So for fathers day, we all decided to get a Canon 400D. I was quietly cheering on from the sidelines thinking it's a great opportunity for me to start doing some deep sky stuff with my telescope.

Well we've ordered the camera, so it's time for me to order an adapter - but (like my last posts regarding video cameras) I'm confused as to what I want. I've already been through some old topics (and used the Search function on the forums) and so I thought I should make a new one to make sure I don't buy the wrong thing.

OK, so I'm going for the prime focus method (because none of my eyepieces are too fantastic). So I figure I'd need something like this to first fit into my telescope's 2" focuser then something like this to attach to the camera and then to the adapter.

Is that right? I am mostly basing it on this image from Dennis.

Thanks in advance!

Geoff45 (Geoff) · #2 15-09-2007, 05:09 PM

Yes
You've got the right equipment.
Geoff

leon · #3 15-09-2007, 05:13 PM

Yep, Chrissyo, that will certainly do it, as long as you get the T-Mount suited to your camera, and making sure it will screw nicely to the 2" camera adapter.

Leon

[1ponders] (Paul) · #4 15-09-2007, 05:13 PM

Do you have the low profile focuser Chris? The low profile prime focus adapter (first link you posted, don't get this one as it will be too high a profile) may be enough, but maybe not. You have just mounted your dob to the eq6 haven't you? You haven't bought a purpose built Newt to go one it?

Geoff45 (Geoff) · #5 15-09-2007, 05:21 PM

If you're having trouble getting focus, an alterantive is one of the barlow adapters from Bintel. It fits into a 1.25" eyepiece tube and accepts a T-ring on the other end. This pushes the focal point out far enough. It works fine on my GSO 12" Dob

[1ponders] (Paul) · #6 15-09-2007, 05:35 PM

Yep that will work, but you will increase your f ratio from 5 to 10 which will increase your exposure time by a factor of 4 for any given object.

Chrissyo (Chris) · #7 15-09-2007, 05:36 PM

Quote:

Originally Posted by [1ponders]

Do you have the low profile focuser Chris? The low profile prime focus adapter (first link you posted, don't get this one as it will be too high a profile) may be enough, but maybe not. You have just mounted your dob to the eq6 haven't you? You haven't bought a purpose built Newt to go one it?

I have a bintel 10:1 fine focuser, this one. It isn't the low profile one. Will that mean I will have focusing problems?

Yeah, I just have my 10" f5 Newt. on my EQ6.

[1ponders] (Paul) · #8 15-09-2007, 05:40 PM

Don't know Chris. Did you change the one that came with the dob or did the 10:1 come with it and if so is it "shorter" than the original by any length?

Chrissyo (Chris) · #9 15-09-2007, 06:16 PM

Quote:

Originally Posted by [1ponders]

Don't know Chris. Did you change the one that came with the dob or did the 10:1 come with it and if so is it "shorter" than the original by any length?

Nah, it's not the original focuser. My scope originally came with a standard rack and pinion. My current one doesn't look any 'higher' or 'lower' than my old one though.

[1ponders] (Paul) · #10 15-09-2007, 06:35 PM

Well either way you are going to need the T adapter (T Ring - EOS to T thread) and the prime focus adapter whichever way you go. Not having used a Dob newt to image with (or a standard newt for that matter

) I don't know if the low profile PFA will be low enough.

What are you going to use to guide through?

Chrissyo (Chris) · #11 15-09-2007, 06:52 PM

Quote:

Originally Posted by [1ponders]

Well either way you are going to need the T adapter (T Ring - EOS to T thread) and the prime focus adapter whichever way you go. Not having used a Dob newt to image with (or a standard newt for that matter

) I don't know if the low profile PFA will be low enough.

What are you going to use to guide through?

Guide through? I didn't think guiding was a big issue with 30 sec exposures (you just line it up, focus and capture)?

Acck, this is why adapters confuse me, everything gets so complicated so quick!

[1ponders] (Paul) · #12 15-09-2007, 06:55 PM

Ok 30 sec exposures if you are well enough aligned will be fine

davewaldo · #13 18-09-2007, 11:10 AM

Hi Chrissyo,

I have a 10" GSO dob and I have had to make major mods to allow focus for my Canon EOS 20D (same focal point as 400D).

To see my mods see this thread: http://www.iceinspace.com.au/forum/s...ad.php?t=18909

and finished result:

http://www.iceinspace.com.au/forum/s...ad.php?t=19212

All this was needed as the mirror is too far away in standard form. Even a low profile focuser would not have been enough. I cut 35mm off the bottom of my scope and now it "only just" comes to focus with my standard crayford focuser and 20D. One way to test where the focus point of your telescope is, is to hold a piece of paper infront of the focuser (no EP) and point it at the moon. By moving the paper in and out you can see the focused image of the moon on the paper. Hold it where you think is sharp (This point is where your CCD needs to be) and measure the distance from the focuser to the paper. This measurement shows you how much room you have for your adapter and the distance from camera front to CCD.

I cut 35mm off as this is the size of EP spacer easily bought from bintel. You could cut 50mm off and use a 50mm spacer/extender. As an extra bonus your tube becomes shorter, lighter and more managable.

Hope this helps and doesn't confuse!

Dave.