canon EOS 10D connection to scope?

[hozepipe]

Hi

I'm going to buy a Canon EOS 10D or 20D camera for astrophotography (and normal photography too) and need to know what adapter and other bits I need to attach it to the scope - an Orion ED80 - for prime focus imaging. Can someone explain please?

Also once attached how do I focus precisely?

[moondog]

You will need a Canon 'T' mount adapter and either a 1 1/4 or 2 ins nosepiece to connect to the scope. Remove the Canon lens, lock the T mount adaptor to the Canon, screw the nosepiece adaptor the T mount. Fit the nosepiece to the scope ( less the diagonal).

Focussing

Way 1) Focus on a bright star first as well as you can using the viewfinder and take a shot at say 1/30 sec @ 200 ISO. Look at the star image on the LCD screen using the zoom button. Adjust focus if needed and take another shot. Do this a few times to get good focus. Lock focusser and go to object you wish to image.

Way 2) Make a Hartman Mask out of cardboard and place over object lens of scope. Look in viewfinder at bright star. You should see three images of the star. Adjust scope focus so that the three images merge into one. Lock focusser as above. For details on the Hartman Mask try 'search' on SGL as this has been discussed in detail before.

If you have a laptop you can buy software that can help you focus the Canon.

I think that one program is called ( unsurprisingly ) DSLR Focus.

I use Way 2) above.

MD

[FLO]

You will need a Canon 'T' mount adapter and either a 1 1/4 or 2 ins nosepiece to connect to the scope.

Here y'go

http://www.firstlightoptics.com/products.php?cat=55

[Kai]

If you want a very easy way to focus then look at ....

http://www.stellar-international.com/

I have just had one arrive from them and it is really simple,just a bit expensive.

[hozepipe]

Thanks guys - the Hartman mask method sounds good.

So T-mount plus nosepeice gotcha, ta.

Kai that's looks expensive :shock: but good.

Steve, thanks if I can't find what I need any cheaper I'll get them from FLO (I'll try s/h frst).

[Kai]

Your right about the price,but

Trying to focus through the camera i find really hit and miss even through a hartman mask.The problem got even worse when near to the zenith .

Luckly i had some universal vouchers for christmas and they funded it .

When i get a chance to use it in anger i will post a review.

[Kai]

Sorry forgot to say that as the £ versus $ is good at the moment it takes some of the sting out of the cost

[hozepipe]

Sorry forgot to say that as the £ versus $ is good at the moment it takes some of the sting out of the cost

Yes true - though I admit I didn't actually look at the price (I feared for my wallet)! Maybe I'll risk a peek...

[Kai]

:nono: you will not thank me

[hozepipe]

[Kai]

Does mean you have ordered one , or does mean you have dared to look

[anthony]

Steve's T mount is a good price - paid more for mine.

Also, for focusing you can make a set of cross hairs with string or something similar. On my refractor I have a 1-2 cardboard collar wrapped around the top end of the dew shield. Two this I have fixed two lengths of string at right angles to each other. On a bright star you can see very clear diffraction spikes when you are in focus. lock the focus and move to your object. Very easy and pretty accurate.

http://billyard.servehttp.com/Hartmann.html This is a link for a hartmann mask template generator. Run one up for the scope, stick it to some stiff card and cut out the holes in the right places. I opt for the triangles. They give diffraction spikes which help a lot. Also, it is much easier to cut a neat triangle than a circle!

Anthony

[Kaptain Klevtsov]

I have one of those Stiletto focus thingies but it doesn't like me. Perhaps its the fast 'scope, but the "in focus" position has too much leeway for me, the disappearing bars don't snap away so much as stretch out so you have to guess when they're totally gone as there might be one lurking just out of view. I haven't had it out of it's box for months now, so I ought to try it out again and do a write up on it.

Captain Chaos

[Kai]

I ordered mine with the 300 lpi screen as i was assured by Sti that it would work on both my scopes.

[hozepipe]

Does mean you have ordered one , or does mean you have dared to look

I did look yes, wasn't as bad as I thought. Will have a go with the other methods first though.