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Halfstar

Unable to Focus Skywatcher ED80 with Canon DSLR

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Just bought a new Skywatcher ED80 400mm Triplet, with a EXOS2GT mount,new to astrophotography, desperately need advice, the telescope works fine with the lenses during the day, but when we attach our Canon EOS 5DMark II to it, then try to focus in the live view, it will not focus, so we bought a Dell laptop, to try to see but still no visible focus.  We tried with lens, with bartlet lens and with a flattner, still no focus.

what  could we be doing wrong.  We tried it on Manual, AV,TV,P. No focus.  We are able to focus on the Moon at night with just the Lens, but when we attach the Camera, no focus.  we are both frustrated, looked online but can't find tips on what to do.

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What was lacking to focus it, more focuser travel outward or inwards? Were you using with a diagonal?

I don't have the ed80,  but if it was more outwards you can add an extension tube or a diagonal. if it is inward travel you may need to use a lower profile adaptor or if you are using a diagonal or extension tube remove it and try without it. 

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Thank You for your reply, yes we tried a diagonal, and extension,a Barlow, we tried focus all the way in, and out, feeling like a real failure here

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Think you need an extension tube to take the place of the diagonal.

Failing that get the matching flattener and an M48 T-ring should sort it.

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Try using your scope with the camera attached in the daytime and focus on a distant object to see if you can achieve focus then with the camera. Make the object you focus on as distant as possible and then mark or note how far in or out you need to have the focused set to. Then you can try the scope at nighttime too at this focus setting and see if you can get anything. Probably easiest first off to go for the moon as that will be the brightest thing in the night sky.

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2 hours ago, Halfstar said:

Just bought a new Skywatcher ED80 400mm Triplet, with a EXOS2GT mount,new to astrophotography, desperately need advice, the telescope works fine with the lenses during the day, but when we attach our Canon EOS 5DMark II to it, then try to focus in the live view, it will not focus, so we bought a Dell laptop, to try to see but still no visible focus.  We tried with lens, with bartlet lens and with a flattner, still no focus.

what  could we be doing wrong.  We tried it on Manual, AV,TV,P. No focus.  We are able to focus on the Moon at night with just the Lens, but when we attach the Camera, no focus.  we are both frustrated, looked online but can't find tips on what to do.

I'd get back to the supplier and ask them what you need. They will (or should) know. Wxsatuser above summed it up. 

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Unscrew the lens from the end of your Barlow.

Camera, adapter, empty barlow tube, telescope.

and try this as a day time rig first.

Works with my ST80 as a camera lens.

Rich

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My ED80 has a Astro Altair flattener/reducer, a M48 T ring then my Canon 1000d and I have no trouble focusing. The draw tube is about 2" out of the scope and I  use a Batinov mask to fine focus. if your set up can't do that then I should get back to your supplier asap...

 

Ron

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There's not enough back focus on the ED80 to use a DSLR without an extension tube. Ditch the flattener and diagonal and go back to the scope only to simplify things. A decent length Barlow with all the lenses removed (tube only) should allow the additional distance you need. 

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I also have a ED80 with a Canon 1000D and I can achieve focus with the drawtube extended out about 1"

I have a FR/FF and the Baader Clicklock

IMG_5710_cr.jpg.692811b5ca710eb615c330f5cdc20e6e.jpg

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My experience in using an ED80 doublet indicates you will need to buy a 50mm extension tube to get focus assuming you are using a T-ring and appropriate nosepiece. This will also work if you are screwing  the detatchable lens from a barlow into the nosepiece to get greater magnification.

This will be the cheapest option and simpler to use instead of a flattener etc

 

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1 hour ago, david_taurus83 said:

This is the Esprit 80 400mm yes? Not the Evostar 80 600mm?

I agree, I think most people are getting mixed up David. There are no issues with the Evostar, but the Esprit is a different telescope. 

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2 hours ago, david_taurus83 said:

This is the Esprit 80 400mm yes? Not the Evostar 80 600mm?

Well spotted I just saw the ED80 !

Forget everything I said as I was talking about the doublet.

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Thank You everyone for the advice, Yes it is an Espirit,   Will try your suggestions and have order a Batinov, hope fully this will help with our focus problem

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18 hours ago, Atreta said:

What was lacking to focus it, more focuser travel outward or inwards? Were you using with a diagonal?

I don't have the ed80,  but if it was more outwards you can add an extension tube or a diagonal. if it is inward travel you may need to use a lower profile adaptor or if you are using a diagonal or extension tube remove it and try without it. 

A newbie question here....but without a bahtinov mask....how do you tell whether the subject is under focus or over focus? i.e. whether you are lacking on focusser in or focusser out?

cheers,

Andy

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2 hours ago, Andywilliams said:

A newbie question here....but without a bahtinov mask....how do you tell whether the subject is under focus or over focus? i.e. whether you are lacking on focusser in or focusser out?

cheers,

Andy

You can tell it by looking at the object and see which way the image is getting sharper. The moon is a good object to practice, or distant trees during the day. If focus is not improving racking in, then you try  racking out until you get a focused image.

Some scopes may lack inward travel,  like my older heritage 114p newtonian , and some other may lack outward travel and need an extension tube to get it to focus properly. 

Edited by Atreta

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22 hours ago, Star Struck said:

 

My experience in using an ED80 doublet indicates you will need to buy a 50mm extension tube to get focus assuming you are using a T-ring and appropriate nosepiece. This will also work if you are screwing  the detatchable lens from a barlow into the nosepiece to get greater magnification.

This will be the cheapest option and simpler to use instead of a flattener etc

 

 

Its' not a doublet ..its a triplet with a 400mm focal length not a 600mm..id guess it's the esprit...

I'd guess as your trying with a Barlow then you have a 2 inch or inch and a quarter nose cone ? Depending what you're trying to image,if it's dso then I'd ditch the nose cone and use the t adapter with the t ring... if it's planets then a 400mm focal length with a DSLR chip is going to give you a small image scale..its not really it's strength..

With my ed80 (600mm) I unscrewed the end off the tube,added the reducer then a adapter from reducer to t ring..its then ridged..you don't want flex or tilt..

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12 hours ago, Andywilliams said:

 newbie question here....but without a bahtinov mask....how do you tell whether the subject is under focus or over focus? i.e. whether you are lacking on focusser in or focusser out?

Try( not with a mask thou) on a bright target first such as the moon and rack the focusser in and it to get near focus..on a star you will see it either getting smaller or bigger..you want it as small as you can.. try on a big bright star..

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my lack of experience came home to roost last night when I couldn't focus my 127 mak with a canon 6d on it. first I tried eye piece projection, then a X2 barlow and finally the barlow with the lens bit removed.....nothing !

I checked the camera, which was on backyard eos frame and focus with my headlight and it showed up bright enough....but alas no Jupiter :(

I tried long extension tube and short.....am at my wits end with it.....any suggestions?

cheers,

Andy

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On 4 June 2018 at 20:59, Halfstar said:

Thank You everyone for the advice, Yes it is an Espirit,   Will try your suggestions and have order a Batinov, hope fully this will help with our focus problem

Is this the Esprit ED super APO? The manual has a useful section on prime focus imaging with a DSLR. Page 7 shows all the components you need, which it looks like you have reading your description in your opening post. 

I wonder whether the problem is using live view. I suggest you set up during the day. Connect the camera as shown in the image from the manual below and, pointing at a distant ground object, look through the camera's view finder whilst adjusting focus. You should be able to tell when you're going in the right direction. If you still can't reach focus there's something wrong. It will also tell you in which direction of focus you run out of travel. Is it too long or too short? But my bet is that, assuming I've got the right scope, if you set up as shown in the manual then it will work. 

I would say a Batinov mask won't solve your problem. Useful to have one to fine tune focus though. 

 

image.png

image.png

Edited by Ouroboros

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On 06/06/2018 at 13:50, Andywilliams said:

my lack of experience came home to roost last night when I couldn't focus my 127 mak with a canon 6d on it. first I tried eye piece projection, then a X2 barlow and finally the barlow with the lens bit removed.....nothing !

I checked the camera, which was on backyard eos frame and focus with my headlight and it showed up bright enough....but alas no Jupiter :(

I tried long extension tube and short.....am at my wits end with it.....any suggestions?

cheers,

Andy

I think I may have solved my own problem for once ! 

The t tube with extension was just too long to bring to focus. So remove the extension tube and voila ! I have great focus on the trees outside plus the x2 Barlow I’ve put in as well and, fingers crossed, when the clouds finally part....I should be good to go 🤞🏻

FF20AB08-1EBE-4C4B-9310-54C58FAD52B9.jpeg

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I put the 1000d on .....as the smaller sensor should help more with the apparent field of view? I think? 

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On 04/06/2018 at 20:59, Halfstar said:

Thank You everyone for the advice, Yes it is an Espirit,   Will try your suggestions and have order a Batinov, hope fully this will help with our focus problem

Whilst you are waiting, can I just check you are seeing something on the live view screen  when trying to focus (hopefully a big white blob if you are trying to focus on a star), and it is just that you can't get the blob to sharpen into a star? 

 

Ady

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 I HAVE A SW EVOSTAR 80ED AND A CANON 5DMKII -AND I USE AN EXT TUBE INTO THE SCOPE FIRST THEN A 2x BARLOW-AND THEN THE CAMERA WITH A -T- ADAPTER. THERE IS A PROBLEM WITH A FULL FRAME SENSOR THAT GIVES A BRIGHTER PATCH OF LIGHT IN THE MIDDLE OF THE IMAGE,THAT MAY BE THE PROBLEM.I HAVE NOW PURCHASED A CANON 50D -THIS GIVES A BETTER IMAGE---HOPE THIS HELPS. 

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