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Imaging with refractor and 700D SLR


Lukeness

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I've just been outside with my ED80 telescope on my EQ5 mount using my 700D SLR but i haven't been able to focus on the orion nebula or jupiter.

I've used a barlow lens and they both still come out as big circles, i can't seem to get any better.

Is there a way around this? to make the image focus more so it actually looks like something?

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I need an extension tube with my scope to reach focus with my DSLR, but I thought the Barlow might do the same? I'm no expert you see....

The other thing is, how are you focussing? Using liveview? I find that very difficult, although I just have a lowly 1100d. I have found it much easier to use a Bhatinov mask and also the APT software which has some useful focussing tools.  Have you tried finding the brightest visible star and focussing on that first?

Of course, if you need an extension tube in the mix, none of these will help, so hopefully an expert will be along to help!

The other thing to try is focussing on the moon and then try some shots of Orion to see how far out you are

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I've just been outside with my ED80 telescope on my EQ5 mount using my 700D SLR but i haven't been able to focus on the orion nebula or jupiter.

I've used a barlow lens and they both still come out as big circles, i can't seem to get any better.

Is there a way around this? to make the image focus more so it actually looks like something?

I don't think that you should have any problems reaching focus with the ED 80 and a Canon DSLR. Try focusing during the daytime on a very distant object as for beginners it is easier to relate to terrestrial  objects. Once done make a small note of the focusers position and use this at night a starting point. If you find that the draw tube extension is uncomfortably long then you may have to use an extension tube.  You have to be very delicate with the focuser movement for AP  as a fraction of a millimetre either way throws the focus out. If you use the SW FF/FR then the draw tube will not need to be extended so far out either as the point of focus shifts inward. The other option is to try and focus on the Moon if it is out which I believe it is at the moment. Hope that this helps.

A.G

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I need an extension tube with my scope to reach focus with my DSLR, but I thought the Barlow might do the same? I'm no expert you see....

The other thing is, how are you focussing? Using liveview? I find that very difficult, although I just have a lowly 1100d. I have found it much easier to use a Bhatinov mask and also the APT software which has some useful focussing tools.  Have you tried finding the brightest visible star and focussing on that first?

Of course, if you need an extension tube in the mix, none of these will help, so hopefully an expert will be along to help!

The other thing to try is focussing on the moon and then try some shots of Orion to see how far out you are

I'm using liveview as I turn the focusing knobs but i can't see any thing until i take a short picture, where it just comes up as big circles.

I'll try again tonight and see what I can do. I did the same thing about 2months ago and I swear i managed to focus in on jupiter, but i can't seem to do it now, for some reason

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I don't have an ED 80, yet, but do use an ST80 with 700D for daytime photography. As you have nothing to lose, try removing the lens from the 2x barlow and then just use the empty barlow tube as an extension.

This could at least show you if you require an extension tube, which I suspect you will.

This pic is purely to give you an idea, note that the Barlow has no lens in it, but also note that I'm only using about half the travel of the focusing tube. This tells me that I do need a correct extension tube because the barlow in this manner introduces vignetting (although for my use I can crop).

Yes I know that an ED80 is different.

post-34135-0-06290700-1424684037.jpg

and this is a simple test shot at about 50yds purely for focus practice.. Focusing is mighty tricky with the poor ST80, at least the ED80 has a much better focuser so you should be able to hit the sweet infinity spot.

post-34135-0-89306300-1424684398.jpg

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