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Barlow for video imaging with a DSLR


prusling
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I have an astro-modified Canon 550d which offers a movie crop mode (640x480 1:1 pixels) and I've been experimenting with it on Jupiter with my SW 80ED.

I appreciate that a short FL frac and a DSLR would not normally be recommended for planetary video imaging but the movie crop mode could make it similar to using a webcam and avoid the need for a PC in a grab and go setup.

In results so far the images are quite small, as you would expect, so I have been experimenting with a couple of Barlows without success.

With a 4 element Antares 2x I can't seem to achieve focus at all, even when trying extension tubes before and after. A generic 3x ED would come to focus in the camera way back from the maximum extent of the focuser but, although I have various extension tubes, I wouldn't want such a long image train.

So I may need to consider buying another Barlow. Any advice on what could work well in this setup and in what configuration would be appreciated, though preferably not as costly as a PowerMate!

Many thanks

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Now then. You could do that or you could do what I did and buy one of these.

http://www.telescopehouse.com/acatalog/Revelation_Projection_Camera_Adapter_1_25__-1.html

You have one of only 3 cameras that has true movie crop mode like my 60D so you are right to make use of it. You just drop your EP in and away you go. I use my 15 or 25mm plossl. Check my Flickr link for the planetary shots all of which are first efforts. Good luck.

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Now then. You could do that or you could do what I did and buy one of these.

http://www.telescopehouse.com/acatalog/Revelation_Projection_Camera_Adapter_1_25__-1.html

You have one of only 3 cameras that has true movie crop mode like my 60D so you are right to make use of it. You just drop your EP in and away you go. I use my 15 or 25mm plossl. Check my Flickr link for the planetary shots all of which are first efforts. Good luck.

Thanks, Chris.  I'll give that a try.

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Now then. You could do that or you could do what I did and buy one of these.

http://www.telescopehouse.com/acatalog/Revelation_Projection_Camera_Adapter_1_25__-1.html

You have one of only 3 cameras that has true movie crop mode like my 60D so you are right to make use of it. You just drop your EP in and away you go. I use my 15 or 25mm plossl. Check my Flickr link for the planetary shots all of which are first efforts. Good luck.

Found a 60mm long one of these and popped a 15mm plossl in, but this only comes to focus some way back from the fully extended focuser. Tried adding a 25mm extension either before or after the EP projection adaptor to no avail. Maybe the 80ED is particularly unsuited to this setup although I can achieve focus OK without a Barlow or EP albeit with a smallish image even in movie crop mode.

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Found a 60mm long one of these and popped a 15mm plossl in, but this only comes to focus some way back from the fully extended focuser. Tried adding a 25mm extension either before or after the EP projection adaptor to no avail. Maybe the 80ED is particularly unsuited to this setup although I can achieve focus OK without a Barlow or EP albeit with a smallish image even in movie crop mode.

 

Most if not all refractors will require a 2" extension at the focuser to allow for the removal of the diagonal this is true if using an eypiece or camera at prime focus.

I have a similar adapter to the one in the link and from the focuser I use a 2" camera adapter a 20mm extension (to reduce the drawtube extension) then the other adapter that contains either an eyepiece or barlow and lastly the T adapter, it ends up looking like this.

Alan

P.S if I am doing daytime macro shots in the garden I sometimes add another 2-4 inches of exension.

post-32578-0-36503500-1423749931_thumb.j

Edited by Alien 13
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Found a 60mm long one of these and popped a 15mm plossl in, but this only comes to focus some way back from the fully extended focuser. Tried adding a 25mm extension either before or after the EP projection adaptor to no avail. Maybe the 80ED is particularly unsuited to this setup although I can achieve focus OK without a Barlow or EP albeit with a smallish image even in movie crop mode.

I use mine with the diagonal.

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Most if not all refractors will require a 2" extension at the focuser to allow for the removal of the diagonal this is true if using an eypiece or camera at prime focus.

I have a similar adapter to the one in the link and from the focuser I use a 2" camera adapter a 20mm extension (to reduce the drawtube extension) then the other adapter that contains either an eyepiece or barlow and lastly the T adapter, it ends up looking like this.

Alan

P.S if I am doing daytime macro shots in the garden I sometimes add another 2-4 inches of exension.

Thanks, Alan

Having checked this out again I would indeed be able to achieve focus with a further extension or camera adaptor around 2" in length.

As in your setup this would create a long sequence including the drawtube at near full extension - hope my focuser will be up to it!

Many thanks to all for your help.

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