My Borg DG-L no longer flattens

[AndyKeogh]

Earlier in the summer I changed the interface on my Borg DG-l focal reducer flattener (7887) from a T2 interface to that for a Canon 5D.

The threads were really tight so I had to resort to WD40 which by the time I had finished had found its way between the lenses of the DG-L.

So I took the device apart and cleaned each lens and reassembled in what I thought was the correct order.  The picture below suggest I failed miserably. 

I am hoping the WD40 has not damaged the coatings.

So when I take it apart again  is there an easy way to determine which way each lens should face on reassembly?

Is there a test which does not require a starry night that I coud use to check for correct assembly?

All advice would be appreciated.

I have checked the web and cannot find any assembly procedures for this device.  The scope is a Megrez 90

Andy

[Purplehayze104]

would you not get a similar effect pointing at a wall an checking the concrete lines between to see if they warp too, you may just have one of the lenses round the wrong way would say its gunna be more trial and error sorry cant be of more help.

hope you sort it soon

john

[Mrbloke]

Oh dear...

I kind of like the effect it's given. It's a bit different! Obviously good luck in the reassembly though.

[ManuelJ]

Warp speed 5

[Alien 13]

As John has said looking through the reducer with the sensor end close to the eye should show a slightly magnified distortion free image (mine does anyway) as a rule of thumb the two ends of the optics should have fairly flat glass which is usually the case for eyepieces too.

I would be a bit worried by the WD40, the coatings should survive but any cemented elements can be damaged if its got to the edges.

good luck

Alan

[philj]

I wouldnt think wd would do that, I woukd expect a foggy image if it had. This is more like you have the elements in the wrong place or back to front. Its always best to keep a note of how optics come apart, marking with pencil on the edge which way points forwards.

If you havent done that then its trial and error Im afraid unless you can get a schematic of the borg

[AndyKeogh]

Thanks everyone I'll have a try with a brick wall and hope it was built by a good brickie.

I did not mark the lenses as they were soaked in WD40 and I assumed nothing would stick to them 

As a backstop I will print a grid on A3 paper and use that as a target.  Has the advantage that I can use the test indoors in the warm and use a light box to illuminate the target if necessary.

All this will have to wait until I get back home next week as I do not have the required tools with me.

I do not recall any cemented elements Alan  but I will try your visual approach

Thanks

Andy

[AndyKeogh]

As John has said looking through the reducer with the sensor end close to the eye should show a slightly magnified distortion free image (mine does anyway) as a rule of thumb the two ends of the optics should have fairly flat glass which is usually the case for eyepieces too.

I would be a bit worried by the WD40, the coatings should survive but any cemented elements can be damaged if its got to the edges.

good luck

Alan

I have had a look as you suggest but cannot see any obvious distortion. 

[Alien 13]

I cant think of anything else apart from a dramatic change in FF to sensor distance or all the elements are in the right order but totally back to front i.e. sensor end is now scope end.

Alan

[AndyKeogh]

I cant think of anything else apart from a dramatic change in FF to sensor distance or all the elements are in the right order but totally back to front i.e. sensor end is now scope end.

Alan

The focal reducer is in 2 halves so that it a spacer can be added for scopes of different focal length. I think there is one element at the scope end but definitely 2 at the sensor end.  They are all in the correct positions but some or all may be facing the wrong way.

I have prepared an excel spread sheet with 50x33 cells containing the letter o and a border round each cell. hopefully this will prove to be a suitable target to investigate further once I am back home.

Andy