Revelation 20x80 collimation advice needed.

[Tim64]

H all

I purchased a pair of Revelation 20x80 bins second hand that are as new but need collimating.

Anyone know if these bins can be collimated by the user and if they can where are the adjustment screws?

Also what is the ideal hight of a tripod for these bins as most seem to go to a hight of 5ft aprox and I imagine we need taller than that for Astro use.will i ned some sort of extender? Any advice is welcome as I am new to big binocular use.

Regards

Tim.

[Tim64]

Sorry admin for double post,, I cant find a way to delete. Please delete for me if you can,, sorry again.

[NGC 1502]

Hi Tim. This http://www.cloudynights.com/item.php?item_id=416 may help perhaps.

If your bins are similar to the link, then there are 4 collimation screws, 2 each barrel, under the rubber, as pics.

Please go carefully, it's easy to make things worse than they are. If it were me, I'd make a diagram, numbering each screw, and note each adjustment as you make them. For example, No 1 screw, + 1/2 would mean half a turn inwards (clockwise) on that screw. If you proceed like that, you can retrace your steps, back to where you started.

Good luck, Ed.

[Tim64]

Thanks Ed, I hope the screws are under the rubber covers, will be easy job if they are.Thanks for the link and the advice as its exactly what I needed to know.i will update this thread soon I hope, maybe a pic or 2 as well of work done. :-)

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[BinocularSky]

As above, but would add: make no more than1/8 turn at a time, at least until you get a good feel for how much the image shifts.

[Tim64]

I will draw the positions of the screws before o move them so I know where to put them back if needed.I now have the binos here, delivered this morning and they look brand new.i can see the optical train looks good and the amout they need adjusting is real small.i had a peek under the rubber covers and bingo., one screw each side at the top and it looks to me like someone has had a go at the left side as the screw has a little paint loss.i will check further before adjusting though.will get back to soon.

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[NGC 1502]

As above, but would add: make no more than1/8 turn at a time, at least until you get a good feel for how much the image shifts.

Hi Steve, yes, fully agree with that, my 1/2 turn to start off with is too much. I think that somewhere in my link it says 'baby steps'.

To Tim : hope you sort it, big bins are a great way to do astronomy.

Best regards, Ed.

[Tim64]

First of all, thanks to NGC1502 and Binocularsky for your advice and help in this little project .

Ok, the binoculars are done and now seem to be collimated, no more double images and round well centred exit pupils to boot.

I still want to star test them before I say they are spot on but as they are they offer a clear sharp image with I would say the same brightness in both eyepieces.It turned out that the right side objective lens was loose in its cradle, both left and right side prism adjusting screws had been tampered with leaving the bins with oval exit pupils, double image and what looked like false colour on the edges of what ever I was looking at (showed blue and green around the image edge like a cheap Refractor telescope).Anyway, they are now good and usable so I guess I had better hit Ebay and get a tripod or maybe a pistol grip.

Again, thank you for help guys.

Regards

Tim.

[BinocularSky]

When you star-test, "fool" your eyes into thinking that they are looking at different things (so your brain doesn't try to merge them) by EITHER

* Defocusing one side and ensuring that the focused star is slap bang in the middle of the defocused one, OR

* Use different coloured filters on each side (e.g. anaglyph 3D glasses or coloured cellophane sweet wrappers) OR

* "Crossed Bahtinov" masks (see method described by Pleiades in these forums).

[Tim64]

Well this pair of binoculars are good again.i used the colour filters from my old Meade dsi pro to test the optics and I find the view to snap instantly into focus under all conditions.i got 5 other people to confirm this just to be sure.Star testing showed pinpoint stars almost to the edge of fov, leaning toward what i would call soft focus at the very edge.M32 showed nice and bright and with plenty of contrast even under light polluted skys as did M15.

To think these bins were sold as scrap just because they needed collimating is imo amazing.

Thank you all again for your advice in the repair of these bins.

Regards

Tim.

[NGC 1502]

Result

Pleased you fixed it, well done to you.

Regards, Ed.

[Tim64]

Result

Pleased you fixed it, well done to you.

Regards, Ed.

Thanks Ed, the job is not hard but what is hard is second guessing your own eyes, thinking your pulling the image together.

Cant wait to get a good cold night and use them.

Thanks for your help, it wont be forgotten and hope I can return the favour some time.

Regards

Tim.

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[Mr Bond]

Well done mate!

Isn't it satisfying to do your own repairs? Personally, I get a real connection with stuff that way.