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Telrad problem...double image of bullseye

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#1 BDS316

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Posted 25 August 2013 - 10:49 AM

I have a 20 year old Telrad and the lens has popped out twice previously and needed to be cemented back in. The last time the lens popped out the warning that something was wrong was that I saw a double bullseye pattern a few monments before the lens popped loose.

Last evening I again saw the double bullseye and assumed the lens was about ready to fall out again. This morning however the lens is noted to be firmly in place and normal single bullseye pattern is present.

Any ideas what's going on here?

I'm going to order a second Telrad anyway as a backup and this 20 year old unit owes me nothing, but I'd like to know what's going on

Thanks

#2 Brett Carlson

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Posted 25 August 2013 - 05:38 PM

not sure...there isn't much to those things. My guess would be something with the lens. There is only the emitter, mirror, and a lens.

Does the lens feel loose?

#3 BDS316

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Posted 25 August 2013 - 05:46 PM

the lens feels solid today and it is working normally now. Im going to call Scope Stuff tomorrow and order a spare but I'd like to know why it malfunctioned last evening in the field but is fine now?

Do the new Telrads have a different lens retaining system than the older ones like mine?

#4 Jon Isaacs

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Posted 25 August 2013 - 06:57 PM

the lens feels solid today and it is working normally now. Im going to call Scope Stuff tomorrow and order a spare but I'd like to know why it malfunctioned last evening in the field but is fine now?



Those pink elephants you saw last night should have been a clue. :)

Jon

#5 Brett Carlson

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Posted 25 August 2013 - 06:57 PM

Not sure...I bought mine 5 years ago. It's the only one I have owned. The lens mounted horizontal seems to be glued in place.

Love that telrad! Great and simple pointing device!

#6 T1R2

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Posted 25 August 2013 - 07:12 PM

could it be the lens is very tight against the cell and the temp. caused the cell to expand or contract, popping out the lens?

#7 GlennLeDrew

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Posted 26 August 2013 - 09:26 AM

I don't see how a double image can occur, even if the lens is not quite in position or is tilted somewhat. All that might happen is defocus and/or some aberration. A double image would result from a reflector window whose two surfaces are not parallel (prism-like wedge), or the presence of another piece of flat glass also reflecting the reticle but not parallel to the one built in.

When seen, how did the brightness of the two images compare? How far offset were they, with respect to, say, the innermost ring? In what direction were the images displaced with respect to the unit's local vertical? Were the two patterns of the same size? We're they both equally sharp?

As you can see, lots more detail can be provided.

#8 Jon Isaacs

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Posted 26 August 2013 - 10:04 AM

I don't see how a double image can occur, even if the lens is not quite in position or is tilted somewhat.


All I can think of is that something was dewed up that normally doesn't. That could cause the illumination to be increased and some otherwise minor reflection to become visible.

Jon

#9 Dakota1

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Posted 26 August 2013 - 11:34 AM

It may have been caused by Bud Lite ?????????????

#10 Doc Willie

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Posted 26 August 2013 - 01:22 PM

Do you have a dew shield? Some of those have a reflective surface that could produce another image if left in place. Sorta like leaving the lens cap on; nobody here has ever done THAT.

#11 rigelsys

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Posted 26 August 2013 - 01:46 PM

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