Over the last few months I have been relating my efforts at getting my T4 up and running.
I keep accumulating literature about the T4 and how it was used and I continually am amazed. And boy do I still have a lot of learning to do. Those astro guys were really something.
I also mentioned how I had figured a way to back light the cross hairs in a T3 to use as a collimating target for the T4. While it worked and I got the T4 adjusted to within acceptable limits, I really wasn't as happy as I could have been with the T3 as a target. The light was a jury rig and I think I was getting a little parallax which caused the image to be just a little fuzzy.
So, the other day I was able to buy a T2 cheap. It read in MILs so that is the main reason it was cheap, but it did have an auto-collimating eyepiece (which means you can illuminate the reticle) so I bought it figuring it had 1.) lots of good parts, or 2.) maybe I could use it as a collimating target.
Well, it turned out to be in good shape other than someone had tried adjusting the reticle and had it totally out of wack. That took me about 15 minutes to correct so I decided to use it as a collimating target. Rather than using a tripod as a stand I made my own out of some angle iron & scrap plate to make a rigid stand.
Finished that up yesterday, set it up, looked at it through a T3 and the reticle was plain as day and sharp as could be. Now I really have a great target for adjusting instruments. Here's a picture of the set up.
Speaking of the illuminating cross hairs...
When I was at the Ft. Sill artillery surveyor school, we had to learn star shots.
In order to do this during the day they set up a completely dark room and up on the window had mounted a large plexiglass disk, painted black, with the various constellations scratched into the paint so the sun shone through. The disk was attached to the minute hand post of a wall clock so it turned very slowly to replicate the earth's rotation. The effect was pretty good for getting a feel for working in the dark with the little red light sets and for tracking the "stars" ("tracking, tracking, TIP").
There were maybe 6 instrument setups at one time in there and it was quite the cluster in the pitch dark.
We were all having a heck of a time sighting the proper star until someone, for no apparent reason, held the little recorder's light to the eyepiece of his instrument, and BAM, a beautiful projection of the cross hairs is thrown up on the "sky". We were done in no time!
A bit of advice... the above technique does NOT work in the field.
> Speaking of the illuminating cross hairs...
> When I was at the Ft. Sill artillery surveyor school, we had to learn star shots.
> In order to do this during the day they set up a completely dark room and up on the window had mounted a large plexiglass disk, painted black, with the various constellations scratched into the paint so the sun shone through. The disk was attached to the minute hand post of a wall clock so it turned very slowly to replicate the earth's rotation. The effect was pretty good for getting a feel for working in the dark with the little red light sets and for tracking the "stars" ("tracking, tracking, TIP").
> There were maybe 6 instrument setups at one time in there and it was quite the cluster in the pitch dark.
> We were all having a heck of a time sighting the proper star until someone, for no apparent reason, held the little recorder's light to the eyepiece of his instrument, and BAM, a beautiful projection of the cross hairs is thrown up on the "sky". We were done in no time!
> A bit of advice... the above technique does NOT work in the field.
You know I once related this same story about 7 or 8 years ago and Chris Wickern, who apparently taught there questioned it. Thank you for reminding me that I'm not crazy. It replicated the locations at a given time and date and mirrored the earth's rotation.
Cheers
Dave, we use a similar illumination setup on our T-3. It does a real good job of illuminating the cross hairs.. When we adjust it, we just park a clean white truck behind the T-3 and some white poster board behind the T-2. The hard part is getting the guys to take the truck to the car wash. Everybody thinks that having the truck washed is someone else's job. But that might change with sequestration.
