- Jul 10, 2015
Remember the beam coming out of the G-2 is very small so 18X that very small beam ends up being 8mm after the last lens......
This is the lens arrangement I'm using, The beam after both of those is 3 feet wide on the wall across the room, Now how it's doing what it's doing ? I don't know, I only know it is and I'm very happy with the results !
Using a NUBM44 with a G2 and 6X cyl pair I get about a 7mm wide ribbon of a beam that expands to twice that at 30-40 feet, this makes a fun burner that I don't have to adjust, just turn it on for burning up to 30-40 feet, add a 3X BE and it lights a paper bag at 105 feet with a little patience.
I set my concave cyl very close to my G2, the G2 produces a 2 inch wide line at 15 feet, adding the concave cyl makes that line 3 feet wide and then placing the convex cyl at 35mm from the concave cyl brings that line down to about 8mm wide at 15 feet.
If I used an 18X cyl pair I should get a much wider beam at my aperture, that's where the leverage comes from, just like the 3X BE makes the beam a lot wider to start, that is the leverage.
We both start near the G2, the G2 is focused to infinity and I have sharpened up the line a little closer but the difference is small.
I just don't see how you get a 8mm wide beam with an 18X cyl pair using the same diode and primary lens.
The leverage is in the wider starting beam even when on just the aggressive axis, I don't understand unless your cyl pair is not 18x
Both these are 44's with G2's and 6X pairs and are fun with that static set up for the short range, moving the convex cyl like you do would fine tune a sweet spot in the short range but would not make an appreciable difference burning at 50-100 feet.
I am not knocking your build or your efforts, I am trying to understand why 18X is not giving you a wider beam at the aperture, if it was and you made the convex cyl adjustable then you would have some additional leverage further out, but you said it's 8mm wide ???? How?
What is your separation between your cyl lenses at infinity, is it more than 35mm, that could create a range for adjustment if your infinity lens separation is more than 35mm.
Looking at Milos original thread I don't know if we can measure center to center the same, the way the 2 concave lenses add up is part of the mystery.
I would think center to center would be from the mid point of the inside concave, and that puts it in near the same 35mm of separation......hmm
I think the best way is for me to build the same set up myself and test it to see what's going on, you used the opt lenses, if you have a like to the sale for these 3 lens sets you can post it or I can find it, I just don't know that it's going to make a big difference, I suppose I should read all of Milos postings, didn't he say his was being rebuilt?
I think the best use of funds would be in finding a 6X BE with a 2.5 inch wide objective and good machining, the perpendicular alignment of higher power BE will need to be very good and uniform across it's adjustment.
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