Mitsubishi ML520G71...Red Holy Grail or Flashlight Fail ??

[badger1666]

I dont think i am to worried about hitting 642nm nicer red
Or might just crank up the tecs

[Laser66]

Here's a TEC I offer on my site if anyone is interested. It's a nice CPU type with heatsink. only $9. Specs there:
http://www.laser66.com/html/TEC.html
or place it in Power Technology Labby (TEC and internal fan) 1.5" diameter X 6" long. $35:
http://www.laser66.com/html/PowerTech.html
- Will

[steve-o]

It's been a while since I built a red.. Got a couple P73s, pulled out the Grail lens drawer and found 2 sets; a large PCV and PCX set and a smaller set. Reading back in this fond ole thread I found references to Dave's sets, an infamous Kiyoucan group buy, and I believe some Dr. Lava's lens sets .. Does anybody remember which is which ?? I need to put something together for tomorrow and was wondering if anyone would like to share who had the best results with which? I mixed and matched from the 2 sets today and got various results, some fairly good and some not .. Anybody want to share their tales of success from this unbelievable thread? Thanks

[planters]

There is no magic solution. Ultimately, both Dave's 2mm aspheric and the Optima 4mm aspheric lenses produce the same result with these telescopes (I have also had similar results with the 4mm Rochester lens as well). The magnification will need to be twice as great with the 2mm lens. None of these telescopes use aspheric lenses and so you can you mix and match. Although I have the lens pairs you mention and they work I use the Edmond Optics lenses because the round OD is more convenient. The large divergence coming out of the collimators means that the distance of the telescope pair is important and for any #1 concave lens position there will be an optimal #2 convex lens position. Don't forget that these lenses are usually not cut perfectly aligned with their optical axes and so the ability to compensate for this by being able to slightly rotate either lens about the laser beam's axis can improve the result A LOT.

According to standard optical practice you're supposed to orient the lenses so that the greatest curvature faces the most parallel beam. I haven't seen that that makes a noticeable difference.

[steve-o]

Thanks Planters. It's all starting to come back to me now .. all 1332 posts heh .. Experimenting around today, hurried conclusions look to be the larger correction/telescopic lenses produce a cleaner looking beam ; looks like less aberration and artifacts with a decent ap size and farfield spot .. Anybody remember where these larger lenses came from?

[planters]

The big ones are the (approx 50mm?) Kayoucan GB lenses

[steve-o]

The convex lens is about 30mm square on all 4 sides .. I don't know the FL right off-hand.. The Kiyo GB? wows .. that's gonna be fun trying to find out where they came from.. ehh ..
-edit- yep I'm using Dave's 2mm aspheric collimation lenses for these experiments .

[CDBEAM]

Hi Steve,

The best combo I found was the 2mm FL from Dave and the Kiyoukan GB Cylindericals. I tried a set of cylindericals with the same Fl s....so....6X.....but they had a smaller size....I do not think they did quite a good a job as the larger size 6X....more FF aberation....and MUCH more..." fiddly " to acheive the perfect alignment.

BEAM OUT

[badger1666]

I would like to find a source for the larger cylinder lens sets
The lava lens are a pain to get right
Maybe ky might let us know his source
Now he is back

[steve-o]

Yeh, you never know..

I agree, the bigger lenses do seem less "fiddly" and are easier to align it seems. Or it could just be my ham-handed fat fingered approach to delicate precision optical alignment techniques lol ..