Hotech

[pvaz]

Well, my hotech is finally here.

Turns out I had the secondary tilted and it was the primary alignment making up for it. I could swear I had it spot on! But, the instant I put the laser in, I had a 1.5 cm offset.

After the alignment, I loosen the hotech a bit and rotated 360º on the focuser and the laser kept in the donut, so I guess it's good now. Toke me well over an hour fine tuning it to "perfection".

Adjusting the primary was a breeze. Toke like 1 min or less.

Seams astro baby's guide was right again: On a (somewhat) fast reflector the secondary holder tends to be slightly oval. When I got the scope, I forced the secondary into a position where it would show as a circle but the laser never hit the center. When perfectly aligned the secondary holder is slightly oval.

Another conclusion is that it's impossible to have a spot on collimation by doing it visually with a cap.

[Doc]

The Hotech is a wonderful piece of kit, works really well and feels like quality.

Looking down my drawtube I can just detect a slightly oval secondaryas well. And I agree with you on the collicap, using just this is very hard to get perfect collimation and you really should use it in conjunction with either a laser oe cheshire.

[michael.h.f.wilkinson]

Maybe the slightly oval look is an optical illusion. From theory I would expect the ideal collimation to show a circular secondary. However, judging the difference between an exact circle and a low-excentricity ellipse is hard. Our eyes can play tricks on us.

Does anybody know a reason the secondary should look slightly elliptical?

[Rusty Strings]

Astro Baby's collimation guide says that the secondary will look eliptcal on a fast newt and mine (F5) certainly looks ovaloid.

John