Please settle this, on collimation...

[pat]

Everything being equal. I have a choice to make in my reflector. When I begin, the laser beam is inside the donut hole on the primary. Going to the rear of the scope I adjust the primary, so the cheshire annulas is in the center of the secondary. To check my work, I put in the laser (no port in laser). Now the beam is on the donut ring itself. It was suggested that it would be better to recenter the beam.Than to recenter the cheshise. So what would be the better course to take? Either I have the laser beam centerd or the cheshire centered. Pat

Too many stars too little time

**************

[Stephen]

Check the collimation of the laser before you do anything else

[studio1one]

Personally I would trust 90% of lasers as far as I could throw them. I stick with a collicap and a cheshire. If I had a Hotech it would be different but why spend the money on one when a simple collicap and a £25 cheshire will give you perfect collimation.

[Stephen]

Personally I would trust 90% of lasers as far as I could throw them. I stick with a collicap and a cheshire. If I had a Hotech it would be different but why spend the money on one when a simple collicap and a £25 cheshire will give you perfect collimation.

The problem with the cheaper (than Hotech) ones is they don't exactly come with instructions. As such they usually aren't collimated - it's a simple job and once it's done you can collimate in the dark with the laser extremely accurately in about .... 10 seconds?

[Damo636]

I had a Baader Mk3 which is supposed to be one of the better ones and was indeed perfectly collimated when i got it. I also use an Antares SCA which essentially made it as accurate as the Hotech. For exactly the same reasons as you have described i didn't get on with it and sold it. I now use a Cheshire and can perfect collimation in a matter of minutes.

[umadog]

"lasers" sound all flashy and very accurate, but if they're not implemented correctly they will be very inaccurate and a total pain. A good laser is great. A bad one is worse than useless. Check your laser collimation.

[studio1one]

The problem with the cheaper (than Hotech) ones is they don't exactly come with instructions. As such they usually aren't collimated - it's a simple job and once it's done you can collimate in the dark with the laser extremely accurately in about .... 10 seconds?

There is also the slop to worry about though with a laser. that would be as much of a concern to me as the collimation of the laser. There doesn't have to be a lot of slop for it to make quite a difference when the laser has travelled almost twice the length of the tube.

[pat]

Oh sorry I didn't answer this fully. The laser is collimated. I have a sweet area in my focuser,where I use my eyepieces, There is no image shift,wobble,or movement of laser beam on primary. Pat

[Revs]

I'd try turning your laser coll. 180* round in the focuser and see if it's still in the same spot.

[Stephen]

There is also the slop to worry about though with a laser. that would be as much of a concern to me as the collimation of the laser. There doesn't have to be a lot of slop for it to make quite a difference when the laser has travelled almost twice the length of the tube.

True, but if your focuser has slop, collimation is always going to be ropey no? Slop is going to affect the cheshire in exactly the same way (replace the laser with the light that enters the cheshire?)

Oh sorry I didn't answer this fully. The laser is collimated. I have a sweet area in my focuser,where I use my eyepieces, There is no image shift,wobble,or movement of laser beam on primary. Pat

If you're certain the laser is collimated, check the focuser as suggested above. Does it rock about when the laser is in, but not when the cheshire is in?

Failing that, do a star test - that's always the defining mark of whether a scope is in collimation or not

[pat]

Thanks for all your suggestions! The laser beam did not rotate when turned. I will try to comprise, between the laser spot position and the cheshire annullas position. Then try a star test. Thanks for all your help. Pat