Collimation.... Spot on.... It does really matter !

[nicoscy]

Yes, I am referring to focuser tilt which needs to be addressed as well. Also, the focuser may tilt on two planes, i.e. up / down and left / right.

The up / down is done as explained above. The left / right is done at the same time when the secondary is removed. Take a drinking straw or a chopstick or whatever is handy and shove it down straight the hole for the main secondary mounting screw. Light up your laser and see that it hits the straw / chopstick / whatever makes you happy in the middle. If not, it's back to the focuser mounting screws.

Full collimation should run as follows:

1. Measure spiders to be equidistant (unless you are offsetting your secondary)

2. Check focuser tilt on both axis

3. Check secondary position in terms of up / down relative to the focuser and for secondary rotation (you want the secondary to point directly to the focuser and you also want full illumination by centering the focuser up / down)

4. Check secondary to primary tilt and collimate

5. Check primary to secondary tilt and collimate.

6. Repeat steps 4 - 5 a couple of times if you are OCD to eliminate any residual marginal error.

Steps 1 - 3 done at home. 4 - 6 prior to observing and remember, if you collimate the scope as soon as you set it up, steps 4-5 must be repeated prior to commencing actual observing and your scope has already cooled down to a sufficient degree.

[laser_jock99]

Yes, I am referring to focuser tilt which needs to be addressed as well. Also, the focuser may tilt on two planes, i.e. up / down and left / right.

The up / down is done as explained above. The left / right is done at the same time when the secondary is removed. Take a drinking straw or a chopstick or whatever is handy and shove it down straight the hole for the main secondary mounting screw. Light up your laser and see that it hits the straw / chopstick / whatever makes you happy in the middle. If not, it's back to the focuser mounting screws.

Full collimation should run as follows:

1. Measure spiders to be equidistant (unless you are offsetting your secondary)

2. Check focuser tilt on both axis

3. Check secondary position in terms of up / down relative to the focuser and for secondary rotation (you want the secondary to point directly to the focuser and you also want full illumination by centering the focuser up / down)

4. Check secondary to primary tilt and collimate

5. Check primary to secondary tilt and collimate.

6. Repeat steps 4 - 5 a couple of times if you are OCD to eliminate any residual marginal error.

Steps 1 - 3 done at home. 4 - 6 prior to observing and remember, if you collimate the scope as soon as you set it up, steps 4-5 must be repeated prior to commencing actual observing and your scope has already cooled down to a sufficient degree.

Very thorough proceedure- but it's important to emphasize that 99% of the time only steps 4 & 5 are needed before a session (unless you have dropped or dismantled your scope! I wouldn't want to put potential Newtonian scope owners off by making it seem more complicated than it is!

For beginners I would not recommend moving the secondary in any way from it's factory position (other than the tilt screws) as this is where most of the troubles seem to start.........

[nicoscy]

You are correct, I forgot to highlight that steps 1 - 3 done at home should be done once every blue moon unless the secondary assembly sees some serious action (like trying to obtain paratrooper's wings by engaging in freefall activities) !!!

[christhebrit]

Having read through this thread, I saw a bit about the importance for planetary viewing.

I'm sure I just have a cheap eyepiece, but could the fuzzyness/ unsharpness come from a bad collimation?

The stars seem good, just not really getting detail.

The seeing changes, but the planets don't by much.