Align your telescope accurately for astrophotography, even if your current laser collimator has a bore-sight error.

This 1.25" to 2" adapter has adjustments to correct imperfect laser collimators. This is made for new astrophotographers who already have an inexpensive laser but discover that it isn't accurate. This tool references the internal cylindrical face of your telescope's 2" drawtube in the same manner it will be referenced by your camera adapter or comma corrector body, making your laser as accurately boresighted as it can be.

Not included: laser collimator, tripod, 2.5mm hex key and sticky note.

For visual astronomy, an imperfect collimator laser is no problem. But for astrophotography, the laser should be aligned to 0.1 degrees or better (typical tolerance - refer to table). If not, the actual camera sensor plane will tilt away from the true focal plane, and so the edges of the sensor can't be focused simultaneously.

Usage Method 1 (preferred): Set a target on the wall and mount the included bearing block on your own tripod. Install your own laser collimator in the alignment tool, snap it into the bearing block and aim the tripod at the target, then rotate the laser 180 degrees in the bearing block. Make adjustments at the screws to bring the laser halfway back to center. Aim the tripod back to the target, rotate 180 degrees, and repeat alignment if needed.

Usage Method 2 (e.g. inside a Newtonian telescope): Install your laser collimator in this adapter tool, place it in the drawtube of your telescope and snug it down with the clamp and sight the beam on the primary mirror. Center the beam on the primary by adjusting the secondary mirror. Rotate the laser and tool 180 degrees and snug it down again, then make adjustments at the screws to move the laser halfway back to center. Repeat alignment of the secondary mirror and collimator tool as needed.

Plastic material is 3d-printed PETG, which has a superior softening temperature compared to PLA.

Here is a tolerance table using the formula: d = N*8*lambda*F#^2

Field stop diam	26	mm
	Tolerance (N waves PV):	0.25	0.5
F #		Field tilt tolerance, +/- degrees
3.5		0.06	0.12
4		0.08	0.16
4.5		0.10	0.20
5		0.12	0.2

To sum up, instead of paying for a much more costly but accurate laser upgrade, you can now correct imperfect lasers instead, as long as your laser fits a 1.25" tube and your telescope has a 2" focuser.

This item is v2, now with bearings and more precise motion.

If you have a 3d printer, my simpler original is open source, and still available on thingiverse.