Drive Training

Here is a simple way I use to Train my drives. I know, if the tube was 45 degrees pointed up, it may be a better sampling, but, I can perform this indoors, and with Dick Seymour's Patch Kit in the software, I can access the Train Drives numbers for RA and Dec. Currently, 26 and 30 after realigning the gears etc.


I use a better laser now, but we start by taping the unit to "On" and then tape it to the finderscope mount. Alignment to the central axis of the OTA is not that important.


I like to use a front surfaced mirror placed as far away as possible. This will reflect the beam back to my end of the house and make it easier to see when things are Happy. The total distance from scope to mirror to door is about 75 ft. Were this a lesser distance, I would use another mirror or two. I did the math and 75 ft will give about 20 arcseconds for 1/10th inches.

75ft x 3.14159 = 471.23 ft circumference

471.23 ft x 12 in = 5654 inches

5654 / 360 = 15.7" / degree

15.7" / 60 = .262" / Minute

1/10" = approx 20 Arcseconds (1/3 of .262)

This is way beyond the tolerance of the GoTos etc where 2 ArcMinutes is the normal tolerance.


This is from the mirror end.



Darkened a bit.


Every laser has some scatter. I marked the chart to take advantage of the fingerprint. Makes knowing when it is centered easier.


Where we start out. Also, it is important at this time to slew into the center from the same direction the first movement will go towards. ie: If the alignment in Dec moves the beam to the right per the arrow, center the beam from the left, to the right then start the training.


When the beam slews out and comes back, about here, slow the slew to Speed #1 or 2. This makes it alot easier to center the beam. This adjustment will not harm the procedure at all.


The new laser. A really nice spot compared to the other one.

I repeat the same process for the Dec and then, repeat the whole thing at least 5x per axis. Read the numbers out each time and average them for your values to rekey back in. This will also allow you to note if the numbers are consistent.