On 4/21/2019 8:38 AM, y.groups@... [ap-gto] wrote:
> 5) Using a carpenter's level, use pier adjustments to level the
> counterweight shaft.
> 6) Using a carpenter's level, use the mount's altitude adjustment to
> level the OTA.
I'd like to propose an alternative to a carpenter's level.
My AP1200 is pier-mounted and drift-aligned, so I don't have the same
situation you do. But I loosen the clutches to re-balance the mount
after changing imaging equipment. I use a level on the CW shaft and the
OTA to return to the Park 1 position after balance is achieved. (Yes,
I'm still using Park 1, not 4, and yes, I know the issues with Park 1.)
Instead of a carpenter's level, I use a Starrett #98-6 precision
This level is super-accurate! One division on the glass vial is 86
arc-seconds. It's easy to read to within 1/4 of a division, or 21.5
arc-seconds. That's MUCH better than I can get on my carpenter's bubble
level, or even on my electronic level that displays only to 1/10 degree.
Here's what I do:
1. Use the keypad to park the mount in Park 1.
2. Set the machinist's level on the CW shaft and take a photo of the
3. Set the level on the OTA and take a photo of the bubble position.
NOTE: Steps 2 and 3 record the MOUNT'S Park 1 position. So, if my
original Park 1 position was a bit off, I can return to the MOUNT'S
NOTE: The level has a V-groove on the bottom that makes it easy to
position it accurately on the CW shaft and the OTA.
4. Remove the level, loosen the clutches, and do whatever I need to do.
5. Move the mount back close to the Park 1 position.
6. Set the machinist's level on the CW shaft and adjust the RA until the
bubble is in exactly the same spot as in the step-2 photo, then tighten
the RA clutches.
7. Set the machinist's level on the OTA and adjust the Dec until the
bubble is in exactly the same spot as in the step-3 photo, then tighten
the Dec clutches.
8. Power-up the mount, and select "Resume Ref-Park 1" on the keypad.
As a testament to the level's accuracy, when I complete this procedure,
I can GOTO a target star, and it will be within the central 15% of my
The Starrett #98-6 isn't cheap. I bought mine specifically for leveling
the telescope, and have never regretted spending the money.
I also use it to level the AP1200's mounting plate on my concrete pier:
Just a suggestion for an alternative to a carpenter's level....
Louisa County, Virginia USA