az encoder 1 jumped 12aug19


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azimuth encoder failures

Pointing errors show the jump

    Azimuth encoder 1 (dome side) is used to point the azimuth. It jumped by 1tooth on 12aug19.

x102 runs show az error vs za.  

    x102 calibration runs in late august and early sep19 showed a linear azimuth error vs za. The problem was resolved on 11sep19.

Plots of pointing error 12aug19-10sep19 (.ps) (.pdf)

An azimuth encoder error will give an almost linear sky azimuth error vs za since:

The sin function is almost linear in its argument for small values.

Correcting the error.

    The pointer, scriber mark:

On 11sep19 at 14:00 osvaldo and adrian  checked the scribe mark/pointer and found that it was off
the pictures show before and after the adjustment

    When repositioning the pointer,

When did the jump occur

    Looking at the x102 data, the first bad az error point was on 12aug19. To verify this is used the azimuth encoder difference.
    There are two encoders on the  azimuth arm

The plots show the azimuth encoder difference for 1-26 aug19 (.ps)  (.pdf)


processing: x101/190911/

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