Category Archives: Maintenance

Discussions on maintenance issues, including down time, and periodic maintenance.

Update on dome

After many tests, we now think either the dome encoder is failing or the dome power supply is incorrectly set, following the powerout for the UPS replacement. More updates soon.

The pointing was recentered (off after worm-gear lubrication work) and the focus was readjusted (for seasonal drift).

RCT update on blank images/guiding

Folks,
Several have noticed the following behavior in the last few nights with the RCT:

  • Several images are blank, likely with the dome completely in the way
  • The centering of the field seems to drift from night to night
  • At high hour angle, there is significant trailing in the images. There is still notable “coma” in images near zenith

    • I believe these are all symptoms of the encoder slippage and worm gear oscillation. I believe they needing cleaning/re-greasing. I’ve put in a service request with KPNO. I still think part of the PSF is mirror support related, but we wont know for sure until we eliminate the other sources of confusion.

    Tonight I was able to zero point the telescope, and test the guider. It appears that the pointing tolerance for accurate guiding is about 15″, or ~20 pix from the absolute center of the chip. Guiding works better now, but it does not improve the PSF substantially.