Prepare for On-Sky Operations

Overview

This procedure gets the AuxTel system ready for on-sky operations, preparing the telescope and dome to be fully open.

In a standard night, it will follow the execution of the venting procedure, but it works from any initial state of the system.

If venting wasn’t possible, observers must prepare for on-sky once the Sun is below an elevation of 25 degrees. The Sun’s coordinates at any given time, along with several other useful ephemeris, can be found at the sky almanac.

Precondition

  • Before making the decision to open, review the weather conditions and weather constraints page.

  • AuxTel is fully ready to operate and all components are enabled.

  • The daytime checkout has been executed successfully.

  • This procedure will take the system from venting, the calibration state or any other initial state to be prepared for on-sky observations.

Post-Condition

  • Telescope is ready for on-sky operations.

    Around 15 minutes before the end of the evening nautical twilight, proceed with the beginning of the night procedure to center, align and focus the telescope.

Procedure Steps

  1. Review preconditions and confirm they have been executed.

  2. Announce in the #summit-announce and #summit-auxtel Slack channel that AuxTel is preparing to go on-sky.

  3. Command the telescope and dome to prepare for on-sky observations.

    Load the auxtel/prepare_for/onsky.py script from the LOVE ATQueue panel, under AVAILABLE SCRIPTS by clicking on the blue icon. The script will be added to the script queue.

    Note

    If the auxtel/prepare_for/vent.py script is still running, the queue will run auxtel/prepare_for/onsky.py once venting is done, around 20 minutes before sunset.

    In the Configuring script:onsky screen that pops up, leave the CONFIG box empty. Make sure there are no spaces in the CONFIG box, as it may prevent the proper configuration and loading of the script.

    ../../../_images/PrepareforOnSky_AuxTel.png

    Screenshot of LOVE launching auxtel/prepare_for/onsky.py script.

    The script includes the following steps:

    • Slew telescope to az = 90 and el = 80, where it is least likely to be hit by the Sun.

    • If primary mirror cover is open, the script will now close it. This will protect the mirror and avoid particles and dust falling on it when the dome shutter opens.

    • Move dome to oppose setting Sun to avoid direct sunlight inside the dome that might create thermal issues.

    • Open dome main shutter.

    • Open primary mirror cover and vents.

    • Activate AOS open loop corrections.

    • Enable dome following.

  4. If the wind speed is below 8 m/s, manually open vent gate #3 using the remote controller and turn on the extraction fan power to 20 % from the dome pier. If wind speed is above or close to 8 m/s, keep vent gates closed and extraction fan off.

  5. Visually confirm in LOVE displays:

    • Telescope is in position; az = 90, el = 80 deg, rot = 0.

    • M1 Mirror cover is open.

    • ATAOS corrections are enabled.

    • Dome shutter is open and pointing towards the east; az = 90 deg.

    ../../../_images/PrepareforOnSky_AuxTel_LOVEdisplayConfirmation.png

    LOVE displaying AuxTel telescope and dome prepared for on-sky observations.

This procedure was last modified Nov 20, 2024.