P3.1 Telescope control – sending preset, telescope mode, offset, and focal plane geometry estimation

• Phase : 3
• Status : Draft
• Category : Nighttime testing (functionality and operability) (C5)
• Recurrence : once at commissioning
• Duration : 3 hours

Description

• Preset of a bright enough on-axis star is sent to the telescope for verifying the communication to TCS, nighttime collimation model for SHARK-NIR, and the pointing accuracy.
• For the correct telescope mode for SHARK-NIR, find the offset direction & magnitude (for the field-stabilized mode), verify the proper image orientation, pixel scale, field of view, and distortion at the SCICAM. Note that this may be performed with and without AO running.

Prerequisites

• Atmospheric conditions: should be able to see bright stars in the sky (preferably close to zenith?).
• Authorize SHARK-NIR on the SX side.

Procedure

• Send preset to the telescope from SHARK-NIR computer/system.
• Check for the position of the star at the SCICAM. If needed, correct the offset to increase the pointing accuracy and record the new nighttime collimation model for the instrument.

Procedure

1. Procedure for sending preset
   • Send preset to the telescope from SHARK-NIR computer/system.
   • Check for the position of the star at the SCICAM. If needed, correct the offset to increase the pointing accuracy and record the new nighttime collimation model for the instrument.
2. Procedure for image orientation
   • Select a filter
   • Place the de-rotator in the nominal "zero" position.
   • Issue a preset to move to a bright star (but not too bright to saturate)
   • Center the star in the science channel
   • Issue a pure elevation offset to the TCS of ca. 5" and verify the expected motion direction on the SCICAM
   • Return to the on-axis position and repeat with a pure azimuth motion.
   • Issue a preset to move to a suitable astrometric binary (typically 5-8 arcsec separation) and center one star in the science channel.
   • Based on the published coordinates of the binary, issue the appropriate offset to center the other star.
3. Procedure for pixel scale/ plate scale
   • Select a filter
   • Issue a preset to move to a suitable astrometric binary to measure pixel scale (typically 5-8 arcsec separation)
   • Center the binary in the upper half of the SCICAM and take several frames. Average these frames
   • Move the binary to the lower half of the SCICAM and repeat.
   • Use the difference image (optionally flat-fielded) to verify the expected pixel scale. This gives two measures.
   • Repeat this for other filters.

Templates

Success criteria

• Successful in sending preset to the telescope and, therefore, communication with LBT TCS.
• The image orientation is as expected. The pixel scale and field of view of the SCICAM are as expected.

Notes

LBTO support

Date performed and by whom