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SkyMapper

SkyMapper. SkyMapper. SkyMapper. What is SkyMapper?. 1.35m telescope with a 5.7 sq. degree field of view Fully Autonomous observing To conduct the Southern Sky Survey: Five year Multi-colour (6 filters) Multi-epoch (6 exposures, each filter) 2 π steradians Limiting mag. g~23

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SkyMapper

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  1. SkyMapper SkyMapper

  2. SkyMapper What is SkyMapper? • 1.35m telescope with a 5.7 sq. degree field of view • Fully Autonomous observing • To conduct the Southern Sky Survey: • Five year • Multi-colour (6 filters) • Multi-epoch (6 exposures, each filter) • 2π steradians • Limiting mag. g~23 • Aiming for regular operations this year • Summary of program: Keller et al. 2007 PASA 24,1 Total Cost: Hardware $15M Software: $1.8M Dedicated Science/Operations: ~ $0.6M/yr 2

  3. SkyMapper Telescope Optics 0.75m secondary Modified Cassegrain design 0.6m fused silica asphere 1.3m primary 2 x 0.45m fused silica spherics 3

  4. SkyMapper The SkyMapper CCDs • 32 E2V CCD44-82 devices: 2048x4096 15 micron pixel CCDs • Broadband coated • 40 micron (thick) devices • Reduced fringing, inc. red response, without bad blue • 16384x163840.5” pixels • Using new Pan Starrs controllers (Onaka at IfA) • Readout in ~12 seconds through 64 channels (64x350 kpix/s) • Readnoise ~5-7e- 4

  5. SkyMapper SkyMapper Filter Set Filter+CCD+Atmosphere 6

  6. SkyMapper SkyMapper Filter Set is sensitive to Stellar Parameters Z g,Z 7

  7. Quantified selection • The metallicity sensitive colour scales as expected with (spectroscopic) metallicity Weird stuff – QSOs; WDs; PNe [Fe/H]=-5 Keller et al. in prep a star with no detectableFe (it has other elements) has been found. Model expectation SSPP derived 11

  8. Other weird things we find A star with rapidly varying photometry and spectra with synchotron? emitting blobs symmetrically around it

  9. OIII 5007 V DSS B H-alpha R DSS R

  10. SkyMapper Expected Survey Limits AB mag. for signal-to-noise = 5 from 110s exposures 13

  11. SkyMapper Calibration • Conduct a Shallow Survey • in photometric conditions cover the southern sky with 3 exposures: 8-15th mag (Hipparchos) • Anchor the deeper Main Survey to the Five-Second photometry and astrometry • Enables the Main Survey to proceed under non-photometric conditions. • Self Calibration via overlaps, colour of main sequence (in low dust areas) and on photometric nights. 14

  12. SkyMapper Calibration • Primary Standards HST-based spectrophotometric standards • Normalised by Hipparchos B and V photometry via Bessell (2000) • Provides spectrophotometric standards across the sky • 6 secondary standard fields chosen with Primary standards in them. These fields observed with dithers and rotations to produce a photometric flat field, with all stars calibrated to primary standards • HST Program to provide network of stars across North and South Sky with spectrophotometry better than 0.5% over optical and 1% from UV through NIR. (These are being completed now)

  13. SkyMapper New Standard System • 6-colour photometry will be reduced as soon as possible. • 6-colours should provide accurate transformations to most other systems • Standard Stars in every southern field 16

  14. SkyMapper Calibration Plans • >20 LEDs covering 0.3-1μ • observed through telescope with NIS calibrated photo diode • absolute calibration and monitoring of optics SkyDice - PI Nicolas Regnault - LPNHE 17

  15. Poor Seeing Time Southern Sky Survey Time Slide

  16. Supernova Poor Seeing Progam (>1.7”) In Collaboration With LPNHE • 1250 sq-degrees v,g,r,i to g~19. Augment with some good seeing data to achieve a 3-4 day cadence. • (125,000 sq degrees per year with a 3-4 day cadence to v,g,r,i~19) • Fields still be determined - balance between very far south (easy to observe), and coverage for peculiar velocity surveys (like to go North and into the Galaxy) Michael Childress Fang Yuan Richard Scalzo Slide

  17. Regnault and Guy (IN2P3) Nicolas Guy from IN2P3 Slide

  18. Sample Light Curves Regnault and Guy (IN2P3) Slide

  19. SN colours within 30 days of explosion

  20. SkyMapper 150 Supernovae per Year • Magnitude Limited (mr=19m) - with complete spectroscopy • Host Galaxy information on Large Fraction of Objects at site of SN • Precisely Calibrated 4-colour light curves of all objects • Spectroscopic series on selected objects • IR photometry on selected objects 23

  21. Some Set Backs • 13 Jan 2013 Slide

  22. Slide

  23. Some Challenges • ˜ Slide

  24. Slide

  25. Some Set Backs • 13 Jan 2013 -> Up and Running Again 4April • Vibration! Slide

  26. Some Set Backs • 13 Jan 2013 -> Up and Running Again 4April • Vibration! • Richard Scalzo Crashed and Burned on his Bicycle riding home down Mt Stromlo Slide

  27. Progress on Vibration • We did Fourier analysis of Accelerometers placed around the entire telescope • Showed that there were a number of vibrations in all parts of the telescope • Modifications have been made to stiffen • Spider • Secondary Mount • Primary Mirror Slide

  28. Dec 2012 4” Apr 2013 1.7” Slide

  29. A SkyMapper Night Slide

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