1. „Pi of the Sky plus” – the evolution of the „Pi of the Sky” project Marcin Zaremba Faculty of Physics, University of Warsaw XXXII-th IEEE-SPIE Joint Symposium Wilga 2013

2. Outline 1.Astrophysical motivation. 2.The „Pi of the Sky plus” team. 3.Project assumptions and constraints. 4.Details of the hardware a)cameras and optics b)parallactic mount – project and construction c)control electronics 5.Summary and outlooks. 2013-05-29Wilga 20132

3. Astrophysical motivation Nowadays research Astronomy concentrates on two extremely important areas: – the evolution of the Universe at large scales – astrophysics of processes occurring in strong gravitational fields This topics are related to violent phenomena e.g. collapse massive star to back hole. The key factor in observations of fast transients of cosmological origin is the prompt reaction of robotic telescopes capable of high time resolution observations. Very short reaction time and high pointing precision set high threshold on construction of such a detector. 2013-05-29Wilga 20133

4. The „Pi of the Sky plus” team Faculty of Physics, University of Warsaw Center for Theoretical Physics, Polish Academy of Science Space Research Center National Center for Nuclear Research Number of people: 10 Project leader: prof. Lech Mankiewicz (CTP, PAS) 2013-05-29Wilga 20134

5. Assumptions & constraints Use existing software framework developed by „Pi of the Sky” – hardware control, data acquisition and analysis (DAQ) – this simplifies site supervision and offline analysis Design or purchase necessary hardware fulfilling new requirements: – faster reaction times, stable tracking – better optical resolution (36 arcsec/pix down to 6 arcsec/pix) 2013-05-29Wilga 20135

6. Assumptions & constraints - cont’d. CAMERAS 4 CCD cameras: 3 frames/sec, large pixel size ~9x9um 2 – initially: commercially available USB 2.0 cameras (this talk) – longer-term: custom made Ethernet cameras with on- board Linux PC faster signal processing self-triggering capabilities 4 Genon 300/1.5 VT78 lenses – 296 mm focal length, 192 mm aperture – 2 fixed FOV configurations: Deep (7 deg x 5 deg) or Wide (13 deg x 9 deg) 2013-05-29Wilga 20136

7. Assumptions & constraints - cont’d. PARALLACTIC MOUNT maximal load: 100-150kg (heavy optics and cameras) maximal speed: 30 deg/sec absolute pointing precision: 20 arcsec mechanical movement range: – 300º in Hour Angle (Right Ascension) – 150º in Declination 2013-05-29Wilga 20137

8. Hardware: cameras FLI Microline camera ML16803 – readout 3 frames/sec – USB 2.0 Interface – KAI-11002 chip 4008 × 2672 pixels 9×9 um 2 size – FoV 7° x 5° (6.3 arcsec/pixel) – 65 mm shutter 2013-05-29Wilga 20138

9. Genon 300/1.5 (VT-78a) – 296 mm focal length – 192 mm aperture Hardware: optics 2013-05-29Wilga 20139

10. FLI Atlas Focuser – 105 000 steps – 85 nm/step – USB 2.0 Camera + focuser + lenses Hardware: focuser and one camera set 2013-05-29Wilga 201310

11. common filed of view mode covering 7° × 5° (“deep” configuration) wide field of view mode covering about 13° × 9° with a small overlap region (“wide” configuration) Hardware: cameras configuration 2013-05-29Wilga 201311

12. Assumption: full acceptance for all objects above 20° over the horizon and observatories location between 20° and 40° geographical latitude Result (4 CCD cameras, the wide mode, latitude of 23° south): Hardware: mount range movement for assumed movement range: - 300° for RA (HA) axis - 150° for DEC axis 2013-05-29Wilga 201312

13. high rotational speed (30 deg/sec) low rotational speed – tracking speed (1 revolution/day) any rotational speed value between high and low to follow other objects extremely high position accuracy (1 arcsec) fluent tracking motion (grain- and vibration-free) high start/stop dynamics for adjusting motion (for 100kg load, located 0,3m from rotation axis, driving torque about 50Nm) HW: mount and drive requirements Not only one existing solution correspond to this requirements? 2013-05-29Wilga 201313

14. harmonic drive AG CPU-H 160 (40) – 294 Nm nominal output torque – 1180 Nm momentary peak torque – 1:160 ratio – driven by stepper motor with additional toothed belt drive stepper motor – 2-3 Nm torque – microstep and high (in stepper motors) revolutions of 2000 rpm – two alternative, replaceable options (one will be choosed for second axis after test phase) PHYTRON ZSH-107/1.200.12,5-FD (with dedicated Phytron MSD MINI 172-140 driver) KOLLMORGEN K41HRLI-LNK-NS-00 (with dedicated Applied Motion STAC6-S-220 driver) Hardware: solutions used 2013-05-29Wilga 201314

15. Renishaw LM13 incremental magnetic encoder – resolution 10240 cpr – A,B,Z outputs – installed directly on the axes of the main motors Renishaw RESOLUTE absolute optical rotary encoders – BISS-C interface, 26 bit resolution – accuracy 1.91 arcsec – installed at the output stage of the harmonic drive gear Hardware: solutions used – cont’d. 2013-05-29Wilga 201315

16. Hardware: Mount design 2013-05-29Wilga 201316

17. Hardware: mount RA axis 2013-05-29Wilga 201317

18. Hardware: mount DW mechanism 2013-05-29Wilga 201318

19. Hardware: mount DEC axis 1,536,000 steps per revolution (assuming 1:20 microstepping at least) 2013-05-29Wilga 201319

20. two linear actuators – Haydon Kerk Motion 87H43-V – 0,0127 mm per step total 0,8° movement range for pointing purposes Hardware: actuator mechanism 2013-05-29Wilga 201320

21. Hardware: mount with cable trays 2013-05-29Wilga 201321

22. Hardware: Mount control system (target version) 2013-05-29Wilga 201322

23. Hardware: Mount control system 2 (testing purposes, backup version) 2013-05-29Wilga 201323

24. HW: RA motor block construction 2013-05-29Wilga 201324

25. HW: RA motor block construction (2) 2013-05-29Wilga 201325

26. HW: RA motor block construction recipe: take few parts and........ voila! 2013-05-29Wilga 201326

27. response and accuracy tests of RA motor block (selection one of the motor) construction DEC motor block design, construction and test custom control electronics (Space Research Center) design final mount, ready for installation (approx. 1 year) installation and connection with existing software (approx. 2 years) Summary and outlooks 2013-05-29Wilga 201327

28. Thank You. 2013-05-29Wilga 201328