1. Variable Stars and the AAVSO Arne Henden Director, AAVSO arne@aavso.org

2. Variable Stars Every star varies during its lifetime Physical variation (pulsation, spots) tell us about stellar structure, cosmology Geometrical variation (binaries) give us masses, densities, sizes Accretion disk phenomena prevalent at all scales Transient events (novae, supernovae, gamma-ray bursts) detail stellar evolution If you are an astronomer, you will study variable stars sometime during your career This is where the AAVSO enters the picture!

3. The American Association of Variable Star Observers (AAVSO) Dedicated to the study of variable stars One of the largest & oldest Citizen Science organizations in the world International: 1000 members in 45 countries 15% professional, 85% amateur members 3000 total observers (800 active per year) 23 million online observations http://www.aavso.org

5. Cumulative observations in AAVSO International Database (current rate: 1.5M/year)

6. AAVSO HQ 2km from Harvard/CfA

7. Today’s Observers

8. Comet PanSTARRs changing tail structure total brightness nuclear brightness rotation period jet activity Comet ISON due in 2014 Credit: Lorenzo Comolli

9. Amateur spectroscopic setup

10. PanSTARRs bright comets can be observed with amateur spectrographs

11. Lunar photos good test target videocam impacts LCROSS

12. T Pyx latest

13. Artist’s conception of the T Pyx system (orbit size of moon’s orbit)

14. T Pyx latest

15. T Pyx latest light curve

16. T Pyx visual and Xray comparison

17. T Pyx 400-900nm outburst spectrum

18. T Pyx Halpha hires spectrum

19. M101 + SN2011fe Credit: Albert Duin

20. SN2011fe latest light curve

21. SN2012aw in M95

22. SN2012aw light curve

23. M65 supernova SN2013am Credit: Wendel & Masi

24. Amateur Spectroscopy http://astrosurf.com/buil/saintcaprais/firs t.htmhttp://astrosurf.com/buil/saintcaprais/firs t.htm Observatoire de Saint-Caprais Rabastens (Tarn) Yvon Rieugné et Pierre Thierry

25. Thierry’s 94cm

26. SN2011fe spectrum

27. MASTER OT J095310.04+335352.8 LP binary or RCB? Denisenko et al. ATEL 4784 Credit: ASAS

28. GR Ori 05:21:34.98 +01:10:10.2 WZ Sge; last outburst 1916

29. AZ Cas

30. Cookbook for VS observing Use VSX or AAVSO Campaigns, observing programs to select object; http://www.aavso.org/vsx http://www.aavso.org/vsx Example: V435 Cam –06:15:20.90 +82:08:13.4 J2000 –13.7 – 14.1 R –Period 112 minutes

31. Generate finding chart http://www.aavso.org/vsp DSS option gives true sky view

32. Acquire data 111min period; use 50pts/period or one every 2 minutes Best if use both B&V, but use at least one filter Cover entire cycle ++ if possible

33. Process data Dark subtract and flat field Extract photometry using sequence to get standardized magnitudes Output in AAVSO Extended format if possible

34. Analyze data Spreadsheet with the correct period Use VSTAR for phase plotting and period analysis: http://www.aavso.org/vstar

35. Submit data Get an AAVSO observer code: http://www.aavso.org/request-obscode http://www.aavso.org/request-obscode Use Webobs to upload your data: http://www.aavso.org/webobs

36. Variable stars are for you! Easy to observe Good subjects for research Collaborate with professionals Can use naked eye, binoculars, DSLR, telescope+CCD, spectrograph, etc. Manuals/tutorials on AAVSO web site You too can do cutting-edge science!

37. AAVSO news

38. 2GSS features Immediate public access Simultaneous color information Prototype fully funded Fwhm smaller than existing surveys Entire sky covered, including galactic plane (50 million stars per night) Long life-time (AAVSO) Pathfinder for LSST

39. 2GSS specs Prototype to be installed at Lowell Observatory in June 2013 Use of APASS for field secondary standards Phase I has photometry available within 24hrs, public, on-line Phase II incorporates real-time alerts

40. 2GSS telescope

41. Anderson Mesa Dark Sky Site (Flagstaff, AZ)

42. 2GSS site

43. Impact on CCD Observers Real-time alerts need to be followed up Photometry degrades below ~15th; provide higher-quality photometry One-day cadence poor for short-period variables, transient objects Only V,I’ photometry, so other wavelengths needed

44. Impact on Visual Observers Real-time alerts need to be followed up One-day cadence poor for short-period variables, transient objects; little change for CV observers Saturates at V=10-11; no coverage of brighter objects Will have problems with moon; won’t go near horizons; blended objects difficult Starting in 2012, but not fully operational until 2013, and then only if fully funded

45. LP binary or RCB?