Provisional sunspot numbers April 1997 +------+----------------+-------------------+-------+--------------+ | | | | | | | Day | Groups | Wolf number | Beck | No. of Obs. | | | | | index | | | | N S Total | N S Total | | N/S T Beck | | | | | | | +------+----------------+-------------------+-------+--------------+ | 1. | 0.0 0.9 0.9 | 0 18 18 | 136 | 10 18 7 | | 2. | 0.0 1.5 1.5 | 0 28 28 | 258 | 9 16 8 | | 3. | 0.0 2.1 2.1 | 0 38 38 | 454 | 9 16 6 | | 4. | 0.0 1.9 1.9 | 0 29 29 | 210 | 6 15 7 | | 5. | 0.0 1.8 1.8 | 0 25 25 | 116 | 3 6 3 | | 6. | 0.0 1.2 1.2 | 0 17 17 | 167 | 9 19 9 | | 7. | 0.0 0.8 0.8 | 0 12 12 | 72 | 10 21 9 | | 8. | 0.0 0.9 0.9 | 0 11 11 | 27 | 7 14 6 | | 9. | 0.6 0.6 1.2 | 11 8 18 | 67 | 9 17 7 | | 10. | 0.8 0.2 1.0 | 16 3 19 | 287 | 7 13 4 | | 11. | 0.6 0.4 1.0 | 12 5 17 | 159 | 7 14 7 | | 12. | 0.8 0.4 1.2 | 12 4 17 | 78 | 7 15 7 | | 13. | 0.6 0.8 1.5 | 9 14 23 | 180 | 9 16 6 | | 14. | 0.3 0.9 1.2 | 4 17 21 | 269 | 6 11 5 | | 15. | 0.0 1.7 1.7 | 0 31 31 | 361 | 9 19 8 | | 16. | 0.0 1.6 1.6 | 0 26 26 | 236 | 9 18 8 | | 17. | 0.1 1.0 1.2 | 1 17 18 | 94 | 9 15 7 | | 18. | 0.0 0.7 0.7 | 0 9 9 | 12 | 9 19 7 | | 19. | 0.3 0.1 0.4 | 4 1 5 | 6 | 7 12 4 | | 20. | 0.0 0.0 0.0 | 0 0 0 | 0 | 9 17 6 | | 21. | 0.0 0.0 0.0 | 0 0 0 | 0 | 10 18 8 | | 22. | 0.0 0.0 0.0 | 0 0 0 | 0 | 6 12 4 | | 23. | 0.4 0.0 0.4 | 5 0 5 | 12 | 12 22 8 | | 24. | 0.4 0.0 0.4 | 4 0 4 | 21 | 10 17 6 | | 25. | 0.2 0.0 0.2 | 2 0 2 | 0 | 6 11 5 | | 26. | 0.0 0.8 0.8 | 0 12 12 | 32 | 6 10 5 | | 27. | 0.2 0.7 0.9 | 2 12 14 | 69 | 4 6 3 | | 28. | 0.0 0.8 0.8 | 0 13 13 | 76 | 5 8 4 | | 29. | 0.0 0.8 0.8 | 0 8 8 | 43 | 3 5 2 | | 30. | 0.0 0.0 0.0 | 0 0 0 | 0 | 6 11 5 | +------+----------------+-------------------+-------+--------------+ | Mean | 0.2 0.8 0.9 | 2.7 11.9 14.7 | 115 | 8 14 6 | +------+----------------+-------------------+-------+--------------+ | Days | 30 30 30 | 30 30 30 | 30 | | +------+----------------+-------------------+-------+--------------+ Based on 431 observations of 23 stations. Edited by Martin Dillig.