Alternate Views: Get Data, FAQ, ISO Rubric, CSW, HTML, Components, XML Sunspot Numbers SUNSPOTS In 1848 the Swiss astronomer Johann Rudolph Wolf introduced a daily measurement of sunspot number. His method, which is still used today, counts the total number of spots visible on the face of the sun and the number of groups into which they cluster, because neither quantity alone satisfactorily measures sunpsot activity.An observer computes a daily sunspot number by multiplying the number of groups he sees by ten and then adding this product to his total count of individual spots. Results, however, vary greatly, since the measurement stongly depends on observer interpretation and experience and on the stability of the Earth’s atmosphere above the observing site. Moreover, the use of Earth as a platform from which to record these numbers contributes to their variability, too, because the sun rotates and the evolving spot groups are distributed unevenly across solar longitudes. To compensate for these limitations, each daily international number is computed as a weighted average of measurements made from a network of cooperating observatories. Get the Data Access Format(s) Distributor(s) / Contact Info Instructions / Constraints http://www.ngdc.noaa.gov/stp/SOLAR/ftpsunspotnumber.html ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS http://www.ngdc.noaa.gov/stp/SOLAR/SSN/ssn.html ASCII Format version: (version is unknown) Solar Data Manager DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce Contact Data Center 303.497.6133 or 303.497.6323 7:30 - 4:30 Mountain Fees Price is depended on how much data is requested. $120.00/$90.00 plus handling and shipping outside the USA Ordering Instructions Non-Digital Form: Paper Pages Ordering Instructions: Prepay by check, money order or bank card There is a standard handling charge, with additional costs for special handling. Orders may be placed via fax, email, regular mail or telephone Custom Order Process: Contact data center for information Ordering Instructions: Product may be ordered directly via: http://ols.nndc.noaa.gov/plolstore/plsql/olstore.prodspecific?prodnum=G01255-CDR-A0001 Custom Order Process: Contact data center for information Legal Constraints Access otherRestrictions Use Limitation otherRestrictions Other Access Constraints: No Constraints Use Constraints: None Distribution Liability: While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.