2025-08-31T18:37:51.000Z http://sot.lmsal.com Mr. Sam Freeland Lockheed Martin Solar and Astrophysics Laboratory (LMSAL) http://www.lmsal.com Lockheed Martin Advanced Tech Center, 3251 Hanover Rd, O/ADBS, B/252, Palo Alto, CA 94304 null null HINODE SOTSP Yoshitake Sakao Cruz (RCO) 412 HOP 412 N-S 17/20 Central meridian SYN SYN 19 20240220_023004 138 161 229 19 59 190 6 1 1 1 0 21 2021 190 1 -20.749 613.151 60.23 129.336 2024-02-20T02:30:04.000Z 2024-02-20T02:46:12.000Z -20.749 613.151 Synoptic SOT Latitudinal Scans (updated version of HOP79) Normal map 30 arcsec, Shorter Irradiance: DO NOT MODIFY! Main Objective: To study how small-scale magnetic flux and solar irradiance varies over the sunspot cycle Scientific Justification: The total solar irradiance varies by about 0.1% over the course of the solar cycle, primarily due to the influence of magnetic structures such as sunspots and faculae on the photospheric spectral irradiance. Short-term irradiance variation (on the scale of days-to-months) is well understood to be due to the balance of sunspots and facular areas as they cross the disk. However on the decadal scale of the solar cycle, questions remain as to why the irradiance variation can lead and/or lag the active region count over the course of the cycle. Explanations ranging from changes inthe solar diameter in response to magnetic flux storage in the convection zone to changes in the surface area of the photosphere due to F-mode modulation have been put forward. We propose to observe a north-to-south latitudinal strip with SOT-SP on a regular basis to better understand the variation of irradiance with rising flux levels in the photosphere. These observations have the potential to reveal new and important aspects of the relation between solar irradiance and magnetic flux emergence over the solar cycle when compared with TSI measurement satellites such as TSIS-1 and TSIS-2. ivo://sot.lmsal.com/VOEvent#2024-02-20T02:30:00Z