1. Kitt Peak Vacuum Telescope -- Raw to Synoptic Map J. Harvey

2. Pre-History KP 40-channel collected daily FD maps in March 1970 to compare with corona at eclipse Randy Levine worked with Marty Altschuler at HAO to make synoptic map and extrapolations; did it again in 1972 Skylab prompted start of daily observations in 1973 & construction of KPVT

3. First KP Synoptic Map – CR 1558

4. More History Synoptic map algorithm was basically derived from Randy’s HAO work 1974: 40-chan replaced with 512-chan 1974: Started doing helium 10830 maps 1993: 512-chan replaced by SPMG 2003: KPVT replaced by SOLIS VSM

5. 512-ch Calibration It was an array of Babcock magnetographs Calibrated with circular polarizer + known displacement 8688 Å linear response to ~9000 G Not much center – limb variation Calibration done very rarely Observations sensitive to I & vel crosstalk

6. SPMG Calibration Used TV images of polarized spectra Still used 8688 Å (small disk variation) Uses whole line profile so Zeeman displacement measured directly Vulnerable to modulator efficiency being less than 100% Did a cross-comparison between 512 for ~9 months

7. Synoptic Map Basic Recipe 1.Clean up full-disk image Filter noisy pixels Geometric fit (P-angle, disk center and radius) Adjust zero point (if needed) Multiply by sec ρ 2.Map to Carrington coordinates (sin B, CMD) 3 resolutions: 180 x 180, 360 x 360, 900 x 900 2 maps: sum and weight Flux conserved

8. Recipe – con’t. 3.Weighted merge of images –Cos 4 CMD for low resolution –1-D gaussians in CMD for higher resolution –Build sum and weight merged images –Divide merged sum by weight 4.Pole correction 5.Publish –Done for B and |B|

9. Pole Correction Remap pole region to polar coordinates Iterative fit of 2-D 5 th -order cubic spline to measured data (rejects wild points) Replace missing and noisy pixels with fit Map back to Carrington grid Latitude-dependent blend with original map Tested by absence of annual signal

10. Variants 1.Snapshot maps started in 1998 until Y2K 2.Polar projections 3.Daily difference maps 4.CR difference maps 5.Neutral line and AR summaries 6.Movies 7.Butterfly diagrams 8.Coronal holes

13. Problems Assumes each image is instantaneous Except for the snapshot maps, does not represent the full solar surface at any specific time Dubious polar correction Dark umbras poorly handled Leaves a small monopole Radial correction is bad in AR Bad in quiet photosphere, too

14. Status Old KPVT mags have been cleaned up New set of synoptic maps from CR 1625- 2007 about to be prepared