1. HMI01567 – Page 1HMI Sun Test Review – November 28, 2005 Sun Test Overview

2. HMI01567 – Page 2HMI Sun Test Review – November 28, 2005 Sun Test Overview – Interdependencies At least three tests are prerequisites for other tests –Focus Can use either Sun or lamp Needed to reduce length of other tests Not needed for many tests due to bad seeing or spatial averaging –Wavelength dependence Either Sun or laser can be used Needed to set tuning positions Not needed for lamp or polarization tests –Polarization calibration Lamp or Sun can be used Needed to make observing sequences. Especially LOS. Note that none of these are dependent on each other Others are needed before analysis can be completed

3. HMI01567 – Page 3HMI Sun Test Review – November 28, 2005 Sun Test Overview – Other prerequisites There are a number of other tests we need to perform before starting Determine exposure times –Lamp –Sun –Laser Test various targets –Determine spatial power and quality of each Alignments –Stim tel –Laser –Heliostat Existing focus test procedure may be used for these

4. HMI01567 – Page 4HMI Sun Test Review – November 28, 2005 Sun Test – Go/no go criteria Several types of criteria –Prerequisites done – See separate charts –Equipment available and properly configured Laser and wavemeter working PCU properly configured Targets available/installed –Sunlight Some require long stretches of clear skies Others can use shorter stretches and/or light clouds –STOLs working –Procedural issues resolved See overview chart and individual tests for details

5. HMI01567 – Page 5HMI Sun Test Review – November 28, 2005 Sun Test – Pass/fail criteria This is not an acceptance test! –However, we are looking for gross errors –Note that in many cases all we need is characterization NOT pass/fail Two levels –Do we have the required data? If no pass/fail then we only need to know when we have data of sufficient quality –Have we analyzed the data? If pass/fail needed or if test is prerequisite for other tests we need short turn around Analysis software for prerequisites is ready Preliminary results and decisions will be part of calibration meetings –In case of gross errors high level decisions needed Abort Sun test and fix problem Continue with other parts of test

6. HMI01567 – Page 6HMI Sun Test Review – November 28, 2005 Sun Test – Priorities Several competing criteria for priority Make good use of sunlight –May not get that many days Do prerequisites first Equipment constraints –Don’t want to fire up laser too often –Don’t want to change PCU configuration too often Allow efficient development and testing of STOL procedures –Easy ones first –Test various types Maximize time to develop and run analysis procedures –Data of marginal quality (eg. clouds) may still allow for some testing May need data from other instruments –MDI under our control, but keyhole –May like to have data from ground based. GONG, SOLIS, ASP,… Near real time flexibility will be required to be efficient! With this in mind…

7. HMI01567 – Page 7HMI Sun Test Review – November 28, 2005 Sun Test – Attack plan Get STOLs for prerequisites ready before test starts –Focus done. Wavelength dependence and PCU both well defined Run all relevant STOLs we have as soon as we can –Can check for proper functioning – may do abbreviated versions to save time –Gives sample data for analysis code development –POR – Don’t do extensive real time debugging –Run STOLs even if ideal source not available –With luck we can have prerequisites done on day one! Does depend on PCU operational Does depend on Sun shining or laser working Don’t use laser on day one –Probably takes too long to get set up –Can use other sources for initial tests –But do get it to work soon, especially if forecast calls for solid overcast Plan further tests depending on weather, people and equipment availability –Try to get prerequisites done as soon as possible –Do weekly and daily planning

8. HMI01567 – Page 8HMI Sun Test Review – November 28, 2005 Data Processing Will use MDI data system (DSDS) for storing data –Should easily be able to handle data volume Will use HMI data system (DRMS) for metadata –Still in beta test, but alternatives exist A few basic utilities will be available –Data query, selection and export –Image reconstruction (remove cross) –Etc. Analysis will be done with ad-hoc code –Mostly IDL –Observables code may have to be optimized to reduce computing time –Codes for prerequisites exist

9. HMI01567 – Page 9HMI Sun Test Review – November 28, 2005 Image Quality: Focus Purpose –Determine the nominal focus position Requirements –Need to take images for other tests near optimal focus. Also needed to set secondary shim. Description –Determine spatial power as a function of focus setting. Fit model to determine ideal focus. Test configuration –Stimulus telescope with lamp and desired target(s) (dots). Sun may also be used to illuminate target. –Also do with direct sunlight from heliostat. Test plan –Take images at all 16 focus positions. Data analysis –For each focus position determine the amount of spatial power. Fit parabola to three highest points to determine best focus. –For the Sun it may be possible to use the sharpness of the limb. –Codes are ready. Procedure –STOL status: Exists. –Shop order status: Does not exist –The test timeline: 16 images of 10s or 3 minutes. Little setup required. –No particular personnel required.

10. HMI01567 – Page 10HMI Sun Test Review – November 28, 2005 Image Quality: Distortion Purpose –Determine the amount of optical distortion. Requirements –0.001% (0.02 pixels) based on Korzennik et al. (204) 0.01pixels desirable. Description –Determine parameters in distortion model by offpointing instrument using alignment legs. Test configuration –Stimulus telescope with lamp and desired target(s) (dots). Sun may also be used to illuminate target. Test plan –At each of 5x5 leg offsets, take images at a few positions around the nominal focus. Data analysis –For each focus position determine the offsets between each pair of images for a grid of points in the images. –Fit distortion model to the measured offsets. –Codes are ready. Procedure –STOL status: Does not exist –Shop order status: Does not exist –The test timeline: Each series is 25 offsets times 5 focus positions for a total of 125 images. At 10s per images this will take 20 minutes. Needs to be run for a few targets plus setup so a few hours. –No particular personnel required.

11. HMI01567 – Page 11HMI Sun Test Review – November 28, 2005 Mechanism induced images motions and distortions Purpose –Determine the image motions and distortions introduced by rotating the optics in the hollow core motors. Requirements –CPS gives 0.1” (0.2 pixels). IPD 4.3 gives a goal of 0.1 pixels. Description –Determine offsets by taking images of fixed target at various HCM rotation angles. Test configuration –Stimulus telescope with lamp and desired target(s) (dots). Sun may also be used to illuminate target. Test plan –For each of 7 HCMs and each of 10 or so angles, take images at a few positions around the nominal focus. Data analysis –At each focus position determine the offsets between each pair of images for a grid of points in the images.. –Code is ready. Procedure –STOL status: Does not exist –Shop order status: Does not exist –The test timeline: About 100 images. At 10s per images this will take 20 minutes. Needs to be run for a few targets plus setup so a few hours. –No particular personnel required.

12. HMI01567 – Page 12HMI Sun Test Review – November 28, 2005 Image Quality: Field curvature Purpose –Determine the amount of field curvature. Requirements –The change of focus as a function of image position should be a fraction of a focus step. Description –Determine spatial power as a function of focus setting, leg offset and image position. Fit model. Test configuration –Stimulus telescope with lamp and desired target(s) (dots). Sun may also be used to illuminate target. –Also do with sunlight. Test plan –Same as for distortion. Also use sun focus series. Data analysis –At each leg position and image position fit mode power as a function of focus position to determine best focus. –For Sun test no additional analysis required. –For lamp test analyze focus as a function of offset and position to separate stim tel and HMI curvature. –Codes are mostly ready. Procedure –STOL status: Exists for Sun test. Does not exist for lamp test. –Shop order status: Does not exist –The test timeline: Same data as other tests, so no additional time required. –No particular personnel required.

13. HMI01567 – Page 13HMI Sun Test Review – November 28, 2005 Image Quality: MTF Purpose –Determine the MTF variation as a function of image position. Requirements –Astigmatism should be a fraction of a focus step. The MTF at any k should not be degraded by more than that corresponding to a(?) focus step. 10% or better knowledge is desirable. Description –Determine spatial power as a function of k and image position at best focus. Test configuration –Stimulus telescope with lamp and desired target(s) (dots). Sun may also be used to illuminate target. –Also do with sunlight. Test plan –Same as for distortion. Also use sun focus series. Data analysis –At each leg position and image position fit mode power as a function of k at best focus. –For Sun test no additional analysis required. –For lamp test analyze power as a function of offset and position to separate stim tel and HMI MTF. –Codes are mostly ready. Procedure –STOL status: Exists. –Shop order status: Does not exist –The test timeline: Sama data as for other tests so no additional time needed. –No particular personnel required.

14. HMI01567 – Page 14HMI Sun Test Review – November 28, 2005 Image Quality: Image scale Purpose –Determine the absolute image scale. Requirements –The image scale should be between 0.494”/pixel and 0.505”/pixel. Description –Take images of Sun. Determine diameter and compare to ephemeris. Test configuration –Sun from heliostat. Test plan –Take solar images at each focus position. Data analysis –Determine solar image diameter. Look up diameter in ” in ephemeris. Divide numbers. –Code exists. Procedure –STOL status: Exists. –Shop order status: Does not exist –The test timeline: Data already taken for other tests. –No particular personnel required.

15. HMI01567 – Page 15HMI Sun Test Review – November 28, 2005 Contamination Purpose –Determine if any large particles are present in the optical path. Requirements –Any contaminants should not be large enough to degrade science. Description –Using a “pinhole” camera mode look for shadows from contaminants and determine their position in the optical path by determining motion when moving pinhole. Test configuration –Stimulus telescope with lamp or Sun and direct sunlight. PCU with hole plate. –Laser in stimulus telescope with leg offsets. Test plan –For each hole position or each leg offset take image in obs and cal mode. –Also rotate each HCM at one or more hole and leg positions. Data analysis –Offset images proportional to pinhole offset. Look for shadows coming into focus. Determine position in optical path from raytrace and proportionality constant used for shifting. –For HCM rotations look for moving shadows. –Codes exists for MDI. Procedure –STOL status: Does not exist –Shop order status: Does not exist –The test timeline: About 100 images each series. A few hours total. –Personnel qualified to change PCU configuration needed.

16. HMI01567 – Page 16HMI Sun Test Review – November 28, 2005 Polarization calibration Purpose –Determine intsrument polarization matrix. Requirements –See IPD. Description –Using light with well determined polarization determine instrument response. Test configuration –Stimulus telescope with lamp or Sun and sunlight from heliostat. Test plan –Using PCU take series of images with various PCU and instrument settings. Data analysis –Too complicated to describe here. –Codes are ready. Procedure –STOL status: Does not exist –Shop order status: Does not exist –The test timeline: 50-100 images in obs and calmode required for Sun and lamp. Total one day. –No particular personnel required.