Jan 21/22, 2009PACS PV Review Photometer Spatial Cal1 PACS Photometer Spatial Calibration PVPhotSpatial D.Lutz PACS PV Review Jan 21/ , MPE

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal2 PCD 2.6.2: Telescope RPE Goal: measure the short term variations around the intended stable pointing Matter of taste whether to place here or under pointing calibration/FPG, was simply implemented here in order to not forget after the procedure was available… Method: Nonstandard AOR doing a chopped/nodded observation but with longer than usual nod period, to avoid the uncertainties associated with repositioning the telescope 2 sources: non-SSO (Alf Boo) and SSO (asteroid) Total time: ~1h

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal3 PCD 3.1.1: Central Pointing Position Now part of pointing calibration, see presentation by Bruno Altieri CAP prototype exists

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal4 PCD 3.1.2: Relation between chopper position and angular Displacement on sky As directly as possible and suppressing telescope repositioning uncertainties compare a known distance on sky with chopper throw [and direction] - important for AOTs! Use double sources with known separation. Not trivial to find, but using a combo of star pairs, galaxy pairs and asteroid conjunctions overall satisfactory – 13 cases with useful brightness, separation and PA found in PV exercise Baseline procedure: Triple chop using nonstandard AOR: 13 pairs, takes ~1h total Fall back procedure: Chop/nod with tailored throw using nonstandard AOR: Tested on 2 pairs ~0.2h total Nonstandard procedures were part of SOVT2, validation started

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal5 PCD 3.1.3: Photometer FOV distortion What we would like to do but would need better and faster pointing: Note: These PACS+testoptics results have been transferred to PACS+Herschel using N.Geis’ modelling

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal6 SIMULATED pointing from testing a procedure in SOVT2 OD63

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal Method A: narrowly spaced scanmaps across bright source Source should be very bright for good S/N in 1/10 of a sec, a little fluff or non-point like nature ok as long a core is symmetric. Baseline PV: Mira 7 chopper positions, 2 orientations, cover full array at 4” cross-scan step slow scan Standard AOR + nonstandard AOR (latter for non-optical zero chopper positions ~15h total

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal Method B: Staring raster on bright source Sloooow due to pointing overheads and minimum OBCP duration but still an important crosscheck to scanmap results Only one staring raster (nonstandard AOR) 3.5”*7” pitch at optical zero, which is the chopper position used for all the scanmap AORs Source: Mira Total duration: 6.5h!

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal Method C: Differential checks by observing a field with a priori unknown but clear structure, placing the same structure in different regions of the array and using different chop throws. Test with two suitable galaxy pairs, two chop throws, raster to move sources further (nonstandard AOR) Total duration: 7h

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal Photometer PSF Because of expected noticeable color effects, include a star (blue SED, e.g. Alf boo), Blazar (red SED, faint, e.g. 3C345), Asteroid (bright, blue, SSO), do for both blue and green filter Method A: non-standard chopped/nodded AOR moving source to the centers of all 8 blue matrices, blue+green filter, total ~7h Method B: default point source AOR as reference, total ~0.5h

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal : Finely sampled PSFs For blue/green/red filter and for a star and a blazar, do more finely sample rasters (5*5 at 1.25pixel step) around chop/nod Method C, nonstandard AOR Note: Pointing quality is again an issue, but may be reconstructable from data Total duration: ~8h

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal : PSF in scanmaps Method D: Scan over Alf Boo and 3C345 with scanmaps at all three speeds and in blue+green filter Modest scan map with 15 legs spaced 3” to improve sampling, default AOR Total duration: ~4h Note: parallel mode is implicitly covered as long as current averaging scheme is kept

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal13 Support spectrometer PSF Non-SSO sources that are bright enough for spec PSF are not strict point sources Take a quick small source photometer AOR on each source scheduled for spec PSF to look for structure, accepting that core may/will be saturated ~0.3h/source Source list recheck TBD

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal14 PCD Ghosts Method A: To re-measure the ‘blue streaks’ seen in ILT, do a 5’*5’ scanmap with 4” cross-scan step on a very bright source (Mira) Blue at 3 chopper positions, green at 1, standard and nonstandard AOR Total duration ~4h Method B: Blind search for new phenomena using 20’ scanmap with 6” cross-scan step Covers ~ “Herschel FOV” Source needs to be very bright, Uranus if available, N3256 otherwise Total duration ~4h

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal15 PCD Straylight 2deg*2deg ‘homogeneous coverage’ fast scanmap, default AOR Source: Uranus if available (could remeasure at different epoch if in doubt about nature of an effect), Mira otherwise Total duration: ~2h Not covered at this point: Straylight at very large angles due to tripod reflex. There are useful measurement methods if a good prediction can be made by straylight WG

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal16 PCD 3.1.7: Background structure Measure background structure and straylight between open FOV and calibration sources by doing chopper scans over full range while telescope is staring Different calibration source and sky flux levels help in disentangling effects Total duration: ~3h

Jan 21/22, 2009PACS PV Review Photometer Spatial Cal17 Keep an eye on validation of non-standard AORs from SOVT2 – quicklook is encouraging Signs - with two dimensions an even number of sign errors may not cancel ;-) Software stability/efficiency