The Cosmic Infrared Background (CIB) as an integrated history of the early universe is important for the study of the Dark Ages, and it may include the light from the first stars at z~10. However, previous CIB measurements suffer from residual contamination from strong foreground emission (e.g. the zodiacal light). We propose to observe two Galilean satellites eclipsed in the shadow of Jupiter as occulting disks at near-infrared wavelengths in order to detect the absolute CIB intensity without any zodiacal light subtraction error. The zodiacal light originates inside the orbit of Jupiter; since the Galilean satellites in eclipse shield all light beyond the Jovian orbit, they should be detected as 'dark spots' if the strong CIB implied by previous observations exists. The intensity deficit of this dark spot relative to the surrounding sky directly measures the strength of the CIB, free from any assumptions about the zodiacal light. The size of the dark spot is approximately 1 arcsec in diameter and the predicted surface brightness is 70 nW/m2/sr lower than that of surrounding sky brightness, which can be detected by WFC3 IR imaging with F140W filter for two orbits integration with S/N=10 even in the strong Jovian stray light environment. The greatest difficulty in this observation results from scattered light due to the close proximity of Jupiter to the target satellites (< 80 arcseconds). According to our estimation, leak energy from encircled energy at 30 arcsec is 0.04%, and Jovian stray light at 30 arcsec is about 5 times brighter than the zodiacal light. Therefore, we will keep Jupiter out of the detector field of view (FoV) during the observation to avoid stray light from Jupiter (Jupiter is 20 magnitudes brighter than the eclipsed satellites). Observations will be conducted with non-sidereal tracking on Jupiter (outside of the FoV) to fix the stray light pattern on the detector array during the observation. This will minimize the systematic error of the Jovian stray light. Since the relative speed of the target satellites vs. Jupiter is ~0.005 arcsec/sec, we use an observing mode of SPARS=25 and NSAMP=14. In this case, the image of target satellite will be smeared because of its movement and non-destructive readouts of the detecter. Therefore, we will reconstruct the image by calculating [Nth - (N-1)th] frames and conducting the "shift and add". Letting the eclipsed satellite move relative to the detector using Jupiter tracking has the advantage of effectively dithering the observations so that we can average out any detector issues such as scattered earthlight, structure in the darks, and the dark features called "blobs" in particular (the latter are believed to result from debris on the pick-off optics). We emphasize that we know the satellite ephemeri with great precision; the size and location of the eclipsed satellite will be accurately known, and therefore easily differentiated from detector effects. We need to put the target sattelite at the specific area on the detector to avoid the 'Death Star', the 'Wagon Wheel', and the spider pattern from the Jupiter. We request two orbits for the eclipse observations themselves, and another two orbits in order to re-image the same field observations once the Jupiter system has passed. This latter data will allow a measurement of any diffuse foreground galaxies which might contaminate the dark spot observation. Since our method relies on specific astronomical events, chances for observation are limited and timing is absolutely critical; in particular, the eclipse observations must begin at the specified time. We have decided not to observe first two minutes from the beginning of the eclipse due to potential complications from latents arising from the target when it is illuminated by sunlight. Similarly, the observations must be scheduled to avoid slewing over Jupiter. We do not want to see the Jupiter even during the maneuver for pointing to prevent from the potential complications from latents. COSMOLOGY 12 false false 0.0 0.0 false false false SUPPORTED SOLAR SYSTEM Target is Europa eclipsed by Jupiter. Visit will be tracking on Jupiter and using a position angle and radius to offset to Europa. SATELLITE SATELLITE EUROPA STD=JUPITER TYPE=POS_ANGLE,RAD=93,ANG=62,REF=NORTH 24 Vegamag/arcsec2 negative brightness at 1.4um during the eclipse SEP OF EUROPA JUPITER FROM EARTH GT 5", SEP OF EUROPA CALLISTO FROM EARTH GT 30", SEP OF EUROPA GANYMEDE FROM EARTH GT 30", SEP OF EUROPA IO FROM EARTH GT 15", ECL U OF EUROPA BY JUPITER EARTH SOLAR SYSTEM Target is Europa eclipsed by Jupiter. Visit will be tracking on Jupiter and using a position angle and radius to offset to Europa. SATELLITE SATELLITE EUROPA STD=JUPITER TYPE=POS_ANGLE,RAD=105,ANG=280,REF=NORTH 24 Vegamag/arcsec2 negative brightness at 1.4um during the eclipse SEP OF EUROPA JUPITER FROM EARTH GT 10", SEP OF EUROPA CALLISTO FROM EARTH GT 30", SEP OF EUROPA GANYMEDE FROM EARTH GT 30", SEP OF EUROPA IO FROM EARTH GT 15", ECL U OF EUROPA BY JUPITER EARTH SOLAR SYSTEM Target is Europa eclipsed by Jupiter. Visit will be tracking on Jupiter and using a position angle and radius to offset to Europa. SATELLITE SATELLITE EUROPA STD=JUPITER TYPE=POS_ANGLE,RAD=95,ANG=80,REF=NORTH 24 Vegamag/arcsec2 negative brightness at 1.4um during the eclipse SEP OF EUROPA JUPITER FROM EARTH GT 10", SEP OF EUROPA CALLISTO FROM EARTH GT 30", SEP OF EUROPA GANYMEDE FROM EARTH GT 30", SEP OF EUROPA IO FROM EARTH GT 15", ECL U OF EUROPA BY JUPITER EARTH SOLAR SYSTEM Target is Callisto eclipsed by Jupiter SATELLITE SATELLITE CALLISTO STD=JUPITER STD=CALLISTO 24 Vegamag/arcsec2 negative brightness at 1.4um during the eclipse SEP OF CALLISTO JUPITER FROM EARTH GT 30", SEP OF CALLISTO IO FROM EARTH GT 30", SEP OF CALLISTO EUROPA FROM EARTH GT 30", SEP OF CALLISTO GANYMEDE FROM EARTH GT 30", ECL U OF CALLISTO BY JUPITER EARTH SOLAR SYSTEM Target is Ganymede eclipsed by Jupiter. SATELLITE SATELLITE GANYMEDE STD=JUPITER TYPE=POS_ANGLE,RAD=100,ANG=55,REF=NORTH 24 Vegamag/arcsec2 negative brightness at 1.4um during the eclipse ECL U OF GANYMEDE-2 BY JUPITER, SEP OF GANYMEDE-2 CALLISTO FROM EARTH GT 10", SEP OF GANYMEDE-2 IO FROM EARTH GT 10", SEP OF GANYMEDE-2 EUROPA FROM EARTH GT 10" EARTH SOLAR SYSTEM Target is Ganymede eclipsed by Jupiter. SATELLITE SATELLITE GANYMEDE STD=JUPITER STD=GANYMEDE 24 Vegamag/arcsec2 negative brightness at 1.4um during the eclipse SEP OF GANYMEDE-3 JUPITER FROM EARTH GT 30", SEP OF GANYMEDE-3 CALLISTO FROM EARTH GT 30", SEP OF GANYMEDE-3 IO FROM EARTH GT 30", SEP OF GANYMEDE-3 EUROPA FROM EARTH GT 24", ECL U OF GANYMEDE-2 BY JUPITER EARTH WFC3/IR Imaging No No F140W WFC3/IR Imaging No No F140W Using ephemeris for target 12980-01-GANYMEDE The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. 1365432165000 83.05380165474679 (Tic-Visit :proposal-id 12980 :visit-id "01" :proposal-version -1 :trans-version "20121031" :date "08-Jan-2013 07:08:35.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 2089072 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12980 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12980 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2822 :al-overhead-at-end 0 :internal-dur-at-end 658 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 1 0 Using ephemeris for target 12980-02-CALLISTO The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. 1360027928000 79.9106714060556 (Tic-Visit :proposal-id 12980 :visit-id "02" :proposal-version -1 :trans-version "20121031" :date "08-Jan-2013 07:08:37.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 2089072 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12980 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12980 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2822 :al-overhead-at-end 0 :internal-dur-at-end 658 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 1 0 Using ephemeris for target 12980-03-GANYMEDE-2 The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. 1362502962000 80.88721395074208 (Tic-Visit :proposal-id 12980 :visit-id "03" :proposal-version -1 :trans-version "20121031" :date "08-Jan-2013 07:08:38.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 2089072 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12980 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12980 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2822 :al-overhead-at-end 0 :internal-dur-at-end 658 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 1 0 Using ephemeris for target 12980-04-CALLISTO-2 The scheduling data was generated by CASM 20.2. CASM was run in Phase II mode. 1383545887000 255.0 (Tic-Visit :proposal-id 12980 :visit-id "04" :proposal-version -1 :trans-version "20121031" :date "08-Jan-2013 07:08:40.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 2089072 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12980 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12980 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2822 :al-overhead-at-end 0 :internal-dur-at-end 658 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 1 0 (Tic-Visit :proposal-id 12980 :visit-id "04" :proposal-version -1 :trans-version "20121031" :date "08-Jan-2013 07:08:40.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 2089072 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12980 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12980 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2822 :al-overhead-at-end 0 :internal-dur-at-end 658 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3229 :pcs-gap 0 ) false 1 0