This is a re-submission in which we have changed our primary filter from F606W to the much broader F350LP. This change was discussed with Tony Roman and Ron Gilliland. Scheduling constraints are unchanged except for Visit 34, where I discovered and removed and accidental constraint that had linked it to Visit 33. That constraint did no harm but was not required. ----- Attempting Submission 1 (Tue Aug 02 15:24:57 GMT 2011) ----- Orbital Evolution and Stability of the Inner Uranian Moons Nine densely-packed inner moons of Uranus show signs of chaos and orbital instability over a variety of time scales. Many moons show measureable orbital changes within a decade or less. Long-term integrations predict that some moons could collide in less than one million years. One faint ring embedded in the system may, in fact, be the debris left behind from an earlier such collision. Meanwhile, the nearby moon Mab falls well outside the influence of the others but nevertheless shows rapid, as yet unexplained, changes in its orbit. It is embedded within a dust ring that also shows surprising variability. A highly optimized series of observations with WFC3 over the next three cycles will address some of the fundamental open questions about this dynamically active system: Do the orbits truly show evidence of chaos? If so, over what time scales? What can we say about the masses of the moons involved? What is the nature of the variations in Mab's orbit? Is Mab's motion predictable or random? Astrometry will enable us to derive the orbital elements of these moons with 10-km precision. This will be sufficient to study the year-by-year changes and, combined with other data from 2003-2007, the decadal evolution of the orbits. The pairing of precise astrometry with numerical integrations will enable us to derive new dynamical constraints on the masses of these moons. Mass is the fundamental unknown quantity currently limiting our ability to reproduce the interactions within this system. This program will also capitalize upon our best opportunity for nearly 40 years to study the unexplained variations in Uranus's faint outer rings.
Astrometry of the Uranian satellites is accomplished via six visits, each consisting of a sequence of long exposures through the broad F350LP filter. Each orbit begins with one unsaturated image of the planet for geometric reference and calibration checking. The orbital plane is oriented within 20 degrees of the X-axis in the images to separate the moons from the wide vertical band caused by saturation bloom from the planet. From orbit to orbit, Uranus is shifted upward and downward by ~ 40 pixels within the 512x512 subarray to achieve some of the benefits of dithering; however, moons can always be distinguished from hot pixels by their motion. Each visit is timed to place one of the smallest moons near its maximum orbital elonagation, because this is where such moons are most detectable. The larger moons will be captured by chance and require no special targeting. Mab is the target of repeated observations in order to study its orbital variations. SOLAR SYSTEM 12 false 0.0 0.0 false false false false SUPPORTED SOLAR SYSTEM PLANET Uranus with Perdita near its maximum southern elongation; Mab also visible STD=URANUS OLG OF PERDITA BETWEEN 70 110, SEP OF PERDITA ARIEL FROM EARTH GT 4", SEP OF PERDITA UMBRIEL FROM EARTH GT 4", SEP OF PERDITA TITANIA FROM EARTH GT 5", SEP OF PERDITA OBERON FROM EARTH GT 5", SEP OF PERDITA MIRANDA FROM EARTH GT 4", SEP OF PERDITA PUCK FROM EARTH GT 2", SEP OF PERDITA BELINDA FROM EARTH GT 1", NOT OLG OF MAB BETWEEN 0 45, NOT OLG OF MAB BETWEEN 135 225, NOT OLG OF MAB BETWEEN 315 360 EARTH SOLAR SYSTEM PLANET Uranus with Perdita near its maximum northern elongation; Mab also visible STD=URANUS OLG OF PERDITA BETWEEN 250 290, SEP OF PERDITA ARIEL FROM EARTH GT 4", SEP OF PERDITA UMBRIEL FROM EARTH GT 4", SEP OF PERDITA TITANIA FROM EARTH GT 5", SEP OF PERDITA OBERON FROM EARTH GT 5", SEP OF PERDITA MIRANDA FROM EARTH GT 4", SEP OF PERDITA PUCK FROM EARTH GT 2", SEP OF PERDITA BELINDA FROM EARTH GT 1", NOT OLG OF MAB BETWEEN 0 45, NOT OLG OF MAB BETWEEN 135 225, NOT OLG OF MAB BETWEEN 315 360 EARTH SOLAR SYSTEM PLANET Uranus with Mab near its maximum southern elongation STD=URANUS OLG OF MAB BETWEEN 60 120, SEP OF MAB ARIEL FROM EARTH GT 4", SEP OF MAB UMBRIEL FROM EARTH GT 4", SEP OF MAB TITANIA FROM EARTH GT 5", SEP OF MAB OBERON FROM EARTH GT 5", SEP OF MAB MIRANDA FROM EARTH GT 4" EARTH SOLAR SYSTEM PLANET Uranus with Mab near its maximum northern elongation STD=URANUS OLG OF MAB BETWEEN 240 300, SEP OF MAB ARIEL FROM EARTH GT 4", SEP OF MAB UMBRIEL FROM EARTH GT 4", SEP OF MAB TITANIA FROM EARTH GT 5", SEP OF MAB OBERON FROM EARTH GT 5", SEP OF MAB MIRANDA FROM EARTH GT 4" EARTH SOLAR SYSTEM PLANET Uranus with Cupid near its maximum southern elongation; Mab also visible STD=URANUS OLG OF CUPID BETWEEN 70 110, SEP OF CUPID ARIEL FROM EARTH GT 4", SEP OF CUPID UMBRIEL FROM EARTH GT 4", SEP OF CUPID TITANIA FROM EARTH GT 5", SEP OF CUPID OBERON FROM EARTH GT 5", SEP OF CUPID MIRANDA FROM EARTH GT 4", SEP OF CUPID PUCK FROM EARTH GT 2", SEP OF CUPID BELINDA FROM EARTH GT 1", NOT OLG OF MAB BETWEEN 0 45, NOT OLG OF MAB BETWEEN 135 225, NOT OLG OF MAB BETWEEN 315 360 EARTH SOLAR SYSTEM PLANET Uranus with Cupid near its maximum northern elongation; Mab also visible STD=URANUS OLG OF CUPID BETWEEN 250 290, SEP OF CUPID ARIEL FROM EARTH GT 4", SEP OF CUPID UMBRIEL FROM EARTH GT 4", SEP OF CUPID TITANIA FROM EARTH GT 5", SEP OF CUPID OBERON FROM EARTH GT 5", SEP OF CUPID MIRANDA FROM EARTH GT 4", SEP OF CUPID PUCK FROM EARTH GT 2", SEP OF CUPID BELINDA FROM EARTH GT 1", NOT OLG OF MAB BETWEEN 0 45, NOT OLG OF MAB BETWEEN 135 225, NOT OLG OF MAB BETWEEN 315 360 EARTH SOLAR SYSTEM PLANET Uranus with Perdita near its maximum southern elongation STD=URANUS OLG OF PERDITA BETWEEN 70 110, SEP OF PERDITA ARIEL FROM EARTH GT 4", SEP OF PERDITA UMBRIEL FROM EARTH GT 4", SEP OF PERDITA TITANIA FROM EARTH GT 5", SEP OF PERDITA OBERON FROM EARTH GT 5", SEP OF PERDITA MIRANDA FROM EARTH GT 4", SEP OF PERDITA PUCK FROM EARTH GT 2", SEP OF PERDITA BELINDA FROM EARTH GT 1" EARTH SOLAR SYSTEM PLANET Uranus with Perdita near its maximum northern elongation STD=URANUS OLG OF PERDITA BETWEEN 250 290, SEP OF PERDITA ARIEL FROM EARTH GT 4", SEP OF PERDITA UMBRIEL FROM EARTH GT 4", SEP OF PERDITA TITANIA FROM EARTH GT 5", SEP OF PERDITA OBERON FROM EARTH GT 5", SEP OF PERDITA MIRANDA FROM EARTH GT 4", SEP OF PERDITA PUCK FROM EARTH GT 2", SEP OF PERDITA BELINDA FROM EARTH GT 1" EARTH SOLAR SYSTEM PLANET Uranus with Cupid near its maximum southern elongation STD=URANUS OLG OF CUPID BETWEEN 70 110, SEP OF CUPID ARIEL FROM EARTH GT 4", SEP OF CUPID UMBRIEL FROM EARTH GT 4", SEP OF CUPID TITANIA FROM EARTH GT 5", SEP OF CUPID OBERON FROM EARTH GT 5", SEP OF CUPID MIRANDA FROM EARTH GT 4", SEP OF CUPID PUCK FROM EARTH GT 2", SEP OF CUPID BELINDA FROM EARTH GT 1" EARTH SOLAR SYSTEM PLANET Uranus with Cupid near its maximum northern elongation STD=URANUS OLG OF CUPID BETWEEN 250 290, SEP OF CUPID ARIEL FROM EARTH GT 4", SEP OF CUPID UMBRIEL FROM EARTH GT 4", SEP OF CUPID TITANIA FROM EARTH GT 5", SEP OF CUPID OBERON FROM EARTH GT 5", SEP OF CUPID MIRANDA FROM EARTH GT 4", SEP OF CUPID PUCK FROM EARTH GT 2", SEP OF CUPID BELINDA FROM EARTH GT 1" EARTH WFC3/UVIS Imaging No No F606W WFC3/UVIS Imaging No No F390W WFC3/UVIS Imaging No No F467M WFC3/UVIS Imaging No No F475W WFC3/UVIS Imaging No No F621M WFC3/UVIS Imaging No No F814W WFC3/UVIS Imaging No No F845M WFC3/IR Imaging No No F105W WFC3/IR Imaging No No F125W WFC3/IR Imaging No No F160W Using ephemeris for target 12665-31-URANUS-PERDITA-SOUTH-MAB The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /Users/mark/Work/Missions/Hubble/12665 Uranus 2011/APT/OP-cache/12665-F350LP-v31.xml Uranus timed to position Perdita near its southern orbital elongation. Mab is also visible. The ring plane is oriented within 20 degrees of horizontal. (Tic-Visit :proposal-id 12665 :visit-id "31" :proposal-version -1 :trans-version "20110509" :date "02-Aug-2011 07:29:59.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 50352 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12665 :visit-id "31" :obset-id "31" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12665 :visit-id "31" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2894 :al-overhead-at-end 0 :internal-dur-at-end 94 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 Using ephemeris for target 12665-32-URANUS-PERDITA-NORTH-MAB The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /Users/mark/Work/Missions/Hubble/12665 Uranus 2011/APT/OP-cache/12665-F350LP-v32.xml Uranus timed to position Perdita near its northern orbital elongation. Mab is also visible. The ring plane is oriented within 20 degrees of horizontal. (Tic-Visit :proposal-id 12665 :visit-id "32" :proposal-version -1 :trans-version "20110509" :date "02-Aug-2011 07:41:27.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 50352 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12665 :visit-id "32" :obset-id "32" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12665 :visit-id "32" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2871 :al-overhead-at-end 0 :internal-dur-at-end 94 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /Users/mark/Work/Missions/Hubble/12665 Uranus 2011/APT/OP-cache/12665-F350LP-v33.xml Uranus timed to position Mab near its southern orbital elongation. The ring plane is oriented within 20 degrees of horizontal. (Tic-Visit :proposal-id 12665 :visit-id "33" :proposal-version -1 :trans-version "20110509" :date "02-Aug-2011 07:39:53.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 50352 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12665 :visit-id "33" :obset-id "33" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12665 :visit-id "33" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2894 :al-overhead-at-end 0 :internal-dur-at-end 94 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 Using ephemeris for target 12665-34-URANUS-MAB-NORTH The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /Users/mark/Work/Missions/Hubble/12665 Uranus 2011/APT/OP-cache/12665-F350LP-v34.xml Uranus timed to position Mab near its northern orbital elongation. The ring plane is oriented within 20 degrees of horizontal. (Tic-Visit :proposal-id 12665 :visit-id "34" :proposal-version -1 :trans-version "20110509" :date "02-Aug-2011 08:11:06.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 50352 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12665 :visit-id "34" :obset-id "34" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12665 :visit-id "34" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2864 :al-overhead-at-end 0 :internal-dur-at-end 94 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 Using ephemeris for target 12665-35-URANUS-CUPID-SOUTH-MAB The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /Users/mark/Work/Missions/Hubble/12665 Uranus 2011/APT/OP-cache/12665-F350LP-v35.xml Uranus timed to position Cupid near its southern orbital elongation. Mab is also visible. The ring plane is oriented within 20 degrees of horizontal. (Tic-Visit :proposal-id 12665 :visit-id "35" :proposal-version -1 :trans-version "20110509" :date "02-Aug-2011 07:33:59.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 50352 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12665 :visit-id "35" :obset-id "35" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12665 :visit-id "35" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2894 :al-overhead-at-end 0 :internal-dur-at-end 94 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 Using ephemeris for target 12665-36-URANUS-CUPID-NORTH-MAB The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /Users/mark/Work/Missions/Hubble/12665 Uranus 2011/APT/OP-cache/12665-F350LP-v36.xml Uranus timed to position Cupid near its northern orbital elongation. Mab is also visible. The ring plane is oriented within 20 degrees of horizontal. (Tic-Visit :proposal-id 12665 :visit-id "36" :proposal-version -1 :trans-version "20110509" :date "02-Aug-2011 07:34:46.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 50352 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12665 :visit-id "36" :obset-id "36" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12665 :visit-id "36" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2879 :al-overhead-at-end 0 :internal-dur-at-end 94 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 Using ephemeris for target 12665-41-URANUS-PERDITA-SOUTH The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /Users/mark/Work/Missions/Hubble/12665 Uranus 2011/APT/OP-cache/12665-F350LP-v41.xml Uranus timed to position Perdita near its southern orbital elongation. The ring plane is oriented within 20 degrees of horizontal. (Tic-Visit :proposal-id 12665 :visit-id "41" :proposal-version -1 :trans-version "20110509" :date "02-Aug-2011 07:35:59.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 50352 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12665 :visit-id "41" :obset-id "41" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12665 :visit-id "41" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2894 :al-overhead-at-end 0 :internal-dur-at-end 94 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 Use as an alternative to Visit 31, if Visit 31 (with additional constraints on the orbital position of Mab) is too difficult to schedule. Using ephemeris for target 12665-42-URANUS-PERDITA-NORTH The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /Users/mark/Work/Missions/Hubble/12665 Uranus 2011/APT/OP-cache/12665-F350LP-v42.xml Uranus timed to position Perdita near its northern orbital elongation. The ring plane is oriented within 20 degrees of horizontal. (Tic-Visit :proposal-id 12665 :visit-id "42" :proposal-version -1 :trans-version "20110509" :date "02-Aug-2011 07:36:46.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 50352 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12665 :visit-id "42" :obset-id "42" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12665 :visit-id "42" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2886 :al-overhead-at-end 0 :internal-dur-at-end 94 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 Use as an alternative to Visit 32, if Visit 32 (with additional constraints on the orbital postion of Mab) is too difficult to schedule. Using ephemeris for target 12665-45-URANUS-CUPID-SOUTH The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /Users/mark/Work/Missions/Hubble/12665 Uranus 2011/APT/OP-cache/12665-F350LP-v45.xml Uranus timed to position Cupid near its southern orbital elongation. The ring plane is oriented within 20 degrees of horizontal. (Tic-Visit :proposal-id 12665 :visit-id "45" :proposal-version -1 :trans-version "20110509" :date "02-Aug-2011 07:37:43.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 50352 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12665 :visit-id "45" :obset-id "45" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12665 :visit-id "45" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2894 :al-overhead-at-end 0 :internal-dur-at-end 94 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 Use as an alternative to Visit 35, if Visit 35 (with its additional constraints on the orbital position of Mab) is too difficult to schedule. Using ephemeris for target 12665-46-URANUS-CUPID-NORTH The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /Users/mark/Work/Missions/Hubble/12665 Uranus 2011/APT/OP-cache/12665-F350LP-v46.xml Uranus timed to position Cupid near its northern orbital elongation. The ring plane is oriented within 20 degrees of horizontal. (Tic-Visit :proposal-id 12665 :visit-id "46" :proposal-version -1 :trans-version "20110509" :date "02-Aug-2011 07:40:17.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 50352 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12665 :visit-id "46" :obset-id "46" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12665 :visit-id "46" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2864 :al-overhead-at-end 0 :internal-dur-at-end 94 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) true 1 0 Use as an alternative to Visit 36, if Visit 36 (with additional constraints on the orbital position of Mab) is too difficult to schedule.