----- Attempting Submission 1 (Fri Apr 27 21:20:30 GMT 2007) ----- Previously Submitted as Phase 1 ACS Proposal 418 Assigned ID: 1072 ----- Attempting Submission 1 (Tue Feb 06 09:46:00 CST 2007) ----- Phase I Proposal 1072 (Cycle16_GO_Replace) successfully submitted. Investigating Near-Equinox Atmospheric Change on Uranus Uranus is approaching its 7 December 2007 equinox, when we will be able to observe the entire northern hemisphere for the first time with modern cameras. The large seasonal phase shift expected from its long radiative time constant implies that it should now exhibit nearly maximal hemispheric contrast, and should be in the process of reversing. Many changes already observed, such as the development of the first visible-wavelength dark spot, discovered in Cycle 15, and the fading of the south polar cap may be indicative of the expected reversal. We propose a detailed characterization of Uranus' current seasonal response with a 7-orbit program consisting of 1 orbit of NICMOS imaging of cloud bands and 6 orbits of WFPC2 imaging using both broadband and narrow-band filters capable of tracking dark and bright discrete cloud features. Filters between 0.467 and 1.87 microns will provide vertical sensing depths scanning through the pressure range where the putative methane and deeper H2S clouds might plausibly exist and provide strong constraints on their contributions and parent gas mixing ratios. These observations have unique combinations of spectral range and resolution with needed temporal and spatial resolution not available from groundbased observations. Only HST is capable of investigating the Uranus dark spot.
Spatial and Temporal Sampling: The 7-orbit observing program is designed to obtain complete longitudinal coverage for the WFPC2 filters, but only center-to-limb coverage for the NICMOS filters. Obtaining complete longitude coverage up to 50 deg N requires at least four orbits with approximately equal longitude spacing. Orbits 1, 4, 6, and 19 provide that coverage for the WFPC2 imaging program. Two additional WFPC2 orbits (16 and 21) provide important temporal coverage that, with other images, allows dynamical measurements of latitudinal and longitudinal motions over the 15-30 hour time domain that is inaccessible from the ground. Because of SAA interference, this sampling has to be obtained as indicated. The coverage varies with latitude because of view angle differences and differences in planetary rotation rates (the longitude scale is defined by the local rotation period at each latitude). The proposed program provides barely adequate longitudinal coverage at 50 deg latitude, and good coverage at more equatorial latitudes, with enough overlap to potentially permit useful wind speed determination and information about cloud evolution. Dynamical information on longer time scales will be obtained from analysis combining any July 2007 groundbased observations that are acquired during our awarded time on the Keck 2, and from images acquired in any SNAP programs that are selected. Our coverage objectives for the NICMOS images are designed to obtain center-to-limb information for deciphering the vertical structure of latitude bands. Filters and Exposures: The F547M, F658N, and F791W are very similar to the ACS filters that revealed the dark spot we discovered in Cycle 15, which displayed maximum contrast at 658 nm. The F467M filter is one that provided the highest contrast for dark spots on Neptune. The F791W and F850LP filters provide high contrast for bright features. The NICMOS filters are aimed at improving our models for the vertical structure of cloud bands. The F187N filter is at a local minimum in H2 Collision-Induced Absorption (CIA), which cannot be used from the ground because it is effectively blocked by water vapor absorption in the earth's atmosphere. The other NICMOS filters sample varying degrees of methane absorption, covering a wide range of penetration depths to probe the vertical structure of cloud bands. The F108N, which probes to the 4-9 bar region in a clear atmosphere, reveals a southern hemisphere cloud band not seen by the F095N filter, which can see down to the 2-4 bar region. SOLAR SYSTEM 12 false 0.0 false false false false false false SUPPORTED SOLAR SYSTEM PLANET Planet Uranus STD=URANUS NOT TRANSIT OF ARIEL ACROSS URANUS FROM EARTH, NOT TRANSIT OF UMBRIEL ACROSS URANUS FROM EARTH, NOT TRANSIT OF TITANIA ACROSS URANUS FROM EARTH, NOT TRANSIT OF OBERON ACROSS URANUS FROM EARTH, NOT TRANSIT OF MIRANDA ACROSS URANUS FROM EARTH WFPC2 Imaging No F467M WFPC2 Imaging No F547M WFPC2 Imaging No FQCH4N15 WFPC2 Imaging No F658N WFPC2 Imaging No F673N WFPC2 Imaging No F791W WFPC2 Imaging No F850LP WFPC2 Imaging No FQCH4P15 NIC1 Imaging No No F095N NIC1 Imaging No No F097N NIC1 Imaging No No F108N NIC1 Imaging No No F160W NIC1 Imaging No No F170M NIC2 Imaging No No F187N CELESTIAL BACKGROUND 8 LINE false true 2 254.800003 LINE 1 false /Users/fry/Cycle16_Ura_GO/OP-cache/Cycle16_GO_PhaseII-v01.xml (Tic-Visit :proposal-id 11118 :visit-id "01" :proposal-version -1 :trans-version "20070325" :date "24-Apr-2007 15:29:39.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "26" :si-bright-earth-limb-angle 20.0 :data-volume 403344 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11118 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11118 :visit-id "01" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2709 :al-overhead-at-end 180 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) true 1 0 /private/tmp/OPVisit40459.xml /Users/fry/Cycle16_Ura_GO/OP-cache/Cycle16_GO_PhaseII-v02.xml (Tic-Visit :proposal-id 11118 :visit-id "02" :proposal-version -1 :trans-version "20070325" :date "24-Apr-2007 15:29:56.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "23" :si-bright-earth-limb-angle 20.0 :data-volume 110432 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11118 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11118 :visit-id "02" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2722 :al-overhead-at-end 0 :internal-dur-at-end 60 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) true 1 0 /private/tmp/OPVisit40460.xml /Users/fry/Cycle16_Ura_GO/OP-cache/Cycle16_GO_PhaseII-v03.xml (Tic-Visit :proposal-id 11118 :visit-id "03" :proposal-version -1 :trans-version "20070325" :date "24-Apr-2007 15:30:14.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "26" :si-bright-earth-limb-angle 20.0 :data-volume 403344 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11118 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11118 :visit-id "03" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2709 :al-overhead-at-end 180 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) true 1 0 /private/tmp/OPVisit40461.xml /Users/fry/Cycle16_Ura_GO/OP-cache/Cycle16_GO_PhaseII-v04.xml (Tic-Visit :proposal-id 11118 :visit-id "04" :proposal-version -1 :trans-version "20070325" :date "24-Apr-2007 15:30:36.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "26" :si-bright-earth-limb-angle 20.0 :data-volume 403344 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11118 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11118 :visit-id "04" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2709 :al-overhead-at-end 180 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) true 1 0 /private/tmp/OPVisit40462.xml /Users/fry/Cycle16_Ura_GO/OP-cache/Cycle16_GO_PhaseII-v05.xml (Tic-Visit :proposal-id 11118 :visit-id "05" :proposal-version -1 :trans-version "20070325" :date "24-Apr-2007 15:30:56.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "26" :si-bright-earth-limb-angle 20.0 :data-volume 403344 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11118 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11118 :visit-id "05" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2709 :al-overhead-at-end 180 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) true 1 0 /private/tmp/OPVisit40463.xml /Users/fry/Cycle16_Ura_GO/OP-cache/Cycle16_GO_PhaseII-v06.xml (Tic-Visit :proposal-id 11118 :visit-id "06" :proposal-version -1 :trans-version "20070325" :date "24-Apr-2007 15:31:17.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "26" :si-bright-earth-limb-angle 20.0 :data-volume 403344 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11118 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11118 :visit-id "06" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2709 :al-overhead-at-end 180 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) true 1 0 /private/tmp/OPVisit40464.xml /Users/fry/Cycle16_Ura_GO/OP-cache/Cycle16_GO_PhaseII-v07.xml (Tic-Visit :proposal-id 11118 :visit-id "07" :proposal-version -1 :trans-version "20070325" :date "24-Apr-2007 15:31:40.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "26" :si-bright-earth-limb-angle 20.0 :data-volume 403344 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11118 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11118 :visit-id "07" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2709 :al-overhead-at-end 180 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3132 :pcs-gap 0 ) true 1 0 /private/tmp/OPVisit40465.xml