FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser Visits (05, 08) have a relative orient link whose targets (14204-05-NGC-1866, 14204-08-NGC-1755-SF) are separated by more than 1 degree. This may make it impossible to get guide stars. Visits (05, 06) have a relative orient link whose targets (14204-05-NGC-1866, 14204-06-NGC-1755-SF) are separated by more than 1 degree. This may make it impossible to get guide stars. FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser Visits (05, 08) have a relative orient link whose targets (14204-05-NGC-1866, 14204-08-NGC-1755-SF) are separated by more than 1 degree. This may make it impossible to get guide stars. Visits (05, 06) have a relative orient link whose targets (14204-05-NGC-1866, 14204-06-NGC-1755-SF) are separated by more than 1 degree. This may make it impossible to get guide stars. FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser Visits (05, 08) have a relative orient link whose targets (14204-05-NGC-1866, 14204-08-NGC-1755-SF) are separated by more than 1 degree. This may make it impossible to get guide stars. Visits (05, 06) have a relative orient link whose targets (14204-05-NGC-1866, 14204-06-NGC-1755-SF) are separated by more than 1 degree. This may make it impossible to get guide stars. FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser Visits (05, 08) have a relative orient link whose targets (14204-05-NGC-1866, 14204-08-NGC-1755-SF) are separated by more than 1 degree. This may make it impossible to get guide stars. Visits (05, 06) have a relative orient link whose targets (14204-05-NGC-1866, 14204-06-NGC-1755-SF) are separated by more than 1 degree. This may make it impossible to get guide stars. FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too low for this exposure or a short subexposure. See extended explanation in the diagnostic browser FLASH level may be too high for this exposure or a long subexposure. See extended explanation in the diagnostic browser 0 ----- Attempting Submission 1 (Fri Jul 10 10:36:26 GMT 2015) ----- post flashing is ok Multiple stellar populations in two young Large Magellanic Cloud clusters: NGC1755 and NGC1866 Multiple sequences are present in the CMD of nearly all the old Galactic globular clusters (GCs) and correspond to multiple populations with different helium and light-elements abundance. Multiple populations are not a peculiarity of old clusters, indeed extended main-sequence turn off (eMSTO) have been detected in most of the analyzed intermediate-age clusters in the Magellanic Clouds with age of ~1-2 Gyr. The conditions under which GCs experience the formation of multiple populations remain controversial. An unique angle on this problem can be provided by the young star clusters but the many investigations from different techniques reported no evidence for multiple populations in clusters younger than $\sim$1\,Gyr to date. Surprisingly, we have recently discovered the first case of a $\sim$300-Myr-old cluster with split main sequence and eMSTO. This finding has been possible thanks to the use of UVIS photometry in the appropriate F336W and F814W filters. To properly constraint the multipopulation phenomenon in young clusters, we propose deep UVIS imaging of the $\sim$150 Myrs-old LMC star clusters NGC1866 and NGC1755 which, according to the analysis of archive {\it HST} data are excellent candidates to host multiple populations. The proposed observations will allow us to understand if multiple populations are present in very-young LMC clusters. We will be able to measure the age difference between the populations with errors of less than 20\,Myr and detect very small He and CNO differences. NGC1755 and NGC1866 have different masses, therefore the presence or the absence of multiple sequences in their CMDs will give information on the minimum mass required for a cluster to host multiple populations thus providing fundamental clues on the formation mechanism. This is a proposal aimed at obtaining high accuracy photometry of the MC clusters NGC 1755 and NGC1866 in the WFC3/UVIS/F336W and WFC3/UVIS/F814W bands. RESOLVED STELLAR POPULATIONS 12 false true false false 0.0 0.0 SUPPORTED STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 STELLAR CLUSTER GLOBULAR CLUSTER This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 WFC3/UVIS Imaging No No F336W WFC3/UVIS Imaging No No F814W ACS/WFC Imaging No No F475W ACS/WFC Imaging No No F814W The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. NGC-1866 - part 1 (Tic-Visit :proposal-id 14204 :visit-id "01" :proposal-version -1 :trans-version "20150609" :date "10-Jul-2015 12:34:29.0" :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 2291888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14204 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14204 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2698 :al-overhead-at-end 122 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3031 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. NGC-1866 - part 2 (Tic-Visit :proposal-id 14204 :visit-id "02" :proposal-version -1 :trans-version "20150609" :date "10-Jul-2015 12:32:42.0" :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 2291888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14204 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14204 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2698 :al-overhead-at-end 122 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3031 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. NGC-1866 - part 3 (Tic-Visit :proposal-id 14204 :visit-id "03" :proposal-version -1 :trans-version "20150609" :date "10-Jul-2015 12:32:44.0" :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 2291888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14204 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14204 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2698 :al-overhead-at-end 122 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3031 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. NGC-1866 - part 4 (Tic-Visit :proposal-id 14204 :visit-id "04" :proposal-version -1 :trans-version "20150609" :date "10-Jul-2015 12:32:46.0" :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 2291888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14204 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14204 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2698 :al-overhead-at-end 122 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3031 :pcs-gap 0 ) true 1 0 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. NGC-1755 - part 2 (Tic-Visit :proposal-id 14204 :visit-id "05" :proposal-version -1 :trans-version "20150609" :date "10-Jul-2015 12:33:31.0" :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 2291888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14204 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14204 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2698 :al-overhead-at-end 122 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3031 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. NGC-1755 - part 4 (Tic-Visit :proposal-id 14204 :visit-id "06" :proposal-version -1 :trans-version "20150609" :date "10-Jul-2015 12:33:32.0" :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 2291888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14204 :visit-id "06" :obset-id "06" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14204 :visit-id "06" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2698 :al-overhead-at-end 122 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3031 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. NGC-1755 - part 3 (Tic-Visit :proposal-id 14204 :visit-id "07" :proposal-version -1 :trans-version "20150609" :date "10-Jul-2015 12:33:35.0" :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 2291888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14204 :visit-id "07" :obset-id "07" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14204 :visit-id "07" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2698 :al-overhead-at-end 122 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3031 :pcs-gap 0 ) false 1 0 The scheduling data was generated by CASM 23.2. CASM was run in Phase II mode. NGC-1755 - part a (Tic-Visit :proposal-id 14204 :visit-id "08" :proposal-version -1 :trans-version "20150609" :date "10-Jul-2015 12:33:37.0" :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 2291888 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14204 :visit-id "08" :obset-id "08" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14204 :visit-id "08" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2698 :al-overhead-at-end 122 :internal-dur-at-end 1015 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3031 :pcs-gap 0 ) false 1 0