Made 2 copies of visit 01, one with the orient constraint and one without. Only one will execute. ----- Attempting Submission 1 (Wed May 02 16:46:48 GMT 2007) ----- ----- Attempting Submission 2 (Fri Apr 25 14:32:12 GMT 2008) ----- Note that only one orbit need be charged to this program if proposal #14, with the same PI, is approved. Assigned ID: 15 ----- Attempting Submission 3 (Wed Jan 17 12:02:55 CST 2007) ----- Determination of Angular Expansion Velocities in the Ring Nebula The Ring Nebula (NGC 6720) represents an important stage in the evolution of planetary nebulae, being large enough that it has entered the post fast-wind stage yet has not reached the late ballistic phase of objects like the Helix Nebula. Understanding this nebula well presents the opportunity to determine how nebulae transition from their creation phase into the form they have as their material enters the interstellar medium. A recent study based on ground-based spectroscopy has derived a new and accurate model for the Ring Nebula. A well defined characteristic of this model is that it predicts a tangential velocity of 20 km/s whereas the application of its quite uncertain trigonometric parallax distance of 700 (+450/-200) pc with the angular expansion velocity determined from HST observations with a 2 year time base indicates a tangential velocity of 69 (+45/-20) km/s. This disagreement indicates that either the distance is even more uncertain than thought or that the earlier angular velocity is incorrect. We propose to make a new set of observations of the Ring Nebula in the diagnostic emission line filters F469N (HeII), F502N ([OIII]), and F658N ([NII]) that will produce much more accurate angular velocities than the previous study by having a time base of 8.8 years and imaging the nebula entirely within a single CCD of the WFPC2. The primary result from this study will be an accurate distance to this important nebula and from this to be able to use this object to refine our picture of how planetary nebulae evolve during middle-age.
We will make WFPC2 observations of the Ring Nebula (NGC 6720) in the F502N and F658N filters for the purpose of determining the tangential expansion velocities within this nebula. ISM AND CIRCUMSTELLAR MATTER 12 false 0.0 0.0 false false false false false SUPPORTED ISM EMISSION LINE NEBULA PLANETARY NEBULA J2000 18 53 35.5400 +33 01 48.00 J2000 WFPC2 Imaging No F502N WFPC2 Imaging No F658N WFPC2 Imaging No F469N This visit uses the same target and orientation as the PI's Visit 1 of program 11231 and optimally would be executed immediately after Visit 1 of program 11231. If that is done, then the exposure times of this program (11232) should be increased to take advantage of not having to do a new guidestar acquisition. (Tic-Visit :proposal-id 11232 :visit-id "01" :proposal-version -1 :trans-version "20070325" :date "02-May-2007 11:31:16.0" :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 268896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11232 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11232 :visit-id "01" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2700 :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 3152 :pcs-gap 0 ) true 1 0 This visit uses the same target and orientation as the PI's Visit 1 of program 11231 and optimally would be executed immediately after Visit 1 of program 11231. If that is done, then the exposure times of this program (11232) should be increased to take advantage of not having to do a new guidestar acquisition. Repeat of visit 1 (Tic-Visit :proposal-id 11232 :visit-id "01" :proposal-version -1 :trans-version "20070325" :date "02-May-2007 11:31:16.0" :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 268896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11232 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11232 :visit-id "01" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2700 :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 3152 :pcs-gap 0 ) false 1 0 This visit uses the same target and orientation as the PI's Visit 1 of program 11231 and optimally would be executed immediately after Visit 1 of program 11231. If that is done, then the exposure times of this program (11232) should be increased to take advantage of not having to do a new guidestar acquisition. Repeat of visit 1 - no orient (Tic-Visit :proposal-id 11232 :visit-id "01" :proposal-version -1 :trans-version "20070325" :date "02-May-2007 11:31:16.0" :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 268896 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11232 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11232 :visit-id "01" :orbit-number 1 :pcs-time 355 :si-vis-utilization 2700 :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 3152 :pcs-gap 0 ) false 1 0