From spencer Fri Feb 25 12:02:58 1994 From spencer Fri Feb 25 12:02:58 1994 Return-Path: Date: Fri, 25 Feb 94 12:02:23 MST From: spencer (John R. Spencer) To: spencer@sunkng Subject: HST Support Details Content-Length: 4530 X-Lines: 215 Status: RO Greetings: Thanks to all those who offered to help with visible photometry or infrared radiometry in support of the March Io observations with the Hubble Space Telescope! Additional support observations are welcome, too. Here are some firmer details: HST OBSERVATIONS --------------------------------------------- Illumi- Longi Wave UT UT nation tude lengths Date Time Status --------------------------------------------- Sunlit 230 All 3/5 15:09 Firm Eclipsed 342 10200 3/6 04:21 Firm Sunlit 054 3440 3/8 07:14 Firm Sunlit 302 All 3/9 12:28 Firm Sunlit 041 All 3/13 13:03 Firm Sunlit 151 3440 3/14 02:08 Tentative Sunlit 206 3440 3/14 08:28 Tentative Sunlit 121 All 3/19 05:51 Tentative --------------------------------------------- Wavelengths in Angstroms. "All" wavelengths means 3340, 4090, 5624, 7829, and 10200 Angstroms, in succession. Below are the UT dates and times from now till the end of March when Io will be at the same orbital longitude as during the HST observations. It will be very useful to have good absolute photometry at these longitudes, at or near the appropriate wavelengths for each longitude, for absolute calibration of the HST images. Io rotates only 9 degrees per hour so observations within an hour or so of the stated time will be useful, but the closer the better. "I" filter or 1 micron photometry is particularly important as both Io's reflectance and the HST calibration are less well known at the longer wavelengths. It's best to observe within a week or two of the HST observations, so that corrections due to varying solar phase are minimised. Be warned that Io is 5th magnitude in the visible and may be too bright for many photometry systems! The "Eclipsed" times are the times when Io enters Jupiter eclipse, taken from the almanac and good to a couple of minutes. Io is visible in eclipse for about an hour after these times, and infrared photometry during eclipse (at 1.7 microns or longer) will be very useful for interpreting the HST eclipse observations. TIMES FOR GIVEN IO LONGITUDE ----------------------------------------------------------------------- Longitude 230 Eclipsed 054 302 041 151 Required Wavelengths All >1.7 micron 3440 A All All 3440 A ----------------------------------------------------------------------- 2/26 13:22 2/27 02:25 2/27 11:00 2/26 21:47 2/25 15:02 2/26 04:07 2/28 07:49 2/28 20:54 3/ 1 05:27 2/28 16:14 2/27 09:29 2/27 22:34 3/ 2 02:16 3/ 2 15:22 3/ 2 23:54 3/ 2 10:41 3/ 1 03:56 3/ 1 17:01 3/ 3 20:42 3/ 4 09:50 3/ 4 18:21 3/ 4 05:08 3/ 2 22:23 3/ 3 11:28 3/ 5 15:09 3/ 6 04:18 3/ 6 12:47 3/ 5 23:34 3/ 4 16:49 3/ 5 05:54 3/ 7 09:36 3/ 7 22:47 3/ 8 07:14 3/ 7 18:01 3/ 6 11:16 3/ 7 00:21 3/ 9 04:03 3/ 9 17:15 3/10 01:41 3/ 9 12:28 3/ 8 05:43 3/ 8 18:48 3/10 22:29 3/11 11:43 3/11 20:08 3/11 06:55 3/10 00:10 3/10 13:15 3/12 16:56 3/13 06:11 3/13 14:34 3/13 01:21 3/11 18:36 3/12 07:41 3/14 11:23 3/15 00:40 3/15 09:01 3/14 19:48 3/13 13:03 3/14 02:08 3/16 05:50 3/16 19:08 3/17 03:28 3/16 14:15 3/15 07:30 3/15 20:35 3/18 00:16 3/18 13:36 3/18 21:55 3/18 08:42 3/17 01:57 3/17 15:02 3/19 18:43 3/20 08:04 3/20 16:21 3/20 03:08 3/18 20:23 3/19 09:28 3/21 13:10 3/22 02:33 3/22 10:48 3/21 21:35 3/20 14:50 3/21 03:55 3/23 07:37 3/23 21:01 3/24 05:15 3/23 16:02 3/22 09:17 3/22 22:22 3/25 02:03 3/25 15:29 3/25 23:42 3/25 10:29 3/24 03:44 3/24 16:49 3/26 20:30 3/27 09:58 3/27 18:08 3/27 04:55 3/25 22:10 3/26 11:15 3/28 14:57 3/29 04:26 3/29 12:35 3/28 23:22 3/27 16:37 3/28 05:42 ----------------------------------------------------------------------- ----------------------- Longitude 206 121 Required Wavelengths 3440 A All ----------------------- 2/26 10:27 2/26 00:30 2/28 04:54 2/27 18:57 3/ 1 23:21 3/ 1 13:24 3/ 3 17:48 3/ 3 07:50 3/ 5 12:14 3/ 5 02:17 3/ 7 06:41 3/ 6 20:44 3/ 9 01:08 3/ 8 15:11 3/10 19:35 3/10 09:37 3/12 14:01 3/12 04:04 3/14 08:28 3/13 22:31 3/16 02:55 3/15 16:58 3/17 21:22 3/17 11:24 3/19 15:48 3/19 05:51 3/21 10:15 3/21 00:18 3/23 04:42 3/22 18:45 3/24 23:09 3/24 13:11 3/26 17:35 3/26 07:38 3/28 12:02 3/28 02:05 -----------------------