Principal Investigator Email Address
valverde@iaa.es
Estimated Total Execution Time (hours, including overheads)
10h 52min 13s for the whole project but 5h 50min 23s for the remaining OBs
General Description
This campaign consists of 11 hours of service mode to study the atmosphere of Titan in the infrared, specifically to detect N2O emission lines and to derive CO and temperature from CO emission lines. Observations are performed in 2 different spectral ranges around 4600 nm, one for N2O and the other for CO. Observations of a standard star are also proposed for telluric correction and precise calibration. There are 22 OB, 11 for the target and 11 for the calibration star, ideally to be performed in pairs (Titan,Star). Each pair lasts 1 hour approx. The OB names are indicative of the pairs (N2O - 1, N2O - 2, ... CO - 1, CO - 2, ...). First priority is given to the N2O observations; second priority to the CO observations. The original observing period was 31-Dec-2007 to 21-Jan-2008, and the campaign was partially completed. This readme file refers to the remaining 12 OBs, for which 3 time periods are proposed here, between 4-June-2009 and 24-Jun-2009. The OB to be completed are 6 pairs of 2, target + telluric star, one pair devoted to N2O detection and 5 pairs devoted to measuring CO abundances, and they correspond to the following numbers: first priority to 294239 and 234245 (for N2O detection), and second priority to the CO observations, OBs 294229-234233 and 294224-294228. Based on Titan's Doppler shift, maximum airmass and Moon proximity, the following periods should be avoided: before June 4th, and beyond June 24th. As explained in the Time-Critical Aspects, the period beyond June 24 fulfills the Critical Observing Conditions, but the available time per night is shorter than 1 hour. The standard star proposed is theta LEO (HP57632), one of many possible telluric stars. Any other A- or B-type standard star brighter than Vmag=4.5 and close enough to Titan should be valid too, for example beta LEO (HP57632). One ephemerides file (for period 8-April to Sept 30, at 00:00 am), is attached to each science OB, and is identical to all them. The differential tracking rate stated in the Titan OBs is approximate; and please note that it varies with date. Dr. Hans Ulrich Kaufl, co-I of the present project, is our contact person for scheduling the observations. Please you can email him (hukaufl@eso.org) for help on this matter when you need it.
Waiver Requests
No Finding Charts are enclosed for our target, Titan. This was solicited by a waiver request, submitted on July 27th, granted on July 31st 2007.
Critical Observing Condition Constraints
There are 3 conditions for us for observing Titan, and should be taken into account if the observations are performed at other dates/times : (1) the Doppler shift is larger than 20 km/s; (2) airmass smaller than 1.6; and (3) the moon-observ-target angle is 60 degree or larger. A revision of the periods of time for P83 has been performed and 3 periods are specified, from June 4 to June 24, listed in the Time Intervals of each OB. Notice that our preference is to perform 1 calibration star's OB inmediately after each target's OB, and that such a pair of OBs requires 1 hour approx. There are 6 pairs of OBs to be completed. Notice also that the available time per night is short, see the Time-Critical Aspects for details.
Time-Critical Aspects
As stated in the Critical Observing Cond., the optimum periods proposed are based on three criteria: a Doppler shift of Titan larger than 20 km/s, an airmass smaller than 1.6, and an angular distance to the Moon larger than 60 degree. Consequently, 3 periods of time are proposed in the Time Intervals of each OB. They span from 4-June to 24-June with only a few hours per night. In total, the available time during June is about 20 hours, ad detailed below. The execution time of the 12 OBs is 5h 50min 23s. Notice that the length of the observing time per night is shorter the later the date within June. For the period 1, there are 2 available hours, from 23.30 to 1.30. For period 2, only 1.30 hours, from 23.30 to 1.00 For period 3, there is only 1 hour of optimum conditions, from 23:30 to 00:30. Notice also that, as stated in the Special Execution Req., a pair of observations target+telluric star lasts for about 1 hour. The observing conditions are still fulfilled beyond June 24th but for periods of time shorter than 1 hour.
Special Execution Requirements
We propose to perform the observations in pairs of observation blocks, alternating target and calibration star. Ideally each of the pairs should be performed contiguously, and most importantly, at the same airmass. Within each pair, the first OB is devoted to the target (Titan), and is about 46 min long, and the other is devoted to a telluric standard star, and is about 13 min long; therefore each pair of OBs lasts for about 1 hour. The are 12 OBs with a total execution time of 5h 50min 23s.
Special Calibration Information
The selected standard star, theta LEO (HP 54879, spectral type A2V), is one among many possible telluric stars. With an Rmag=3.3 the estimated SNR at 4563 nm is larger than 50. Anyother A- or B-type star brighter than Vmag=4.5 and close enough to Titan should be valid too. One such example is beta LEO (HP 57632, spectral type A3Vvar, Rmag=2.3). It is important that the airmass of the standard star is similar to that of our target (Titan).
ToO Information
ToO Activators List
Do the README file and the instrument comments of the telluric stars OBs include the required S/N/pixel of the spectrum of the telluric star, its spectral type and allowed spectral range?
Do any OBs include wavelength or flatfield calibrations?
If you are observing Moving Targets, have you attached suitable ephemeris files to your OBs?
If the slit viewer guide star is different from the target, are the RA and DEC offsets accurate to within 0.05 arcsec and do they take into account the relative proper motion between the two objects?
N/A
If you have preferences which OBs should be executed first for objects at similar RA, did you make use of the User Priority field in the OBs?
N/A