Principal Investigator Email Address
sekataja@utu.fi
Estimated Total Execution Time (hours, including overheads)
8:00 hrs
General Description
A short summary of observing run 077.D-0699 (A) The aim of this run is to identify new Cataclysmic Variables (CVs) in old open clusters and to study and constrain by this way stellar and binary evolution. The lack of reliable estimates for the ages of CVs is very problematic when their evolution is studied. Recent CV-evolution models are totally unable to explain the observed orbital period distribution as well as the observed minimum in orbital periods in Cataclysmic Variables. This survey will allow us for the first time to study a small sample of CVs with well known ages, distances and chemical abundances and thus old star clusters provide us with a totally new approach for studying these open questions.
Waiver Requests
No Waiver Request was submitted
Critical Observing Condition Constraints
We have aplied GRAY time in the application (said in the BOX 9 in application). We have also typed wrong by mistake in BOX 3 d in Moon, but that should had been g (=gray). We have keep here the seeing constrain as 1.0 arcsec as it was already in proposal, and also CLR for the Sky. The proposed Moon light illumination we have set here in Phase 2 as 0.4 and Moon Angular distance 0.4 (betweemn 0...1).
Time-Critical Aspects
We have here three separate OBs for each three targets, and it would be very desirable if OBs related to each target, for example, such like Coll261_sc_1, Coll261_sc_2 and Coll261_sc_3 could be observed in three different nights. And similar way OBs for NGC 2506 and NGC2658 could be observed in three different nights also, if possible. So, by oserving each targets three OBs in three different nights, no matter how many nights separated, (naturally OBs of different targets observations in the same night are ok), improves highly our possibilities to see if any of stars in the cluster is a variable star, and as CVs have typically variabilty time scales of 10 hrs or so, by observing each targets all three OBs in the line (within less than 3 hrs) would mean that we will not probably notice if some stars are variable or not.
Special Execution Requirements
We originaly applied in our aplication 2 observing nights, i.e. 16 hrs in total to cover the 4 targets in our sample down to B=23.0, R=23.0 and Halpha=23.0. Now, as we have been granted only 8 hrs, we have been forced to "fine-tune" our original observing-plan slightly, to maxime the best scientific output. This is done by observing only three targets, instead of four, in that 8 hours, ensuring enough datapoints (more than 10 datapoints, well separated, for variability studies) and enough deep imaging (up to 23. mag) for the most important targets. The theree targets chosen from four original targets are NGC 25056 (very crowded field), Collinder 261 (the oldest!) and NGC2658 (which is in the some direction on the sky as NGC 2506). The corresponding exposure times for the B and R filters will be 110 and 270 seconds according to the WFI ETC (Version 3.0.4). For Halpha we have also used the ETC to determine the exposure time which is needed for the V-filter and then looked it up in a table WFI manual, which gives the integration time factors with respect to the V-filter. As to the V-filter integration, a time of 197 seconds is needed for S/N=10 for a 23rd magnitude object, and thus we will need 3700 sec. exp. time in total in Halpha. We have also included V-filter observations in our Phase 2 strategy, as we will not have enough time to do any calibrations such as we planned to do within 16 hrs (about one hour in total). By including a V-band observations also for these open cluster fields, we will make the use of the data more convenient for us in calibrations, which will be done by using existing WFI and ESO 2.2 m calibrations and zero point corrections etc. Also, there are very many B- and V-band calibrations already done for many stars in these clusters, but almost none for R-band, and thus differential photometry will be possible. A second OB for all three targets contains few slightly shorter exposures, where 23. mag limit with S/N=10 in not quite achieved, instead 22.7 or so is more likely, but this choise is made to give us few more datapoints, in B, V, and R. The Finding Charts for 3 target fields are from DSS by using recommend CADC Digitized Sky Survey Interface, and the Filter Bj is used in those Schmidt Survey Plates (Bj=IIIaJ+GG395), corresponding closely B-band. We have also choosed not to dither any images as we are interesting in variability of stars here, and their colours and magnitudes and dihrering patterns, i.e. moving telescope a slightly from exposure to exposure would make our data-analysis more complicated than what it will be without any dithering (which is not needed here).
Special Calibration Information
Nothing, as we will use the existing WFI zero points corrections and also previous calibrations for the stars in these clusters. Within granted 8 hrs and taken into account very tight schedule of our program,it is not possible to perform correct calibrations (by using Landolts, for example) for 2.2 and WFI in that time.
ToO Information
ToO Activators List
Is this a Pre-imaging run ?
false
Pre-imaging Requirements
Source(s) of Pre-imaging
Pre-imaging sources not listed above
Do all your OBs comply with the instrument-specific requirements listed on the instrument-specific Phase 2 web page ?
If this is a pre-imaging run, did you select PRE-IMAGING for the Observing Category for each Observing Template ?
N/A
Do all your finding charts comply with both the general and instrument-specific Phase 2 Web Pages ?
If you submitted OBs for standard stars, did you specify the magnitude and spectral type of all standard stars in the OBs ?
N/A
Have you included OBs for any calibrations that you need but which are not part of the Calibration Plan ?
If you are observing Moving Targets, have you attached suitable ephemeris files to your OBs?
N/A
If you have preferences which OBs should be executed first, did you make use of the User Priority field in the OBs ?
If this is a run that requires coordinated observations with other facilities, did you give proper instructions in the Time-Critical Aspects Section ?
N/A
Did you set 'New Preset' flag in all acquisition templates to 'True'?
Have all your submitted OBs the same filter for the acquisition template and for the first science template?
Did you combine calibration templates with science templates for any OB?
Did you combine imaging and spectroscopic templates for any OB?
Did you submit any Focus template?