README web version of /home/usg/OPS/MTS/readme_xml/readme_77014500

Principal Investigator Email Address

```
pascale.jablonka@obs.unige.ch
```

Estimated Total Execution Time (hours, including overheads)

```
20h
```

General Description

We are trying to get extremely deep photometry of the halo of NGC 3957
To reach this goal, we are using 2 CCDs of VIMOS. When the galaxy is put on one
 CCD chip, the second
CCD chip is used to get the sky. Therefore we switch the galaxy between 2 positions,
 which correspond to the 2 CCDS, called POSS1 and POSS2. Each POSS1 must have a POSS2
 executed, right after or before it.
This means that at least 2 OBs must always be executed in a row when our program
 is on the sky.

At each POSS1 or POSS2 (telescope preset), we are dithering the short exposures

Waiver Requests

1. Rotator = 0 degrees  Approved : 06/02/06
2. Offset box = 60 x 60 arcsec Approved : 24/02/06

Critical Observing Condition Constraints

If possible + - 2 hours from meridian. In any case, far from twilight.

Time-Critical Aspects

```
None
```

Special Execution Requirements

Please always execute one POSS1 and one POSS2 OBS2 consecutively (whatever
 the order,
POSS1 and then POSS2 or POSS2 and then POSS1)
This is of MAJOR importance: one OB serves as SKY for the other one.

Special Calibration Information

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ToO Information

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ToO Activators List

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Is this a Pre-imaging run ?

```
false
```

Pre-imaging Requirements

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Do all your OBs comply with the instrument-specific requirements listed on the instrument-specific Phase 2 web page ?

```
N/A
```

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 ?

```
N/A
```

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 ?

```
N/A
```

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 specify suitable guide stars for all your OBs using Guidecam ?

Did you check that the chosen guide stars are suitable for all the offset positions and that they do not produce unacceptable vignetting of the field of view ?

Last creation of page: Tue Oct 6 15:40:12 2009
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