README web version of /home/usg/OPS/MTS/readme_xml/readme_76081000

Principal Investigator Email Address

```
piotto@pd.astro.it
```

Estimated Total Execution Time (hours, including overheads)

```
17.0
```

General Description

This is a low resolution spectroscopic run on HB stars in the Omega Centauri
 field.
Spectroscopy is performed by FORS2 (grism=600B+22, slit=0.51'') on 233 stars
with B-V  < 0.50.
The goal is to provide new observational inputs in the attempt to understand 
the nature and the formation history of Omega Centauri by investigating the
Helium content, temperatures and gravities of its HB stars with Teff >= 10000
 K.

Waiver Requests

In order to maximize the number of useful targets, we realized 
that the best solution is obtained using 12 (twelve) MXU masks 
(still staying within the assigned 17 observing hours, including 
overheads): this in order to avoid the too crowded internal region 
of the cluster (Omega Centauri).
Because the program requests the observation of the largest number
of targets (for statistical reasons) we request to be allowed to
exceed the limit of the ten masks.

Critical Observing Condition Constraints

We need at least a variable sky transparency with thin cirrus. 
We need seeing <= 0.80'' to reach the desidered S/N.
We need airmass <= 1.60.
Observation can be performed with any Moon condition
and with a Moon angular distance >= 60 degrees.

Time-Critical Aspects

```
No Time-critical Aspects
```

Special Execution Requirements

---(Empty)---

Special Calibration Information

---(Empty)---

ToO Information

---(Empty)---

ToO Activators List

---(Empty)---

Is this a Pre-imaging run ?

```
false
```

Pre-imaging Requirements

---(Empty)---

Source(s) of Pre-imaging

```
WFI
```

Pre-imaging sources not listed above

---(Empty)---

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 ?

```
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
```

If you have prepared your finding charts with tools other than FIMS, do they comply with the specifications on the FORS2 Phase 2 web page ?

```
N/A
```

Last creation of page: Tue Oct 6 15:40:11 2009
If you have comments, please contact usd-help@eso.org