VMMPS: The VIMOS Mask Preparation Software

What is VMMPS?

The VIMOS Mask Preparation Software (VMMPS) is a SkyCat plugin to specify the VIMOS instrumental setup for Multi-Object Spectroscopy (MOS) during Phase 2 Proposal Preparation. VMMPS creates and manages the instrumental setup by means of files containing the Aperture Definition in Pixels (ADP) of the MOS slitlets. The ADP files need to be loaded into the P2PP tool to become part of an Observation Block (OB). For further information, please refer to the VMMPS Tutorial in Chapter 6 of the VIMOS User Manual.

Warning concerning the HR_blue grism: with the HR_blue grism please only place slits in the lower portion of the CCD (y<1400pix) in order to ensure that at least 10 arc lines fall on the detector. Neglecting to do so will result in a significant degradation of the wavelength calibration and in the failure of the automatic pipeline.

Important Note concerning Releases

Since period 90: VMMPS has been updated to make optimal use of the field of view and to use the correct configuration parameters for the new HR-blue grisms that were installed in March 2012. The previous release (v3.24) remains valid for P95 but we recommend all users to upgrade for the preparation of their P95 MOS observation blocks.

The current public release of VMMPS is version 3.28 of the software (+ plug-in for Finding Charts).

This version of VMMPS is released as a tarball which also includes the appropriate SkyCat version (see below for download).

Supported Platforms

The latest version of the VIMOS Mask Preparation Software (VMMPS) is available for Scientific Linux 4.3 and has been used successfully on other Linux operating systems as well, both 32-bit and 64-bit. Conversely, it is currently not possible to run VMMPS on the MacOS X platform. If you do not have access to a PC or workstation running Linux, please contact the USD for assistance.

VMMPS Distribution

The VMMPS can be retrieved via anonymous FTP:

How to Use VMMPS

For information about the use of VMMPS, please refer to the chapter 6 of the VIMOS User's Manual.

Problem and Bug Reports

Please report all VMMPS problems and bugs to the ESO User Support Department  (USD). Here we list some documented problems, and describe how to avoid them. Unfortunately due to lack of resources these problems could not be fixed in version 3.28 of VMMPS. Therefore the mask preparation using VMMPS has to be done with care. Once the ADP files are created they cannot be modified.

Problems with checksum in ADP files

  • When attaching the ADP file, created with VMMPS, to an OB in P2PP I get the message that the file is corrupt. What does it mean?

    Answer: The P2PP reports that the file is corrupt due to inconsistent CHECKSUM value. This may happen due to opening the file with some editors which add some invisible characters (e.g. end of line character), or sometimes by tranferring files between windows and linux computers (depending on the protocol and encoding used for the transfer).
    Additionally, recently a bug was identified in the step where VMMPS writes the final ADP file. If the button "Make 1 final ADP" is selected, the pop-up window is displayed asking whether to overwrite and save the resulting file .adp. The users should answer "yes" to this question in order to have the correct CHECKSUM written in the ADP file. However, at this point it is not possible to make any more modifications to the mask design. If the button "Make 1 final ADP file" is selected again and the file saved again the resulting .adp file will have incorrect CHECKSUM saved, even if no modifications are made.
  • The ADP file created with VMMPS has empty CHECKSUM, which then creates error when I try to submit the OBs

    Answer: Make an ADP file by following the usual procedure and at the end when your reach the step where the button "Make 1 final ADP" has to be selected, a window is popped-up saying that the file .adp exists and asking whether you want to overwrite it. If you say NO, the adp file will still be there (because it was created before the question was issued) but it has empty checksum value. ADP files with empty checksum are not accepted when submitting OBs. Please make sure that when you create ADP files, you answer YES to the question whether to overwrite the file. However, never do this step twice, because this will write an incorrect CHECKSUM.

Automatic slit allocation

ADP files and FITS headers

  • The coordinates of MOS targets in the FITS headers make no sense. They are different from those in the VMMPS ADP files.

    Answer: If, after the automatic slit adjustments, a slit is modified interactively (manually), then the coordinates written in the ADP file are in format: hh:mm:ss.ddd for RA and dd:mm:ss.ddd for DEC. Instead for all slits automatically assigned the coordinates are written in decimal degrees. Then when the FITS header is written the coordinate keywords: HIERARCH ESO INS SLIT7 OBJ RA
    HIERARCH ESO INS SLIT7 OBJ DEC
    get truncated just before the first ":" and therefore have incorrect values. This may create problems for some data reduction pipelines (e.g. VIPGI).

Instrument selector

This page is specific to VIMOS

VMMPS