Submission of MOS OBs for VIMOS

For the preparation of MOS OBs the pipeline processed VIMOS pre-imaging files have to be used together with VMMPS mask preparation tool. Therefore MOS OBs can only be prepared after the pre-imaging OBs have been observed. Typically the pipeline processed pre-images are released within about 2 working days from their observations. All VIMOS pre-imaging OBs are observed in Service mode.

MOS OB submission Rules (Service Mode)

It is important to prepare the follow-up MOS OBs as soon as the pre-imaging OBs are released. Since MOS effectively is only a dark time mode, it means that Phase 2 proposers should strive to submit MOS OBs such that they are ready for execution during the dark time following that of the pre-images (i.e. within 2 weeks). If one dark time is missed (i.e. 4-5 weeks used for MOS preparation), this limits the window of opportunity. If two dark times are missed (i.e. 8-9 weeks used for MOS preparation), the MOS OBs will be in serious jeopardy of failing to find a slot in the schedule. Tight constraints on observing conditions will work towards making it even harder to execute the OBs.

For these reasons, users are strongly encouraged to submit their MOS Phase 2 material as soon as possible after receiving the preimaging data. Failure to submit this Phase 2 material within 4 weeks after delivery of the preimaging seriously decreases the chances of completion of MOS runs. Furthermore, incomplete class A runs at the end of the period will not be carried over to the next period if the reason for non-completion is a late submission of MOS OBs.

In summary: Phase 2 proposers should prepare MOS OBs as soon as at all possible after pre-images have been obtained, and they should think carefully about how tight constraints on observing conditions it is realistic to set given the additional limitation of observing within ±2 or ±3 hours from the meridian, depending on the target declination and the rotator offset angle, see the Observing Constraints page.

MOS OB submission Rules (Visitor Mode)

Visitor Mode (VM) observers who wish to use VIMOS in MOS mode must submit part of their MOS OBs to the ESO OB repository in Garching minimum 3 weeks before the first night of the VM run. This is unlike any other VLT instrument, so VIMOS VM observers should read this section carefully.

We need to start the MOS mask production well before a VM run starts. Therefore we need some of the OBs (as they include the mask definition files) complete and verified in the repository no later than 2 weeks before the VM run starts. The rules and deadlines for MOS VM OB submission are as follows:

  • A minimum of 40% (rounded up) of all masks to be used during a given VM run must be submitted (attached to valid OBs).
  • During a VM run a maximum of three (3) sets of MOS masks can be manufactured per night. Therefore, in addition to the 40% it is the responsibility of VM observers to count how many masks can be produced during their run, and make sure that validated OBs containing mask definition files for the remainder are available in the Garching repository.
  • The deadline for submission of VM MOS OBs is 3 weeks before the first VM night of the run.
  • As soon as OBs are verified the masks will be manufactured. Therefore, the submitted masks are FINAL. After manufacture they cannot be changed.
  • Contrary to the Service Mode case, there is no need to notify once the submission is complete.
  • After submitting MOS OBs for the visitor mode run, please send an e-mail to the and e-mail addresses (both in the 'to:' field!) in order to inform the VIMOS support astronomers about the new masks to be manufactured. Please provide information on: (1) Programme ID, (2) number of OBs and number of mask sets (each mask set has 4 masks for the 4 quadrants) and (3) the date of the first night of observations.

ESO will make every possible effort to obtain and release the pre-imaging for VM runs no later than 6 weeks before the first night of the VM run. In cases where this may prove impossible (because of weather or technical reasons), the above mentioned deadlines may be changed on a case-to-case basis.

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This page is specific to VIMOS