
What about Filter NEWS ...         La Silla  January 95  - Alain Gilliotte 
==========================

This present new database has been finaly completed. Timing was quite long 
but as we say in French , le jeu en valais la chandelle ... The new proposed
filter context is much more powerfull than in the past.
Instrument transmission can be calculated for EMMI, SUSI and the Efosc
instruments.

This nice package developed by J.P Kneib and latter by C. Levin has really 
many advantages:

- The filter database includes both image and normal quality filters.
- The filter parameters required for an astronomer are all listed including
  the red leak quantification. The classification is done only by ESO number,
  but it is possible to select only the filter within a specific wave and
  bandwidth ranges.
- Filter characteristics are accessible for printing including also the 
  transmission curves.
- Scaling on wavelength or transmission is also available for detail search.
- It is possible to simulate the instrument througput taking in account 
  all observational parameters (standard star, sky and airmass compensation,
  filters, grism, fresh or old aluminium coating and CCD detector).
- At last but not at least a News windows (where you are now) will gave the 
  opportunity to inform you about new filters availability ....

Of Course all optics team has been envolved on the new database progress for a
new complete re-measure of all our filters availables at la Silla.

The La Silla filter database will be always updated.
A version is foreseen for Garching with weekly update. 

Do not hesitate to contact us by e-mail (filters@eso.org) to bring usefull 
comments on the way to improve this service...


                                   With my best, 

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News Filters
============

#708 new Halpha spare  (656.7 nm CWL and 6.9 nm FWHM)
#709 new Halpha red shifted spare  (664.5nm CWL and 7.1nm FWHM)

#734  Washington C filter  (399.6nm CWL and 111.9nm FWHM)  
      (first type, we will tried to improve the transmission)

#759/760 new Passband Gunn z  (996.7nm CWL and 48.2 nm FWHM)

#761/762/763/764 NII filters (658.5nm CWL and 2.6 nm FWHM)

Filters Of EMMI have been included
==================================

#765 special EMMIR (489.5nm CWL and 14.9nm FWHM)
#766 special EMMIR (505.9nm CWL and 21.2nm FWHM)
#767 special EMMIR (546.4nm CWL and 20.7nm FWHM)
#768 special EMMIR (602.6nm CWL and 53.7nm FWHM)
#769 BG39 2mm for EMMIR (to be use with Grism#5 to avoid red stray light)

For the first database offering only the image quality filters will be 
presented. 
Normal quality ones will be added continuously until completion of the 
750 filters available on La Silla Facilities.
