| Date: | 2003-10-09 12:42:00 | |
| Sender: | F. Pierron <Francis Pierron <francis.pierron@obs-azur.fr>> | |
| Subject: | [SLR-Mail] No. 1139: Barometer change on 7845, Wavelength in npts data:532.4 to 532.1 | |
| Author: | F. Pierron | |
| Content: | ******************************************************************************** SLR Electronic Mail 2003-10-09 12:42:00 UTC Message No. 1139 ******************************************************************************** Author: F. Pierron Subject: Barometer change on 7845, Wavelength in npts data:532.4 to 532.1 Dear colleagues, About the barometric indication on 7845 : As a result of traveling barometer experience in Eurolas network (2002) we observed a very good agreement for 7835 and FTLRS system (0.1 mb) but detected a little barometric error with the device of the 7845 system (0.5/0.8 mb) We decided to replace this 7845 device with a Vaissala model carefully calibrated on august, 4th 2003. This barometer has been too tested with the other standards in our lab and we can now advance an underestimation of 0.5 mb between mars 2001 and june 2002 and 0.8 mb between june 2002 and 2003/08/04 for this station (slr and llr data). Although that such an error does not exceed 4 mm on the correction range up 25 degrees elevation, it seems us all the more important to know these values since we are currently tracking ”High Orbiting Satellites” to 5 degrees elevation to help analysts in modelizing atmospheric correction. All the meteo data of our stations are now at a very good accuracy (0,1 mb, 0,5 °C and 5 % for humidity) and we are able to indicate on request for specific analysis on very low elevation 7845 data the pressure correction to aplly at specific date. About the reported wavelength (all the French systems : 7835,7835,7848,7830) Following a Van Husson´s remark, we realized that we have been in Grasse reporting a wavelength value of 532.4 nm in the normal points for the very beginning of the Yag. In fact the correct value should be 532.1 nm and in spite of a very weak difference in the refraction correction (0,4mm at 20 degrees), we´ll put from now on this correct value of 532.1 nm for all our French systems (fixed and mobile). Thanks to Van for having it pointing out. Best regards and excuses for the inconvenience Francis *--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--* + Francis Pierron Tel : (33) [0]4 93 40 54 20 + Grasse laser ranging operations fax : (33) [0]4 93 09 26 14 + Ultra mobile and permanent station email : francis.pierron@obs-azur.fr + + Observatoire de la cote d´azur + + Av N Copernic 06130 Grasse - France + + Phone from foreign country: 33 4 93 .. .. .. *--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--* From: Francis Pierron ******************************************************************************** |