From pgoude@keck.hawaii.edu Wed Nov 14 15:58:06 2001 Date: Thu, 18 Oct 2001 10:34:01 -1000 From: Pat Goude To: "'a.adamson@jach.hawaii.edu'" , "'denault@ifa.hawaii.edu'" , "'jpeysson@gemini.edu'" , "'rjw@ifa.hawaii.edu'" , "'ando@subaru.naoj.org'" , "'grundseth@cfht.hawaii.edu'" , Doug Summers Cc: Fred Chaffee , "'fahlman@cfht.hawaii.edu'" , "'aschinck@cfa0.harvard.edu'" , "'mmountain@gemini.edu'" , "'jmoran@cfa.harvard.edu'" , "'phillips@submm.caltech.edu'" , "'irobson@jach.hawaii.edu'" , "'pickles@ifa.hawaii.edu'" , "'tokunaga@irtf.hawaii.edu'" , "'takami@optik.mtk.nao.ac.jp'" , "'dsimons@noao.edu'" , "'veillet@cfht.hawaii.edu'" , "'gaessler@subaru.naoj.org'" , "'bellerbroek@gemini.edu'" , "'cdorgeville@gemini.edu'" , "'jsebag@gemini.edu'" , Paul Stomski , Hilton Lewis , Peter Wizinowich Subject: Letter to observatories requesting LTC URL participation [The following text is in the "iso-8859-1" character set] [Your display is set for the "US-ASCII" character set] [Some characters may be displayed incorrectly] (Copies of the following letter from Peter Wizinowich are being mailed to you today.) October 18, 2001 Andy Adamson, Head of Operations Hiroyasu Ando, Director United Kingdom Infrared Telescope Subaru Telescope 660 N. A'ohoku Place 650 N. A'ohoku Place Hilo, HI 96720 Hilo, HI 96720 Tony Denault Bernt Grundseth Infrared Telescope Facility Canada-France-Hawaii Telescope Corporation P.O. Box 4729 P.O. Box 1597 Hilo, HI 96720 Kamuela, HI 96743 Jacques Peysson Doug Summers Gemini Observatory W. M. Keck Observatory 670 N. A'ohoku Place 65-1120 Mamalahoa Hwy Hilo, HI 96720 Kamuela, HI 96743 Richard Wainscoat Institute for Astronomy UH Manoa 2680 Woodlawn Dr. Honolulu, HI 96822 Gentlemen: I am contacting you on behalf of the Mauna Kea Laser Guide Star Technical Working Group and W. M. Keck Observatory. This working group was established by the Mauna Kea Directors a number of years ago to develop a Laser Policy Statement for Mauna Kea and to coordinate joint Laser Traffic Control (LTC), aircraft safety and Space Command efforts. A presentation was made on behalf of these two groups to the Mauna Kea Directors at their Oct. 3 annual meeting (this presentation is enclosed). The catalyst for the presentation to the Directors and for this letter is Keck's desire to project a laser beacon from the Keck II telescope this December. The purpose of this letter is to ask for your collaboration in implementing an LTC system for Mauna Kea. Briefly, the LTC system is intended to gather telescope pointing data, compute whether a laser beacon will intersect the field of view of other Mauna Kea telescopes and automatically shutter the laser prior to any intersection. Keck and Gemini are already taking the lead in implementing an LTC system, however we need each participating observatory to make available a URL with the information defined in the enclosed document. We recognize, and apologize for the fact, that we have provided very short notice for this request. In our ideal world we would request that your URLs be in place, with read permission from IP address 128.171.136.122, by Nov. 26 to allow time for testing. We are currently planning to project a laser beacon on Dec. 11, 22 and 23. Our first request is to ask you to inform us of when you will plan to implement the URL or if you do not feel a need to participate in the LTC system. If you are not the appropriate contact for your observatory for implementing this URL, could you please put us in contact with the appropriate person. Please feel free to contact myself, or Doug Summers (dsummers@keck.hawaii.edu) for more technical questions; we can both be reached at (808) 885-7887. The potential concern for other observatories is not the 589-nm sodium beacon, but the Rayleigh scattered light from dust and aerosols, which may be seen up to a height of about 8 km above the summit. On a moonless night at Lick Observatory the Rayleigh scattered beam can be seen from as far away as 1.5 km, but only if you know where to look. The Working Group intends to coordinate measurements of the scattered light from other observatories during December and some observatories may want to wait until we have some quantitative scattered light data available before deciding whether they need to participate in the LTC system. The first Keck experiments will be quite limited and we can discuss alternative means to protect your observations in December if necessary (for example: projecting in relatively benign directions, making the Keck pointing data available to you, providing a temporary way to communicate pointing data, etc.). Thank you in advance for your support. The projection of laser beacons from Mauna Kea represents an exciting new capability on Mauna Kea, and we hope that you will join in our enthusiasm. Aloha, Peter L. Wizinowich Chair Mauna Kea Laser Guide Star Technical Working Group PW:pg Enclosures (2) cc: Mauna Kea Directors Mauna Kea Laser Guide Star Technical Working Group (Christian Veillet - CFHT, Doug Simons - Gemini, Hideki Takami - Subaru, Richard Wainscoat - UH) Wolfgang Gaessler, Subaru Brent Ellerbroek, Gemini Celine d'Orgeville, Gemini Jacques Sebag, Gemini Paul Stomski, Keck Hilton Lewis, Keck