The main reason to put in the middle of the ocean (or the first range of mountains that the air mass encounters) is to have a very stable atmosphere above the observatory, though it is true that Mt. Wilson above Pasadena used to be a very good site before the aerosol and light pollution…
Laser guide stars are 589nm (sodium)… My guess would be that the main effect would simply be a loss of photons from scattering; both the upward laser and the downward light from the sodium layer at 90km, so a squared effect, but still, if one is talking about 5% or so loss of light (to get 1% reflected back to space), not a huge deal. But I should ask… From: [email protected] <[email protected]> On Behalf Of Russell Seitz Sent: Sunday, April 7, 2019 3:14 PM To: geoengineering <[email protected]> Subject: Re: [geo] Re: SRM optical impacts Stephen Some of the biggest telescopes have been atop tall islands in the middle of the ocean like Hawaii and Grand Canaria to get away from light pollution and dust and aerosol scattering on land. Douglas I mentioned the UV because the medical concernns Andrew mentioned largely arise from short wavelength photons. Can you tell us how stratospheric aerosols might effect the preformance of the laser guide stars on which deformable mirror correction systems depend- would ring images be a problem at the diffraction limit? The dimensionless aerosol scattering efficiency coefficient Ms is of the order of the Mie integral of the number density over the range from r max to r min- Q Ms (r) πr2n (r) drQMs (r) π r2N (r) dr On Sunday, April 7, 2019 at 10:08:37 AM UTC-4, Stephen Salter wrote: Russell Some of my best friends are astronomers but few of them use telescopes in mid ocean so you and I can remain on good terms. Stephen Emeritus Professor of Engineering Design. School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh EH9 3DW, Scotland [email protected]<javascript:>, Tel +44 (0)131 650 5704, Cell 07795 203 195, WWW.homepages.ed.ac.uk/shs<http://WWW.homepages.ed.ac.uk/shs>, YouTube Jamie Taylor Power for Change On 07/04/2019 14:31, Russell Seitz wrote: Why would reductions in the downwelling tropospheric light flux increase any of the above? I'd instead ask instrumental astromomers what they think SO2 scattering would do in the UV , as they have a lot to lose from scattered light, which can cost them contrast and degrade the signal to noise ratio in interferometry and spectroscopy. Try the Magellan and OWL teams On Wednesday, April 3, 2019 at 7:47:35 AM UTC-4, Andrew Lockley wrote: Has there been any investigation of SRM effects on vision? Eg perceived glare, macular degeneration, corneal sunburn, vision development in infants, object recognition when driving (and their equivalent in animals)? Andrew Lockley -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]<javascript:>. To post to this group, send email to [email protected]<javascript:>. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]<mailto:[email protected]>. To post to this group, send email to [email protected]<mailto:[email protected]>. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
