Re:Exoplanet transits

[Dominic Ford (site admin)]

Posted by Robin Leadbeater at 14:05 on 2012 Nov 21

TonyAngel wrote:

I am starting to get ready to try and do some radial velocity observations in the new year. This is a lot more tricky than transits. if i can do both a transit and a radial velocity on the same target, then it is possible to know the mass, size and orbit of the exoplanet.

Hi Tony,you may have come across this already but if not you should definitely take a look at Christian buil’s work on exoplanet doppler shifts. http://www.astrosurf.com/buil/extrasolar/obs.htmAs far as I am aware apart from Tom Kayes’s Spectrashift team they are the only amateurs to have been able to do this and only on a few systems with the largest doppler shifts. I see you mentioned an SBig SGS. Unfortunately it is unlikely that you will detect expolanet doppler shifts with this instrument.The main issue is stability and this means an off telescope fibre fed spectrograph. A wide spectral range is also important so you can measure many lines simultaneously (using cross correlation techniques) hence the use of an Echelle design. CheersRobinwww.threehillsobservatory.co.uk