Exoplanet transits

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    Posted by TonyAngel at 22:49 on 2012 Nov 05

    Is anyone else doing exoplanet transits in the BAA? I have just had my first light curve – Wasp-50-b – accepted for the ETD – Exoplanet Transit Database, with two more to be sent.


    Posted by Richard Miles at 09:37 on 2012 Nov 06

    Morning Tony,Several folk are doing exoplanet transits and a paper by Darryl Sergison entitled "High precision photometry: detection of exoplanet transits using a small telescope" was accepted for publication a few months back so should be appearing in the Journal soon. Hopefully Darryl’s fine work will encourage many others to observe these transit events.I suppose one implied question in what you write is: "Should we coordinate the work on exoplanets that BAA members are doing?" The observing methods used have a lot in common with eclipsing binary observations and also with determining asteroid rotational lightcurves. I don’t believe that exoplanet, work is so different that it requires the setting up a new observing section however. We could from time to time highlight people’s work in the Observers’ Forum part of the Journal as a start.Do members have any views, I wonder?Richard Miles


    Posted by TonyAngel at 10:50 on 2012 Nov 06

    Hi Richard, I did ask Roger Pickard at the TA and VSS meeting if he would be including Exoplanets in his section (after all they do cause stars to vary :).I have read through Bruce Gary´s book and am slowly working through a couple of others. As you know the Czech Astronomical Society have a very good Variable Star and Exoplanet Section which runs their TRESCA Project, which includes the ETD – Exoplanet Transit Database. The organisation I am working with – Searchlight Observatory Network – has started submitting observations to them. The data I sent to them was collected from the observatory located on my farm which I operate for them. Upto now I have produced light curves of four exoplanets and only bad weather has caused a short halt. The setting up of the ETD must have involved a huge amount of effort and would take quite a long time to produce something similar, including all the utilities. Maybe it would be worthwhile considering forging a link with this organisation. They are far ahead of the AVVSO in this field.Most of the exoplanets that I have been observing have a change of magnitude in the range of 0.02. The great majority of exoplanets have a change of magnitude far less than this and require specialised software such as Mira or better equipment. The observing runs tend to be in the two to three hours, taking an image every one minute, so a good mount and guiding system is required. Yes a small(ish) telescope can be used. After all the SuperWasp project were just using Cannon lenses. It would be helpful for there to be a talking shop for this. There is a Yahoo Group but there is not much discussion on it. There are some good papers in the MNRAS and in the arXiv database.Perhaps a starting point would be to have a dedicated discussion area on the forum for exoplanets.


    Posted by Callum Potter at 11:32 on 2012 Nov 06

    Hi Tony,I have felt for a while that the BAA could be more flexible with regard to the creation of Special Interest Groups rather than trying to make everything fit within the current Section structure.Of course we do have one such SIG already – the Radio Astronomy Group. But I have thought that we could/should have a Spectroscopy SIG (as there are number of members who pursue this), and Exoplanets would be another ideal candidate SIG.These would help provide a focus for members who have interests in these areas – and I think would be good to support, coordinate and report observations, and prepare papers or articles for the Journal.Regards,Callum


    Posted by TonyAngel at 13:18 on 2012 Nov 06

    Well said Callum 🙂


    Posted by TonyAngel at 23:36 on 2012 Nov 07

    A good place for anyone to start is by reading Bruce Gary´s book "Exoplanet Observing for Amateurs". It can be downloaded free from his site. http://brucegary.net/book_EOA/x.htm Just make sure you have lots of paper and printer ink.


    Posted by TonyAngel at 23:39 on 2012 Nov 16

    I now have registered four exoplanet transit sets of observations with ETD, they are based on over a thousand images. 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.


    Posted by Americo Watkins at 00:39 on 2012 Nov 17

    Hi Tony,I do have an interest in doing some Exo planet transit work. My other main interest at the moment is asteroids. I have just set up an observatory with these objects in mind. I have a long way to go and a lot to learn before I’m able to submit useful work in both fields.Your correct about Bruce and his book plus his online articles. I believe I received the last published copy of his book – so he told me.As for some of the fainter objects, one might consider using the online, rentable robotic telescopes, true they could proove expensive for extended study, but, I have used them for particular projects to good effect.As regards a BAA section devoted to them, I would suggest their study could be covered by a sub-group of the asteroid or variable star section as many of the techniques used are at the very least similar. I’m sure that if a sufficent number of active members participate such a group might then develope into a section naturally. Certainly an active group in some form for sharing experiences and results would be welcome I would have thought. Cheers Eric


    Posted by Jeremy at 10:05 on 2012 Nov 17

    A variation on the exoplanet theme is the SPADES (Search for Planets Around Detached Eclipsing Systems) project which is designed to look for Jupiter-sized substellar companions orbiting around eclipsing binaries: http://www.variablestarssouth.org/index.php/science-case-for-spades. This is run by Variable Stars South (part of the RASNZ). The target list is mainly, but not completely, southern stars.Go well!Jeremy


    Posted by TonyAngel at 10:25 on 2012 Nov 17

    Thank you for your comments. I would be more than happy for there to be just a section on here entitled Exoplanets and then perhaps its own web pages. I suspect that there will not be the numbers for a section or subsection for quite a while, but as you say there is a need to have a means of sharing experiences and problems.A 14" can do quite a bit of serious research, though I am hoping to have a 1 meter scope in about 12 months. I do have a Sbig spectrograph here.


    Posted by TonyAngel at 10:27 on 2012 Nov 17

    Thanks. I will have a look at SPADES later today.


    Posted by TonyAngel at 10:31 on 2012 Nov 17

    Americo, my email address is tony_angel_uk@hotmail.com


    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


    Posted by TonyAngel at 14:42 on 2012 Nov 21

    Thank you Robin. Yes I had read Christian Buil’s page. As I already had the use of the SGS I was hoping that I could at least see if it could have spotted the larger doppler shift exoplanents, or failing that spectroscopic binaries just to do a proof of concept before seeing if a more expensive spectrograph could be justified. Perhaps I can just use the SGS for confirmation of exoplanet’s star spectrum, (allowing this could be contamininated by the planet). As you can guess I am rather new to spectroscopy from a practical angle.I will create a Topic for Radial Velocity for future discussions.


    Posted by Gary Poyner at 16:19 on 2012 Nov 21

    This has just appeared on the AAVSO web site..http://www.aavso.org/exoplanet-wasp-11bhat-p-10b-dslrA nice light curve taken with a 20cm SCT and DSLR (Mike Durkin).You don’t need to be a member to view, but you do to post comments.Thought someone here might find it interesting!Gary


    Posted by TonyAngel at 16:53 on 2012 Nov 21

    I will have a look. I have looked at their site before, but it would mean joining (and paying) and I already in a few 🙂 I think that the ETD has a greater number of observations and better tools, though please correct me if I am wrong. It is also free 🙂


    Posted by Robin Leadbeater at 23:15 on 2012 Nov 21

    Hi Tony, Most of AAVSO is free. http://www.aavso.org/aavso-membershipeg you can view data, register and post on the forums, register as an observer and supply data all without paying. (I have even published in their Journal without the page fees via their partly grant funded Citizen Science project) I agree though, there is not much sign that exoplanet transits is a big thing for AAVSO. CheersRobin


    Posted by Robin Leadbeater at 23:29 on 2012 Nov 21

    Also back in 2005 when amateur transit detection was in its infancy and was I playing detecting transits with a modifed webcam (yes it can be done -just!), pro exoplanet hunter Greg Laughlin set up something called transitsearch. The website is still there but seems to have become dormant in 2009www.transitsearch.org.He still runs a fascinating blog though (well to me anyway) here http://oklo.org/CheersRobin

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