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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 13:46 on 2012 Nov 20
Thank you Callum. Could we have a Forum Section for Exoplanets please?
Posted by TonyAngel at 10:31 on 2012 Nov 17
Americo, my email address is tony_angel_uk@hotmail.com
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 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 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 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 D A Dunn at 13:40 on 2012 Nov 12
Just to add my bit. I think there is some danger of diluting discussions if the general public has unfettered write access to the forum. Can non-members not be given read only access?I would, however, like to see much more use of the forum by the members. It would be good to have an active forum which, we would be proud to let the public see.RegardsDavid
Posted by Callum Potter at 13:03 on 2012 Nov 12
Certainly it would be good to have more members using the website and contributing on the Forum.I think it’s around 1/3 to 1/2 of the members that are registered on the site. I did a quick look, and it was around 170 individual members that logged into the site in the last 4 weeks (it’s not possible to tell how many times each logged in).Often when ebulletins are sent out with new videos or journal to download, there is a flurry of registrations or password reminders. But I guess that the BAA site is not the place most members view when they are on the net.I think what will make more members visit more often, is more new content – and content production is the biggest problem to tackle.This (and other initiatives) are amongst the objectives of the new website design.Callum
Posted by Richard Miles at 10:50 on 2012 Nov 10
The key is to attract more BAA members to use this forum. People’s attention is split between the various items potentially grabbing their attention, of which there are loads these days. We shall have to advertise its use more rather than leaving it as more or less a background activity – it’s a sort of competition for people’s attention and so we need to enhance the value of the forum to our members. How we might do this would be the subject of some other thread.Getting back to Nick A’s point about having this area of the BAA Web viewable by non-members might be considered a negative move, if we enhance the content of the forum then those non-members who can only read and not post their own comments will feel increasingly left out or missing out on what we are doing. Overall, that ought to make them more inclined to join the BAA, which would then further liven up the forum.Richard
Posted by David Basey at 10:19 on 2012 Nov 10
I wonder if it comes down to visibility and accessibility?According to the last Journal we have around 3,000 members and the whole BAA site has something like 180,000 page requests per month. So if the site was ONLY accessed by members this would equate to 60 page requests per member per month or roughly 2 per day. Now obviously many non-members access the site as well pulling this figure down quite a bit. Ive no idea what the multiplier is between members and non-members but as I write this on a wet Saturday morning the home page states that there is one member online (me) and 34 guests. Clearly some of these will be members not logged in but my point is that likely a large majority of the membership will never access the BAA web pages on a regular basis to even see the forum.The 34 guests bring up the point of accessibility. To access (until recently) the Forum, never mind contribute you have to be logged in and some people are not. Now it may be they are not aware of having a log in, have forgotten their password, cant be bothered or indeed all of the above. Whichever, its an impediment to access and you have to be bothered to do it.For ease of use I have the BAA set up as the home page in my browser so every time I access the Internet, there it is in front of me and by using the remember me facility in the login the Forum is only a single click away.Maybe what we need is a note in the Journal, perhaps in the From The President column pushing the virtues of the site in general and the Forum in particular?David.
Posted by Gary Poyner at 18:13 on 2012 Nov 09
That puzzles me too. I’d like to see a live chat room also. That might be lively :-)Gary
Posted by TonyAngel at 17:05 on 2012 Nov 09
We also need to encourage BAA Members to access the site more. I do not know why it is not used more. Perhaps at one of the meetings someone could ask why they do not use the forum much.
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 Marlyn Smith at 12:29 on 2012 Nov 07
Sorry I’m a bit late in replying to your question and Callum has given you an excellent answer. I can only add that the current solar Cycle is a quiet one, probably the quietest we’ve seen in a 100 years. Solar flares are still happening of course but it is not possible to predict when something extraordinary will occur. Sunspot groups are monitored and a close watch is kept on complex groups that could be candidates for X ray flares so that vital equipment can be shut down hopefully in time to prevent or at least minimise damage.The danger doesn’t come so much from direct harm done to life on the Earth due to such a flare as the Sun has been firing off such events for 4.5 billion years and life has flourished ok. It is our technology that has become so vulnerable and our reliance upon it. It is probably the chaos that may ensue and possible civil unrest as a result that could be the problem should electricty/communications etc be knocked out for any length of time.Interestingly NASA scientists have some evidece that the Sun could be on the verge of going into another quiet phase similar to the Maunder Minimum from 1645 to 1715. If so, then our worries of devasting flares will be minimal for the foreseeable!
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 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.
