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Thanks David, and Nick for posting the video from the March 29th meeting that I was unable to attend – so being able to watch the recording was great. The sound and vision quality were very good – comments from the audience occasionally breaking through into the audio. With YouTube it is possible to switch on auto-generated subtitles, which might help non-native English speakers from around the world. Good to see the report of Peter Birtwhistle’s latest achievement too as well as Tony Angel’s comet observations. Well done everyone. Richard
Hi Paul, Peter and Andy,
Trappist-1 and its system of at least 7 planets is fascinating. Yesterday we held our second BAA/UCL exoplanet workshop in London and I finished the day able to read Gillon et al.’s 2017 paper in the journal Nature on the subject. Shame that I am away in Australia and so not able to attend Winchester Weekend.
I think I may have seen Didier Queloz in 1991 when I participated in a French-language workshop at Haute Provence Observatory – I was working in France at that time. The astronomers had plans to build a new high-res spectrometer for the telescope there with a view to detect planets by the radial velocity method: this led to the ELODIE spectrometer in 1993. People thought that they were ambitious at that time. Michel Mayor was also involved and Andre Baranne was the main protagonist at OHP.
As to the question of liquid water: despite not yet measuring its presence directly, we can infer it should exist on one or more of the Trappist-1 planets. H2O is a very common constituent in the universe and almost certainly should exist as a liquid somewhere on one or more of its planets!
Cheers, Richard
Sorry to hear that, Keith. I haven’t had the problem myself but I know that the vestibular system can be affected by viruses, etc but it eventually sorts itself out. Hopefully that will happen soon in your case.
Visual observing is great to do – I was round at a friend’s last night eyeballing the Trapezium in the Orion Nebula last night for instance – but do consider not just imaging with a camera, but also taking quality monochrome images of stuff like comets, asteroids, or variable stars. Generally speaking you need an astronomical CCD camera and a photometric V hfilter for asteroids or variables, or a Cousins Rc filter or Sloan r’ filter for comets.
As we get older our eyesight inevitably declines in performance, whereas as time goes by the power of CCD cameras in the hands of amateurs is increasing year on year. This is partly because of the improvements in software such as Astrometrica, Canopus and MaximDL, but also because of the better star catalogues that are coming out. We are only a few years away from the completion of the Gaia mission, the data from which will further transform this type of observing by amateurs and others.
Excellent – the date is in the diary and will keep it free.
As for Gary and Winchester 2017, unfortunately I shall be in Australia during late March / April so will miss the VSS knees-up. My apologies.
Eric – Distilled water is usually difficult to come by as these days, de-ionised water is often sold (e.g. for lead-acid accumulators). If you can get it then you would only need to use ‘half a drop’ of washing up liquid, i.e. as little as possible, in say a litre of pure water. So say 1 mm cube of detergent would give 1 part in 1 million. Then there’s the problem of getting pure Cotton Wool BP to wipe the surfaces with. You would need the medical sort.
It would be good if some of this could be the basis of an article in the Observers’ Forum of the Journal, Alun. Something about the kit and a few examples of the resulting observations using your dual spectrograph. I haven’t seen anyone operating two systems in parallel before. Nice.
Nick, Re. the very bright meteor image – one way you can do photometry on the image to measure its brightness is to calibrate the degree of attenuation in the lens system of the internal reflection, which can be seen diametrically opposite a bright source across from the optical axis. See the secondary reflected image of the meteor towards the bottom of the frame. Try imaging a bright planet so you can integrate the light of the secondary image of it. Then image a starfield and calibrate the zeropoint of the direct image. You can then determine the equivalent brightness of he secondary image and therefore the attenuation factor in the lens.
Yes – when the daytime sky is really clear and blue you could even try to observe the brighter stars in a GoTo telescope but beware of getting too close to the Sun, Paul. Clear skies. Richard
For info: The email from Jeremy about the Survey reached me at 16:05 today (Feb 13).
I encourage everyone to complete it as the more that do so, the better the wishes of members can be reflected in any changes made to the Website in the near future.
Go for it!
Hi Roger – Your issue isn’t so much trying to focus but rather ‘How to obtain a flatter field?’
One explanation can be that the focal plane of your camera is not exactly orthogonal with the optical axis. That may mean that the way the camera has been attached is skewed slightly.
Got back from France at 10pm last night and woke at 4am. Sky here suffered from high misty cloud with one or two clearer patches. The cloud made the sky very bright within 10-15 degrees of the Moon. Since the main observatory is ‘hors de combat encore’, I would have had to use a tripod-mounted 4″ short-focus refractor to observe, but from experience I was convinced I would never have found the star in question. With a telescope of 10″ aperture or more, it might have been possible. Looking at the track of the shadow, the location here in Dorset would have been very close to that of Tim Haymes and David Arditti so not a great deal lost in the event. Congratulations to those two folk and to Peter Carson for their positives. Not easy!
Richard
Very good suggestion – since the light is supposed to be associated with emission then your spectrograph would be an ideal way of tackling what is supposed to be an ephemeral phenomenon that comes and goes. You’ll have to work out a good methodology of offseting to measure the sky and back again – bobbing to and fro on some time-scale to ensure changes in the Earth’s atmosphere are properly subtracted from the Venus signal. Beware of scattered light from the bright side contaminating the signal you are after. You might therefore need to also measure the bright side (with the gain turned down on your spectrograph – or by just measuring the sky north/south of the cusps to quantify this). That makes for 2 or 3 sky positions as well as the dark side of Venus herself.
Richard
These r-band data were recorded from McDonald. Not quite overlapping with your data, Nick.
Further to what Nick has added, I have now received 23 reports from observers. Sky conditions in the UK did not lend themselves to photometry. Nick should have the best sequence but hopefully once he has measured his hundreds of frames I can add data from other observers. Roger Drew obtained a nice sequence as it skirted the edge of the open cluster Praesepe (Messier 44) in Cancer for instance – that occurred at around 5.00-6.00 am so it was a fine effort on his part to obtain high-quality data at that time. Soon to appear on the ARPS web pages …
Richard
Back in April, Graham e-mailed a number of BAA folk, but which did not include David A., the following: “The astronomy content is at a very introductory level. One aim is to get existing photographers out there to be as amazed as I have been in recent years by what can be done with ordinary digital cameras as long as you get away from the light polluted towns. The book should also be useful to those who are already astronomers but have not yet tried photography (Part 3 is about practical techniques and every photo in the book has full details of how it was taken).
Another aim is to get youngsters interested in something technical. The book is intended to be suitable for school pupils.
Hopefully this puts the book more in perspective.
Richard
David Arditti’s review is well-constructed and not quite as negative as Sheridan’s words make out. Looking at other comments about the book on the Web, it is clear that Graham has several objectives in writing/producing the book and so it will definitel;y appeal to several audiences. How well it satisfies the budding astrophotographer is possibly a bit like asking the proverbial ‘length of string’ question. Maybe David is indeed expecting too much of an in-depth approach. I see that Graham is a member of the Tynemouth Photographic Society and I can imagine it could have a strong appeal amongst amateur photographers especially if they can exploit local dark skies.
Richard
