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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
