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Thanks for the kind feedback!
Please rest assured that there is a lot of support in the BAA for this, and they absolutely will continue.
We will take a break for the holiday season, but a new season of webinars will start soon.
Thanks – that’s interesting.
My lens doesn’t have a grub screw to hold the focus, so perhaps a bit of tape or glue is the way to go. The quality of focus doesn’t seem to strongly affect the number of meteors I record, so I may be being too picky. I guess meteors are moving so quick that they’re inevitably spread over many pixels, so having a soft focus doesn’t make such a difference. The one benefit to a really sharp focus is that I see a lot more stars, which is handy for calibration.
I use an easycap usb dongle to connect the Watec 902H2 Ultimate to the RPi. See the photo below. The whole setup fits inside a Genie TPH2000 enclosure, powered via power-over-ethernet so only one cable is needed. A custom Pi Hat converts the 48V supply from the PoE into a 5V supply for the RPi and a 12V supply for the camera. There’s a transistor to allow the RPi to turn the camera on/off via one of the GPIO control lines. Previously I was using a RPi model 2, which had issues with dropping frames. But I’m now using a RPi model 4, which is a pretty fast machine. Very occasionally frames still get dropped, possibly due to USB errors, but 99% of the time it’s fine.
At some point I’d like to get my software to produce output in a compatible format with UFO Capture, so that we can share data. At the moment my biggest concern is calibrating the pointing, though. I’m doing a polynomial fit to the radial distortion in the lens, and then using astrometry.net to determine the pointing of each image. I periodically take one-minute exposures through the night for this purpose. I then take the median of all the pointings determined each night to arrive at a single (alt, az) estimate for each camera each night.
It works up to a point… but I’m still seeing ~5 pixel offsets in the fitting a lot of the time… which isn’t very good.
That link is indeed the best place to find old eBulletins. It should remain accessible indefinitely, despite recent changes to the BAA’s mailing lists.
There used to be an alternative archive here… <britastro.org/ebulletins>… which is probably the one Nick was thinking of, but it’s no longer advertised asn nobodywas updating it.
I don’t know what archival plans anybody has for the new email lists.
It’s not just amateurs using off-the-shelf communications hardware to do radio astronomy, incidentally.
On a larger scale, I believe the Australian SKA Pathfinder (ASKAP) is built out of standard 12-metre dishes that are used by telecoms companies. Of course, the detectors and mounts needed to be bespoke, though.
The times are as follows (all times in BST):
Friday 24 April – 12 noon – A Special Image for the 30th Anniversary of the launch of the Hubble Space Telescope
Saturday 25 April – 2.30pm – Spring webinarI’m not sure where you saw these erroneous times.
Apologies folks!
As Andy says, I migrated the BAA website to a new server last night, and that is almost certainly the cause of these teething issues. I’ve actually seen exactly the same issue that Jeremy and Chris describe, but I wasn’t able to reproduce it, as once I’d hit refresh once, it seemed to completely disappear.
On the old server, we used a tool called varnish, which encouraged web browsers to cache pages when users weren’t logged in, in order to reduce the load on the server. The caching should have been inactivated whenever you logged in.
The new server is a lot more powerful, and varnish is a bit of a troublesome beast, so I’ve tried experimentally turning it off for now. I’m surprised turning it off would have caused the issues people seem to be seeing, but it seems like the most likely cause.
If the culprit is indeed old cached data from varnish, my guess is that this issue will probably entirely disappear within 24 hours as the caches in everybody’s web browsers expire. But please do let me know if anybody has longer term issues.
Here’s my effort from Cambridge. I’m afraid I took my picture a bit early… 19:09 GMT… which may screw up your experiment, but it was the last chance I had before the clouds rolled in. Nice bit of Earthshine.
Pete Lawrence has suggested on Facebook that they could be a pair of birds. This seems quite plausible, especially as the two tracks cover the whole height of the frame, are of very similar brightness, and have no evident flares.
Blimey – where did this spirit of toleration suddenly come from? Back in 2000 you could have a proper brawl about this…
Surely all Proper Astronomers measure their dates in Julian Day numbers, and so count in units of Julian decades (3652.5 days) from Jan 1, 4713 BC (Julian calendar). So, as everybody knows, the current decade started on 14 Jan 2018 (Gregorian calendar).
Does the BAA really allow people in who count their decades in lesser calendars? I shall write to the President directly about how standards are slipping…
As regards wavelengths causing problems, I think that’s very unlikely.
It’ll produce plenty of UV and X-ray photons, but assuming they come out uniformly in all directions, it wouldn’t have the power to do anything serious from a distance of 700 lyr. If it beamed them in a jet in our direction, that might be a different story. Luckily there’s strong evidence the rotational pole is inclined at an angle of about 20 degrees to our line of sight, and any jets would be directed out of the poles. So I think we can sleep easy.
But as Xilman says, the world’s professional astronomers may struggle to find high-resolution spectrographs that can deal with something that bright.
I believe this service is working at our end, but I fear there’s strong probability that any messages sent via these forms will get caught in spam filters nowadays (by which I don’t just mean they end up in the recipient’s spam folder; delivery may be completely refused).
The ever-rising volume and sophistication of spam messages mean that spam filters are always trying to stay one step ahead. Any email which originates from an unexpected place on the internet is treated as highly suspect, and unfortunately that’s exactly what happens when you use these forms: the BAA’s servers generate an email which appear to have come from your personal email address.
Perhaps the time will eventually come where we need to retire this service, though that would be a shame, since it’s useful to allow members to communicate without us disclosing their private email addresses.
How about Wil Tirion’s Sky Atlas 2000.0, 2ed Edition? I fear it may be becoming a collector’s item, though: second hand copies on Amazon seem to start around £50 and go up to silly prices. I picked up a copy a few years ago and I don’t remember it being that expensive.
This would be my entry for the “alternative” category. It is more colourful than the other images, at least.
This is what you get if you hold a phone camera up to the eyepiece of a telescope rather incompetently, so that it’s misaligned and not very much of the Sun is visible.
I almost chucked the picture away, but if you look closely at the full-resolution attachment, Mercury is clearly visible! I’m not sure you can see it in the low-resolution version below. Taken about five minutes into the transit.
But in this case you’ve got no shortage of photons. You are quite right that it would be madness to propose detecting a transit of a Mercury-like exoplanet.
That’s about right, I think.
I agree it’s tough, and almost certainly impossible under the UK’s changeable skies. But with a 6D at a good site, averaging over 20 megapixels, it seems tantalisingly within reach? Depends how well-behaved the noise is, and I don’t have a feel for how “good” a good site would need to be.
James: I had been wondering about doing something similar on 11 November. Set a DSLR to take frames of fixed exposure, pointed either at the sky, or in fact at the ground. Averaging the brightness across the frame, I wonder how easy it would be to detect a brightness step at Mercury’s ingress and egress from transit…
Alex,
If speakers offer us copies of their slides, there’s no problem with putting them online, but be aware that many speakers are uncomfortable about this. At a recent conference I went to, less than a third of speakers were willing to share their slides.
There can be all sorts of reasons for this: they may plan to reuse the slides at future events, they may have shown figures or images that belong to other people, they may worry that people will steal their work, and professionals may have shown results that aren’t published yet.
If you do approach speakers about this (note that the web ops team has previously advised meeting organisers not to do so), I’d recommend going very gently, and making anything you receive accessible to members only.
Best wishes,
Dominic.
My understanding is that the limitations in Dec have more to do with the altitude of the celestial pole, rather than the mounts the telescopes use (as Xilman says, most large telescopes are alt-az). Pan-STARRS is observing from a latitude of 20°N, so the pole is only 20° up and it’s not really worth wasting valuable observing time on it!
I imagine it depends what material the film is made from. Old celluloid films have a nasty habit of spontaneously combusting when they degrade. I’m not sure when films became safe, but I have a feeling cellulose acetate was still pretty common in the 70s, if not later still?
The most recent versions of all Microsoft Office programs have facilities to export documents to PDF format.
Wherever possible, please do this in preference to uploading documents in proprietary Microsoft formats (e.g. docx, pptx, xlsx, and so on). Not everyone has these programs installed on their computers.
Of course, if there’s a strong reason why people will need to open the document in Office (e.g. a form to be filled in and emailled back, or a Powerpoint file for display at a meeting), then that’s different. You might consider uploading both the original file and a PDF version to keep everyone happy.
