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My dome is controlled by LesveDome and very successfully too.
The major problem, from my POV, is that LesveDome is Windoze only and I want to move to a Linux-based TCS. The only thing stopping me is the lack of an INDI driver for the Velleman K8055 controller board. If anyone knows of one, please let me know.
Steer a (virtual) radio telescope around the sky. Listen to whistlers from Jupiter, the repetitive pock-pock-pock from a pulsar, the loud noise from the sun and the constant faint hiss from the CMB no matter where the receiver is pointed.
Many years ago I observed the sun with a small dish controlled from the visitor centre at Jodrell Bank.
This is going off at a bit of a tangent and might be more suitable for older people in astronomy but we should keep in mind that astronomy is much more than imaging.
Celestial mechanics was traditionally illustrated with orreries.
Mechanical models of solar system objects to scale (either by size or by relative separations) are relatively straightforward to make.
Cerenkov telescopes pick up flashes of light from individual incoming gamma rays. Modern neutrino telescopes pick up individual flashes of light too, and also have an angular resolution of a significant fraction of a radian. (Early ones were omnidirectional and were lucky to pick up one collision per day.) Throwing ping pong balls at an observer, or at a sheet held by the same, would illustrate this effect nicely. Alternatively, a number of “pings” from speakers scattered around a fixed source provides a sonic analogue.
Spatially resolved spectroscopy measurements permit the development of three-dimensional models of external galaxies and the way in which they rotate. C.f. solar system models.
Astrometry from Gaia allows three-dimensional models to be made of our local stellar environment and the motions of the constituent stars. C.f. orreries.
I’m sure that other examples can be given with a little thought.
A few years ago I was given a chocolate teapot as a Xmas present. It worked entirely according to spec.
It was designed to melt when boiling water was added, the liquid then to be used as a fondue-like coating for other edibles such as pieces of fruit, biccies, etc.
Thanks for prompting me to re-visit the S-G algorithm. As a result I found https://cran.r-project.org/web/packages/ADPF/ADPF.pdf
which describes an implementation which automatically optimizes the polynomial order. The window width still needs to be chosen by hand.
Two standard approaches, one lazy and the other more rigorous.
Lazy: guess the width of the signal peaks and set the smoothing window to be around 3 times that. Use degree 2 or 3 polynomials unless the window is very large (over 20 say) when you could choose degree 4 or 5.
Rigorous: Compute residuals for a range of window widths and polynomial degrees. Perform statistical tests on them and choose the filter which best passes your acceptance requirements of high noise to signal ratio (that way round because you are trying to remove all the signal from the noise). The Durbin-Watson statistic, which measures autocorrelatIon at lag 1, is a simple test which tends to work well, but a fuller autocorrelation at a variety of lags might be more appropriate.
Wikipedia has good articles on S-G, D-W and several other tests for signal in the presence of noise. Easy to use implementations are all over the place. I tend to use R as it is free and portable, unlike Matlab and Mathematica.
Fascinating!
Have you tried good old Savitzky-Golay smoothing? It was specifically designed for smoothing (and differentiating) spectra. If so, how does it compare with the wavelet approach?
Here it is: https://ui.adsabs.harvard.edu/abs/1997ApJ…482..420L/abstract
Hydrogen burning continues in the fully convective body of a low mass white dwarf until the temperature drops below 2000K.
White dwarfs in binary systems very often undergo hydrogen fusion. The BAA-VSS observes them all the time. I admit this is stretching the terminology for “energy output in white dwarfs” but still …
The temperature may be quite low but the density is so high that hydrogen fusion still occurs in white dwarfs. I have seen an estimate that about 5% of the luminosity of a 10,000K WD is due to this process. I will see if I can dig out the reference if anyone is interested.
“But for the amateur discovery and initial classification of SN 2018gwo, it might have been missed.”
Nice one Robin.
https://tvlapalma.com/not/18598/incendio-palma-continua-estabilizado-vecinos-evacuados-aun-no/ has a good report and an aerial view showing the burnt area and (apparent) lack of active fires. It explains that evacuees can not return until the authorities are certain the fire will not start up again.
If you don’t read Spanish, Google Translate will come to your aid.
The fire is mostly under control, though there are still some hot spots that need attention.
A major problem has been the weather. About 20% humidity, winds up to 50km/hour and temperatures up to 35C.
Last night I opened up the observatory and took some images. The dome temperature never fell below 20C and the wind-induced seeing was about 6 to 7 arcseconds. No good for pretty pictures but photometry was possible, albeit at the cost of markedly increased exposure times.
Wind is really howling now …
To be fair to Python (which is hard for me because I have a profound dislike of the language) the various point releases (e.g. 3.7 versus 3.8) appear to be very backward compatible. Something written for 3.7 will almost certainly run without any issues on 3.8 and, when it arrives, 3.9. Problems can arise in the other direction but old code tends to run well.
The real problems arose when Python 2.x reached end of life earlier this year. Vast amounts of code is now on emergency life support with kludged-together installations of Python 2. Much more is unavailable. To give just one example, my favourite GUI network scanner, zenmap, is no longer part of the Linux systems I run.
So do I. The calimas around here have been dreadful recently. Last night had noticeably better seeing but poor transparency. Saharan dust and a full moon are not conducive to good imaging. Some more data was taken, down to an altitude of 20 degrees this time, but my expectations are not high.
It is many years since I last had contact with Graeme. We used to see each other moderately often when we both worked at Oxford University.
Any chance that you could pass on my contact details to him please?
Indeed. A comet in an orbit with eccentricity of 0.99999 has a large but finite period. One with an eccentricity of 1.00001 has infinite period in that (pending a gravitational interaction with some other body) it will never return to the inner solar system.
As expected, the image is not very good. The 19 minute exposure in ~5 arcsec FWHM seeing was not long enough for an 18.4 magnitude object only 15 arcsec from a star six magnitudes brighter.
The position of the WD is marked, the star is just about visible but not obvious. For comparison a snippet of the DSS2 image is included. The fainter (north-easternmost) star between the two brightest is mag 17.8 in Gaia DR2. The poor seeing is especially well demonstrated by the inability to resolve the ~6 arcsec double which is visible in the DSS2 image.
I will try again with a longer exposure in much better seeing conditions before uploading to my personal web page.
Tonight was the first session of this stay in La Palma. I imaged the field and there is something there but the WD is rather drowned out by the bright star.
Not a very good night with some moon-lit haze and high winds, which makes for poor seeing at this site. The relatively low altitude of the star (30-33 degrees tonight) at this latitude most certainly does not help.
I will process the data tomorrow and see whether there is anything worth posting.
Now that I´m back in Tacande I’ve been able to see the comet for the first time. In the UK I had an obstructed northern sky which is brightly lit by Cambridge city. Here (at latitude 28 degrees north) UMa sets behind the mountains around midnight or so but was well above the horizon at about 2100 local time (circa 18:45 UTC).
The comet was an easy naked-eye object. I guesstimated a roughly 3-degree tail when viewed through 7x50B. The sky was slightly hazy so perhaps more could have been seen under ideal conditions.
Far too big for me to photograph much more than the coma, so I won’t even try.
