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I grabbed copies of AotDS V1,2,5,6,7 a few days ago while they were still available from astroshop.eu, though V6 will not ship until the new year.
Well pleased with them, but the text badly needed a proo-freader [sic] before printing. Now wondering whether to create a list of errata and make it available — assuming that no-one has already done so (I haven’t checked).
Now wondering what will become of vols 8 through 23-ish.
A more serious response this time.
In my view, the arrow of time would not stop, abruptly or otherwise. Everything other than photons, neutrinos, electrons and positrons would have decayed (we do not presently know enough about dark matter if it exists and supersymmetrical particles — if any — to know whether they are stable). However, positronium atoms would still be around, albeit with a typical size of a parsec or more. Plenty of opportunities for them to interact and form structures. So what if it takes petayears for each interaction?
I like Douglas Adams’ take on this:
“In the beginning the Universe was created. This has made many people very angry and has been widely regarded as a bad move.”
At the consumer / beginner level I suspect that the EA telescopes are the future, in the same way that smart phones became the future of the Polaroid Instamatic.
Those who wish to play with the big boys and girls are very likely to have diffraction-limited adaptive optics, automatic plate-solving, DSS charts (or their successors), the Gaia DR4 astrometric and photometric catalogue, and multiple photometric filters with associated analysis data & software built into their scopes as standard. I suspect that cameras which image in the main near-IR atmospheric windows will also become mainstream at an amateur level.
We are going to have to agree to disagree on bias images. As an amateur photometrist I often take Light exposures which vary between a second or few to a minute or few — roughly two orders of magnitude — for each sub. Bright stars saturate in less than five seconds; faint ones are barely measurable after stacking an hour’s worth of subs.
Taking bias frames is a matter of a few minutes work in my experience. Each image has essentially zero exposure time (almost by definition) and at most a few seconds download time. Also in my experience, processing bias frames is essentially cost-free in most (all?) software. After co-adding the bias images to create a master bias, flush their subs to recover the storage.
Very strongly agree with the advice about taking a good number of dark, flat (and bias!) frames to average out the noise. I generally use somewhere between 10 and 100 depending on my patience and the brightness in each filter of the fluorescent panel used for the flats.
You may have gathered that there are almost as many opinions as photometrists…
As far as charts are concerned Aladin and DSS are both free and far in excess of what printed media can realistically provide. I use them all the time and print off what I require as and when it seems like a good idea.
It is more the replacements for Burnham’s and Annals of the Deep Sky with which I am concerned.
I love the smell of old paper in the morning. It smells of contentment. I own many astronomical publications, a few of which are over 200 years old though very few can honestly be described as useful except in very unusual circumstances.
True. I had overlooked the possibility of actions such as detection of outbursts and period searching in time series of observations. Crazy, really, because I generally go unfiltered when observing exoplanet transits.
Hi Darren,
It is truly pleasing to learn of someone who wishes to do science as well as art!
I would strongly recommend getting a Johnson-V filter. It is by far the most used photometric filter and although it is possible to emulate its results by taking images in several other filters at the same time, that process is really not recommended unless you have no choice. It requires more exposure time with complicated calibration and data reduction processes to give inferior results.
Until your filter arrives you can spend your time productively working through the data reduction process on whatever images you have to hand. The results will not be compatible with measurements made in standard pass bands but you will learn much about what needs to be done. There are all sorts of niggles that need to be dealt with, as I have learned the hard way.
The LP weather forecast is also a bit Novemberish, i.e. typical for the rainy season. Tonight is a washout and we will be returning back to the UK on Friday, assuming Iberia doesn’t cancel our flights a third time, but I will see what I can do.
Three possibilities immediately spring to mind, two of which require that the neutron star is on the very brink of collapse anyway.
1) Accretion from the remainder of its earlier circum-stellar planets, dust and gas tip it over the mass limit protecting it from collapse.
2) Its rotational period slows down to the point where centrifugal force no longer keeps its equator far enough away.
3) Merger with an orbiting star tips it over the mass limit.
There could well be other explanations. I do not know enough about the equation of state of neutron-rich matter (who does?) to be able to decide whether cooling (for instance) could also cause a transition.
We may have to agree to disagree. There are quite a few “Paul Leyland”s on the net and finding the right one can be difficult. About once every year or two I receive wrongly addressed mail intended for one new to me. I am currently trying to fight Halifax Bank into accepting that I am not the droid they are looking for.
Accordingly I use two pseudonyms, Xilman and Brnikat, both of which are very unusual and so form excellent terms to feed into a search engine if you wish to find me.
Just finished a 2-hour set of exposures in Johnson-V. Nothing obvious in the quick-look stack and I don’t expect to be able to measure anything when the subs are processed properly. Best guess is <20.5 mag. but all will become clear soon enough.
A real pity conditions were not good enough here the previous couple of nights. Wind is still ferocious but at least the dust and clouds have gone.
Oh well, at least there is a nice GC in the field (at least one, perhaps more) and a whole bunch of supergiant stars resolved in the galaxy. An in-depth examination and comparison with sundry catalogues will doubtless turn up quite a few more interesting objects. I find it fascinating that we amateurs get about as good a view of M31 these days as Galileo did of our own galaxy.
I was observing AF And and AE And last night at about 20201030T2300Z. The full moon was so bright that I had difficulty getting an adequate SNR for them at around V=17 so didn’t even try for the recurrent nova.
It might have been possible, I suppose, but certainly would not have been easy to get an unambiguous re-discovery and almost certainly not decent photometry.
Tonight promises to be clear.
I have found errors in VSP. A few people with whom I have corresponded have also found errors. Some objects are missing from the VSP; some non-existent objects are included.
Unfortunately it appears that it may be difficult to get errors corrected.
How excited to get is a matter for you to decide. What I do is always to check with the MPC asteroid calculator and to compare with the DSS images available through Aladin. If something new passes both those tests, then I get excited and ask for confirmation. The last time this happened it turned out that the suspected transient was actually a ghost of a bright star. The slightly embarrassing details can be found on my personal collection of images here on britastro.org.
Just a reminder: M31N 2008-12a is due to go off any day now. This recurrent nova goes into outburst at roughly 11-monthly intervals and reaches mag 18 or so at maximum. It is visible for only a few days each time and nightly monitoring of the field is recommended.
https://arxiv.org/pdf/1607.08082.pdf contains a finder chart and magnitudes in a number of photometric bands for a number of comparisons.
This might be a completely off-the-wall suggestion but I observe that C-c{l,r}amps are available with a grasp of at least six inches, or 150mm. Almost the first link I found is https://www.yandles.co.uk/tools-machines/clamps-cramps/c604
Not entirely convenient perhaps, but very likely functional.
You reaction is understandable. Clavius is clearly not on the dark side of the moon because I have seen it for myself. Mare Moscoviense is on the dark side of the moon (*)
Anyway, there is no dark side of the moon really. As a matter of fact, it is all dark (+).
* In the same sense as Africa used to be the dark continent.
+ According to Pink Floyd. As the albedo is roughly the same as that of tarmac they make a good case IMO.
