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I don’t have a SQM either, but I still find the numerical value useful, and for essentially the same reason as you like the NLM.
Both give an indication of when the brightness of a stellar object is comparable to the brightness of the sky when observed with a particular optical train and detector. My eyeball is 100 times (5 mags) less sensitive than my CCD and has a resolution 30 times poorer (circa 1arcmin compared with 2 arcsecond seeing limit), so one resolution element of my eye collects 900 times as many photons as in one of the CCD, another 7.4 magnitudes.
Plugging in the numbers, a NLM of 6.3 corresponds to 6.3+5+7.4 =18.7 sky limit for my scope.
The corresponding instrumental estimate is 21.2 – 2.5 * log (2 * 2* π) magnitudes for the sky, which evaluates to 18.5.
That is a remarkably satisfactory agreement!I support this request and would add another, closely related one.
The Bortle scale, as well as being a simple number, is also a measure of sky brightness in terms of equivalent stellar magnitude per square arcsecond. I can never remember that Bortle 4 is, for example, 20.49–21.69 and invariably have to look it up at https://en.wikipedia.org/wiki/Bortle_scale
If the Bortle scale is added, could it be something along the lines of “Bortle 4 = 20.49-21.69 mag/(sq-as)”?
Thanks,
Paul
What a shame.
KK Tel at a declination of -52.3 degrees rises above my physical horizon (or so I believe, as I’m not sure what the physical horizon is any more) but is too far south for the design of the mount which limits me to a declination of -47.5 degrees. V877 Ara at -65.5 is much too far south.
PU CMa is no problem. I already monitor HL CMa.
Even if KK Tel was accessible it would be so low that precision photometry would be exceedingly difficult. The best I could do is pick up and announce an outburst.
Oh well. If you find any others north of -47, please let me know by posting here.
I asked Jonathan McDowell about the value of tracking the Ariane for as long as possible.
He responded that it would be very useful to get as good an orbit as possible so that it can more easily be recovered when it returns to this neck of the woods in 2047.
The astrometry is being co-ordinated by Bill Gray at http://projectpluto.com and I urge anyone here, especially the asteroids people, to follow it as long as possible.
Undoubtedly worth a try but you may have difficulties finding the target without a well-calibrated mount and having suitable comparisons in the FOV might also be hard. It goes without saying that the sky brightness will be so perhaps observing in the red and near-IR (r’, i’, z’, Rc, Ic, etc) might be advisable.
One of my images of a Venus – Neptune conjunction shows a 12th mag field star in a 2 second exposure in i’ — though not bright enough to be measurable, taken just 37 minutes after sunset. Essentially everything on the binocular program should be accessible.
Thanks for a good suggestion, I may try it when back in La Palma.
I will see what I can do, but as Tacande Observatory won’t be back in operation until February at the very earliest it will likely take relatively long duration imaging. Gaia is still within range of my kit (must try for it one day) so JWST shouldn’t be too much of a problem.
Thanks for suggesting this target!
“Maximum on A4” when printed in 3-pt FlySpeck font?
While I agree with your general sentiments, I believe any limit should be a little more precise. Perhaps 1000 words or something like that?
That said, both storage and bandwidth are essentially free these days. A picture is worth a thousand words — well, costs more anyway — and the BAA is quite happy to host many thousands of images. No technical reason to be parsimonious; the judgement should be based purely on aesthetic issues. My opinion, anyway.
My bit added to the pot.
I have also publicised this survey on the social media fora I frequent. Others might wish to do likewise.
I have the electronic subscription for two main reasons:
a) I am a cheapskate and it’s cheaper;
b) I already have far too many chewed trees in each of two houses. Doesn’t stop me collecting more, unfortunately …
I read both JBAA (and similar publications) formats about equally often and likewise in depth. There is something immensely comfortable about having a physical artefact, especially one which is much safer to read when lying in a hot bath or a sauna. That said, the portability and physical storage space of a digital version has a lot going for it.
Horses for courses.
I would love to have the C11, so I am in that minority.
Unfortunately I can not justify buying one but I can ask around.
For what it’s worth, I have heard from a couple of sources that if you want to buy a Meade OTA it can be cheaper to buy one fork-mounted and then throw away the mount than it is to buy one not so encumbered. That is a pretty damning assessment of the quality of a Meade fork mount as it implies its value is negative!
Takeaway message: if your kit is fork mounted, try advertising the OTA and offer to throw in the mount at a small increment in price.
As always, YMMV.
Since you haven’t found much in VSX have you considered looking for new CVs? Patrol lowish galactic latitudes and the SMC/LMC regions, perhaps, and see what shows up. Most will be Miras, semiregulars or eclipsers but you can ignore the red ones by checking with GAIA B/G/R photometry. It’s a shame the variability flag isn’t set in EDR3 or we could try to characterize newcomers.
Might be an interesting sideline. Certainly a golden opportunity to learn about how to handle big data — something amateurs are beginning to catch up with the professionals for many of whom it is now routine.
Good luck with whatever you decide.
In a further ATel a claim is made that IceCube picked up a neutrino from this object. If true, and significant doubt has been cast on the claim, it would be the first ever detection of a nova by a neutrino telescope.
https://astronomerstelegram.org/?read=15067 and 15073 for more.
Let me take a look at the ones I’ve observed from La Palma. Not sure whether by “southern hemisphere” you mean negative declination or so far south they can not readily be observed from the UK. Some equatorial stars are visible from both Chile and the UK.
… Checking … OK:
Not observed any ER or UGSS very far south, sorry.
HL CMa is a UGZ/IW so might be ok but not ideal for you. Very nice bright guide star near by, as is a white dwarf worth observing. The declination is -17 degrees.
BW Scl — a UGZZ+GZ/GWLIB Declination is -39 degrees.
There are doubtless thousands if not hundreds more. The previous advice to consult VSX is strongly recommended. Those two are just a couple I’ve observed.
How do you propose to observe them? Both Magellanic Clouds are full of variables of all kinds, so if you fancy more of a challenge …
