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Thanks, Andy. No need for apologies – I appreciate that these things take time to sort!
Very best,
BillHi Andy,
I seem to have fallen victim to the “full name problem” reported by others. My preference is for “Bill Leatherbarrow” but it keeps defaulting to a rather pompous title plus full forenames on my web profile. I have changed this back on a few previous occasions, but now I cannot get through to edit my profile. Any suggestions?
Thanks in advance,
BillDenis,
so sorry to hear of this. I never met Rob, but am of course aware of his great contribution to the Lunar Section, often in difficult circumstances. I hope that a case for a Journal obituary can be made despite his not being a BAA member at the time of his death.
Bill
Rother Valley Optics do a lot of EQ6 belt mods, so it might be worth giving them a ring for advice. Their shop is closed, but still manned, I think, and I have always found them very helpful.
Can’t help further with the mount, but it’s snowing heavily here in Sheffield so I’m prepared to make a good offer for your hot-water bottle…
Good luck!
Bill
Hi James,
Good question!
The short answer is that because of the combination of various librations (libration in longitude, libration in latitude, and diurnal libration) the cycle of librations does not map onto the Moon’s monthly cycle. A more detailed explanation will require someone with a greater grasp of celestial mechanics and maths than I possess. Perhaps someone such will be along soon!
Bill
My guess would be that the central peak crater is just a perfectly positioned impact crater – the result of a ‘lucky strike’. Despite what Patrick Moore used to say, the ‘bomb’ does fall into the’bucket’ from time to time! I can see nothing to suggest the feature is of volcanic origin. The central peak complex is the result of ‘rebound’ following the impact that created Albategnius – it is not a volcanic cone with a summit caldera.
Sometimes, as in Gassendi’s central peak, what look like summit craters turn out to be just dimples between multiple peaks, but this one does indeed look like a proper crater.
Incidentally, the central peak complex appears to be off-centre, suggesting either that Albategnius might have been the result of an oblique impact or that the central peak was once a peak ring, the lower parts of which have been submerged beneath whatever has infilled Albategnius.
Hi Gary! I am finding the supply of eggs in Sheffield to be highly variable. Would you like me to draw a curve when I have made enough observations…?
Very best!
Bill
Hi Alan,
Difficult to be certain of identification without without seeing your sketch and knowing more details. It was certainly a favorable libration. Your best bet is the NASA Dial-a-Moon Phase and Libration 2019 website, which replicates phase and libration for whatever time you enter:
https://svs.gsfc.nasa.gov/4442
If you enter the date and time of your observation and then press the update button, the image will change to reflect the Moon’s appearance at that time. If you then click on the image you can download a detailed and zoomable image that should be identical to what you saw in your eyepiece and which identifies craters near the terminator. That should solve your problem.
Good luck!
Bill
Andrew,
Yes, that’s the one. It should help you find your way around the Moon using your refractor with a diagonal.
Happy hunting!
Andrew,
By far the best lunar atlas (and it fully meets your aesthetic criteria) is the one by Antonin Rukl, published some years ago by Sky Publishing. Unfortunately, it is now out of print and second-hand copies command very high prices.
Sky also publishes laminated maps of the Moon by Rukl, and these are still in print. They are available in normal and SCT-with-diagonal orientations. They are reasonably priced.
Hope this helps!
Hi David,
The NASA app Dial-a-Moon, when set for the hour of your observation, replicates what you saw exactly. I attach a crop from what it throws up. If you don’t know the website (which is excellent) you can find it at https://svs.gsfc.nasa.gov/4442.
I think the key to understanding the impression you gained is that the terminator bisects the floor of the crater, leaving the curve of the far wall catching the light beyond the terminator and producing the impression of a raised hump.
Hope this helps
Interesting article, Jeremy. Blagg’s colleague on the Collated List of Lunar Formations, S.A. Saunder, also has a (somewhat larger) crater named for him on the Moon. Coincidentally, I imaged the latter on the evening of 11th April – although my effort is not quite as good as the LROC image of crater Blagg! Saunder was President of the BAA 1902-1904.
Yes please, Tom. You can e-mail it to me at the address given inside the back page of the Journal.
Many thanks,
Bill
Yes, several reliable reports have been received and images taken. There will be a fuller report in the next Lunar Section Circular.
There have been several reports of a possible impact flash in the Byrgius-Lagrange area of the Moon, near the western limb, during the 21 January eclipse. It occurred at 04.41 UT and several observers managed to capture images of the event. There will be a full report in the February Lunar Section Circular, but in the meantime I would be grateful if members could check any images or video captures taken around that time.
Hi Garion,
As I mentioned in my earlier e-mail to you, a good map is an essential starting point. Nick mentions the BAA map, which is fine and can be bought from the BAA shop, but it has south up which might confuse you. The Philips map I suggested has north up. I also sent you a link to the ‘Dial a Moon’ website, and the 2019 version is now available alongside the 2018. If you key in the dates and time of your images it will identify craters near the terminator.
The images you posted show large areas of the Moon and it is not clear which features you are trying to identity. I can tell you that the large crater on the terminator in your first post image is Gassendi and the large crater to the left in your sixth image is Posidonius.
Hope this helps. Contact me directly if you need further advice on Dial a Moon.
Bill
Hello Lars,
Thank you for your careful and very thoughtful reading of my book. You raise some very good questions! Of course, contemporary lunar science cannot yet produce definitive answers for everything, but the case for how the lunar maria were formed is pretty convincing. This is probably not the place to go into lengthy detail, but I can certainly try to address some of your questions.
We should bear in mind that the recent Hawaiian eruptions and lava flows were on a microscopic scale compared with the events that created the lunar maria. The enormous energies released in the impacts that created the huge basins at the sites of subsequent mare development would have compressed, shattered, melted and fractured the lunar crust at the impact site. Such a compromised site would have provided a preferential route for the subsequent eruption and flow of magma on to the surface, magma that had been kept molten by the effects of churning in the interior magma ocean and the decay of radioactive elements.
As Wood says, once vented onto the surface the lavas would indeed have flowed relative easily over great distances, being much less viscous than lavas on Earth (the Moon as a whole is made up of less dense material). Also the larger maria at least would have been formed not in one go, but by successive lava flows. This is obvious in the Mare Serenitatis, where the flows of different lavas are obvious even to the eye at the telescope and appear as different colours and shades.
This would all have gone on until the Moon had cooled sufficiently to prevent the eruption of lavas on such a huge scale, (although smaller forms of volcanic activity continued long afterwards).
Thank you again for your interest!
Bill
