Zermelo

https://www.firstlightoptics.com/diagonals/stellamira-1-25-90-di-electric-diagonal.html

I think quite a few physicists agree with this. For example, when GR predicts an infinite density for a black hole singularity, it's an indication that the theory has broken down, and not that there really is a point with infinite density. In my mind I distinguish between, for example, (a) the universe may in principle have infinite extent, and (b) some physical quantity may take on an infinite value at a specific point. I'm comfortable with (a), but not (b). Perhaps in the same way that mathematicians (at least, before Cantor!) were careful to distinguish between the "potential" infinite and the "completed" infinite. The latter was considered beyond the pale: division by zero does not give "infinity" as an answer, it is undefined.

If anyone missed the link to the key, it's here. My home is placed within the 20.91 - 21.25 band, probably around 21.05 - 21.10 based on the neighbouring regions. This agrees quite well with my experience - the darkest I've measured here with my meter is 21.02. Intresting that (in the Wikipedia mapping, at any rate), anything better than 21.75 is mapped to Bortle 1. But on the Lorenz map, that range is split across five colour bands, because the bands are narrower at the top. So, for example, the darkest parts of Exmoor National Park are claimed as Bortle 1 in their guide, and the map is not inconsistent with that, showing in the 21.69 - 21.81 band. But there are parts of Wales, and especially Scotland, that are in the darker bands.

I pre-ordered before release and paid £127 direct from Svbony. When the word got around about how good it was, I expected the price to firm up a bit, but in fact there have been some sporadic discounts from that level. Worth watching for a bit before buying.

The Bortle scale is defined descriptively, but it is often simpler to assess in terms of a numerical sky brightness value, mapped to the Bortle scale as in the link above. The definitions are discussed here : https://en.m.wikipedia.org/wiki/Bortle_scale https://skyandtelescope.org/astronomy-resources/light-pollution-and-astronomy-the-bortle-dark-sky-scale/

Spoken in true SGL fashion

Thanks, that's worth knowing. For now, if I need to separate the mount and tripod, I just detach the top part of the pillar by slackening off the three screws, so I don't need to disturb the 3/8" connection.

That is fascinating, @vlaiv. I'd come across the -1/12 business previously, but only as an isolated oddity, a cautionary tale against careless manipulation of infinite series that don't converge absolutely. I was also vaguely aware of the renormalization practice for removing infinities in QFT, and whlie the maths was beyond me, it did seemed to be a bit of an ugly cludge. Bringing the two things together like this is very intriuging. One of the onward Youtube links is to another video that does discuss (unlike this one) the connection with the zeta function and its analytic continuation, and the spooky ζ (-1) = -1/12. It would be amazing if this new paper does prove to be onto something fundamental. It would be another example of deep connections between pure maths and fundamental physics.

I found this too, with the same tripod. The short plastic pillar connected the tripod and mount easily, but when I substituted the longer alloy pillar, the threads seemed to bind.

I've always used my right eye, but it has more astigmatism than my left, which becomes a problem with larger exit pupils. It has deteriorated another 0.25 cyls at my last checkup, so I've been experimenting with the left eye for observing with longer FL eyepieces. It still feels a bit uncomfortable, but the stars are rounder. Like you, I see floaters with the moon at higher mags, but they're as bad with either eye.

on the plus side, leaving the cover on means that you don't need to bother with a shroud.

I'll be watching this closely, when I'm not watching that feed of the pitch dropping.

Just to check - you're saying there's now a way of setting a top speed in SkySafari that won't be exceeded during goto operations? I've been waiting a long time for that. Which version are you running? I have 7.1.10.8, which is the latest in Play Store, but I can't see any setting in my version for that feature.

This is how I use it. I sometimes think it's fixed, but I've gotten used to it.

If it's connecting initially and then disconnecting, have you told your device not to go looking for a WiFi with Internet access? I've had that before, and I needed to tell my phone that it was OK to stay connected to my mount WiFi even though it had no Internet connection.

I just came across the following account of the history behind the helicopter proposal, the strong opposition that it faced throughout, and the efforts made by a few key individuals to safeguard it: https://arstechnica.com/space/2024/02/before-ingenuity-ever-landed-on-mars-scientists-almost-managed-to-kill-it/

Yes, connect with SynScan first. SkySafari needs configuring with a connection on 192.168.4.2, port 11882.

We have had the 10" Dob out again. Conditions were good for a couple of hours; seeing was better than of late, around II, and quite transparent. The Dob was well cooled this time, and I could really see the effect of the extra aperture. The fourth component in Sigma Ori was obvious, and nearby Alnitak (2.1") was comfortably split, so I went up to 32 Ori. That was a harder at 1.4", but eventually yielded to the Svbony 3-8mm zoom at x254. Encouraged, I went for 52 Ori (1.0"), which I seldom split with smaller scopes. It was actually easier than 32 tonight, perhaps down to the closer mags. Down to the Trap, backed off the Svbony to x212 and the E and F stars were both obvious. I'm fairly sure I've only seen the six once before. M42 itself showed some astonishing subtleties to the nebulosity in the Morpheus 14mm (x91). M45 was not quite contained in the 30mm UFF (1.6°, x42), but with surprisingly good contrast. M37 was impressive in the 17.5mm Morph, but by then some high cloud was forming. So M33 was barely seen, and Jupiter not as good as I've seen it. But overall a very decent session, and I'm happy with the mirror now that I've tweaked it a bit. Collimation was probably not spot on, but close enough.

Perhaps you are looking for a single formula that takes all the parameters into account? I've not seen one. The capabilities of the instrument and of your eyesight both impose limits on the resolving power, and either may be the limitation in practice. Usually, it's the instrument (aperture) that is relevant, and the usual formulae assume perfect instrument optics, normal visual acuity, and the absence of other limiting factors. If you're splitting doubles, then it would be more usual to be employing higher magnifications.

The aperture is relevant to the initial answers you received. It sets a lower limit on the tightness of doubles that can be split, irrespective of eyesight. Then you need to take account of the limits of your eyes, and if the instrument is operating at a low magnification, the retinal cells may not be close enough to take advantage of the resolving power of the instrument. An eagle might be able to see finer splits with your binoculars than you can.

The presence of another WiFi network shouldn't stop you connecting, though with some phones you have to tell them not to switch from the mount to another network in order to get an Internet connection (which the mount network does not provide, of course). Also, make sure to switch off the phone's mobile network connection.

I dip in occasionally, but I don't find it as easy to use.

I have a saved search on eBay for second hand Morpheuses. It finds one about once a month, but they're often priced more than the new price.

All the forecasts were for cloud this evening, but I popped my head out of the window at 7pm and saw stars. So, just time for "first light, part three" - not a Rambo sequel, nor a season finale for Star Trek:TNG, but another attempt to get a decent star test on my new Dob. Earlier today I had taken the primary cell off again, and slackened off the mirror clips a second time. In fact, I undid each one until I could rattle the mirror under it, then tightened it just until it couldn't move. The 10" Bresser has a nine-point mirror support, so I also checked the screws there. Then re-collimation, of course, which I'm not 100% sure about, but looked OK. I found Jupiter first, and it looked good. Then the cloud appeared. I just managed to switch to a brightish star and defocus. This time, the pattern was symmetrical and round, with no hint of the triangular aberration I saw on the previous two occasions. It was still mushy and boiling a lot, but probably still cooling down, and I couldn't really assess the seeing either. So, I'm happy not to tinker again until I've had a decent session with it.

I don't know if you count this as serious, but I did read somewhere that this series contains a plastic element: https://www.svbony.com/optional-lens-4mm-10mm-23mm-eyepiece/#F9301AA I have a pair of the 23mm.