Zermelo

That might take the record as the most significant purchase ever made to avoid a postal charge.

Courtesy of @The60mmKid, some excellent books. Although I use planetarium software to manage sessions and and create plans, I also like to have books to browse and inspire me.

Hello, have you seen this current thread:

Vulcans are known to be stronger than the average human

I've just come in, as cloud is starting to appear. The forecasts for the last three nights were far too pessimistic (apart from the BBC) so I set up anyway. It was a really excellent evening, transparency and seeing were both very good. The milky way was obvious and detailed, withe the great rift showing well. In the Mak, a variety of targets looked excellent. Open cluster IC4756 filled the widest eyepieces with stars. The Wild Duck was also on good form, at low magnifications showing granularity more like a glob, and resolving at higher power. M92 was as good as ever, while NGC 6934 in Delphinus is one of the less impessive globs, just a faint patch. Planetary NGC 6572 was obvious, but without colour, and M27 was showing its apple core shape well. Doubles included HD 203358 and HR 7083, and iota Cassiopeiae was much better than it was last month - three components were showing very clearly, and the set was motionless and very beautiful. Saturn in a yellow filter showed the Cassini division and the barest hints of cloud banding, along with moons Titan and Rhea. Jupiter showed four bands, but went behind the encroaching cloud before I could get a decent look. It was also the first outing for my 12.5mm Morpheus, and it did not disappoint. In particular, it gave very contrasty views and a dark background. The second light for the SvBONY 9-27mm was also very successful - sharp, with decent contrast.

Yes, the problem is the additional phosphors. As soon as cheap blue LEDs became available, it was possible to create a tri-colour bulb that looked white, but the reflected light from such a source does not render many colours faithfully (ie as sunlight does). Hence the incorporation of broadband phosphors, using their continuous spectra to produce more natural colours. LED bulbs are now often described with their colour rendering index, in addition to their luminance and colour temperature. I suspect that the market for interior lighting has driven the change, but in surveys people often say that they value "natural" street lighting too. Since I bought a pocket spectrograph, I've looked at white LEDs (inside and outside) to see if I can find any pure tricolour bulbs, but every one I've tried has had a continuous spectrum.

Excellent. What sort of ages were the punters?

The 4.5mm I managed to pick up all the others second hand, but I may have to get that one new.

I already have the case 😀 The final EP will be on my Christmas list.

An amazing evening and an enthralling write-up. Thanks, Magnus.

Courtesy of @Astro_Dad , a barely-used 12.5mm: I'm now in serious danger of completing a set.

Yes, the clothes peg is a must, I'm surprised SW don't include one as standard. Cheapskates.

Now available on Sounds, with a few extra minutes at the end https://www.bbc.co.uk/sounds/play/m001qdx1?partner=uk.co.bbc&origin=share-mobile

That is true, but you won't see any difference between F/15 and F/11.8, if that's why you're asking.

Just after 9 o'clock this morning, on BBC Radio 4. Melvyn Bragg and guests will be discussing Albert Einstein.

One of the annoying features of the switchover is the lack of consistency between local authorities/their chosen contractors, and the slow emergence of best practice. Some have done their research, and sourced and fitted new units that direct the light downwards, make them no brighter than absolutely necessary, remove the blue end, and automatically switch them off at some time. If such a scheme replaces older lighting that was intrusive, then it is possible that it might constitute an improvement (though the point about filtering would still apply). Too many do not.

Without wishing to pry ... one factor you haven't mentioned is managing the weight and awkwardness of a larger scope. I currently have a 6", and I know I will want to get a larger one at some point, but I doubt it will be a 12". I could manage it now, but I'm thinking ahead a few years, when it will become more of a struggle. Obviously some makes and designs are lighter than others of the same aperture, and an important consideration is whether a specific scope is easy to assemble/disassemble, so that you can transport it in easy parts. Some manage with larger scopes because they have a handy shed and need only trundle it a few metres to the observing spot. The same scope might not be feasible if it lived upstairs in the house. And it probably won't be a binary decision - a scope might be manageable without causing hernias, yet just that little bit too much hassle for those evenings with a borederline weather forecast, so it might end up getting less use than it ought. Flocking - yes, it can increase contrast and improve visibility of fainter objects. It's difficult to be definitive, because it depends on context, such as how dark the inside of the tube was beforehand, and how much stray light from neighbours you have to contend with.

Yes, that is something. When they did my road, they directly replaced the low-pressure sodium bulbs with swap-in LED versions. Because the existing fitting within the housing was 2-3 cm below the flat upper surface, it meant that the light could spill out of the sides, even above horizontal. Other factors will be: - brightness. Many of the LED street lights are much too bright. Even if the light is directed downwards, it can be so bright that a lot gets reflected up from the road, especially if it's wet. - colour temperature. Many of these lights have a very broad spectrum, including a fair amount of blue. You won't really be able to judge until it's dark. From an observing perspective, I'm not sure that any of the LED replacements are better than low-pressure sodium (orange) lights. But your new ones may be among the better LEDs. Please let us know.

I can't find my dictionary, so I asked Chatgpt: The word "ethos" is a Greek term, and its plural form in English is "ethoses" or "ethe" (pronounced as "ee-thay"). Both forms are considered correct, but "ethoses" is more commonly used. I rather like "Ethe".

It's certainly intriguing, though don't forget the "phosphine in Venusian atmosphere" business.

I feel a change request coming on ....

You're correct in thinking that more has been said about the Skymax 127 than the Bresser, and I suspect there aren't too many people out there who have owned both. I have only the Skymax, so I can't give you any personal comparisons, though I'm very happy with the one I have. The Bresser is perhaps the more typical Mak at F/15, and most suited to smaller targets with higher magnifications. So certainly solar system, which you mention, and also the brighter globulars, planetaries and doubles. The narrow field of view will be a limitation on larger DSOs. My understanding is that the Skymax has more of a compromise design (effective aperture of less than 127mm, slightly larger secondary spot, tweaked baffling) in order to achieve a faster ratio of around F/11.8. This increases the maximum true FOV to just over 1 degree using a 1.25" visual back (more is possible with a 2" back, though it will vignette the outer field slightly). This makes the Skymax a bit more versatile in terms of targets, though possibly not quite as good as the Bresser as a planet killer. Some threads discussing one or both: https://stargazerslounge.com/topic/289452-bresser-or-sw-mak https://stargazerslounge.com/topic/413328-mak-127-or-102/ https://stargazerslounge.com/topic/334665-bresser-messier-127mm-f15-maksutov/ https://stargazerslounge.com/topic/406070-bresser-127

For this zoom - yes, there are no click stops. Others have them, like SvBONY's 3-8mm zoom.

Now that's interesting. I just checked my AZ-GTiX, and it does have the same knob. I thought it was different, just a locking mechanism, but the manual says it is indeed the Az clutch. I've never used it, I've just had it very loose, but the goto and tracking have been fine. It must be set up that way. My Star Discovery mount has an altitude clutch but nothing for azimuth.

That would be the "Tilt device to slew" settings option? I've never tried that, but I should give it a go. The Help text says that the manual slew buttons are hidden if the option is active. I'm wondering if the slew speeds in that mode are continuous, rather than the four discrete speeds available with the manual buttons. The app would be receiving information from the gyros at quite high resolution, so it should be possible. I find that I usually want something like a speed "2.5" as the best compromise between speed and noise, so that would be quite handy.