globular

That's a good offer John. I accept. Where should I post my right arm in return for your ES 17/92 ?

Thank you John

Snowman on 2nd August… very nice

@jetstream Have I got this right…?….. When used visually / in real time the ccd filter will show a dimmer nebulae because it’s cutting 10% of the oiii light (rather than 1% with the visual filter) and because it’s losing all but the 501 band (while the visual one keeps the less intense but still important 497 band too). When used photographically the lower transmission is not an issue because exposures are longer. And narrower bands keep the images tighter.

According to well established physics, we're all doing both until someone opens the box and looks.

In case you hadn't noticed, the 30mm ES 100 is a 3" eyepiece. Can your scope handle that? If you are limited to 2" EPs and are looking for something around 30mm then the widest undistorted FOV you can get at that fl is (theoretically) about 88 (90 with some minor distortion) ... but most quality EPs at this focal length don't go above 82 or so. If you're all set up for 3" EPs then ignore me .... and enjoy.

I’m another visual only. And fairly new too. SGL posting is not an accurate way to gauge the answer - nor is Stu’s idea of asking retailers - but both of these methods will likely point to the majority of new to the hobby users being imagers. I personally (and without any evidence) suspect visual only will still be in the majority over all protagonists. You, John, have been a long term visual poster (and long may it continue) sparking interest and enjoyment in parts of the sky the rest of us have forgotten or overlooked. And there are many others here too of course. But it’s not as easy as it looks to write interesting and engaging visual observation reports. So the numbers engaging in it are, sadly, low. p.s. like Jiggy67 I draw like a one year old too but I’m sticking with sketching and very much enjoy the process - I feel it improves my observations. I just don’t share them as often as perhaps I should.

Your astronomy delivery got canned?

You say you have "just" got your scope? So maybe you don't know about the evolution's mirror locks? These knobs, when engaged (i.e. fully screwed in), clamp the mirror - useful for avoiding mirror flop. When you're focusing though, they should NOT be engaged (i.e. unscrew them a good number of full turns) so that the mirror is able to move freely and come to focus. [Apologies if you already know this.... just thought it was worth mentioning.... it caught me out the first time out with my evolution.]

Skysafari says the distance is 510pc (=1700ly) but in the description says it's 18,600 ly. A quick google seems to suggest it's not just Skysafari that list both of these measures. e.g. wikipedia entry: I though 1pc = 3.26ly but that means 512 pc=1770 ly and 18600 ly=5705 pc So which is it? Or maybe it's not an inconsistency and I'm comparing apples and pears?

aside: for me the exit pupil limit is 0.5mm - much lower than you but just the same impact on my thinking.... I was convinced there was an issue with the EP(s) or my barlow(s) or my diagonal(s) or the scope.... and I would not believe people who told me otherwise... until I'd tried so many combinations that it couldn't possibly be the same issues in each... and the realisation hit that it was the limit of my eyes and there was little I could do about it.... Some people find binoviewers help... i.e. can take a small exit pupil with binoviewers before floaters spoil the view.... but everyone is different and I've also heard that some people think binoviewers make it worse.... I suspect you'll have to try and find for yourself what works best for you.

Presumably the EP is fine in the refractor without the barlow?... i.e. when the exit pupil is larger? Personally I think this confirms that 1.3mm is the point at which exit pupil is getting too small for you - rather than confirming there is a problem with the EP. I suspect any and every EP at 20mm you try in the Daystar (or together with a 2.5x barlow in your refractor) will give you this issue. It's amazing what tricks your eyes play when at their limits... both the small and large ends of exit pupils... so I personally would not rush to spend money chasing dust bunnies in EPs that are probably not there... but rather I'd pick scope and EP combinations that keep your exit pupil above 1.3mm.

Do you have a 2.5x barlow? Try the pentax + barlow in the refractor and that will give similar exit pupil as pentax in Daystar - and hence a more similar comparison of impact of bust bunnies and floaters. (assuming your refractor is F6.25 ??)

Same issue in multiple EPs seems to suggest it's not the EPs themselves. Do you have a 40mm EP and a 2x barlow you could try.... does that combination give the same effect? If so that's a third EP and so even less likely to be them at fault. (Unless you are storing all your EPs face down on two spikes? 🤣 ) It sounds like it might be exit pupil issues to me. What exit pupil are you getting with these 20mm EPs in that scope? (exit pupil = EP fl / scope F ratio) And how do you get on at that same exit pupil in other scopes That said - isn't the scope F/15.5 ish? Making exit pupil 20/15.5 = 1.3mm ish. This is not usually small enough to cause serious issues... but everyone's eyes are different....

@vlaiv what do you make of this…. https://www.anthropic-principle.com/preprints/manyworlds.html You can safely fast forward to ‘Q23 How do probabilities emerge within many-worlds?’ - the rest can be skipped. This isn’t really the point I was trying to make, and failing badly, but it is perhaps a more mathematical argument that probabilities and many worlds do work together? Maybe this will give you a new way of looking at it? Or maybe you can set out what bits of it you are not convinced by?

The weights are the amplitude of the wavefunction of the vibration that has just collapsed. And the sum of the amplitudes of all the vibrations (in this case 2 vibrations, H and T) is the amplitude of the originating worlds wavefunction. But once you are sitting in world H then you can't know anything about the amplitude of T... because that world is: Therefore you can't work out the amplitude of the originating world... and so you can't work out your 'privilege' in the universe. All you can do is postulate about the relative size of worlds that will stem from yours. ..... This is now the conversation we had before. I thought the lightbulb moment that you describe above might have brought us closer together on probabilities - as it seemed to have done on the general many worlds theory. I'm pretty comfortable with probabilities sitting nicely within many worlds - but I know you and many others are troubled by it. I'm sure you know more about this than I do - I eagerly await your next lightbulb moment when you can explain to me how probabilities really work.

You can't just count the branches, you need to weight the branches (using amplitude of the collapsed wavefunction as weight). If you know the amplitudes (i.e. if you know the 1/3 2/3 thing) then you get the right answer. But sitting in one of those worlds you have 'lost' all information about the wavefunction - because it has collapsed. All you can do is theorise about the wavefunction of what might happen next - not about the ones that have already happened. You might conclude that they are the same.... but they might not be.

and if the wavefunction that just collapsed had an amplitude of 100 then the H vibration will have amplitude 67 and the T vibration amplitude 33. So the single wave of amplitude 100 is now 2 with amplitudes 67 and 33. The HHH world resulted from the collapse of a vibration of amplitude 30 (=100*2/3*2/3*2/3), HHT's amplitude was 15, HTH 15, HTT 7, THH 15, THT 7, TTH 7 and TTT 4. They all add up to the original 100 - but we now have 8 smaller amplitude vibrations than collapse into 8 different worlds. This means that someone sitting in the TTT world will not know the relative amplitude of the wavefunction that collapsed to create it compare to the other worlds that they might imagine were also created.... so while they can guess that their world is 1/2 * 1/2 * 1/2 = 0.125 compared to them... they would be wrong (it's 4/100 = .04) .... but they don't know it as there is no longer any interference between worlds.

I think of the probability as proportional to the amplitude of the 'vibration'. If you are in a particular world you no longer know what the amplitude of the wavefunction that has collapsed to 'create it' was... but if anyone could see all the possible vibrations before collapse then the probability of ending up following a particular one is related to the amplitude of that vibration. I know I've offered this thinking before on another thread... and you were not overly impressed with my contribution.... but I thought I'd offer it again.

Frustrating for you. All seems well for me on that version... maybe some small comfort that there must be a solution? I presume you've checked the Safari app for any updates?... I seem to remember there was one pushed out to me a few days ago...to 6.8.5.2

My ipad is on 14.6 (18F72) and Skysafari 6 Pro seems fine.... I've just launched it and used a few functions and all seem well..... does any function in particular cause the message to pop up?

To my eyes all the stars look brighter in your last 12 subs compared to your first 12 - so I think it was a change in local conditions (our atmosphere or your local pollution perhaps?) rather than a very rapid change in the nova brightness. Good spot though - and nice captures

Like the colour coded bike

Any news? It seems rather odd that these are so hard to get in UK/EU and yet are not at all scarce in the USA. May be the local distributor isn't trying very hard? Just as frustrating for you as it is for me I'm sure.

When you get a glob picture you're happy with maybe you could send it my way for use as my avatar? 😇 I'm not an imager and the stock one I'm using is... well.... I'm sure you can do better 😉