Brutha

Hi All,

I'm using Autostakkert and waveSharp to create images of the Sun from my Seestar avi movies.

I'm very happy with what I can get in the interior part of the Sun, but there seems to be an abrupt change to quite a blurry image as we get near to the edge. I've included two images, the one with red/green shows the parts I'm happy with / not happy with.

I'm not totally sure where this is starting - but I have a suspicion it's Autostakkert - any ideas about how to troubleshoot?

Thanks for any thoughts!

EDIT: would like to resize these pics a bit smaller, but not sure how!

Ok, managed to sneak out for 5 minutes during lunch! Sun a bit livelier today - still some way to go to get the best out of the software, but happy with this one!

3 hours ago, Rusted said:

Some nice detail! Good first effort! Keep at it!

I liken a decent white light image of the sun to a hen's egg. Subtle but just visible surface texture. Your image is leaning just a little too far towards over-sharpening. IMO. The uniform texture is the clue. The texture should vary across the disk and be finer at this scale.

I am not familiar with waveSharp. You might try ImPPG. A free software much loved by solar imagers everywhere. Again it has the potential to seriously over-sharpen when used clumsily. A gentle touch will astonish with the real, solar detail which can be brought out.

Thanks! Will play further!

Hi All,

Have only had one clear day / night since I got my Seestar, so am now playing around with processing - all the astro programs are quite new to me so finding my feet a bit!

This comes from a one minute AVI taken the other day through the provided solar filter:

• Stacked in Autostakkert
• Sharpened in waveSharp (bilateral filter which avoids bright lines at edge of sun)
• Colour adjusted and cropped in Photoshop

What I'm wondering is if I've oversharpened it - it looks like the grain of the Sun is showing nicely (since I can also see detail around the sunspots in the top left). But maybe I am just sharpening noise in the image!

Any thoughts?

Thanks!

EDIT: Oops, I think I used the wrong forum and it should have gone in "Imaging - Solar" - is it possible for some kind mod to move this? Thanks!

11 hours ago, Giles_B said:

I've sent some subs of M42 by PM - sorry for the wait!

Received, thank you very much! No worries at all, about the wait, wasn't long at all!

45 minutes ago, PeterCPC said:

@jweaver100

I find that a tripod leveler is really useful. In spite of in built software I still want it level if possible.

 

One interesting note, is that there are many brands selling what appears to be exactly the same thing, for prices between about £20 and £50! Look for “LP-64” to see the range!

1 hour ago, Giles_B said:

You can use some of mine. I'm out at the moment, but I'll dig some out when I get home. Would you prefer nebulae or galaxies?

 

Perfect thanks! Not too worried, either is fine - something that doesn’t need huge numbers of subs would be a good start, M42, something like that!

Hi all, well my Seestar has arrived, and of course so has the bad weather! So, in the meantime I thought I'd have a go at learning the basics of Siril for stacking and image processing. 

Does anyone know of a set of Seestar subs shared on the web somewhere that I might use as an example to work on? Doesn't need to be 100s of frames, just enough to learn the process!

47 minutes ago, Elp said:

This is quite poor marketing by ZWO really. They should be more specific. Although technically it is a light pollution filter, more specifically it is a wide bandpass hydrogen alpha and oxygen iii dual band filter, so will provide some added contrast separation from background signal and emission objects rich in HA and O3 ionisation. As suggested try it and see, you'll see the effect pretty much straight away after a few minutes of live stacking.

And yes please post further queries in the much much larger Seestar thread.

 

Thanks! Will do!

4 minutes ago, Beardy30 said:

Try both and see what happens 

Will do, just wondered if there was a reasoning behind it! Actually I realised i hijacked the wrong thread, meant to put it in the main Seestar thread!

Hi All, have ordered my Seestar and looking forward to it arriving!

One question in the meantime: I'm aware it has a "light pollution" filter which can be switched on or off. However, I live somewhere where we don't really have light pollution (nominally Bortle 1): are there still cases where I should leave the filter on? For example emission nebulae?

Thanks!

21 minutes ago, Macavity said:

P.S. I live close to Sea, but gave up ambitions for a "Tidal Clock".
That's an entirely different Can o' Worms?!? (+ I don't even Fish!) 😅

Hehe, I have long wanted to do something similar as I’m also close to the sea, but in the UK the government guards the harmonic constants you need very jealously (because the tides depend a lot on the local seabed shape and have to be empirically measured)…. And I didn’t figure out an easy way to reverse engineer them from the short predictions they give for free!

On 29/10/2023 at 15:54, Chriske said:

We often shared files, Gina and myself
Gina's giant clock was one of here favourite projects. She printed it on here 'Giant printer'.
She sent a copy of here clock(she drew it her self..!!) to me. If I'm not mistaken it has a diameter of nearly 500mm
It used a small stepper...

Ah thanks for that! Yes, I am thinking of using a small stepper (maybe a 28-BYJ48, since as it has gears I can switch it off after moving it, and not use much power).

Currently I am thinking of something like the pic show - I will rotate the whole bit in the middle over the course of the day (with the notch showing local solar time), then update the hands maybe once a day.

But I haven't figured what to use to move the hands in the middle!

Cheers

1 hour ago, Andy ES said:

Best of luck with your project, it should be fascinating. if I ever finish decorating I would like to try something like this. 😂I I love my orrery app.

There was a very talented person, called Gina, on this forum, who is sadly no longer with us.

You could look at some of her posts maybe, as she made all sorts of clocks and 3D printed things.

Yes, I read a lot of Gina’s posts, they were always interesting, and I was very sad to hear she had passed away,

The picture you posted is very interesting - rather than just one large clock with lots of hands, probably a large clock with various small dials is the way to go - time for a ponder!

2 hours ago, Mr H in Yorkshire said:

In 1410 it was done like this! Do you have a big enough wall? Sorry facetiousness only no clever ideas.

Hehe, this was exactly one of the inspirations!

Hi All, 

I’m thinking of making an astronomical clock - not really as a really functional object because I need it, but rather as a nice thing to have on the wall and glance at occasionally! And also as a fun electronics and maker project.

The basic idea is that it will be a 24 hour clock face with 12 midday at the top (corresponding to due south). Then there will be hands corresponding to various objects - the sun, local sidereal time, the moon and as many planets as I can cram in! So, broadly speaking if the Jupiter hand is pointing to 9am, I know it’s currently up in the south east for example.

The electronics and programming to figure out *where* the hands need to point I think I can figure out (maybe a Pi zero or similar, or could be something more basic with an internet connection).

The trick is powering the hands though. Normal stepper motors use too much power I think to be left on 24/7. So it will have to be something similar to the Lavet-type steppers used in clock mechanisms - but these are generally very low torque, and I will want 8 or 9 of them powering different hands, so the gearing will be complicated, and I’m not sure the cheap clock mechanisms you can get on eBay will have anything like the torque required (although I have ordered one and will start some experiments!). Possibly I can build my own Lavet type mechanism with coils and magnets - but not sure!

An alternative idea was to have concentric rings on bearings, with each object being one ring. But again we have the issue of driving the rings.

Does anyone have any clever ideas?

Cheers

Brutha

Thanks for the detail response! So, I think I’ll start with the star analyser since it’s cheap enough to buy it as something to play with, then see how things go!

Hi All,

Somewhat inspired by the online astrophysics course I've been doing, I'm now tempted to have a go at a bit of spectroscopy.

The "Star Analyser" looks like a good place to start, but I was also looking at the "Solex" 3d printed spectrograph. The Solex would be quite a lot more expensive I think, but if I'm right it can with a bit of additional cost be used both to produce images of the Sun and star spectrographs.

So, question: with Solex, the approach is that you take a single slice of the sun and an image of all the spectra of that slice. Then, you let the slice drift across the sun, creating images as you go. Finally you can take the data and create images using a whole bunch of different wavelengths of light.

Has anyone tried the same thing with the Star Analyser? I guess you need a very thin slit and some kind of neutral density filter to do it?

And re: Solex, when used as a star spectroscope - is it a lot higher resolution than the star analyser?

Thanks!

Brutha,

2 hours ago, vlaiv said:

a) shine a laser one towards the other

Question - are these supposed to happen at the same time, t0? If so, how do ensure that?

49 minutes ago, vlaiv said:

Yes of course - both speed of light to be detected and sync pulse change depending on direction - question is does this cancel out?

 

I think so! But we'd need to do some examples with maths to be sure I think!

51 minutes ago, vlaiv said:

upon detection of sync pulse

Won't the sync pulse also be affected by the change in speed of light?

8 minutes ago, vlaiv said:

 

If we start rotation of machine on one end, we can distinguish two cases - we can either rotate it clockwise or anticlockwise. These two cases differ in what sort of effect they produce.

Are those actually different though in the end? Since in one case for the experiment to work the angle difference has to be negative, but in the other positive? 

I.e. if we rotate clockwise, I need the notch at the bottom to be e.g. 1 degree "behind" (as per a clockface assuming we are looking up the tube) the notch at the front.  But if I rotate anticlockwise, the notch at the bottom has to have the angle 1 degree "ahead".

2 hours ago, andrew s said:

Yes. It's a bit like trying to design a perpetual motion machine. Cannot be done.

Of course the impossibility is now build into the SI system of units.

Regards Andrew 

Thanks - now I get it!

As @vlaiv said, it takes time for any change to propagate along the apparatus, and this will depend on the speed of light in that direction.

If the speed of light is faster coming down the tube towards me, it will also take longer for the rotation to move up the tube.

So, if I've understood correctly, my experiment is also actually measuring the *two way* speed of light!

8 hours ago, vlaiv said:

Implicitly, such synchronization happens when we start to spin our device - that motion is in fact not transferred instantaneously from one end to another - it is after all mediated by same mechanism of EM force between atoms in the machine, so it takes some time for motion to arrive at the other end.

This is measurable though. You have a sensor next to each disk, that triggers a signal when the notch passes, and a device in the middle that checks the difference. Then you slowly ramp up the rotation till you get the timing difference you want.

EDIT - oh wait, I’ve assumed isotropic speed of electrons in the wire, haven’t I?!

10 hours ago, vlaiv said:

I think this is very interesting idea.

Varying the angle, rotation speed and / or distance can be used to "tune" wanted speed - and then we can use that to either have light pass thru or nor - which is confirmation that we have good speed selected.

Not sure what the margin of error would be for such measurement - but it could certainly rule out significant anisotropy.

We don't need star to do it - we can use laser / led diode - and this means that we could rotate setup in any direction.

Thanks! It sounds plausible doesn’t it?

But, I assume there must be some reason why it’s not as easy as I say. Although a 20m tube rotating at 500hz sounds a lot, we are not talking about something the size of a planet rotating at mhz! And this must surely be easier than the experiments measuring gravity waves….

My guess is that I’ve not understood the physics right - I’d love to know why!