Jump to content

NLCbanner2024.jpg.2478be509670e60c2d6efd04834b8b47.jpg

Odd transient spikes coming off the sun

Kaptain Klevtsov

By Kaptain Klevtsov
in Imaging - Lunar

Recommended Posts

Kaptain Klevtsov

Kaptain Klevtsov

Posted
Posted

Playing with a PST this PM I had the webcam on and, because of the clouds, I had to edit the AVI files to cut out the black frames. Whilst scrolling through one of the files I noticed that there were radial spikes from the limb to the edge of the frame. These lasted 1/5 second or less as they appeared on one frame only, so I thought I'd ask the people who might know what they are called. I tried Googling "spiky sun things" but got nowhere, if I know the name I can learn more about them.

image.jpg

image.jpg

image.jpg

In this sequence there is a normal frame, then one with a spike event to the left of the hump bit, then another to the right. They show up better when they are shown in sequence but they are just visible here.

TIA

Captain Chaos

Link to comment
Share on other sites
  • Replies 26
  • Created
  • Last Reply
Kaptain Klevtsov

Kaptain Klevtsov

Posted
  • Author
Posted

Nice one CC. I am thinking about a PST come the new year. How are you finding it?

OK Gordon, quickie review.

Not enough focus travel to get the webcam to work normally, you need to use a Barlow lens to get it to focus.

DSLR will not focus without loads of trial and error, haven't finished this bit yet so I can't say if it will or wont at the moment.

Visually the effect goes from "wow!" to coarse Anglo Saxon depending upon the age of the viewer and those around at the time. The view is outrageous, as you can see stuff on the sun that you normally don't get to look at. The edge of the sun looks like some guys live there and they are lighting big fires around the edge. The disc looks like it has texture in a way that's not easy to convey using language, but it shouts at anybody who looks at it. We had my mum, my kids, my gorgeous chick, my neighbours, their kids, all lined up to have a look when the clouds allowed. My go was limited to aiming and twiddlng the tuning ring to get the "flames" showing, then when I looked round they were all queued up again. We all looked at it in turn for about an hour until the clouds messed it all up.

Today I had the thing to myself as the clouds were worse, so I tried the webcam and got some useable AVIs. None of them very good as they all had black bits from where the clouds came over. This all started after going to my nephew's first birthday for lunch so it was 5PM before the session started. I'm assuming that the AVIs will be better with the sun higher and a cloud free day would be useful as well with the seeing.

All in all a one trick pony that does it's trick very well indeed and well worth a look down. What I saw visually taught everybody who had a look a great deal and the webcam files showed up some fascinating stuff. Each frame is very slightly different, unlike planet zapping where they are all supposed to be the same, showing real time stuff happening on a scale that is awe inspiring when you work out how big these details are.

Fave toy at the moment, and I'm wondering about selling the Mak. as it is no longer my day 'scope. Shame the PST doesn't do planets or the stumpy white thing would be going.

More to follow,

Captain Chaos

Link to comment
Share on other sites
Kaptain Klevtsov

Kaptain Klevtsov

Posted
  • Author
Posted

Sounds good CC. I was considering buying one of these but then i saw that some people are using the Ha filters attached to ED80's for higher resolution. I look forward to your next solar posts! Keep us informed :laugh:

Not at all the same thing I think Gordon. I have the setup with Baader film on the front of the Mak. and a Ha filter on the EP / webcam. Result - no "flames" off the edge, no Leopard skin rug effect on the disc, all in all it doesn't work anywhere near as well.

If you mean the Coronado filter on the front of the ED80, then that costs more I think, bu then the effect should be better than the PST due to the bigger aperture.

HTH

BTW that Chewy guy is selling his just a couple of days after I bought mine.

Captain Chaos

Link to comment
Share on other sites
Astroman

Astroman

Posted
Posted

Are those consecutive frames, CC? If not, how many frames between? If so, you've got me stumped for the moment, because if they rise and fall from consecutive frames, they'd be superluminal, given the distance they travel. I'm kind of leaning toward seeing effects, but can't be sure. Were they repeatable? Meaning, did they show up, disappear, then reappear? Interesting, at any rate.

Link to comment
Share on other sites
Kaptain Klevtsov

Kaptain Klevtsov

Posted
  • Author
Posted

Movie should be here thanks to Grant!

http://stargazerslounge.co.uk/uploads/Sunspikes.wmv

The clip is unedited but snipped out of the middle of the file, so that the bit you see is in "real time". The first "event is to the left of the bonfire, the second to the right of it.

Hope it works

Captain Chaos

edit, just tried it, it does, YAY!

Link to comment
Share on other sites
Grant

Grant

Posted
Posted

For those who don't want to download it, this should work (hope its ok doing this CC)

Absolutely mate, thanks for letting me park it on your server.

Captain Chaos

No worries mate, feel free to chuck anything you like on there that you want to share, you've got the details now... regardless of the size too, we've got plenty of space!

Link to comment
Share on other sites
Astroman

Astroman

Posted
Posted

Ok, I think I have the answer. When you observe the Sun in H-A, you necessarily have to look at a very narrow waveband, on the order of a fraction of a nanometer. Most features on the Sun are moving very, very fast. The loops you have recorded are visible at the wavelength the PST is tuned to. The transients are parts of the same loops, but due to their velocity are momentarily doppler shifted into and out of the waveband of the PST. In other words, they are moving very, very fast and only momentarily are within the tuned range.

As I looked at it carefully, with the ambient lights off, I could also see seeing effects, but these were not the answer.

So, does the above make sense?

Link to comment
Share on other sites
Kaptain Klevtsov

Kaptain Klevtsov

Posted
  • Author
Posted

Absolute sense, dunno what else it could be.

So what you are saying is, if I got my head round it correctly, that the narrow bandpass of the PST means that everything in view is travelling in the same direction and at the same speed, either towards us or away from us, according to the tuning ring setting. That's because the Ha waveelength is modified by the things moving by the Dopper effect.

So the thing that I snapped was momentarily travelling at the right speed to show up as a transient flash in a similar way to the sunlight reflecting off a car window that you occasionally see. The reflection flash is very fleeting, but the car is there all along.

The spikes could be carried around by the rotation of the sun or be moving around on their own and only show up for a split second when they match the tuned wavelength correctly because their velocity is correct.

Makes sense to me

Captain Chaos

Link to comment
Share on other sites
Astroman

Astroman

Posted
Posted

Well, that's close, but not quite. Your initial sentence isn't quite right, but the rest is pretty good. H-Alpha is a narrow wavelength and very specific. Features don't have to be moving in the same direction or speed to be seen, but they do have to be moving slow enough not to be doppler shifted to either side of the center frequency. All features move very fast and are doppler shifted, but not enough to change their wavelength enough to shift it out of H-A. The loops you see are probably moving at, say, Mach 25 or more. High speed, but their doppler shift would be minimal, maybe .02 nm. The transients may have been moving an order of magnitude faster, say Mach 50, causing a logarithmic increase in doppler shift, perhaps .1 nm. This would be enough to shift it out of the tuned wavelength and back in when it decellerated. The window flash is a fair analogy though.

The spikes were probably not carried around by the rotation in a time frame sufficient to cause or affect what we saw. It may bave been more of a polarization effect. If you've seen my second solar talk, I talk about how an etalon wors. It describes the factors in play for it to function. One of which is the angle at which the light enters the etalon. If it's shifted slight, it may be reflected rather than passed. If your PST had been rotated slightly with respect to the transient, you may have seen a complet loop, while other parts of the stable loops were less visible.

One thing that tipped me off was if you look closely, the spikes are indeed aligned with the stable loops you can see all the time. This told me that the polarization was ok, but the velocity may have caused the effect. These things don't travel at a constant speed. Since they're propelled by magnetic flux, the density of the field has a lot to do with their speed. If they hit denser field, they may slow or accellerate, depending on their own ionisation or charge.

Link to comment
Share on other sites
Kaptain Klevtsov

Kaptain Klevtsov

Posted
  • Author
Posted

I'm still scratching my head over the logarithmic increase in Doppler shift bit here. Also I can't get the entry angle bit to gel yet. Are we talking polarisation angle (how would that happen from a prominence?) or something else?

I will get to learn about these things when my brain gets enough sleep, kind of a benzene thing with me.

Captain Chaos

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.