This is the filament I have spent most time analysing. It can be seen forming on the east side of the sun in the August pictures, but is at its biggest a full rotation later. The main difference between this and the previous filament is the strength of the magnetic field around it. One does not need to look too closely at this one to see where the polarity inversion line might be! As a result, a lot of the images here deal with the magnetic field, and the way it changes as the filament forms.
To start with, here's a hydrogen-alpha image of the filament. You can see that it is a lot thinner than the August filament, and much more clearly defined. It is also easy to see the white patches on the image, around the filament. These correspond (as seen later) very well with regions of stronger magnetic field.
Here's the full range of types of image, all taken on the 27th September 1997. From left to right we have: hydrogen-alpha, helium-1, MDI magnetogram, Yohkoh soft x-ray and finally EIT ultra-violet. As you can see (click the thumbnails to enlarge as usual) the filament is placed along the neutral line of a rather strong area of magnetic field. The same region shows up very clearly in each image, as oppose to the August filament, where it was more difficult to pick out features in the magnetogram or x-ray images. So now we have a full range of image types that all show something about this filament. Theoretically, it should be easier to produce and study interesting images.
Here is an example of the magnetogram image contoured over the hydrogen alpha. If you click on the image, you can see the full set of them. It is obvious straight away that the magnetic neutral line is where the filament sits, and the whole thing is more clear than for the August filament.
Here, rather than post a list of all the hydrogen-alpha images, I have made them into 2 short movies. It is best to view these slowed right down, since there are only 10 and 8 images in each, respectively. The first shows the early formation of the filament, and the second the week before it erupts. It is interesting to see the way the filament retains it's s-shape for such a long period of time. Hopefully it should also be clear that the filament grows and connects up during the month before its eruption.
This is my first attempt at an animation of the overlayed images. It wasn't possible to use the same techniques as I used for the other movies, so I have still got to work on improving it. If you click on the image, the movie will load and play, but it can't be controlled like the other movies. When I work out what's going on, I'll change it!
Movie of flux cancellation
Here, I have again put in arrows to denote a place where there is obvious flux cancellation. There is a much stronger magnetic field here than for the August filament, and so you can see a fairly big patch of negative polarity move closer to the white positive patch and start to disappear. I didn't think I needed to overlay a picture of the filament in h-alpha, from looking at all the images above it should be obvious where it lies. These images run from the 24th to 25th September 1997.
This is a movie of the early movement of the magnetic field. It covers a couple of days, from 31st August to 2nd September 1997. Being in black and white, I had a lot less trouble setting up movies like this. Bear in mind when you look at it that the filament lies along the polarity inversion line
This is the extent of my images for this filament. I could carry on for ages, making more movies and comparing every type of image availabe, but I believe I have the main properties covered. I have been able to chart the formation of the filament, and show flux cancellation. I would have liked to have been able to make a better overlayed image movie, but the one I did make was jumpy, and didn't show anything more than can already be seen, so I haven't included it.