Small prominence on Sun

[DaveM]

The sun is pretty quiet, but there was one small prominence worth practising my imaging on.

[jjjnettie (Jeanette)]

It's a beautiful image David.
The colours are rich and the detail on the Sun's edge is incredible.
Is the bulge on the surface, under the Prominence, associated with it do you think?

[DaveM]

Yes, I think the 'bulge' is associated with the prom, though it is not the surface bulging out as such, but a brighter area that gets cropped along with the bright disk in this exposure. Next time, I would like to do separate images of the surface and proms with appropriate exposures and combine them into one image. Always something more to try...

[Matty P (Matt)]

Nice capture Dave, Well done. The Sun sure has been quiet lately.

Was this image taken with your DMK?

[DaveM]

Yep, along with a 3X barlow, (giving 1200 mm focal length). I've just upgraded it to 60 fps which helps. I am still mucking about with exposure time, gain and capture rate to see what works best. I've only just worked out how to stop the auto exposure switching over as the image drifts a bit from the edge to the surface and the brightness steps up...

[Matty P (Matt)]

Originally Posted by DaveM

Yep, along with a 3X barlow, (giving 1200 mm focal length). I've just upgraded it to 60 fps which helps. I am still mucking about with exposure time, gain and capture rate to see what works best. I've only just worked out how to stop the auto exposure switching over as the image drifts a bit from the edge to the surface and the brightness steps up...

I was just wondering,

how did you make a colour image?

[DaveM]

I colourise the monochrome image in Photoshop, with the final image still effectively being a single colour, just varying intensities of red rather than grey. This works because Hydrogen-alpha light is essentially just a single wavelength, and I try to match the final colour to what I see in the eyepiece (if any of that makes sense). This is pretty much the standard way of doing solar imaging.

[Craig.a.c (Craig)]

Very nice image.
Don't mean to hyjack your thread but, how long do prominences last for?

[DaveM]

Although some are unstable and change over the course of minutes or hours, most are pretty stable, with the glowing gas suspended above the surface along magnetic field lines (you can kind of see the loop between areas of different magnetic polarity in the image). These can last weeks or months, but their shape does change with time. You don't see the same ones from day to day along the limb, however, because of the sun's rotation.

[Craig.a.c (Craig)]

I was told that with my Baader solar film I would see these but I am yet to see one. I take my telescope out almost everyday with the hope of seeing them but have not.

[DaveM]

Unfortunately the solar film only reduces the total brightness of the image, which does not allow you to see prominences. You need a hydrogen-alpha filter with a bandpass of less than 1 Angstrom to see prominences. With the solar film you can see granulation (the 'graininess' on the sun's surface, basically continent-sized convection cells) and sunspots. As you can tell, we are at solar minimum at the moment and sunspots are few and far between. It is worth checking to see if there is much activity on the sun at www.spaceweather.com or http://sohowww.nascom.nasa.gov/ before you go out for a look. Basically, hang in there until there is a decent sunspot group to have a look at.

The plus side of the solar film is that when there are sunspots you can use the larger aperture of your white light telescope to magnify the sun's surface more than you could with a small aperture H-a filter or telescope and see as much as the atmosphere allows.

[Alchemy (Clive)]

nice image