Prominences a bit subdued this morning.

This is the last solar post for a while as we are off to Scotland for 2 1/2 weeks.

Nice new prominences with complex structure this morning AND Sunspot AR 2722

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Nice new prominence with complex structure this morning AND Sunspot AR 2721. Took advantage of the window-sill observatory’s instant availability to look through a hole in the clouds!

Nice prominence with complex structure this morning.

Although still quiet, a good array of prominences today.

After a considerable period of inactivity, there are some rather nice prominences today;

I have wondered about the resolution I get with my solar scope, so here are some fag-packet calculations:

Telescope diffraction limit (in radians)= 1.22 X wavelength in cm/scope dia. in cm

Telescope diffraction limit (in arcseconds)= 206265 X 1.22 X wavelength in cm/scope dia. in cm

Ha light  wavelength = 6562 angstroms = 6562 X 10^-8 cm

Lunt LS35 THa is 3.5 cm dia

Diffraction limit = (206265 X 1.22 X 6562 X 10^-8)/3.5

= 4.7 seconds, or about 5

Solar diameter is around 30 arcminutes, or about 1800 arcseconds

In this image the distance between the 2 spots is around 0.135 X the solar diameter, or around 250 arcseconds

The lines or striations around spot 2620 at their thinnest, are around 1/50^th of this distance, or around 5 arcseconds.

So. my Lunt LS35THa images could, in fact be diffraction limited!

The GONG cameras have an aperture of 2.8cm, so they are similar.

Conclusion, to get images like this one (http://spaceweathergallery.com/indiv_upload.php?upload_id=147458)

are:

1. Win lottery
2. Buy Lunt LS152 THa
3. Get bigger window-sill

Of course, a Quark fitted to a 80mm scope should be pretty good! (Andy)