Solar Activity 15 Mar

[brianb]

Poor conditions again today, much thin high cloud (contrail derived - ugh) & also periods of mid level cloud cover. As the day wore on the high cloud thickened and the mid level cloud became more persistent. Observations were begun as soon as the sun cleared my neighbour's house in order to make the best of the conditions.

The chief interest is AR 1054 which remains large and active, though there are further signs of decay in the trailing part of the area & the minor outlying active patches seem to be dying.

2010 Mar 15, Solarscope 60 @ f/24, DMK21.

2010 Mar 15, WO FLT 110 @ f/21, Lunt B1200 CaK diagonal, DMK41.

2010 Mar 15, WO FLT 110 @ f/21, Baader solar film (ND5.0), DMK41.

The whole north western sector of the disc remains covered in filaments of varying size & shape, giving a "bruised" appearance:

2010 Mar 15, 0934 UT. Solarscope 60 @ f/24, DMK41 (2 frame mosaic). There is a full size version of this image here.

There is also interesting activity on the north east limb:

2010 Mar 15, 0912 UT. SOlarscope 60 @ f/24, DMK21.

Prominences are minor but there is an interesting group on the NNE limb:

2010 Mar 15, 0919 UT. Solarscope 60 @ f/24, DMK21.

Finally the CaK overview:

2010 Mar 15, 0859 UT. Coronado PST CaK @ f/10, DMK41.

Transparency variable, mostly poor, at best moderate, with thin high cloud & drifting mid level cloud. Seeing mostly fairly good. Temp 10C, wind N force 4-5.

[NickH]

Nice!!

[Takahashi]

Having recently acquired a full-aperture solar-filter, I'd love to dabble into this level of solar obsy'ing, especially when you serve-up these delicious shots, Brian... and then I remember the cost of the filters involved.

Until that distant day, I'll just bask in the beauty of these photos.

[brianb]

then I remember the cost of the filters involved.

The white light filter cost about £10 (half a sheet of Baader solar film, a few bits of scrap cardboard & a foot or two of gaffer tape).

[Takahashi]

Yep, that's what I was referring to when I said I'd already acquired a "full-aperture filter". It's the others, the ones that show the filaments and prominences, the narrowband ones, aren't they expensive?

[brianb]

It's the others, the ones that show the filaments and prominences, the narrowband ones, aren't they expensive?

"Expensive" is a relative term ... my Solarscope 60 costs around £4000 but a PST or Lunt 35mm Ha scope can be obtained for £500 - £600

[Takahashi]

Yes, in relation to other filters, not dedicated solar-scopes - this is what I meant. Narrowband filters intended for use with standard OTAs... are they not generally quite costly?

[brianb]

Narrowband filters intended for use with standard OTAs... are they not generally quite costly?

TS have Lunt LS50Ha2/B600 listed at 1,365 euro or 1,625 euro with the B1200 (needed for scopes with focal lengths exceeding 600mm). Whether that's expensive or not depends on your point of view. It starts to look cheap compared with "narrow band" deep sky filters which have a pass band about 100 times as wide.

[NickH]

Mod a PST all in for about £1K and blow that other one out of the water :-)

But nothing much comes close to a solarscope..