Calcium Sun - 6th April

[marktownley]

Tuesday offered a shift in wind direction for me, more north westerly, and experience tells me that despite MeteoBlue saying 3" seeing it would be locally better. This direction often brings cumulus clouds, and the blue gaps in between the clouds often offer some decent seeing. This was confirmed when I started off with the CaK full disk at 60mm f16, and a considerably more stable view than of recent days.

CaK-FD-bw by Mark Townley, on Flickr

CaK-FD-colour by Mark Townley, on Flickr

Today also offered a chance to continue my CaK triple stack journey, I tried a few configurations i'd thought of the previous evening. Whatever I try I get consistently better results in double stack, and using the sky bender I am able to tune the second filter of the stack to give maximum contrast which in turn reveals the chromospheric fringe and proms. Double stack also has about 3-4 time shorter exposure which when fishing in the better moments of seeing is a must...

Deciding to chance it I went for 100mm f28 with the IMX174, and taking 4000 frame captures figured there would be enough good sub frames to make a decent image: Firstly departing AR12813... All closeup images have a decent amount of zoom left in them, so double click for the view in Flickr.

ar12813-CaK-bw by Mark Townley, on Flickr

ar12813-CaK-colour by Mark Townley, on Flickr

And the decaying area of plage, yesterday had several pores, but was struggling to make them out today...

Magnetic-active-region-CaK-bw by Mark Townley, on Flickr

Magnetic-active-region-CaK-colour by Mark Townley, on Flickr

On the north east limb there was more plage but was struggling to get a decent view of this one.

East-patch-cak-bw by Mark Townley, on Flickr

East-patch-cak-colour by Mark Townley, on Flickr

Then, just to be silly, and because i'm testing out a couple of different optical configurations, I went for 100mm f46, again with the IMX174, I knew seeing wasn't up to it, so increased the frame count to 6000 with a view of stacking only the very best. Some silly colour just for fun too!

NE-limb-cak-close-bw by Mark Townley, on Flickr

NE-limb-cak-close-colour by Mark Townley, on Flickr

ar12813-cak-close-bw by Mark Townley, on Flickr

ar12813-cak-close-colour by Mark Townley, on Flickr

Then this cheeky little number came out of stacking, looks like there is some potential for this when in the constraints of the seeing...

magnetic-region-CaK-close-bw by Mark Townley, on Flickr

magnetic-region-CaK-close-colour by Mark Townley, on Flickr

Quite pleased with the last closeup, definitely my favourite from today and worth the full size view. I want to see if I can get somewhere around f40 for slightly better sampling. More CaK experiments for tomorrow assuming the blue skies carry on a bit more.

Hope you like.

Mark

[EGRAY_OBSERVATORY]

You certainly are working-hard to try out these experimental set-up's Mark. And in the cold too. Better you than me. Even the possibility of some snow in the SE, as has occurred in SW-Holland According to my Daughter there and with our temps today around 6 to 8-degsC, you are brave...

The close-up's of AR2813 are my favs - even though decaying as it nears the limb.

Cheers
Terry (in the warm)...

[dhkaiser]

Impressive results Mark.

[Montana]

Oooh these make my mouth water, especially the last few shots

Alexandra

[Stardust5858]

Lovely captures Mark, your experiments are paying off. I managed some cak imaging between the clouds too.

[Martin_S]

Great work Mark ,well done. I looked at your hi res images and noticed some very faint proms in the background that is some amazing detail that you have captured.

Martin

[marktownley]

Thanks everyone for the kind words and the SPoD!

[John]

Super set of images, great to see the spicule fringe and proms. Which telecentrics/barlows were yo using for the closeups?

John

[DeepSolar64]

Very nice Mark. The small spots show up very well too!

[MAURITS]

Superb Cak images Mark.

[marktownley]

Thanks everyone for the kind comments!

Which telecentrics/barlows were yo using for the closeups?

I used the Airylab 2.79x telecentric John, I find it just as good in CaK as in Ha. For the f46 closeups in addition to the Airylab I used the nose of a 2x cemax barlow on the shortest c-mount have, which gives a 1.6x magnification factor. I have another barlow nose peice which when used on the shortest c-max gives an additional 1.25x magnification factor which should take me up to about f35. It's just about finding the ideal combos for the different conditions...

[krakatoa1883]

Great images, Mark. Which scope,TAL or Bresser ?

[marktownley]

Thanks Raf, it was the Tal on this occasion. I think it is a superb performer (even at full aperture) in CaK. The Bresser has delivered the goods so far but is difficult to compare as for me the increase in aperture steps above the usual summit of my seeing conditions. What is apparent though is they both let through incredibly similar amounts of light, both running at f10, which is good.

[christian viladrich]

Nice set of images Mark !
Can you post some triple stack ones ? Just to have a look at it.

[marktownley]

Hi Christian, i'll take some comparisons for you this weekend.