ATT Essen Pictures

Some Belgian Friends at the ATT Essen (May 11, 2022); see this link for more pictures. 

 

Sun May28 - H-Alpha Full Disk

Some more trial and error using my focal reducer 0.5x with SolarMaxIII and ASI290MM. I noticed that the flats taken from yesterday are popping up when imaging in SharpCap Pro. I renewed the flat and after restarting SharpCap Pro the full disk image was much better. I could image on 80fps with an exposure time between 0.3 and 0.5ms - gain set on 100.

Setting: SolarMaxIII 70/400 f/5.7 DS BF15 and ASI290MM

Software: SharpCap Pro, AS3!, IMPPG, CS4.
Adding Color CS4 : RGB1,8 - R 1,33- G 0,44 - B 0,2

Full Sundisk H-Alpha

Using my ASI290MM on SolarMaxIII 70/400 f/5.7 the Sundisk could not be 100% captured. Therefor I bought a 2" focalreducer x0.5. 

The first result is promising.

Setting : SolarMaxIII 70/400 f/5.7 DS BF15with ASI290MM (and focalreducer 0.5x)

Software : SharpCap Pro, AS3!, IMPPG, CS4

Compilation of the Sun in H-Alpha, White Light and CaK

 

Sun H-Alpha with Sunspot AR3014

 Imaging the Sun today in H-Alpha. My objective was to use my new 0.5x reducer but I was unable to connect with my ASI290MM and missing the right adapter. So I made a couple of pictures with the idea to merge both images. It looks good but bot great!

Setting : SolarMaxIII 70/400 f/5.7 DS BF15 and ASI290MM

Software : SharpCap Pro, AS3!, IMPPG and CS4.

The sundisk shows also the region with sunspot AR3014. See this link for more information on sunspot AR3014 

Sunspot AR3014 in CaK and White Light

Sunspot AR3014 is still huge and about 940MH counting 14 individual spot and classified as EKC. As part of my learning I used a CaK filter together with Barlow x2. Beside CaK I also imaged AR3014 in white light using ND5.0 filter. 

Setting : TAL200K f/8.5, ND3.8, CaK and ASI290MM

Software : SharpCap Pro, AS3!, IMPPG, CS4

Sunspot and (inverse) Evershed Flow

The Evershed effect is named after the British John Evershed and is the radial flow of gas across the photospheric surface of the penumbra of a sunspot from the inner border with the umbra towards the outer edge. Evershed discoverd this back in 1909 when working at the  Kokaikanal Solar Observatory in the south of India. See also this video about the Evershed Effect. There is also an inverse Evershed flow (IEF) going in the opposite direction. 

Ref. C. Beck and D. P. Choudhary 2020 ApJ 891 119

Above sketch of the magnetic topology of a sunspot and the various wave and flow phenomena. Left panel: side view of a sunspot. The gray and green rectangles indicate photosphere and chromosphere. Gray and red lines indicate magnetic field lines. Orange lines and arrows show the wavefront and assumed propagation of global sunspot oscillations. Black and blue arrows highlight the direction of the EF and IEF. The apparent radial propagation of umbral and penumbral waves is indicated by green and purple arrows. Right panel: magnification of the assumed magnetic field vector and the flows in the penumbra inside the yellow rectangle of the left panel.

Ref D. P. Choudhary and C. Beck 2018 ApJ 859 139

Above figure of different flow scenarios. A: inverse Evershed flow (IEF) through a siphon flow mechanism. B: IEF caused by mass shedding of rising field lines. C: IEF through coronal rain. D: photospheric Evershed flow. Magnetic field lines in cyan are those that are most relevant for the IEF. The black rectangle indicates the formation height of the Ca ii IR line at 854.2 nm from the continuum-forming layers to a height of about 1 Mm.

Postage Stamp India - Evershed Effect

My picture from April 23, 2022 of Sunspot AR2993/94 showing the penumbra, umbra and fibril structure of the penumbra.