Solar

Solar Images in H alpha, Calcium K and Visible

Posted by Peter Hill

Most of my solar images have been taken in visible or H alpha , the Baader CaK filter in conjunction with a Herschel wedge provides a relatively “cheap” way of imaging in CaK.

Images in Visible light give detail of the photosphere , which we can consider as the Suns “surface”, above this is the chromosphere, the upper part of which is viewed in H alpha and mid section can be viewed in Ca K wavelengths. (Not quite this simple as there is some overlap, but broadly works this way) The Cak is sensitive to magnetic fields and the stronger the magnetic filed the brighter the image, this gives more detail of the plages around sunspots and more detail of how magnetic field varies in these areas.

After some time setting up a system to image in all 3 wavelengths a fine clear day arrived on Friday 22nd June and I imaged the sunspots and prominences , then went away, which is why I’ve only just finished processing images.

All images were taken using a mono CCD camera : Imaging Source DMK41, the H alpha images were taken using a Coronado PST, the Visual White light images with a Herschel wedge with a ND.3 filter and Baader continuum filter on the camera, using a Skywatcher Evostar 120 refractor. The Cak images were taken with a Baader Cak filter attached to DMK41 and using a Herschel wedge with either a ND.3 or ND 0.6 filter on Skywatcher  ST102 ( for full disc) and / or Skywatcher Evostar 120. All Images were 600 frame avi’s stacked in AutoStakkert, wavelets tweaked in Registax 6 and final processing in Photoshop CS6. Not having imaged for a while I soon realised that I needed to do some cleaning before the next session as the “dust bunnies”  were more numerous than usual, luckily I was either able to manipulate image to avoid most of them or eliminate them in processing.

I have left the images as mono as features show up better for comparison rather than processing in false colour.

Whole disc in CaK and H alpha, no prominences visible in CaK.

 

 

 

 

 

 

 

 

 

 

 

 

 

Main surface features in Cak in Evostar 120, left to right : faculae, AR2715, AR2713

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Faculae in Halpha x2 barlow

 

 

AR2715 In Cak, Vis,  H alpha (x2 Barlow)

 

 

 

 

 

 

 

 

AR2713 in Cak, Vis , H alpha (x2 Barlow)

 

 

 

 

 

 

 

 

Prominences x2 Barlow

 

 

 

 

 

Sun 09/07/2018 – – – New facula

Posted by Roger Samworth

Yesterday, Spaceweather said:

“WHITE SUNSPOT: This weekend, observers of the sun have been waiting for something to emerge over the sun’s eastern limb. We knew it was there because of a farside solar flare on July 6th. Today it arrived, and it appears to be a white sunspot.

The correct name of this phenomenon is “faculae.” It is a cousin of sunspots.

Regular dark sunspots are magnetic islands on the surface of the sun. Magnetic fields in these areas are thousands of times stronger than Earth’s magnetic field. Sunspot magnetic fields are so strong, they block the flow of heat from the nuclear furnace below. They appear dark because they are relatively cool compared to their surroundings.

Faculae are also made of magnetic fields. However, the magnetism of faculae is concentrated in much smaller bundles than in sunspots. Instead of blocking heat from below, they essentially form corridors that allow us to see into sun’s hot interior, creating an apparent bright spot on the surface of the sun.

It is still possible that a dark core will follow these faculae over the limb in the hours ahead, establishing the region as a normal sunspot group. Stay tuned.” 

 

This is what it looked like this morning.

Nice prominences and “filaprom” too.

For some reason, I reckon this one looks better in colour.

More explosions

Posted by Roger Samworth

Spaceweather says:

 

FARSIDE SOLAR EXPLOSION: Something exploded on the farside of the sun yesterday. On July 5th around 1300 UT, the Solar and Heliospheric Observatory (SOHO) observed a coronal mass ejection (CME) billowing over the sun’s western limb: movie. NOAA analysts believe the cloud is moving away from Earth and will not hit our planet.

 

Wonder if we will see anything when it comes round our side – – –

Sun report 03/07/2018

Posted by Roger Samworth

Some filaments and nice prominences today.

As explained in a recent email dialogue,

The Lunt LS35 is tilt tuned and you can alter the emphasis twixt surface features and prominences by adjusting the (un-calibrated) tuning wheel. This is true for visual use at least. I seldom do this, and when imaging it isn’t that sensitive as you can compensate with processing, as I showed at RAG on friday night. I don’t change it between the surface and prominence images. I seem to get results generally very similar to those on GONG, which is my yardstick. Mind you, with published Ha images, you often see “hair” around spots, but you NEVER see this on GONG, nor do I get it.