AR3615 - X-flare on 23Apr & M-flare on 24 Apr (Singapore) [New Images Added]

[yltansg]

My CAK setup:



23Apr24 - AR3615 sent an X-flare but I can't see it in this image at 9:38am local time -


Taken single Alluxa filter (tilted in 3D Skybender) - image lacks the usual details - I am still figuring what went wrong

24 Apr - AR3615 emitted a M-flare flare. This image was taken with double-stacked Alluxa CAK filter (without tilting):


From GOES X-RAY FLUX


While I have obtained some good single filter (tilted in 3 D Skybender), I wasn't not able to repeat the same performance on several subsequent tries. I am getting uneven illumination and bright cones of lights in the image. Needs to learn more about it.

Enjoy and do give me your comments. Thanks

Alfred

[DeepSolar64]

Very nice CaK resolution and contrast. Professional class work Alfred!

[marktownley]

The second cak image has turned out well Alfred. The first one looks like the tilt is completely wrong to me, excessive tilt infact, uneven illumination is the same as when a ha etalon is tilted too much. The cones of light also imply excessive tilt. I have found there is not really much need to mess around with the tuning too much once you have found the onband position, just a subtle tweak between observing sessions.

[yltansg]

The second cak image has turned out well Alfred. The first one looks like the tilt is completely wrong to me, excessive tilt infact, uneven illumination is the same as when a ha etalon is tilted too much. The cones of light also imply excessive tilt. I have found there is not really much need to mess around with the tuning too much once you have found the onband position, just a subtle tweak between observing sessions.

Dear Mark,

Thank you for your comments. I am very glad I had a good first light. I would need more time to play with the tilting

Alfred

[OlegLviv]

Nice but why do you not write your equipment?

[ffellah]

Great image of AR3615, Alfred. You have put a lot of work in tuning your setup and the results show it.

Franco

[arnedanielsen]

Very nice, Alfred!

[xinghai]

Great

[eroel]

Alfred:
Beautiful images.
Thanks.
Eric.

[Dennis]

Excellent results Alfred. Just a matter of time with the perfect tuning.

[KMH]

That second one looks really good!

Kevin

[cybermayberry]

Very well done

[yltansg]

Nice but why do you not write your equipment?

Dear OlegLviv,

Thank you for asking. The equipment used in that session:
A 15 year-old 6CR achromat refractor (bought used) with re-spaced objective lens optimised for CAK imaging. It is fitted with a Calcium Solar filter system comprising 2 Alluxa 0.14nm Ca K filters. Camera - IMX290 Mars-M USB3.0 Mono Camera.

Alfred

[yltansg]

Great image of AR3615, Alfred. You have put a lot of work in tuning your setup and the results show it.

Franco

Thanks, Franco. I am still learning, through trial-and-error and advice offered by friends how to optimise the performance by the tilting of the filters.

Alfred

[yltansg]

That second one looks really good!

Kevin

Dear Kevin,

Thanks for your kind comments. At this image scale, I can replicate great results without tilting.

Alfred

[yltansg]

Excellent results Alfred. Just a matter of time with the perfect tuning.

Hi Dennis,

I wish there is a inexpensive way to measuring on-band tilt instead of tilting by trial-and-error

Alfred

[marktownley]

Excellent results Alfred. Just a matter of time with the perfect tuning.

Hi Dennis,

I wish there is a inexpensive way to measuring on-band tilt instead of tilting by trial-and-error

Alfred

There is Alfred and you can do it already...

When the image is on band it has the highest contrast, ie the 'bright features' are at their brightest and the 'dark features' (reverse granulation) are at their 'darkest' - the image has the highest dynamic range. You can see this visually on the first 2 images, but you can also measure this using capture software (firecapture for example) - just look for where this histogram is at it's widest. After a while you will be able to do this visually without the histogram when you know what you are looking for.

It should only be the primary filter (the one closest to the etalon) that you do this with. The secondary filter (closest to the camera) should be tilted enough so that the reflected ghost image is a couple of degrees out of the field of view. The latter is easy to do by increasing the exposure time until the 'ghost' image is revealed.

Mark

[Montana]

Wow!!!

Alexandra

[pedro]

Great HR CaK image Alfred

[rigel123]

That 2nd image is simply crackling with action!

[MapleRidge]

Really sharp images Alfred and the second shows so much detail

It will be good to see how the setup works with more tuning adjustments!

Brian

[WMoore]

Love the contrast and detail of the second image.
Like your viewing location, very little concern about tree-tops :-)

Thanks for sharing!
Wayne

[KMH]

Nice but why do you not write your equipment?

Dear OlegLviv,

Thank you for asking. The equipment used in that session:
A 15 year-old 6CR achromat refractor (bought used) with re-spaced objective lens optimised for CAK imaging. It is fitted with a Calcium Solar filter system comprising 2 Alluxa 0.14nm Ca K filters. Camera - IMX290 Mars-M USB3.0 Mono Camera.

Alfred

Alfred,

Is there any filtration other than the two Alluxa filters (like a front-mounted ERF, or something analogous to a wider bandpass blocking filter)?

Thanks,
Kevin

[MAURITS]

Great resolution Alfred.

[yltansg]

Excellent results Alfred. Just a matter of time with the perfect tuning.

Hi Dennis,

I wish there is a inexpensive way to measuring on-band tilt instead of tilting by trial-and-error

Alfred

There is Alfred and you can do it already...

When the image is on band it has the highest contrast, ie the 'bright features' are at their brightest and the 'dark features' (reverse granulation) are at their 'darkest' - the image has the highest dynamic range. You can see this visually on the first 2 images, but you can also measure this using capture software (firecapture for example) - just look for where this histogram is at it's widest. After a while you will be able to do this visually without the histogram when you know what you are looking for.

It should only be the primary filter (the one closest to the etalon) that you do this with. The secondary filter (closest to the camera) should be tilted enough so that the reflected ghost image is a couple of degrees out of the field of view. The latter is easy to do by increasing the exposure time until the 'ghost' image is revealed.

Mark

Dear Mark,

Thank you very much for a detailed and yet easy-to-follow instructions. I hope to post good results from a properly tilted DS filter system.

Alfred

[yltansg]

Nice but why do you not write your equipment?

Dear OlegLviv,

Thank you for asking. The equipment used in that session:
A 15 year-old 6CR achromat refractor (bought used) with re-spaced objective lens optimised for CAK imaging. It is fitted with a Calcium Solar filter system comprising 2 Alluxa 0.14nm Ca K filters. Camera - IMX290 Mars-M USB3.0 Mono Camera.

Alfred

Alfred,

Is there any filtration other than the two Alluxa filters (like a front-mounted ERF, or something analogous to a wider bandpass blocking filter)?

Thanks,
Kevin

Dear Kevin,

I have a blue filter installed at the front of the 6CR. It is from a friend. Unfortunately I don't have the specifications of this glass.



Cheers

Alfred

[yltansg]

Thank you, James, Mark, OlegLviv, Franco, Arnedanielsen, Xinghai, Eric, Dennis, Kevin, Cybermayberry, Alexandra, Pedro, Warren, Brian, Wayne, Maurits for your kind comments.

I have many fair images from the same session. I have added 2 more images for your viewing pleasure.

AR3614:

Is that a thin light bridge tunneling through the sunspot? I am always amazed by formation of straight lines on the Sun.

AR3619:


For you to have a sense of where these images are, here is the solar disk from Spaceweather.com. Credit: SDO/HMI



Pleas do a right click to enjoy the images in full resolution.

Alfred

[marktownley]

Excellent addition Alfred

[DeepSolar64]

I see white dots in the penumbra of the first additional picture. I wonder what they are?

[rigel123]

Great additions Alfred!

[yltansg]

I see white dots in the penumbra of the first additional picture. I wonder what they are?

Hi James,

Besides imaging AR3615 I was also observing AR3614 from 8:08 to 8:37. The "white dots" starting forming before 8:14 am and became more pronounced at 8:18am and there went away at 8:37am. I have shown the images taken from 8:08 to 8:37am.

There was no white dots on the penumbra at 8:08am


The image below shows the penumbra at 8:14am (left one) and 8:18am (right image). At 8:14am white dots were seen left image. More white dots were seen on the penumbra at 8:18am. You would need to do a right click to see the full image.


And white dots totally gone at 8:37am


I don't really know what they are. I thought it may be a light bridge. Anyone know what they are?

Alfred

[DeepSolar64]

Maybe Alexandra or Christian may have an answer for us.

[marktownley]

Nice additions Alfred, I believe the bright points you are talking about are called penumbral grains, and represent material welling from deeper within the sun aligned with the magnetic field lines. There's bits and pieces about them online but not much.

[yltansg]

Maybe Alexandra or Christian may have an answer for us.

Dear James,

It would be great to know more about these bright spots/lines in the fibrils getting into the penumbra. That would enhance our understanding of our observations.

I am grateful for the resolution improvement resulting from the 6CR refractor objective lens respacing. It has provided me details never seen before for Calcium-K imaging. As friends in this forum has suggested and guided me to do this improvement, I would also like to suggest forum participants to do the objective lens respacing if they are using a achromat refractor for CAK imaging.

Cheers.

Alfred

[Peterm]

These are very impressive. Nice to see your set up with the Solar protective shield.

[yltansg]

These are very impressive. Nice to see your set up with the Solar protective shield.

Hi Peter,

Thank you for your kind comments. The shield is supposed to prevent the 6CR tube from heating up. Recently I received a comment that it may cause the heat build-up within the tube to be trapped in it instead. It is too troublesome for me to remove the aluminum cladding so I am going to keep it since the images are turning out ok

Alfred

[yltansg]

Maybe Alexandra or Christian may have an answer for us.

Hi James,

A friend of mine suggested that it may be an Incendiary penumbral filament like the one shown below.



Alfred