SHG from july 14th

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DSobserver
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SHG from july 14th

Post by DSobserver » Tue Jul 14, 2015 6:01 pm

Long time that I did'nt play with my SHG!

Ha : our sun looks really sad.... :cry:
Image

Hb :
Image

Cak :
Image

I've been really surprise to see 3 emission line near Calcium... Any explanation?
Image

And finally He : a disaster, no detail! Any support to help me here?
Image

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Re: SHG from july 14th

Post by marktownley » Tue Jul 14, 2015 7:35 pm

Nice set of images there!
Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

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Re: SHG from july 14th

Post by p_zetner » Wed Jul 15, 2015 3:49 am

Nice images, Vincent. I especially like the H alpha.

I'm assuming the 3 emission lines are (top to bottom) H epsilon, Ca H and Ca K.

To see any surface detail in He D3 requires subtraction of an image made in the nearby continuum.

Cheers.
Peter.

(Wah will probably object to, and repair, the lines / banding !)

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Re: SHG from july 14th

Post by Wah » Wed Jul 15, 2015 4:39 am

It seems the images are not raw which the bandings are not vertical. That will dramatically increase the difficulty of removing them.

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Re: SHG from july 14th

Post by Montana » Wed Jul 15, 2015 9:05 am

The Halpha and CaK are amazing!! :bow :bow :bow well done :)

Alexandra

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Re: SHG from july 14th

Post by DSobserver » Wed Jul 15, 2015 12:44 pm

thanks for your comments!

Here are some answers :

Peter :
never heard about H Epsilon...have you ever try it?
For He D3 how do you substract an image made in continuum

Wah
Indeed I only resize HE D3 quickly without removing the band that I used to remove with Gimp software. Gimp is not as good as PS software that you are used to take...The issue is that I don't have PS...Do you know any freeware for this?

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Re: SHG from july 14th

Post by p_zetner » Wed Jul 15, 2015 3:05 pm

Hi Vincent.

I've tried H eps but found it difficult to observe much surface detail. I think Wah has imaged this one (?). I know he's done H gamma and delta. In my opinion, images taken in the Balmer lines shorter than H beta look very similar to H beta but with less contrast.

My technique for extracting the He D3: I take a series of images through the region of the He D3 line and load this series, as an image sequence, in ImageJ. I then choose one image of the series (near the beginning or end) and subtract it from all images in the series. Generally, I can detect a couple of images which then show He D3 structure. One of these is then selected to process further. There is usually a lot of noise and image irregularity to deal with. One way to proceed is to use the ImageJ FFT bandpass on each image of the series before subtraction. Sometimes, rather than selecting one image, I take an average over several (this is the case for the latest image uploaded here).

Let me know if this helps.
Peter.

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Re: SHG from july 14th

Post by Wah » Wed Jul 15, 2015 3:17 pm

Hi Vincent, I think you must have at least rotated or skewed the images from the raw, haven't you?

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Re: SHG from july 14th

Post by DSobserver » Fri Jul 17, 2015 9:00 pm

Wah wrote:Hi Vincent, I think you must have at least rotated or skewed the images from the raw, haven't you?
yes it is. As mentioned I only wanted to show you how bad was my He D3 shot :|

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Re: SHG from july 14th

Post by DSobserver » Fri Jul 17, 2015 9:01 pm

p_zetner wrote:Hi Vincent.

I've tried H eps but found it difficult to observe much surface detail. I think Wah has imaged this one (?). I know he's done H gamma and delta. In my opinion, images taken in the Balmer lines shorter than H beta look very similar to H beta but with less contrast.

My technique for extracting the He D3: I take a series of images through the region of the He D3 line and load this series, as an image sequence, in ImageJ. I then choose one image of the series (near the beginning or end) and subtract it from all images in the series. Generally, I can detect a couple of images which then show He D3 structure. One of these is then selected to process further. There is usually a lot of noise and image irregularity to deal with. One way to proceed is to use the ImageJ FFT bandpass on each image of the series before subtraction. Sometimes, rather than selecting one image, I take an average over several (this is the case for the latest image uploaded here).

Let me know if this helps.
Peter.
Sorry peter, not sure to understand it correctly....

Would it be possible to clarify it with some pictures?

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Re: SHG from july 14th

Post by Wah » Sat Jul 18, 2015 1:10 am

Can you post the raw images, so I can help you to de-band them? :D

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