Stargazing How Can You Improve Your Amateur Solar Imaging Techniques?

[sophiecentaur]

Hi and welcome to PF
Can you tell us how that image was obtained? I have a Baader ASTF 80 and I'd like to be able to do more interesting images than I have obtained so far - not much more than the more obvious spots.

 

[Zeke_D]

I am using a Nikon P900 with a Baader 5.0 filter on a regular camera tripod. Usually shoot at maximum optical, 83x, sports mode for a burst of 7 in 1 second. Greater than a minute between shots, it starts to noticeably blur the final image.

I'll post some images to walk through the process.

The spectral response of Baader in the NIR and into the IR appears like an etalon comb response, it is a multilayer metallic sandwich - so maybe. My IR blocking filter extinguishes completely at ~ 750nm, so there are only a few candidates for the NIR terrestrial spectrum making it to my camera.

'Grain extract' subtracts two images and adds 128. Differences between my images are caused by many things, image stabilization being the most consistent for sub-pixel offsets, then there is my inherent alignment error between the stacks.

I have spent a few months comparing the SDO and SOHO images to the Baader/differencing technique - I am posting this because the correlations are significant. The thermal envelopes and shock waves are almost like a ghost of the UV activity seen in SDO.

Working on OpenCV for real time video processing with this technique, will move the design over to an FPGA next month to get the frame rates up.

 

[Zeke_D]

Sun 6 10 2018 7:51MST
Nikon P900, 83x, Baader 5.0, sports mode burst on standard camera tripod.

Horizontal banding appears to be layers of the atmosphere. Differencing technique works well for imaging objects close to, or crossing the Sun.

 

[sophiecentaur]

@Zeke_D Thanks for that. So you seem to be basically temporal high pass filtering (plus some DC offset) and that removes most of the energy - explaining the high noise, I guess. I would imagine that processing a long sequence of movie frames could allow you to dredge more patterns up from the noise with long sequences of frames (less than one minute, from your comment about gap between frames.)
It's encouraging to see that worthwhile information can be obtained about the Sun without having to spend vast sums on filters.

 

[davenn]

I am using a Nikon P900 with a Baader 5.0 filter on a regular camera tripod. Usually shoot at maximum optical, 83x, sports mode for a burst of 7 in 1 second. Greater than a minute between shots, it starts to noticeably blur the final image.

I'll post some images to walk through the process.

Hi there Zeke_D

welcome and thanks for posting in the thread. It's good to see something a bit different
Even with your walk-through of your processing, I have to admit, I'm still not totally sure of what I am looking at … detail wise ??
Continue to post and keep up the explanations regards

Dave

 

[Stavros Kiri]

I'm still not totally sure of what I am looking at … detail wise ??

See e.g. post #150
https://www.physicsforums.com/threads/solar-imaging-and-techniques.925656/page-6#post-6011017

 

[davenn]

See e.g. post #150
https://www.physicsforums.com/threads/solar-imaging-and-techniques.925656/page-6#post-6011017

yeah, I had read that before I made the comment
since I don't appear to see any specific detail/feature in the images …. I'm not sure what I am missing

D

 

[sophiecentaur]

Hi there Zeke_D

welcome and thanks for posting in the thread. It's good to see something a bit different
Even with your walk-through of your processing, I have to admit, I'm still not totally sure of what I am looking at … detail wise ??
Continue to post and keep up the explanations regards

Dave

Yes. There is just one image where there is a clear area, to the right of the Sun where 'something is going on' but I think we need some help to make more sense of some of the images in post #152.

 

[davenn]

16 June 2018, The Sun in Ha.
Some small prom's and a large but ( for me, ill defined) active region probably mainly due to poor atmospheric conditions
LUNT LS60THa and ASI1600MM

Dave

 

[sophiecentaur]

16 June 2018, The Sun in Ha.
Some small prom's and a large but ( for me, ill defined) active region probably mainly due to poor atmospheric conditions
LUNT LS60THa and ASI1600MM
Dave

Nice images as usual, Dave.
The first and third images seem to have areas of light as if it's a slightly polished sphere, illuminated from one side. The spherical appearance is quite noticeable. How's that happening, I wonder? It's almost as if the Dodge Tool had been used.

 

[davenn]

Nice images as usual, Dave.
The first and third images seem to have areas of light as if it's a slightly polished sphere, illuminated from one side. The spherical appearance is quite noticeable. How's that happening, I wonder? It's almost as if the Dodge Tool had been used.

Thanks

are you referring to the 2 circled areas ?

if yes, then yes, I had to do a bit of editing specially on the right ovalled area …. that region was a lot brighter and I had to darked it down a bit

The left ovalled area has the active region in the middle of it ad I have done a little enhancing there ( Lightroom clarity control) to bring of as much
detail as I was able to)
BTW, that little dark area below the right oval is a real feature … a small filament
and also image 1 and 3 are the same one. #1 is monochrome version and #3 is tinted with a little yellow... makes it look a little sun like and I often find it improves the detail a bit

Here is an unedited version …. so you can really see the difference

You can see just how bright the right side is. I had to try and tone that down a bit

OK there are 2 quirky things occurring here … one involves the Ha filter and the other is the CMOS sensor in the camera

1) The filter …. I have discovered from day one of use, that the view of the sun through the filter is not uniform across the field of view.
and it is the least sensitive around the outer 1/3 of the FOV … within that area a prominence or active region etc can completely disappear
from view and as I move area of interest into the central area of the FOV of the filter the details "pop" into view

2) the second thing now involves when I am imaging and it is a mix of #1 discussed above added to the quirks of the camera(s).
I can move the sun across the FOV of the camera sensor and it will go through brighter and darker areas ( can't describe it better than that)
as with the unedited image above. Now I can find an area of the sensor where the whole solar disk has even exposure. but an area of interest
a prominence or active region is not so clearly seen because of the combined quirk if the #1 comments.
So for the above image, I had to move the solar disk to the right to get the active region to the best /clearest place in the FOV.
This resulted in the right side of the disk being a bit overexposed

Could you follow that ? haha hope so Dave

 

[sophiecentaur]

Yes I followed it.

are you referring to the 2 circled areas ?

Yep. I'm pleased that I spotted your bit of tinkering. They make the image much more attractive. I wonder whether, on a future occasion, it might be worth while rotating the sensor / scope (even) to see the result. Astrophotography is probably less concerned with accuracy of flat fields (except for vignetting) than regular pics so solar images are the only ones where our eye is looking for very subtle facial type features.
It's hard not to assume that the Sun should be totally uniform at all times. But those images are really good to look at.

I can move the sun across the FOV of the camera sensor and it will go through brighter and darker areas ( can't describe it better than that)

Have you tried a flat to see how the sensor, scope , filter is actually performing? But I really think the pictures are so nice that it's hardly worth bothering except for interest.

 

[davenn]

It's hard not to assume that the Sun should be totally uniform at all times. But those images are really good to look at.

The interesting thing is, when I look through the scope with an eyepiece ( visual observing), I don't see that variation of brightness.
But I am well aware of the variation in the sensitivity of the Ha filter. So I have to believe it must be the camera sensor in how it is
reacting to the light level from the sun across it's surface.
Yes, I have rotated the camera and I still see the same effectD

 

[sophiecentaur]

I still see the same effect

. . . . due to the sensor orientation?
You could deal with that with Flats, n'est-ce pas?

 

[davenn]

17 June 2018, The Sun in Ha.

Todays images... will just post the active region and one prominence image. There were several other prominences visible
but they were smaller than this one

A lot more detail visible in the AR today, tho conditions were still poor …. note the rippled limb
See the black filament within the AR between the 2 white areas

Dave

 

[davenn]

. . . . due to the sensor orientation?

yes, even with changing the orientation, a changing brightness is still visible

You could deal with that with Flats, n'est-ce pas?

Possibly ? doing " flats " is not something I hear guys doing for solar images even when they are stacking
Stacking for solar, lunar and planets is different than for deep space … ( are probably aware of that ?) ...
it's done by doing a video clip say 500 - 1000 frames, then using software to stack individual frames of the video

 

[sophiecentaur]

Possibly ? doing " flats " is not something I hear guys doing for solar images

If you have any constant variation of sensitivity over any image, a flat would help you. Flats help to give a good even background field and that grey / near black level shows up even small variations but they don't visibly affect the relative brightnesses of stars. AP'ers are obsessed with their quality. I am still too excited at just seeing something new on my images to be too bothered.
I'm sure it would be worth trying - if you feel the need together rid of those pretty effects.

See the black filament within the AR between the 2 white areas

Smashing!

one prominence image

Very sharp looking. Scary when you think just how big it is compared with Earth. Glad they don't get any nearer to us.

 

[davenn]

The Sun in Ha for 23 June 2018
A couple of nice active regions and a couple of small prominences
Lunt LS60THa and a ZWO ASI1600MM Camera

Dave

 

[davenn]

The Sun in Ha, 08 July 2018.
Other than a few filaments, the disk of the Sun is blank.
There are some nice prominences in 2 groups along the right hand (West) limb.
Lunt LS60THa scope and a ZWO ASI1600MM astro camera

cheers
Dave

 

[sophiecentaur]

The Sun in Ha, 08 July 2018.
Other than a few filaments, the disk of the Sun is blank.
There are some nice prominences in 2 groups along the right hand (West) limb.
Lunt LS60THa scope and a ZWO ASI1600MM astro camera

cheers
Dave

Keep 'em coming Dave. If you can supply enough fab pictures, it will prevent me from lusting after kit like yours!

 

[Stavros Kiri]

The Sun in Ha, 08 July 2018.

Yeah, keep them coming, because I am bored to go outside ... (this here is much better too anyway! ...)
[especially on a Sunday, like in this case]

 

[davenn]

Keep 'em coming Dave. If you can supply enough fab pictures, it will prevent me from lusting after kit like yours!

hahaha
well that isn't good I want more people to get on board and have fun

There's a new active region just coming around the east limb

 

[davenn]

[especially on a Sunday, like in this case]

I did look briefly on Saturday, but it was too windy to do imaging
Yesterday ( Sunday) the wind had dropped to a chilly breeze

 

[Stavros Kiri]

A) + see the edited:

Yeah, keep them coming, because I am bored to go outside ... (this here is much better too anyway! ...)
[especially on a Sunday, like in this case]

B)

There's a new active region just coming around the east limb

Looking forward to that! I will get up there to look at it tomorrow.

 

[Stavros Kiri]

There's a new active region just coming around the east limb

I think it's the old AR2715 returning (weakened) ...
Current stretch spotless days: 13

 

[davenn]

Current stretch spotless days: 13

if that came from spaceweather.com ... they are not overly accurate. I have already sent them emails in days gone by
stating how blind they are in not seeing spots and saying it was a spotless day when in fact there were obvious spots

This happens quite regularly

Dave

 

[Stavros Kiri]

if that came from spaceweather.com ... they are not overly accurate. I have already sent them emails in days gone by
stating how blind they are in not seeing spots and saying it was a spotless day when in fact there were obvious spots

This happens quite regularly

Dave

I've been suspecting that myself, on occasion. What is the exact meaning of "stretch" in the quote?

 

[davenn]

What is the exact meaning of "stretch" in the quote?

one would assume that they are referring to 12 actual days in a row without spots
it would appear to be their definition

ohhh, note they are saying 12 days ... maybe you typo'ed with the 13 ?

 

[Stavros Kiri]

ohhh, note they are saying 12 days ... maybe you typo'ed with the 13 ?

I read 13 yesterday morning (July 9), on my location. It's probably the time difference of our updates or their inaccuracy (since the spot group had already appeared!).
But I used as source spaceweatherlive.com (https://www.spaceweatherlive.com/en/solar-activity/sunspot-regions), not spaceweather.com (which is probably better [i.e. the latter], as you had pointed out to me in the past). I use both at times.

 

[davenn]

I read 13 yesterday morning (July 9), on my location. It's probably the time difference of our updates or their inaccuracy (since the spot group had already appeared!).

hahaha but I am ahead of you in time unless you are in New Zealand or up in Fiji, Cook Islands etc LOL

But I used as source spaceweatherlive.com (https://www.spaceweatherlive.com/en/solar-activity/sunspot-regions),

ahhh yeah
As you stated, I use the main site that also has all the other info

http://www.spaceweather.com/

Spotless Days
Current Stretch: 12 days
2018 total: 99 days (52%) cheers
Dave

 

[Stavros Kiri]

Lol ..., no I am not in Fiji or anything (no such luck). But now I realize that the site has US time, I think. Anyway, here is what it currently gives now (some "history data"):

"Last X-flare: 2017/09/10 X8.2
Last M-flare: 2017/10/20 M1.0
Last geomagnetic storm: 2018/07/05 Kp5 (G1)
Number of spotless days in 2018: 97
Current stretch spotless days: 14"

(From https://www.spaceweatherlive.com/en/solar-activity/sunspot-regions)
I'm surprised the two sites do not agree! ...

 

[davenn]

Current stretch spotless days: 14"

that doesn't seem right

I would have to check my solar records when I get home

I'm surprised the two sites do not agree! ...

and yeah totally stupid that their own 2 sites cannot agree ... another reason that they are not to be relied on

 

[davenn]

09 Sept. 2018
The Sun in Ha

Hi guys,
first solar observing for a month. Winter time isn't conducive for having the sun in the sky outside of work hours. Some nice prominences to be had this weekend
Lunt 60mm Ha solar scope, 12mm BF, Televue x2.5 Powermate, ASI1600mm Cam and Sharpcap

cheers
Dave

 

[davenn]

The Sun in Ha 30/09/2018
Nice hedgerow prominence and a small spot group
Lunt LS60 THa and ASI 1600MM
The first 2 images just scope and camera last 2 images with Televue x2.5 Powermate

Dave

 

[davenn]

After months of no solar images from me ( for various reasons) I finally managed to get some today (Sat 13th Apr)
These are just single shot images ( no stacking) with my Lunt LS60THa ... the close up image is with the Televue x2.5 Powermate inline. Camera is the ZWO ASI1600MM

 

[sophiecentaur]

Fab detail!

 

[davenn]

Fab detail!

Thankyou

You may have noticed that curved banding in the closeup image ( also on an earlier post)
These are Newtons Rings caused by slight misalignment along the optical path somewhere
It isn't noticeable on the usual images, but as soon ad the 2.5 multiplier is in line, they become very obvious.

I have a tilt adaptor on order, hope to see it in a week or 2

https://www.bintel.com.au/product/zwo-t2-tilt-adjuster/?v=6cc98ba2045f

The above shows the tilt adjuster with the imaging camera mounted behind it

Interestingly, the NR's can be removed using FFT processing of the image. A fellow solar photographer took that image of mine and processed it in Photoshop with a FFT plug-in

Before...

After ...

DANG ... what a difference !

I have tried and tried to do this with the PS plugin that he uses, and I just cannot figure out how he does itDave

 

[sophiecentaur]

Those Newton's rings, although they are a bit of a pest, show that the optics is pretty good - because they are very even. Your corrector would well take care of them. So could a bit of tinkering with photoshop, if you can produce a flat or even generate your own Newton pattern.
Whoops - I just read what you wrote about FFT / spatial filtering.

 

[davenn]

The Sun today - 07 May 2019 0130UT (1130 AEST) ( Australian Eastern Standard Time)
Lunt LS60THa single frame exposures with an ASI 1600MM Camera
AR2740 and with AR2741 just coming around the limb
(AR = Active Region)

Well the Tilt Adjuster works and got rid of the Newtons Rings in the higher magnification images

https://www.bintel.com.au/product/zwo-t2-tilt-adjuster/?v=6cc98ba2045f

if you follow the link you can see that there are sets of screws that can be adjusted. The adjustment of these removes alignment errors between the optics and the imaging sensor that cause the Newtons Rings that can be seen in images I have previously posted.Dave

 

[davenn]

The Sun, 14 May 2019
One significant active region AR2741
One reasonable prominence on the limb
LUNT LS60THa Solar scope, ASI 1600MM and ZWO Tilt Adjuster

Dave

 

[sophiecentaur]

I was looking through a friends Coronado (?) which is an entry level solar scope with a dim red display (the filter). We could see flares and the amazing thing was that they were visibly changing over a morning. What speed that stuff must be moving for the changes to be that visible.

 

[Stavros Kiri]

We could see flares and the amazing thing was that they were visibly changing over a morning. What speed that stuff must be moving for the changes to be that visible.

Not surprising. Impulsive solar flares can even last for only a few minutes (and one is lucky to see them ...). What you observed was flares or prominences?

 

[sophiecentaur]

Not surprising. Impulsive solar flares can even last for only a few minutes (and one is lucky to see them ...). What you observed was flares or prominences?

Ah well - I was told they were flares.

 

[Stavros Kiri]

Ah well - I was told they were flares.

They could have been. Solar flares can even be long duration events, even lasting up to an hour or more ...
When exactly was that? (we may check with solar records /+ Dave may know more ...)

 

[sophiecentaur]

WE saw whatever it was around midday BST on 5th May. Then the danged clouds came over.

 

[davenn]

Ah well - I was told they were flares.

were they bright areas on the face of the sun near the active region ?
If so then quite possibly they were flares

or

were they the features on the limb of the sun like you see in my above fotos ?
If yes, then they are prominences, not flares ... many don't realize they are not flares
including possibly your friend Dave

 

[Stavros Kiri]

WE saw whatever it was around midday BST on 5th May. Then the danged clouds came over.

Here is the solar activity records for solar flares that day: https://www.spaceweatherlive.com/en/archive/2019/05/05/xray
Based on approximate time ... yep, it could have been flare

 

[davenn]

Based on approximate time ... yep, it could have been flare

depending on where on the sun it was :)

still awaiting @sophiecentaur 's reply to my questions :)

 

[sophiecentaur]

depending on where on the sun it was :)

still awaiting @sophiecentaur 's reply to my questions :)

What I was looking at was on the edge ('limb"?) and was perhaps a few percent of the diameter of the disc. Whether that was what my companions were referring to is anyone's guess; they may have spotted flares too. But I thought the prominences (?) did change in size. I was surprised at the apparent speed if you translate it to many thousands of km/hr. I mean, when you think of the time that stuff ejected by the Sun takes to get here then it doesn't seem to scale with the apparent distances / heights of the features I was seeing. I have obviously got something wrong in my intuition about this.
Edit:
Perhaps those flares do not actually involve matter traveling as fast but, instead, appear and disappear like clouds in our atmosphere. So the speeds wouldn't;t need to be as high.
BTW Once again - lovely images @davenn .

 

[davenn]

I was looking through a friends Coronado (?) which is an entry level solar scope with a dim red display (the filter

Ohhh I had meant to comment on this. They are actually a very respectable Ha solar scope
have a friend on a Facebook solar page that does wonderful imaging with a Coronado PST
and a ZWO ASI120MM cam ...

Juan Payá from SE Spain
He's an expert at capturing movie clips stacking their frames and doing outstanding editing as above
That was just a couple of days ago

Dave