Exploring the Sun: Amateur Solar Imaging Techniques

[NFuller]

What sort of mount do you have for it ?

I have a celestron cgx mount I use for this as well as another scope.

 

[davenn]

I have a celestron cgx mount I use for this as well as another scope.

nice mount

that now begs the question ... what is the other scope ?

 

[NFuller]

nice mount

Thanks, I've been happy with it so far.

that now begs the question ... what is the other scope ?

The other scope is a celestron EdgeHD 800. I use this one for smaller objects like planets and galaxies.

 

[davenn]

I have a celestron cgx mount I use for this as well as another scope.

Thanks, I've been happy with it so far.

the one you see in my posts #102 and #129 is the Skywatcher HEQ5 PRO, also a good solid mount :)

The other scope is a celestron EdgeHD 800.

Sweet !

My main scope is the Celestron CPC925, bought that at the beginning of 2012, it's a fork mount scope on an Al/Az mount

without going back through pages of posts, I can't remember if you have any sort of solar filter

I commented to Sophicentaur a few posts ago that the Baader filters are good white light filters for sunspots, and some other visible light surface features. It can be purchased as a roll or sheet of film
quite cheaply. I bought a roll of it, enough to make several filters for scopes and camera lenses etc.

eg ...
https://www.ozscopes.com.au/baader-astrosolar-safety-film-large-100cm-x-50cm.html
https://www.ozscopes.com.au/accessories/eyepieces/filters?p=3

the first link is the one I got ... will do many filters

dunno where you live, probably some where with sales closer to you
Dave

 

[NFuller]

without going back through pages of posts, I can't remember if you have any sort of solar filter

Currently, I don't, but I have been thinking about getting an Ha setup for my 80mm and a white light filter for the 8" from 1000 oaks optical. I've heard many good things about their products. Here are the links below.

http://thousandoaksoptical.com/shop/solar-filters/full-aperture-solarlite/
http://thousandoaksoptical.com/shop/h-alpha/h-alpha-9-angstrom-complete-system/

 

[davenn]

The Baader filters are good white light filters and I will still use my one for sunspot imaging

and a white light filter for the 8" from 1000 oaks optical. I've heard many good things about their products.

yup, the 1000 Oaks W/L filters are good, I have 2 of them one for the CPC925 and one for the 100-400mm Canon camera lenshadn't seen this system before ...
http://thousandoaksoptical.com/shop/h-alpha/h-alpha-9-angstrom-complete-system/

just be aware that at 0.9A you are not likely to see the filaments on the face of the disk ( at minimum only a hint of the very largest ones)
as you can see from their supplied images ... the surface features are very blurred
0.9A is quite a broadband bandwidth. for every 0.1A you drop in bandwidth, the features become sharper and sharper
so dropping from the 0.9A down to the 0.65 - 0.7A of my Lunt system lots more details appear.
Dropping to the 0.45 - 0.5A, of my Daystar Chromospheric filter, is even better for surface/disk face features

I would suggest you do some research on the different filters and spent the most your budget can afford ...
it will possibly save disappointment and having to pend a whole bunch more money later on

when buying expensive gear, I'm a firm believer in the saying "do it once, do it right"

you have spent good money on excellent scopes ... DON'T skimp on a lesser quality a Ha solar filter

hope that all makes sense ?

Dave

 

[NFuller]

just be aware that at 0.9A you are not likely to see the filaments on the face of the disk ( at minimum only a hint of the very largest ones)
as you can see from their supplied images ... the surface features are very blurred
0.9A is quite a broadband bandwidth. for every 0.1A you drop in bandwidth, the features become sharper and sharper
so dropping from the 0.9A down to the 65 - 0.7A of my Lunt system lots more details appear.
Dropping to the 0.45 - 0.5A, of my Daystar Chromospheric filter, is even better for surface/disk face features

Thanks for the advice. I just started looking at Ha solar filters so I haven't really decided what to go with. The daystar filters look very nice, but you definitely pay a premium on them... $10000 for 0.3A

 

[davenn]

Thanks for the advice. I just started looking at Ha solar filters so I haven't really decided what to go with. The daystar filters look very nice, but you definitely pay a premium on them... $10000 for 0.3A

Take your time, wouldn't want you to have any regrets
it took me 25+ years to finally be able to afford a Ha filter/scope, their prices have dropped considerably ( also their quality has probably improved in that time)
It was only last August (2017) that I finally lashed out on the Lunt LS60Tha ... AU$2599.
The Daystar Quark Chromosphere one came a month later at around AU$1600 (~US$1295)

My wish list for another filter, if I could afford it, a Calcium-K filter. It gives a very different view of the disk features

Photo credit: Guilherme Grassmann

he is one of the member s of the
Uk Solar Imaging & Observations. on facebook

a good group to see what people are up to with solar observing
Dave‎

 

[davenn]

The Sun in Ha 21 Apr 2018
Absolutely crap seeing conditions... even the "blue" parts of the sky between the cloud gaps had a high haze.
Nice new active region with spots and a nice prominence showing a large detached section
Lunt LS60THa, ASI 1600MM camera and Sharpcap capture software

Full Disk

AR2706

large detached prominence

Dave

 

[Zeke_D]

Thermal flows imaged with Baader Astrosolar 5.0

 

[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