Exploring the Sun: Amateur Solar Imaging Techniques

[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

 

[sophiecentaur]

They are actually a very respectable Ha solar scope

I suppose that the visual images will be not very stunning through any useful narrow band filter. Monochrome or false colour with the right exposure can do wonders - as it does for nebulae.

 

[davenn]

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.

Yup, definitely prominences, not flares. Ohhh yeah I have often detected changes even in 15 - 30 mins of observing ... it's pretty amazing seeing the sun do stuff in real time.

I was surprised at the apparent speed if you translate it to many thousands of km/hr.

Coronal mass ejections CME's can vary from ~ 20 km/sec to ~ 3000 km/sec

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.

CME's take on avg 2-3 days to get here (150 million km). those prominences in that last photo I posted will be between 50 and 150 km in height above the sun

 

[davenn]

I suppose that the visual images will be not very stunning through any useful narrow band filter. Monochrome or false colour with the right exposure can do wonders - as it does for nebulae.

most solar scopes produce a reddish colour for the sun, after all we are viewing down in the red end of the spectrum ... 656.28 nm

Remember a He/Ne laser is 633 nmD

 

[Stavros Kiri]

depending on where on the sun it was :)

True! ...

... bright areas on the face of the sun near the active region ...
... flares

or

... the features on the limb of the sun like you see in my above fotos ...
... prominences ...

 

[Stavros Kiri]

Yup, definitely prominences, not flares.

I agree. I too doubt it was the possible flare candidate B7.2 that started at 11:45 and ended at 11:51 (UTC) ...
[AR 2740 was right on the limb on May 3, not May 5 ... (though close around those days) (https://www.spaceweatherlive.com/en/solar-activity/region/12740)]

 

[sophiecentaur]

most solar scopes produce a reddish colour for the sun, after all we are viewing down in the red end of the spectrum ... 656.28 nm

Obvious when you think about it.
But that's what you get from all that false colour in images - example: the 'photos' of that black hole we all saw in the papers and on TV.

 

[neilparker62]

Don't know anything about the technicalities of solar photography but though this would be a good place to ask following question:

Is it possible to create an "artificial eclipse" ? That is to arrange an blocking disk exactly like the moon in a total eclipse so that one can examine the solar chromosphere. And obtain emission spectra such as the following:

https://apod.nasa.gov/apod/ap170907.html

 

[russ_watters]

Is it possible to create an "artificial eclipse" ? That is to arrange an blocking disk exactly like the moon in a total eclipse so that one can examine the solar chromosphere.

Yes, that is a technique that is used. Not sure if by amateurs.

 

[sophiecentaur]

Don't know anything about the technicalities of solar photography but though this would be a good place to ask following question:

Is it possible to create an "artificial eclipse" ? That is to arrange an blocking disk exactly like the moon in a total eclipse so that one can examine the solar chromosphere. And obtain emission spectra such as the following:

https://apod.nasa.gov/apod/ap170907.html

I found this esa link which shows a big boys' solution to the problem.
Coronagraphs have been used for a long time on Earth with varying success.
You made me wonder about the possibility of achieving something (much inferior DIY) for an amateur setup. The problem is that most astrophotography uses Prime Focus imaging, which uses just the telescope objective lens (just like a normal camera lens) and any occulting ( blocking) disc would actually need to be very close to the plane of the image sensor if you want to produce a good sharp shadow. Also, the disc would need to be exactly the right size as there is no 'zoom' facility on an astronomical telescope. It would be hard to achieve with a DSLR camera (a favourite low cost solution) although 'clip filters' do exist for Canon cameras which sit very close to the image sensor.

 

[neilparker62]

I found this esa link which shows a big boys' solution to the problem.
Coronagraphs have been used for a long time on Earth with varying success.
You made me wonder about the possibility of achieving something (much inferior DIY) for an amateur setup. The problem is that most astrophotography uses Prime Focus imaging, which uses just the telescope objective lens (just like a normal camera lens) and any occulting ( blocking) disc would actually need to be very close to the plane of the image sensor if you want to produce a good sharp shadow. Also, the disc would need to be exactly the right size as there is no 'zoom' facility on an astronomical telescope. It would be hard to achieve with a DSLR camera (a favourite low cost solution) although 'clip filters' do exist for Canon cameras which sit very close to the image sensor.

Many thanks - very cool video on the "big boys' solution". Indeed so! Should yield an excellent very high resolution version of (for eg) the following (can't find anything similar from more recent eclipses):

http://articles.adsabs.harvard.edu//full/1930ApJ...71...1M/0000001.000.html
Would be brilliant if someone could come up with the DIY / amateur solution you mention above. However in terms of resolution I would guess the 150m gap - and precision alignment - in the "big boys'" answer is necessary and not very amenable to DIY solutions.