The sun

[Madweasel]

Hi all, how about our nearest star? Not a very interesting subject at the present (unusually deep) sunspot minimum - just a blank disk. But I was playing with the B&W 10-stop ND filter. I still needed 1/8000 at f/25 though, but using the 100-400L at 400mm + 1.4x extender and spot metering, I got a correctly-exposed disk of impressive sharpness. So, if any sunspots do appear, I've got the wherewithal to catch them. My main reasons for getting the filter were for partial solar eclipses and long daytime exposures. This is the whole frame on a 40D, no cropping.

http://i72.photobucket.com/albums/i192/garlicpickle/Canon/lr1-5422.jpg

[dpastern]

I hope you didn't look at the sun throught the setup? Even with a ND10, I doubt it would be safe. The only safe way is through a dedicated solar filter imho. Good shot though.

Dave

[siddr20]

Do be careful when you are taking pictures of the sun.
It will damage your eyes!! There are special filters you can use tho..
Is ND filters suitable??

Anyways gd image :)

[kellieprinzel]

WOW

[kellieprinzel]

Damage your eyes my ass

[Skonk]

The 40D has Live View which I assume he will have used to setup the shot?

[troypiggo]

Damage your eyes my ass

What a foolish attitude. I hope you were joking. Ever focus the Sun through a magnifying glass as a kid to burn leaves or whatever? Subsitute telescope/eyepiece/viewfinder for magnifying glass and your retina for the leaves.

[troypiggo]

@ Madweasel - Impressive. I've been looking into solar filters a little at the moment. As suggested above, do be careful. Not sure if a ND filter stops harmful rays outside our visible spectrum. There are special filters etc that do. You can get special solar films, or there are (expensive) Hydrogen-alpha filters too.

[Karl Johnston]

Damage your eyes my ass
Yeah who woulda thought?

High magnification optics + your eye + the sun = permanent blindness?....Never..:rolleyes:

I am being sarcastic by the way! You shouldn't look at the sun with your naked eye, directly, god help you a telephoto.

[Bill Boehme]

Hi all, how about our nearest star? Not a very interesting subject at the present (unusually deep) sunspot minimum - just a blank disk. But I was playing with the B&W 10-stop ND filter. I still needed 1/8000 at f/25 though, but using the 100-400L at 400mm + 1.4x extender and spot metering, I got a correctly-exposed disk of impressive sharpness. So, if any sunspots do appear, I've got the wherewithal to catch them. My main reasons for getting the filter were for partial solar eclipses and long daytime exposures. This is the whole frame on a 40D, no cropping.

There are sunspots, but your exposure was too bright and not focused sharply enough to see them. The ND filter is not adequate to do the job as indicated by the fact that you needed to go to the maximum shutter speed of 1/8000 second and an aperture of f/25 (which is going to kill sharpness) at ISO 100. If you used live view, you have probably permanently damaged your camera's sensor. If you looked through the viewfinder, you have risked getting some retinal damage.

Damage your eyes my ass

I build custom canes for the blind. If you will inform me of your height, I will get to work on yours.

Consider that the exposure was for only 1/8000 second through a tiny f/25 aperture. Can you blink fast enough to set the focus in that length of time.

[Madweasel]

There are sunspots, but your exposure was too bright and not focused sharply enough to see them...
Incorrect on all three counts Bill. Sorry. :(

[Bill Boehme]

Incorrect on all three counts Bill. Sorry. :(

OK, try this --
Using either a resolution test chart or simply a newspaper page at about 15 meters, get the sharpest images that you can at f/8 and then at f/25 and see which you can read.

There are plenty of prominences that should have been visible on a proper exposure along with a major coronal hole across the middle of the sun.

[Madweasel]

Yes, I know all about diffraction effects limiting resolution, but they are not as strong as you suggest. The focus is sharp, achieved by autofocus without the converter first. The exposure is not overexposed, as can clearly be seen from the RAW histogram (with the 1.4 extender, minimum aperture would be f/57, so I was not at minimum exposure). Yes there is currently prominence activity visible at the limb (but only in hydrogen-alpha light - prominences are much dimmer than the photosphere). Check spaceweather.com for an update on sunspot activity. Today is the 11th consecutive day with no sunspots.

[SteveInNZ]

NASA produce a bulletin for solar eclipses that includes information for photographing the full disc and partial phases. They list materials that are suitable and those that are not and have spectral response curves for commercial filter material as well as some alternatives.
They list photographic ND filters as not suitable. An easilly available, suitable filter is welders glass.

The upshot is that it must have the same optical density from the visible wavelengths, right up through the IR range to 2500nm. That way you/your eye/the camera will limit the exposure to the damaging wavelengths by the same amount as the visible/metered wavelengths.

Steve.

[Bill Boehme]

Yes, I know all about diffraction effects limiting resolution, but they are not as strong as you suggest. The focus is sharp, achieved by autofocus without the converter first. The exposure is not overexposed, as can clearly be seen from the RAW histogram (with the 1.4 extender, minimum aperture would be f/57, so I was not at minimum exposure). Yes there is currently prominence activity visible at the limb (but only in hydrogen-alpha light - prominences are much dimmer than the photosphere). Check spaceweather.com for an update on sunspot activity. Today is the 11th consecutive day with no sunspots.

Yes, I am familiar with spaceweather.com, but I did misstate things when I was thinking one thing, but not typing my thoughts very well -- I meant to say that there should have been visible things like the prominence activity and I also was thinking in terms of a proper filter for viewing the sun. As Steve pointed out, an ND filter is not the best choice. I am not familiar with the characteristics of the 100-400 zoom telephoto lens and was just extrapolating what I could expect to see with my 400mm f/5.6 lens with a TC attached. I have made some test shots to evaluate performance at various apertures and, for my expectations, apertures smaller than f/22 are just too soft to adequately resolve fine details.

[kellieprinzel]

What a foolish attitude. I hope you were joking. Ever focus the Sun through a magnifying glass as a kid to burn leaves or whatever? Subsitute telescope/eyepiece/viewfinder for magnifying glass and your retina for the leaves.


Obviously no one can take sarcasm too well. I think everyone and their Mom knows that it is never a good idea to look directly into the sun. It was a just a joke.

[kellieprinzel]

There are sunspots, but your exposure was too bright and not focused sharply enough to see them. The ND filter is not adequate to do the job as indicated by the fact that you needed to go to the maximum shutter speed of 1/8000 second and an aperture of f/25 (which is going to kill sharpness) at ISO 100. If you used live view, you have probably permanently damaged your camera's sensor. If you looked through the viewfinder, you have risked getting some retinal damage.



I build custom canes for the blind. If you will inform me of your height, I will get to work on yours.

Consider that the exposure was for only 1/8000 second through a tiny f/25 aperture. Can you blink fast enough to set the focus in that length of time.

Awesome. I'm 5" 1'

[kellieprinzel]

Yeah who woulda thought?

High magnification optics + your eye + the sun = permanent blindness?....Never..:rolleyes:

I am being sarcastic by the way! You shouldn't look at the sun with your naked eye, directly, god help you a telephoto.

Hah, I was too! I know better than to look into the sun. That's one thing I think everyone was told while growing up. :D

[Karl Johnston]

Thank god! You never know because on the web you can't detect voice tones :lol: I always worried about how you never came back to respond, thinking you had gone blind :( from trying it out!

[Chopper Al]

Cool shot of the sun.

And yes, the sun can do nasty things to your eyes. When I was younger, I fell asleep outdoors. Had a nasty habit of sleeping with my eyes part way open. Needless to say, I burned the whites of my eyes. Called into work sick the following day, and my boss did not believe what I had done. Went in the following day with my eyes swollen half shut, all red and feeling like sandpaper scratching over them as I blinked. My boss then believed my reason for not coming into work the day before.

Al

[Celestron]

I won't harper on the proper way to image the Sun . Everyone that stated something was right already . What i will state is that the 10th of July (http://www.spaceweather.com/archive.php?view=1&day=10&month=07&year=2009) was the last time to see the latest sunspot as it rounded behind the sun . No sunSpots the 4th of April (http://www.spaceweather.com/archive.php?view=1&day=04&month=04&year=2009) either .

[kellieprinzel]

Thank god! You never know because on the web you can't detect voice tones :lol: I always worried about how you never came back to respond, thinking you had gone blind :( from trying it out!

Hahah, I just forgot that I posted here. I was going back looking at some older ones and saw this. I laughed so hard! I can't believe some people thought I was serious. You're right though, it is VERY HARD to detect sarcasm over the interweb much less any kind of emotion at all!

[hollis_f]

I meant to say that there should have been visible things like the prominence activity

I thought that prominences were too dim to be seen in a shot that correctly exposes the solar disk. I can't see any in this shot - and the exposure and focus look to be pretty good...

http://photos.imageevent.com/frankhollis/astropix/websize/sunspot.jpg

Whereas, in this shot you can see a prominence. But this exposure even shows the corona. So the prominence must be very dim.

http://photos.imageevent.com/frankhollis/eclipse/websize/eclipse%2007.jpg

[Celestron]

I thought that prominences were too dim to be seen in a shot that correctly exposes the solar disk. I can't see any in this shot - and the exposure and focus look to be pretty good...



Whereas, in this shot you can see a prominence. But this exposure even shows the corona. So the prominence must be very dim.



First off you cannot see Solar Prominence without the Proper Solar Filters . Read THIS (http://www.astronomics.com/main/category.asp/Coronado/Telescopes/catalog_name/Astronomics/category_name/T3DARDLGR89L8MUHURHXLWS3J6/Page/1) and you will understand .

Second in your second image which is very very good you do not see Solar Prominence , your seeing the Suns Corona (http://www.astropix.com/HTML/SHOWCASE/TOTAL1.HTM) only .

Solar Promince looks like THIS (http://apod.nasa.gov/apod/ap090531.html) , which is called Solar Flares (http://hesperia.gsfc.nasa.gov/sftheory/flare.htm) from the Sun when explosions occur and blows out away from the Sun . This is what helps us to see Auroras (http://www.exploratorium.edu/learning_studio/auroras/) when they pass earth .

Hope this might help everyone understand about the Sun a little better .

[hollis_f]

Second in your second image which is very very good you do not see Solar Prominence , your seeing the Suns Corona (http://www.astropix.com/HTML/SHOWCASE/TOTAL1.HTM) only.

Sorry, that second image came out a bit small. Here's a crop -

http://www.frankhollis.com/temp/Eclipse%20Total.jpg

You can see the prominence quite nicely. You can also see the corona which is, as I'm sure you know, fairly dim (this is no filter 1/125s f8).

Now here's a shot during the partial phase of the eclipse. Using a filter (Baader astrofilm which, as far as I know, doesn't filter colours preferentially).

http://www.frankhollis.com/temp/Eclipse%20Partial.jpg


Now I can't see any sign at all of that prominence (even if I whack the exposure all the way up in post-processing). And I don't think it appeared in the 15 minutes between images.

So I don't think one can expect to see prominences in a shot that's uccurately exposed for the Sun's disc. For the same reason that one doesn't expect to see the corona.

[Celestron]

I must say i could not see that at all in your first image . Quite amazing ! Did you do any PP ?? Do you send this image to APOD ? When and where did you get to see this event ? It's a rare opportunity for most ppl to have the chance to see one like this unless they live in that area . BTW i found one other image like yours at APOD (http://antwrp.gsfc.nasa.gov/apod/ap060407.html) . Thanks for posting this other image . I still might add tho that on any other day and not an eclipse with a Baadar filter you will not see these type solar Prominence or Flares .

[hollis_f]

I must say i could not see that at all in your first image . Quite amazing ! Did you do any PP ?? Do you send this image to APOD ? When and where did you get to see this event ? It's a rare opportunity for most ppl to have the chance to see one like this unless they live in that area . BTW i found one other image like yours at APOD (http://antwrp.gsfc.nasa.gov/apod/ap060407.html) . Thanks for posting this other image .

Hardly any PP at all for the total image. I would imagine that there are quite a lot like it - it was the total eclipse of March 2006 - viewed from Antalya, Turkey. A (non-photog) friend tried shooting the eclipse with her P&S and you can see the prominence (well, a few reddish pixels) in her image. With the number of lenses pointing in that direction at that time I expected a lot of similar pics.

Love the PP done on that APOD image - I'm going to have to try that with one of mine, where the corona is more visible. The APOD image must have been taken soon after totality, as you can see a second prominence. That only appears in my very early shots.

[markjpcs]

Sorry, that second image came out a bit small. Here's a crop -

http://www.frankhollis.com/temp/Eclipse%20Total.jpg

You can see the prominence quite nicely. You can also see the corona which is, as I'm sure you know, fairly dim (this is no filter 1/125s f8).



Nice shot!

[troypiggo]

Hahah, I just forgot that I posted here. I was going back looking at some older ones and saw this. I laughed so hard! I can't believe some people thought I was serious. You're right though, it is VERY HARD to detect sarcasm over the interweb much less any kind of emotion at all!

I get sarcasm, I'm pretty sarcastic myself.

And you may very well know the hazards of looking direct at Sun through lens/scope. That's fine.

I was more concerned with others who may have read your post and found it misleading. There's all types here at POTN. Those with common sense, those without, kids, adults, and so on.

Maybe a smilie or something would have intimated your attempted humour a little better. :)

[ejicon]

Wow. that's a nice shot.