The Sun 7 January 2012 *GREEN* and white light

[Bizibilder]

I finally ordered and received my #58green filter (thanks RVO) this week so it was out this morning for my first go with it on the Sun. Another steep learning curve!!

Anyway today's Sun with an extra "green Filter" image for your perusal. Usual set-up SW 120 (stopped to 100) Achromat, Canon 1000D, Baader Solaer filter. White light was ISO100 1/1000sec and Green light was ISO200 1/250sec. Both stacks of 64 images in R5 and processed in PS CS5.

I need to learn how to process the green images - all I did here was turn it to an RGB "black and white" image and then more or less follow my "normal" processing routine for white light.

"WHITE" version:

And the "GREEN":

[Merlin66]

Good presentation!

IMHO I think the "green" version looks definately "tighter"

Did you also have a UV-IR filter fitted to the camera? ( I haven't measured that filter for leakage in the IR....yet)

[Bizibilder]

No, no UV/IR filter. I agree - it would seem that some finer detail is there in the "green" image - especially full size. To be fair it was quite hazy with a very low Sun when I took these so it's not really fair to dismiss one or other image until I can take (and learn to process) images with the Sun higher and seeing that is more favourable.

[markt]

Very good results!

[Montana]

Very good indeed! The green does seem to have small granules and better penumbral details.

Regards

Alexandra

[markt]

The green does seem to have small granules and better penumbral details.

I agree, the green image is much 'cleaner'.

[Cschur]

Any green filter resembling a Wratten 58 is a good thing for solar, and your shot shows a contrast improvement for sure. If you have any IR blocker filters, you might add that to see if you gain a bit more.

[Tzetze]

Cracking shots Bizibilder, well done.

I've been trying to get to grips with some white light imaging through a #56 filter. Just need to learn how to stack with Registax now. Thanks for detailing your solar filter build using the ventilation reducer - I'll be getting to work on one of those asap.

One quick question - any tips for achieving best focus? I've been using live view on my 450D but it's far from easy to tell when best focus has been reached.

[SaraG]

Why not just buy a Continuum filter and an IR Cut filter (you already have an IR cut on the solar film and one on the DSLR sensor, but some still gets through, Continuum and IR Cut gives the best solar images in white light.

You can use the Camera Live View Histogram (hockey stick shape) to focus as well as zooming in to the edge / sunspot.

Here is a write up on the histogram focusing technique. http://www.hapb.net/Solar/histogram/histogram.html

[Bizibilder]

Tzetze - I usually run my 1000D via the lappy and focus using live view on the lappy screen, usually with zoom enabled. You will find the image will tend to move about quite a bit and I often (clouds permitting) take 4-5 minutes to focus. After that I reset the exposure and take a swift snapshot. If you then look at this full size on the screen you can quickly tell if focus is right.

I also always stack my images (usually 64 of them) as this tends to give better definition across the whole disc.

Sara - sorry but focussing accurately using the histogram just doesn't work.

[Tzetze]

Thanks for the link Sara, plenty to chew on there.

[Tzetze]

Bizibiler - I'll have to use the netbook too. I suppose it's worth taking the time over it and getting it right from the outset. Netbook screen will give better indication of focus than the camera LCD. Cheers.

[SaraG]

I can focus fine (also helps me FIND the sun ) using the histogram AND I also use the live view ZOOM onto a sunspot.

I also use a cheap (hahah no) RnP motor focuser to help me get it tighter.

You will get a better focus if you use a laptop screen sure, bigger image to use than a live view, I just cant be bothered hauling all the power and equipment outside and back in again. Let's not forget this is just white light, not Narrowband where the real good images are at.

You are not going to print a good white light image or sell one, HA or CaK maybe.

Best images, Continuum, IR CUt filter, Hertschel Wedge.

I think it is better spending the money on a HA PST than on a Wedge TBH at current prices. You will get better satisfaction at that price for a different type of image than just sharper higher contrast, Wedges are seriously overpriced compared to the prices of narrowband PST's for what you gain. For a that kind of money you will open up a completely different view of the sun, rather than just a sharper view of the same old. I wouldn't risk more than a cheap Achro on solar (especially a wedge due to the tube heating). I don't think I would want to heat up a Apo scope at their current prices.

[Bizibilder]

One trouble at this time of year is that the Sun is so low that getting anything like a steady image is near impossible!!!