May 20th h-alpha sun

[Peter Ward]

Some nice proms this morning.

Can be seen here (http://www.atscope.com.au/BRO/gallery94.html)

[multiweb]

Very busy limb. Great stuff as usual. :thumbsup:

[Peter Ward]

Thanks Marc. I've tweaked the image a tad and uploaded a slightly large version for all the big screen users.... :)

Seems like we are finally headed toward an excellent solar maximum.

[Derek Klepp]

Very nice especially all the detail on the limb, only clouds up here.

[iceman]

Firey!

Nice one Pete.

[Peter Ward]

Thanks Mike. :)

[leon]

Very nice indeed peter, it amazes me every time just how close you guys can get to that Sun.

Leon

[Jen]

Wow that looks so kool Peter, nice one :thumbsup:

[AstroFlyer]

Fantastic!
Great processing, thanks for sharing.:thumbsup:

[Merlin66]

Another great capture!
Well done.
When I compare last year's activity to now -things are certainly hotting up!
I'm getting the chance next week to set up a double stack SM60, a 88mm modded PST, a SM60/PST double stack and a 60mm double stack Lunt - now that should be interesting!

[Peter Ward]

Humm... interesting combinations. I'd expect the Lunt DS and SM60 DS would work best.

[Paul Haese]

Nice work Pete. That is a prety large prominence. Not seen one that large for several years now.

[Clayton]

Very nice Peter, and great detail

[icytailmark]

always love your work peter. Does your solarmax have double stack?

[Peter Ward]

Thank you one and all for the positive feedback. :)

I'm thinking I'm slowly getting a handle on this high-res h-alpha solar imaging...but I have to say: the seeing on the day pretty much defines the end result.

That said, the system I use is a double stack. you can read about it here (http://www.atscope.com.au/BRO/gallery80.html)

I am not convinced, from an imaging point of view, double stack is a required, as contrast can easily be improved with image processing.

That said, the DS visual picture is often pretty cool so I'm sticking with it for now.

[Merlin66]

Peter,
Great set-up!
I have and use the SM60 pair as a double stack on an ED80.
Reading your write-up I have to disagree with the method of tuning...
Each etalon must be tuned off band but in DIFFERENT directions ie one slightly towards the blue the other towards the red - this gives maximum resolution and minimum band width. When properly tuned the peak intensity should be about 50% of that with a single etalon.
I've just gone through the "tuning" process with a 60mm Lunt DS and the difference was noticeable (unfortunately the "deadband" on the internal etalon makes the jobs doublely difficult.)
The attached sketch shows what we are trying to achieve.
(I also show my "patented" Vegemite DS controller! and a method of using the PST etalon as a double stack)

[Peter Ward]

The Meade SM90 is a little different to the original Coronado, in that it has a form of "pressure tuning" that does not work in the same fashion as the tilt stage, I think, but am not sure, it alters the central frequency in the opposite direction to that of the tilt stage.

Your conclusions for the standard configuration look like they are valid....I will have to test this to see if the system can't be tweaked a little more!

Hummm Vegemite. :D

[Merlin66]

Worth looking into...
(With the spectroscope behind the single and then the double etalon you can easily see where the bandwidth is sitting - not a job however for the fainthearted)

[Merlin66]

http://www.lightmachinery.com/Specifying-Fabry-Perot-Etalons.html
http://www.luntsolarsystems.com/forum/viewtopic.php?f=2&t=100
Some "light" reading on etalons and tilt vs pressure tuning

[Martin Pugh]

Superb result Peter

Just bought a Coronado Solarmax II DS90, used it once so far and just getting to grips with the tuning.

I am trying to use a DSLR (550D) for my solar imaging - how do you find the Skynx 2-2?

and I assume that you adjusted the tuning to capture the surface detail, then adjusted it again to get the prominences, and then overlaid?

cheers
Martin

[Paul Haese]

Martin you should be able to do both at the same time. Finding the right tuning point is all that is needed. I also found that using the DMK41 works well too.

[Merlin66]

I find I have to re-tune the double stack to accommodate the changing doppler shift between various parts of the filaments and proms. They change shape and visiblity depending on the setting.
I use the DMK21 and DMK41 - 1/120 s exposures for the surface and up to 1/11 s for the proms. gain set around 300.
HTH

[Peter Ward]

Hello Martin...Thanks. Once I get an optimal image, I don't change the H-alpha tuning. I do change the gamma of the Skynyx 2-2 ( there are other cameras out there, but this one works fine for my purposes)
and do two passes over the sun, one for Proms (faint) the other for the disk (bright) with appropriate layering in PS

[Martin Pugh]

Thanks for the details folks.

Martin