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July 15, 2013 Sun

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#1 BYoesle

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Posted 15 July 2013 - 03:48 AM

While the continuum view was a bit blasé, the view in H alpha was quite interesting, with many fine filaments and prominences on display, and a bit of minor flare activity in the active regions.

Conditions: winds from the W 5-15 kph, seeing conditions 3/5, transparency excellent, temp ~ 35 C.

Equipment: Orion ED100/900, Baader DERF 110/Coroanado SM90/90/BF30 (0.45 Å FWHM), cooled PGR Chameleon. Software: FireCapture, RegiStax 6, PSP7, four pane mosaic w iMerge, ~ 00:58 UTC.

Thanks for looking!

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#2 R Botero

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Posted 15 July 2013 - 07:15 AM

Great shot Bob! Thanks for sharing.

I am hoping WL "improves" by the end of the week as I'm carrying out my first solar outreach event at a local primary school and would like the kids to have "something to look at"! Ha should keep them busy though...!

Roberto

#3 Peter Z

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Posted 15 July 2013 - 12:24 PM

Beautiful image, Bob!

Cheers.
Peter.

#4 ValeryD

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Posted 15 July 2013 - 01:20 PM

Very nice disk with prominences around!

Do you use 16 bit data to bring the prominences by histogram stretching?

#5 wes

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Posted 15 July 2013 - 01:29 PM

Very nice Bob a lot of new activity coming from the east, do you use a lot of gamma when you capture.

Thanks,

Wes Higgins

#6 BYoesle

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Posted 15 July 2013 - 05:13 PM

Thanks very much guys!

Valery & Wes: My Chameleon output setting is for 8 bit avi files. My FireCapture gain slider setting is usually the very lowest setting – 160 in my case. My gamma slider setting is usually also very low at 1000, sometimes 1500, with no histogram stretch. My exposure is 5 ms, which many would consider underexposed, but which I find preserves all the detail even in the brightest regions.

It is in the processing where I do a small amount of histogram stretching - Low (black levels) are raised to eliminate any residual noise, and High levels are decreased to brighten the disk. Here is where Gamma is raised significantly, and Midtones are compressed, as shown for this afternoons effort below:

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#7 BYoesle

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Posted 15 July 2013 - 05:14 PM

I generally do not attempt to directly adjust brightness and contrast settings. The end result from above is then treated with various amounts of sharpening and unsharp masking (sometimes multiple passes) - I usually have a radius of 0.5 pixels, and a strength of 100 to 200. This seems to give me a result very close to my visual impression showing both good disk detail as well as the prominences... I believe double stacking, which removes the excess brightness of the disk from the photosphere's contribution, is also important.

My biggest issue is attempting to preserve the detail when converted to a jpg and re-sized to meet the CN file size limits, which reduces the image quality...

July 15, 2013 6 pane mosaic capture mosaic @ ~ 18:14 UTC:

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#8 FJA

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Posted 15 July 2013 - 05:44 PM

Wow! The detail in that image!

I didn't get to see the Sun today...well okay I looked and just saw a featureless reddish billiard ball. It was technically out but the view was ruined by contrails spreading themselves all over the sky.

#9 wes

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Posted 15 July 2013 - 07:53 PM

Thanks! Bob for the detailed information.

Wes

#10 HPaleske

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Posted 16 July 2013 - 03:36 AM

interesting information!
The pictures are very sharp. Can you increase the focal length even further and take the exposure time for a bit longer?

cs Harald
www.unigraph.de

#11 Chuck Hards

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Posted 16 July 2013 - 08:26 AM

I've got the same Orion 100mm scope, and have often wondered about using it for solar imaging. You've removed all doubt from my mind.

Thanks for sharing, wonderful image!

#12 BYoesle

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Posted 16 July 2013 - 10:42 AM

Thanks everyone.

Can you increase the focal length even further and take the exposure time for a bit longer?


Hi Harald - yes - when seeing conditions allow. I try to minimize the exposure time increase at larger image scales, and increase the FireCapture gain and gamma slider settings as necessary, while still avoiding over-saturation to preserve the detail.

The close up below is near my usual limit of 1.8 meters EFL with a 2 x barlow and my 90 mm of aperture. On very rare occasions I have managed up to 2.5 meters with a 2.8 x Klee barlow - but I really need more aperture (to keep exposures short) and better seeing for this EFL. Hope to be putting a "mini unigraph" of 150 mm aperture together for this purpose...

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#13 AstroPaolo

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Posted 17 July 2013 - 09:24 AM

great details and contrast
i also use a 100mm but pass to a 150-180mm would be great eheh :p

#14 Ralph Smith

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Posted 18 July 2013 - 07:09 AM

Wonderful results

#15 raylal

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Posted 18 July 2013 - 08:53 AM

That mosaic is exceptional Bob, so much details on the surface and the proms really pop out.

#16 BYoesle

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Posted 20 July 2013 - 10:22 AM

Thanks guys!

i also use a 100mm but pass to a 150-180mm would be great eheh :p



Astro-Paolo -- I'm actually starting work on a 150 mm reflector for multi-wavelength use. Here's the H alpha set up, but it will also use my other 100 ED scopes to do Continuum and CaK as well.

I will use an optical window with a hot mirror coating similar if not identical to that of a Lunt/Baader ERF. The 150 mm primary mirror is made of fused quartz, and the field lens will also be made from fused quartz -- therefore eliminating a significant amount of IR and any thermal deterioration concern.

I'm currently in the process of having the components procured - GlassFab will be supplying a BK7 optical window disk which will be polished by Lunt, and I'm making the grinding stand and foucault tester to be used in grinding and figuring the f10 quartz primary mirror.

All three 100ED refractors are "piggy-backed" on the 150, and will be able to be used independently for low-med scale viewing and imaging. When seeing permits, they can be rotated into the 150 optical path for the observation and imaging in Continuum, CaK, and H alpha - much like Harald Paleske's Unigraph reflector.

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#17 ValeryD

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Posted 20 July 2013 - 04:15 PM

Many thanks for your explanations, Bob. I will try to repeat your experience.
However I have a 16bit data output on my PGR Flea3 1,3Mpx GigE mono camera. In the reality they consist only about 11-12 bit data though. This may help.


My biggest issue is attempting to preserve the detail when converted to a jpg and re-sized to meet the CN file size limits, which reduces the image quality...


If you got a PhotoShop CS, then you can save your final pictures for CN limits as follow:
1. From the Save menu choose the "Save for Web".
2. Adjust the quality accordingly to meet the size limit requirement (200Kb).
3. Save.

If you save directly in PS or other graphical editor at the size 200Kb, then the CN forum will show
some artifacts. I believe, that "Save for Web" in PS has some special compressions which different forums engines like.

Hope this helps.


Valery.

#18 BYoesle

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Posted 24 July 2013 - 08:48 AM

Thanks Valery - I did a search and found a similar JPEG Optimizer in Paint Shop Pro. Much easier than the process I have been using! :thanx:

#19 LarryAlvarez

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Posted 24 July 2013 - 09:15 AM

Pretty Awesome Full disk and the close up is outstanding Bob. :)

#20 dbowlin

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Posted 24 July 2013 - 09:06 PM

Great photo's, and thanks for sharing the info.
Dale

#21 BYoesle

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Posted 27 August 2013 - 12:44 PM

Thanks Larry & Dale (you're welcome)!






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