After ten days of rain, finally a sunny day!
Seeing was mediocre, with the usual whitish haziness.
SS60 Quark etalon on an 80ED scope
Basler acA1920-155um
2020-11-18_T1 by Fabio Immovilli, su Flickr
Also captured my first prominence , found it an the northern limb, just opposite to AR2783
2020-11-18_P2crop by Fabio Immovilli, su Flickr
Concerning proms, which is the best approach to picture them: long exposures with low gain or max gain with short exposure?
Cheers
Fabio
18 Nov 2020 AR2783 and prominence
- eroel
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Re: 18 Nov 2020 AR2783 and prominence
Fabio:
You got the Sun in spite of bad seeing, so the session was a success.
Regards,
Eric.
You got the Sun in spite of bad seeing, so the session was a success.
Regards,
Eric.
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Re: 18 Nov 2020 AR2783 and prominence
Thanks Fabio.
I tried to capture the spot in WL with Baadar film, without success due to thin-clouds
Terry
I tried to capture the spot in WL with Baadar film, without success due to thin-clouds
Terry
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Re: 18 Nov 2020 AR2783 and prominence
Not bad at all considering the conditions, Fabio.
Regarding your question; I always try to keep the gain low (and of course that means slightly higher exposure times). More gain = more noise, which I find always shows in prominences.
Regarding your question; I always try to keep the gain low (and of course that means slightly higher exposure times). More gain = more noise, which I find always shows in prominences.
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Re: 18 Nov 2020 AR2783 and prominence
Hi Jochen,
Thank you for the info.
I asked, because in today's imaging session I tried two different settings resulting in similar histogram:
a) 150 ms exposure, low gain
b) 50 ms exposure, max gain
After stacking and post processing I found no difference between a) and b) in terms of noise (maybe it got averaged out by the stacking?)
but b) was noticeably more crisp in details.
Anyway, this was just a single quick test, I'll investigate further under better seeing conditions.
Cheers
Fabio
Thank you for the info.
I asked, because in today's imaging session I tried two different settings resulting in similar histogram:
a) 150 ms exposure, low gain
b) 50 ms exposure, max gain
After stacking and post processing I found no difference between a) and b) in terms of noise (maybe it got averaged out by the stacking?)
but b) was noticeably more crisp in details.
Anyway, this was just a single quick test, I'll investigate further under better seeing conditions.
Cheers
Fabio
Flickr album https://www.flickr.com/photos/190949744@N08/
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Re: 18 Nov 2020 AR2783 and prominence
Hi,
Very good.
Very good.
regards Rainer
Observatorio Real de 14
San Luis Potosi Mexico
North 22° West 101°
Observatorio Real de 14
San Luis Potosi Mexico
North 22° West 101°
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Re: 18 Nov 2020 AR2783 and prominence
Nice images of the AR and prom Fabio...well done !!!
Brian
Brian
Brian Colville
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Photos: https://www.flickr.com/photos/185395281@N08/albums
10'x15 Roll-off Roof Observatory
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iOptron CEM70G Mount carrying:
Orion EON 130ED, f7 OTA for Day & Night Use
Ha Setup: Lunt LS80PT/LS75FHa/B1200Ha + Home Brew Lunt Double Stack/B1800Ha on the Orion OTA + Daystar Quantum
WL, G-Band & CaK Setup: Lunt Wedge & Lunt B1800CaK, Baader K-Line and Altair 2nm G-Band filter
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Re: 18 Nov 2020 AR2783 and prominence
Wonderful images the prom is fabulous
I would answer the same as all the above. It is a question of testing in your system, you want as low gain as you can get away with and as quick an exposure as you can get away with. You have to balance the two out. Every prominence is different so difficult to always use the same method each time. For each prom I usually image a range of gain vs exp and see which comes out best. Also, like Alfred said, play with the gamma too. Increasing the gamma can also make it easier to see the prom and lower the exposure, but be cautious! the more gamma you add the more white haze you get and the more stacking artefacts you get. I only change this marginally as I have learned the hard way
Alexandra
I would answer the same as all the above. It is a question of testing in your system, you want as low gain as you can get away with and as quick an exposure as you can get away with. You have to balance the two out. Every prominence is different so difficult to always use the same method each time. For each prom I usually image a range of gain vs exp and see which comes out best. Also, like Alfred said, play with the gamma too. Increasing the gamma can also make it easier to see the prom and lower the exposure, but be cautious! the more gamma you add the more white haze you get and the more stacking artefacts you get. I only change this marginally as I have learned the hard way
Alexandra
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Re: 18 Nov 2020 AR2783 and prominence
Hi Alexandra,
Thank you for your suggestions.
I noticed that below a certain amount of gain I was losing details (or dynamic resolution), even if by increasing the exposure the hystogram was similar.
Time for more experiments
Actually I never touched the gamma slider during acquisition: I was under the impression that it could always be corrected in post-processing.
Cheers
Fabio
Thank you for your suggestions.
I noticed that below a certain amount of gain I was losing details (or dynamic resolution), even if by increasing the exposure the hystogram was similar.
Time for more experiments
Actually I never touched the gamma slider during acquisition: I was under the impression that it could always be corrected in post-processing.
Cheers
Fabio
Flickr album https://www.flickr.com/photos/190949744@N08/