Search found 355 matches

by george9
Sun Mar 10, 2024 1:24 am
Forum: This is SolarChat !!
Topic: Coronal and prominence views from sea level
Replies: 26
Views: 534

Re: Coronal and prominence views from sea level

Thanks, all, for the nice comments. Christian, on the IMX 533, I would love to have the extra bits of depth, but the 11.3mm sensor would mean I need more reduction and therefore more back focus. My sensor is now 13.4mm. I think the ASI1600 is supposed to be 12 bits, but I don't know if that is accur...
by george9
Fri Mar 08, 2024 11:51 pm
Forum: This is SolarChat !!
Topic: Coronal and prominence views from sea level
Replies: 26
Views: 534

Re: Coronal and prominence views from sea level

That is correct. The 10A only works because I have the occulting cone blocking most of the photosphere and all the other stops and spots to reduce scattered light. That H-alpha shot was in my ASI1600MM Pro at 16 bit, 10ms exposures, 50 gain (i.e., very low), 10 seconds long. Stacked using 50% of fra...
by george9
Fri Mar 08, 2024 1:22 pm
Forum: This is SolarChat !!
Topic: Coronal and prominence views from sea level
Replies: 26
Views: 534

Re: Coronal and prominence views from sea level

On my ASI1600MM Pro camera, I take 30 seconds of 500 msec exposures at gain 150 or in the last photo, 200 (at 16 bit). That's either 60 or 61 frames. I use AstroSurface to stack for usually 30 or 31 frames, but sometimes 45 frames. It does not seem to make much difference. I limit to 30 seconds beca...
by george9
Fri Mar 08, 2024 3:11 am
Forum: This is SolarChat !!
Topic: Coronal and prominence views from sea level
Replies: 26
Views: 534

Re: Coronal and prominence views from sea level

Here is another shot at processing. The loops are brighter, but the residual fringes are also brighter, and the dust aberrations.

George
by george9
Fri Mar 08, 2024 2:22 am
Forum: This is SolarChat !!
Topic: Coronal and prominence views from sea level
Replies: 26
Views: 534

Re: Coronal and prominence views from sea level

Ai image processing would probably be ideal for my fringe problem. I don't have the time or the experience but it more or less goes like this: I guess a convolutional neural network, but not sure if that is just for image classification or can also do image processing (filtering). Make a training se...
by george9
Fri Mar 08, 2024 12:39 am
Forum: This is SolarChat !!
Topic: Coronal and prominence views from sea level
Replies: 26
Views: 534

Re: Coronal and prominence views from sea level

Re my statement here: "instrument scatter becomes predominant," I don't actually know that. The Empire State Building shot https://solarchatforum.com/viewtopic.php?p=407793&hilit=empire#p407793 has a pretty dark Empire State Building compared to the sky background. As you boost the bri...
by george9
Thu Mar 07, 2024 9:11 pm
Forum: This is SolarChat !!
Topic: Coronal and prominence views from sea level
Replies: 26
Views: 534

Re: Coronal and prominence views from sea level

Here is a quick copy of the Gong image that I snapped near the time. I see that my image is a little rotated. Mine is more exposed compared to the Gong image, and I get those filaments that are not really visible here.

George
by george9
Thu Mar 07, 2024 4:01 pm
Forum: This is SolarChat !!
Topic: Coronal and prominence views from sea level
Replies: 26
Views: 534

Re: Coronal and prominence views from sea level

Alexandra, thanks. Yes, great to compare them. In general, I find the coronagraph allows me to see faint filaments that are not visible in my Lunt LS80 DSII double stack. My transmission in H-alpha is over 90% with a filter I got from Solar Spectrum, and its 10A width guarantees that I have the whol...
by george9
Thu Mar 07, 2024 4:26 am
Forum: This is SolarChat !!
Topic: Coronal and prominence views from sea level
Replies: 26
Views: 534

Coronal and prominence views from sea level

Sunday was a strange day with record high temps in NYC, but ultra clear. At 9am I was headed to the market and I just happened to look near the Sun and could see blue sky to the very edge, as good as any mountain view. By the time I got home and dragged everything out it was about 10:30am, and some ...
by george9
Tue Feb 27, 2024 3:17 am
Forum: This is SolarChat !!
Topic: Routine pressure release in Lunt etalon
Replies: 5
Views: 197

Re: Routine pressure release in Lunt etalon

When my LS80 DSII was new 12 years ago, it would hold its pressure for up to six months between burbs. Since then I have replaced the O-rings but it still does not hold air as long. I burb it maybe every one to two weeks. If I find I am positioning the pistons much further in than usual, I burb it. ...
by george9
Wed Jan 10, 2024 2:09 pm
Forum: This is SolarChat !!
Topic: Corona and unfiltered prominence at sea level today
Replies: 14
Views: 752

Re: Corona and unfiltered prominence at sea level today

James, I was not going to answer because I don't want to hurt anyone's eyesight, but I see now I already admitted to looking in the original post. Any time we look through our homemade solar telescopes we are taking some risk and we do what we can to reduce that risk. E-coronal viewing is easy becau...
by george9
Tue Jan 09, 2024 12:43 pm
Forum: This is SolarChat !!
Topic: Corona and unfiltered prominence at sea level today
Replies: 14
Views: 752

Re: Corona and unfiltered prominence at sea level today

Thanks, all. James, yes it is the combination of all the lines. H-alpha is by far the brightest. H-beta and helium D3 seem to be next. There is also H-gamma, and so on. The result is that pink. I think putting H-alpha and H-beta together would get you close.

George
by george9
Tue Jan 09, 2024 4:48 am
Forum: This is SolarChat !!
Topic: Corona and unfiltered prominence at sea level today
Replies: 14
Views: 752

Corona and unfiltered prominence at sea level today

We had a storm pass through this weekend followed by a forecast sunny (not partly sunny) day. ClearSkyClock transparency was forecast to be poor, but I have learned that that is not very predictive of coronal skies. A rain storm followed by zero clouds is almost always a winner on clarity. Sure enou...
by george9
Sat Dec 30, 2023 1:13 am
Forum: SPoD Archive
Topic: December Solarchat Zoom meeting! Dec 10th 1800GMT
Replies: 27
Views: 2363

Re: December Solarchat Zoom meeting! Dec 10th 1800GMT

Hi sorry I had missed this question. I am using an old cast metal Vixen focuser from a Celestron FirstScope. Not the fanciest focuser but when its locking screw is tightened, it is incredibly solid, more so than many expensive focusers. My tolerance is only 0.2mm about 250mm out from the focuser (3 ...
by george9
Sun Dec 10, 2023 7:32 pm
Forum: SPoD Archive
Topic: December Solarchat Zoom meeting! Dec 10th 1800GMT
Replies: 27
Views: 2363

Re: December Solarchat Zoom meeting! Dec 10th 1800GMT

Thanks, Alexandra, and thanks so much for inviting me to talk. It was great fun. Alexandra, I think you could convert your Baader Prominence viewer. I would be happy to help, and I am sure Klaus would lend advice, too. The main challenge is the cost of the 5303A filter. We just have to look and see ...
by george9
Thu Dec 07, 2023 3:28 pm
Forum: SPoD Archive
Topic: December Solarchat Zoom meeting! Dec 10th 1800GMT
Replies: 27
Views: 2363

Re: December Solarchat Zoom meeting! Dec 10th 1800GMT

I am looking forward to getting feedback. Thanks all.

George
by george9
Thu Nov 16, 2023 3:17 am
Forum: This is SolarChat !!
Topic: Looking for opinion on corona processing
Replies: 15
Views: 892

Re: Looking for opinion on corona processing

By the way, here is a raw frame from the Empire State Building video. No adjustment other than lowering the resolution for posting. It gives you a feel for what is due to instrument scatter versus sky background and corona. Dim grey area over the Empire State Building: this is due to scatter in the ...
by george9
Tue Nov 14, 2023 12:42 pm
Forum: This is SolarChat !!
Topic: Looking for opinion on corona processing
Replies: 15
Views: 892

Re: Looking for opinion on corona processing

Thank you all for the awesome response! And very useful because I was not necessarily expecting this result. I think aesthetically, people are preferring the cleaner images of #2 and #4. So for presentation, I should be careful to keep it clean. As Rainer said, I was focused on what is the max you c...
by george9
Sun Nov 12, 2023 4:46 pm
Forum: Annular Solar Eclipse October 14 2023
Topic: Moon approaching Sun over corona before first contact
Replies: 17
Views: 2718

Re: Moon approaching Sun over corona before first contact

Another shot at processing, from 15 minutes before first contact to one minute after. I used curves to try to highlight the Moon coming in better. You should be able to see the Moon in all seven images. You will probably need to click on the thumbnail to see it better.

George
by george9
Sun Nov 12, 2023 4:43 pm
Forum: This is SolarChat !!
Topic: Looking for opinion on corona processing
Replies: 15
Views: 892

Looking for opinion on corona processing

I am looking for opinions on processing. Of these versions of the same coronal image from 2023-09-16, it would be helpful to hear which processing people like best. I have been working on how to fit the wide dynamic range into what is visible on the screen. I've been trying brightness-contrast, Phot...
by george9
Thu Nov 09, 2023 10:41 pm
Forum: This is SolarChat !!
Topic: A couple from last nights aurora
Replies: 16
Views: 1071

Re: A couple from last nights aurora

So happy to see this. Thanks.

George
by george9
Fri Nov 03, 2023 11:49 pm
Forum: This is SolarChat !!
Topic: Corona passing behind Empire State Building
Replies: 8
Views: 416

Re: Corona passing behind Empire State Building

Here is a shot with better processing, and it shows where on the Empire State Building the camera was pointing.

George
by george9
Fri Nov 03, 2023 5:32 pm
Forum: This is SolarChat !!
Topic: Corona passing behind Empire State Building
Replies: 8
Views: 416

Re: Corona passing behind Empire State Building

Thanks, Alexandra! Let me admit that much of the grey light is light scattered in the atmosphere, mixed in with actual corona. The streamers are the part that are clearly only corona.

George
by george9
Fri Nov 03, 2023 1:21 pm
Forum: This is SolarChat !!
Topic: Corona passing behind Empire State Building
Replies: 8
Views: 416

Corona passing behind Empire State Building

Yesterday was a relatively clear day, and the Sun was at about the right height, so I lugged my coronagraph and mount and camera on the subway to West 34th St and 12th Avenue (the Hudson River) to image the solar corona behind the Empire State Building. Here is my first attempt at processing. I hope...
by george9
Sat Oct 21, 2023 3:00 pm
Forum: Annular Solar Eclipse October 14 2023
Topic: Montage of Moon approaching Sun in front of corona
Replies: 24
Views: 4088

Re: Montage of Moon approaching Sun in front of corona

I processed my last image before second contact. I was busy looking at the Sun during annularity, and then some light cirrus moved in. Not enough to notice in white light but bad for coronal viewing. With the Sun 90% covered, most of the scattered light should be gone, so this should be a great imag...
by george9
Fri Oct 20, 2023 1:38 am
Forum: Annular Solar Eclipse October 14 2023
Topic: Montage of Moon approaching Sun in front of corona
Replies: 24
Views: 4088

Re: Montage of Moon approaching Sun in front of corona

Thanks again. The mount is a new ZWO AM5 harmonic drive unit that I like a lot, on a TC40 pier with PE160 pier extension. The 50mm is f/20 for 1000mm, the white dew shield helps avoid dust (maybe 300mm), and then the chronograph is a series of lenses that adds another 400mm. So about 1700mm total. T...
by george9
Thu Oct 19, 2023 9:35 pm
Forum: Annular Solar Eclipse October 14 2023
Topic: Montage of Moon approaching Sun in front of corona
Replies: 24
Views: 4088

Re: Montage of Moon approaching Sun in front of corona

Here the coronagraph is set up at Comb Ridge in southeast Utah, USA. Other than the battery, that all came with me from New York.

George
by george9
Thu Oct 19, 2023 2:09 pm
Forum: Annular Solar Eclipse October 14 2023
Topic: Montage of Moon approaching Sun in front of corona
Replies: 24
Views: 4088

Re: Montage of Moon approaching Sun in front of corona

Thanks, and thank you for the SPOD.

FYI, here is a closeup of the 15:08.

George

Hripcsak 2023-10-14-1508_0-CapObj_____100r_48T_30reg half.jpg
Hripcsak 2023-10-14-1508_0-CapObj_____100r_48T_30reg half.jpg (253.42 KiB) Viewed 3939 times
by george9
Thu Oct 19, 2023 2:17 am
Forum: SPoD Archive
Topic: Montage of Moon approaching Sun in front of corona
Replies: 3
Views: 1340

Re: Montage of Moon approaching Sun in front of corona

Maybe this one is more clear.

George
Hripcsak 2023-10-14 eclipse corona montage 3.jpg
Hripcsak 2023-10-14 eclipse corona montage 3.jpg (452.7 KiB) Viewed 1440 times
by george9
Thu Oct 19, 2023 2:17 am
Forum: Annular Solar Eclipse October 14 2023
Topic: Montage of Moon approaching Sun in front of corona
Replies: 24
Views: 4088

Re: Montage of Moon approaching Sun in front of corona

Maybe this one is more clear.

George
Hripcsak 2023-10-14 eclipse corona montage 3.jpg
Hripcsak 2023-10-14 eclipse corona montage 3.jpg (452.7 KiB) Viewed 4087 times
by george9
Thu Oct 19, 2023 2:04 am
Forum: SPoD Archive
Topic: Montage of Moon approaching Sun in front of corona
Replies: 3
Views: 1340

Montage of Moon approaching Sun in front of corona

This is taken from Comb Ridge in SE Utah in my 50mm homemade coronagraph at 5303 Angstroms during the annular eclipse. Universal times label the images, and they all have south up. The dark black disk in the center is the shadow of the coronagraph’s obscuring cone. The Moon is a more subtle grey dis...
by george9
Thu Oct 19, 2023 2:04 am
Forum: Annular Solar Eclipse October 14 2023
Topic: Montage of Moon approaching Sun in front of corona
Replies: 24
Views: 4088

Montage of Moon approaching Sun in front of corona

This is taken from Comb Ridge in SE Utah in my 50mm homemade coronagraph at 5303 Angstroms during the annular eclipse. Universal times label the images, and they all have south up. The dark black disk in the center is the shadow of the coronagraph’s obscuring cone. The Moon is a more subtle grey dis...
by george9
Tue Oct 17, 2023 9:17 pm
Forum: This is SolarChat !!
Topic: Coronagraph to 4300m (14,000ft)
Replies: 5
Views: 1478

Re: Coronagraph to 4300m (14,000ft)

Better resolution. George
Unfiltered Sun 2023-10-16b cropped.jpg
Unfiltered Sun 2023-10-16b cropped.jpg (136.83 KiB) Viewed 1474 times
Unfiltered Sun 2023-10-16a cropped.jpg
Unfiltered Sun 2023-10-16a cropped.jpg (142.32 KiB) Viewed 1474 times
by george9
Tue Oct 17, 2023 9:04 pm
Forum: This is SolarChat !!
Topic: Coronagraph to 4300m (14,000ft)
Replies: 5
Views: 1478

Coronagraph to 4300m (14,000ft)

Yesterday I went to Pikes Peak CO, with my coronagraph at the end of my eclipse trip. It is over 14,000 feet or 4300 meters. My planned day was met with snow, so I delayed my flight a few hours and got there before I had to head to the airport on my last day. It was a pretty cloudless day, but not s...
by george9
Tue Oct 17, 2023 2:12 pm
Forum: Annular Solar Eclipse October 14 2023
Topic: Moon approaching Sun over corona before first contact
Replies: 17
Views: 2718

Re: Moon approaching Sun over corona before first contact

It would have been visible to the eye before first contact, but only as it got closer. That active region was visible before I attached the camera, so I would have seen it. The problem was that I had to choose between imaging and visual. It only takes a minute or two to switch, but that's long enoug...
by george9
Mon Oct 16, 2023 10:27 pm
Forum: Annular Solar Eclipse October 14 2023
Topic: Moon approaching Sun over corona before first contact
Replies: 17
Views: 2718

Re: Moon approaching Sun over corona before first contact

Thanks, all. Yes, I was hoping to get this shot. I have a series of images and hope to show the early progression. There was a haze, and I could not get negative shots to subtract, so it is limited how faint I can go on the corona.

George
by george9
Mon Oct 16, 2023 3:56 am
Forum: Annular Solar Eclipse October 14 2023
Topic: Moon approaching Sun over corona before first contact
Replies: 17
Views: 2718

Re: Moon approaching Sun over corona before first contact

You may have to shift the image to the left to see the Moon on the right. Not sure why it didn't resize it. George
by george9
Mon Oct 16, 2023 3:55 am
Forum: Annular Solar Eclipse October 14 2023
Topic: Moon approaching Sun over corona before first contact
Replies: 17
Views: 2718

Moon approaching Sun over corona before first contact

I went out to Utah to get the Moon in front of the corona, and here is an early shot. I have a lot of processing to do and to create a montage of the Moon approaching the Sun. But here is one shot with minimal processing with the Moon’s shadow coming in from the right before first contact. Just happ...
by george9
Thu Oct 05, 2023 10:42 pm
Forum: This is SolarChat !!
Topic: Corona versus insect
Replies: 6
Views: 1458

Re: Corona versus insect

Thanks, all. James, yes, that is 5303A for Fe XIV. The FWHM is about 1.2A by using two 2A filters. It is slightly tunable in the sense that if I drop the temperature by over 12C, it goes off band. 20C is pretty much completely off band. At 12C it is far enough to use as a negative image. On the skie...
by george9
Wed Oct 04, 2023 8:07 pm
Forum: This is SolarChat !!
Topic: Corona versus insect
Replies: 6
Views: 1458

Corona versus insect

i went to Utsayantha Mountain on Oct 1 and was shooting the corona. In between my on-band shot and my off-band shot, an insect laid a gossamer thread across the dew shield in front of the objective. It was too thin to see normally, but it glinted for a moment when I was taking down the scope at the ...
by george9
Mon Sep 25, 2023 1:00 am
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3823

Re: Detailed design of a Corona-imaging Coronagraph

Eric, yes. JB Weld is very strong and tolerates very high temperatures. The main challenge is that it can pull the coating off the glass. If that happens, just reglue it, and then the glass will break before the screw releases. So far it has only happened on cheap lenses with presumably cheap coatin...
by george9
Sun Sep 24, 2023 10:40 pm
Forum: This is SolarChat !!
Topic: Imaging the Inner Corona in the Red Line of FeX (6374.51 Angstroms) by Jim Daley, Springfield Telescope Makers
Replies: 5
Views: 790

Re: Imaging the Inner Corona in the Red Line of FeX (6374.51 Angstroms) by Jim Daley, Springfield Telescope Makers

Very nice! Congratulations to Jim. We spoke for over an hour at Stellafane this summer as he was about to try the new filter. Not mentioned here, but his coronagraph takes amazing prominence shots, too.

George
by george9
Sun Sep 24, 2023 10:35 pm
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3823

Re: Detailed design of a Corona-imaging Coronagraph

Sorry for the duplication because these are already posted, but in case someone comes straight into this thread, here are recent images through the coronagraph. 2022-12-10 Utsayantha Mountain (3200 feet altitude) Hripcsak 2022-12-10-1549_2-1588_0-50 unsharp gradient smallest unrot.jpg 2023-08-01 Nor...
by george9
Sun Sep 24, 2023 10:22 pm
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3823

Re: Detailed design of a Corona-imaging Coronagraph

Now in daytime, here is the image out of the second relay lens (before the 5303A filter) when the Sun is centered. Blue light is out of focus and gets around the cone, causing the bright blue ring. The 5303A filter blocks it. IMG_9648.jpeg I think this one was when I was still working on it. IMG_127...
by george9
Sun Sep 24, 2023 10:20 pm
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3823

Re: Detailed design of a Corona-imaging Coronagraph

For debugging inside, I use a black-painted box and a bright LED, shown in the overexposed image. Test bench IMG_3080.jpg Then I can look up the second relay lens and see the focused objective lens. Those small but obvious white dots are microscopic dust on the lens. The method is very sensitive. Th...
by george9
Sun Sep 24, 2023 10:13 pm
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3823

Re: Detailed design of a Corona-imaging Coronagraph

Objective lens scale used for aligning and spacing the instrument.
Objective lens scale.jpg
Objective lens scale.jpg (46.98 KiB) Viewed 3812 times

Managing dust in every way possible. Also shows the black paint.
Dust IMG_6033.jpg
Dust IMG_6033.jpg (351.27 KiB) Viewed 3812 times

George
by george9
Sun Sep 24, 2023 10:11 pm
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3823

Re: Detailed design of a Corona-imaging Coronagraph

Back at the camera end, but I replaced the Baader X-Y shifter with a GSO 0.5x reducer.
ASI1600 and oven.jpg
ASI1600 and oven.jpg (136.94 KiB) Viewed 3814 times

Full system on the mountain.
IMG_1849 copy 2.jpg
IMG_1849 copy 2.jpg (643.88 KiB) Viewed 3814 times

George
by george9
Sun Sep 24, 2023 10:07 pm
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3823

Re: Detailed design of a Corona-imaging Coronagraph

The oven to hold the 5303A filters. The thermistors can just be seen wedged by the white pads. 5303 oven IMG_1541.jpeg The oven, its controllers, and its wiring. Oven IMG_1673.jpg Debugging the controllers. Temperature controller.jpg Retaining rings became a major pastime. Retaining ring tools IMG_2...
by george9
Sun Sep 24, 2023 9:59 pm
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3823

Re: Detailed design of a Corona-imaging Coronagraph

The 19mm field stop on a T2 adapter, before painting. IMG_2973.jpeg IMG_2974.jpeg The 4.2mm Lyot stop (outer ring) and 0.4mm spot (tiny dot in the middle). Before painting. Stop and spot.jpg I added nubs to the Lyot stop so I could center it over the Lyot spot. Stop and nubs.jpg Now painted. Lyot sp...
by george9
Sun Sep 24, 2023 9:52 pm
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3823

Re: Detailed design of a Corona-imaging Coronagraph

How I glue an M3 screw to a lens to hold the cone. I made the wood jig to be sure it was perpendicular. IMG_0351b.jpg And the result. IMG_0353b.jpg By the way, here are my tools. You don't need a machine shop. IMG_2948.jpeg I drill a lot of holes and pick the best one. That's a 150-year-old hand dri...