Search found 346 matches

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: 2660

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: 2660

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: 2660

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: 2660

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: 1449

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: 1449

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: 3704

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: 786

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: 3704

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: 3704

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: 3704

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: 3704

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 3693 times

Managing dust in every way possible. Also shows the black paint.
Dust IMG_6033.jpg
Dust IMG_6033.jpg (351.27 KiB) Viewed 3693 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: 3704

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 3695 times

Full system on the mountain.
IMG_1849 copy 2.jpg
IMG_1849 copy 2.jpg (643.88 KiB) Viewed 3695 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: 3704

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: 3704

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: 3704

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...
by george9
Sun Sep 24, 2023 9:47 pm
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3704

Re: Detailed design of a Corona-imaging Coronagraph

Here are the sections of the main working part of the coronagraph. Front row has the optics, back row has the spacers, and it goes from RIGHT to LEFT. Top right, the Baader 43mm to T2 adapter and first T2 section. Bottom right, the cone, the field stop, and the field lens. Second from right top row,...
by george9
Sun Sep 24, 2023 9:41 pm
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3704

Re: Detailed design of a Corona-imaging Coronagraph

Here is a shot of the objective cell, attached to the end of the Celestron FirstScope 80 dust cap to extend the focal length to 1000mm. IMG_9604.jpeg Here is more of the scope in perspective. IMG_9637.jpeg Here is the outside of the working part of the coronagraph, which screws into the FirstScope's...
by george9
Sun Sep 24, 2023 9:35 pm
Forum: Solar Reference Library
Topic: Detailed design of a Corona-imaging Coronagraph
Replies: 13
Views: 3704

Detailed design of a Corona-imaging Coronagraph

(I've been working on a more detailed description of my scope in case it helps anyone who wants to build their own, and figured this would be a nice place to post it. Images will follow. George) Detailed Design of a Corona-imaging Coronagraph George Hripcsak I describe here the design I use for a co...
by george9
Tue Sep 19, 2023 3:57 pm
Forum: This is SolarChat !!
Topic: Corona from 16 September 2023
Replies: 8
Views: 325

Re: Corona from 16 September 2023

Thanks for the comments! George
by george9
Sun Sep 17, 2023 11:22 pm
Forum: This is SolarChat !!
Topic: Corona from 16 September 2023
Replies: 8
Views: 325

Re: Corona from 16 September 2023

Here is the SDO 211A image from the same time. George
by george9
Sun Sep 17, 2023 11:18 pm
Forum: This is SolarChat !!
Topic: Corona from 16 September 2023
Replies: 8
Views: 325

Corona from 16 September 2023

Here is the corona from yesterday from the Black Forest Star Party in the US, at about 2300 feet altitude. I also have images from the day before, but this day was better. I am trying to pull out all the detail, so you see more of the artifacts, like the filter fringes and the circular reflection. B...
by george9
Mon Sep 04, 2023 3:38 pm
Forum: This is SolarChat !!
Topic: HR images taken with the N300 mm at St Véran on August 8, 9, 10 and 11
Replies: 25
Views: 1135

Re: HR images taken with the N300 mm at St Véran on August 8, 9, 10 and 11

Thank you, Christian! That’s exactly what I was wondering. Congrats again on an image the practically rivals a 1500mm professional scope.

George
by george9
Mon Sep 04, 2023 1:42 am
Forum: This is SolarChat !!
Topic: HR images taken with the N300 mm at St Véran on August 8, 9, 10 and 11
Replies: 25
Views: 1135

Re: HR images taken with the N300 mm at St Véran on August 8, 9, 10 and 11

Christian, gorgeous images! Wow. The following is a bit of a newbie question, since I am not much of an imager. Given the very highest quality of your images, I have a question on processing. What kind of sharpening are you doing? Compare your first image in the original post to say a GREGOR image h...
by george9
Fri Aug 25, 2023 4:42 pm
Forum: This is SolarChat !!
Topic: Corona from August 23 in Connecticut
Replies: 6
Views: 285

Re: Corona from August 23 in Connecticut

Thanks all. With the increasing success in getting images when I least expect it, I do start to wonder about someone producing a commercial product. With the 5303A filters, you won't blind yourself, and that was one original concern. It's very finicky though. It has to be perfectly aligned, which I ...
by george9
Thu Aug 24, 2023 11:06 pm
Forum: This is SolarChat !!
Topic: Corona from August 23 in Connecticut
Replies: 6
Views: 285

Corona from August 23 in Connecticut

Here is another shot of the corona from northwest Connecticut and the SDO 211A image. I am very surprised to be getting these from Connecticut in the summer time. It's general a day following a rainy day. And the Sun has been active. I could not get a great negative shot, so the subtraction of fring...
by george9
Sun Aug 06, 2023 12:21 pm
Forum: This is SolarChat !!
Topic: Solar corona from August 1
Replies: 31
Views: 1763

Re: Solar corona from August 1

Many thanks, George. PS. If memory serves me well, I remember that B. Liot has used the touth of skin fat from the side of the nose and polished the lens with a piece of lint-free flannel. Honestly, I can't imagine how this helped Liot to keep the lens scatter lower. Valery Ha. Yes, I read that, to...
by george9
Sat Aug 05, 2023 12:04 pm
Forum: This is SolarChat !!
Topic: Solar corona from August 1
Replies: 31
Views: 1763

Re: Solar corona from August 1

Valery, thanks. I am limiting my aperture to the following extent. The lens is 50mm, or 48mm clear aperture, and about 40mm effective aperture after you get past the Lyot stop. The native focal length is 1000mm or f/20, but by the time I am in the back of the scope, it is around f/30 (40mm effective...
by george9
Sat Aug 05, 2023 3:30 am
Forum: This is SolarChat !!
Topic: Solar corona from August 1
Replies: 31
Views: 1763

Re: Solar corona from August 1

Thanks for your explanations, George. But my question was not about the photosphere vs chromosphere on the disk. I am interested in better corona emission isolation on the sky background. In this case a narrower and more rectangular transmission profile will be more efficient in the case of transmi...
by george9
Thu Aug 03, 2023 9:23 pm
Forum: This is SolarChat !!
Topic: Solar corona from August 1
Replies: 31
Views: 1763

Re: Solar corona from August 1

Thanks, all. And thanks so much for posting the image! Valery, as Klaus said and as is also in that thread, we are probably near the limit. The big difference for me is that in H-alpha the chromosphere is helping you out by blocking 656nm light from the photosphere. That's why you can see filaments....
by george9
Wed Aug 02, 2023 12:18 pm
Forum: SPoD Archive
Topic: Solar corona from August 1
Replies: 16
Views: 1247

Re: Solar corona from August 1

Thanks, all. I am in Norfolk, CT. I don't usually get to see the corona from here. I am about to check out today's conditions. I have seen the corona from sea level (Peconic Bay) but it was very subtle, not like this shot. For 5303A, I use a pair of Andover custom-made 2A filters, resulting in 1.2A ...
by george9
Wed Aug 02, 2023 12:18 pm
Forum: This is SolarChat !!
Topic: Solar corona from August 1
Replies: 31
Views: 1763

Re: Solar corona from August 1

Thanks, all. I am in Norfolk, CT. I don't usually get to see the corona from here. I am about to check out today's conditions. I have seen the corona from sea level (Peconic Bay) but it was very subtle, not like this shot. For 5303A, I use a pair of Andover custom-made 2A filters, resulting in 1.2A ...
by george9
Wed Aug 02, 2023 2:05 am
Forum: SPoD Archive
Topic: Solar corona from August 1
Replies: 16
Views: 1247

Solar corona from August 1

It's been a while since I have had a shot at getting the solar corona due to weather. Today at about 1200 feet altitude in northwest Connecticut, I had a deep blue sky and saw a great corona at 10am in my homemade coronagraph. In the eyepiece, I could see detail on the biggest area with streamers an...
by george9
Wed Aug 02, 2023 2:05 am
Forum: This is SolarChat !!
Topic: Solar corona from August 1
Replies: 31
Views: 1763

Solar corona from August 1

It's been a while since I have had a shot at getting the solar corona due to weather. Today at about 1200 feet altitude in northwest Connecticut, I had a deep blue sky and saw a great corona at 10am in my homemade coronagraph. In the eyepiece, I could see detail on the biggest area with streamers an...
by george9
Thu Jul 13, 2023 11:04 pm
Forum: Solar Scope Modifications
Topic: Circular polarizer measurements and thoughts
Replies: 15
Views: 5040

Re: Circular polarizer measurements and thoughts

I did some testing today with a good result. I removed the UV-IR cut (knowing the DERF was there) and no change in reflections. So it put it back. I failed to mention that I have a Siebert very low power Barlow right before my blocking filter. I put a second circular polarizer between the back of th...
by george9
Thu Jul 13, 2023 3:47 pm
Forum: Solar Scope Modifications
Topic: Circular polarizer measurements and thoughts
Replies: 15
Views: 5040

Re: Circular polarizer measurements and thoughts

Thanks, Mark. Will do. One clarification, though. My AP155-LS80 has no more BG38. Just the KG3 and right now UV-IR. The BG38 that was doing too much dimming at 656nm. So I've got the 6A blocker, the KG3, and the DERF. If I don't trust the DERF (in case it gets forgotten), then my UV-IR cut handled t...
by george9
Wed Jul 12, 2023 12:34 pm
Forum: Solar Scope Modifications
Topic: Circular polarizer measurements and thoughts
Replies: 15
Views: 5040

Re: Circular polarizer measurements and thoughts

Addition: I realize that my DERF is probably blocking enough near-IR. But I don't like relying on an ERF for my eyesight, especially one that I could forget to put in front of the objective some day. i could also tilt the UV-IR cut. Or just move it as the last element in the B1800, after the narrow ...
by george9
Wed Jul 12, 2023 12:09 pm
Forum: Solar Scope Modifications
Topic: Circular polarizer measurements and thoughts
Replies: 15
Views: 5040

Re: Circular polarizer measurements and thoughts

Thanks, Mark. That's a great idea because my standard Lunt LS80 DSII has less glow but its blocking filter has a thin BG38 instead of a KG3 plus UV-IR cut. I was assuming most of the extra glow was just extra brightness, but you are right, it may be actual extra reflection right there. I will experi...
by george9
Mon Jul 10, 2023 10:16 pm
Forum: Solar Scope Modifications
Topic: Circular polarizer measurements and thoughts
Replies: 15
Views: 5040

Re: Circular polarizer measurements and thoughts

I just tried the double circular polarizer. I saw no significant improvement. I think it means the small residual glow I see has another source and I should look elsewhere. So that’s good news. Reducing the inter-etalon glow by a factor of 12 seems to be enough, and perhaps no need to worry about an...
by george9
Mon Jul 10, 2023 1:53 pm
Forum: Solar Scope Modifications
Topic: Circular polarizer measurements and thoughts
Replies: 15
Views: 5040

Re: Circular polarizer measurements and thoughts

I realized I made a small error on reporting my measurements. I compared the circular polarizer twice through with a mirror doing it the right way through the polarizer (attenuate reflection) versus the wrong way through the polarizer (don't attenuate). Therefore that 10% transmission is compared to...
by george9
Sun Jul 09, 2023 8:29 pm
Forum: Solar Scope Modifications
Topic: Circular polarizer measurements and thoughts
Replies: 15
Views: 5040

Circular polarizer measurements and thoughts

When we put two etalons too close to each other but still air spaced and when sufficient titling is not practical, we get reflections between the etalons that looks like a glow around the Sun. We can put a filter between the etalons to reduce the glow since the main image passes through the filter o...
by george9
Sun Jul 09, 2023 2:40 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: New "built in" double stacked Lunt 80, anyone?
Replies: 23
Views: 5116

Re: New "built in" double stacked Lunt 80, anyone?

The HRG works because the primary beam goes through once but the reflections pass through three times. So if the HRG reduces the brightness by say 50%, the reflections will be reduced by an additional 75% (87.5% total). (I have not measured the actual HRG transmission.) The circular polarizer exting...
by george9
Sun Jul 09, 2023 1:06 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: New "built in" double stacked Lunt 80, anyone?
Replies: 23
Views: 5116

Re: New "built in" double stacked Lunt 80, anyone?

You will need to build something. I use a Lunt HRG cell from which I removed the HRG filter and inserted a circular polarizer in its place. Others have built and used various adapters. Do a Web search on circular polarizer and Solar Chat or Cloudy Nights, and you will find descriptions and photos. I...
by george9
Thu Jun 15, 2023 2:09 pm
Forum: This is SolarChat !!
Topic: Animation of floating Prom
Replies: 15
Views: 563

Re: Animation of floating Prom

Really nice. Some beautiful proms recently. George
by george9
Mon Jun 05, 2023 5:56 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Detailed solar spectrum wanted
Replies: 5
Views: 976

Re: Detailed solar spectrum wanted

I don't have the link right here but perhaps search for BASS2000. George
by george9
Fri Jun 02, 2023 1:29 pm
Forum: This is SolarChat !!
Topic: When was the first hydrogen alpha solar telescope available for consumers?
Replies: 26
Views: 1007

Re: When was the first hydrogen alpha solar telescope available for consumers?

Yes, great thread. Just to point out that the PST came later. Coronado started with the AS series (e.g., 90 and 60mm) in the late nineties and perhaps earlier models. They were kind of affordable. The ASP-60 was $2650 in 2000. My astro buddy still has our two (we each bought one and took turns doubl...
by george9
Tue May 30, 2023 7:48 pm
Forum: This is SolarChat !!
Topic: An unexpected result with an 12nm H alpha filter
Replies: 5
Views: 342

Re: An unexpected result with an 12nm H alpha filter

This is really good. Have you posted the design of your spectro-coronagraph? This may be of interest, by Klaus_160. He took prominence images through a coronagraph and various filters, including no filter. https://www.cloudynights.com/topic/756957-what-filter-do-i-need-to-observe-prominences/ George
by george9
Fri May 26, 2023 6:43 pm
Forum: This is SolarChat !!
Topic: Is it possible for there to be portable H-Alpha solar binoculars?
Replies: 15
Views: 515

Re: Is it possible for there to be portable H-Alpha solar binoculars?

I mean in general, Georges experiment looks like fun, but i doubt he got the filter just for to use on the binoculars. Yes, exactly, it was just for fun. I mainly used it on my AP155EDF, usually double stacked with a Lunt DSII unit to get rid of the double limb. It worked great. It ran into prematu...
by george9
Thu May 25, 2023 1:27 pm
Forum: This is SolarChat !!
Topic: Is it possible for there to be portable H-Alpha solar binoculars?
Replies: 15
Views: 515

Re: Is it possible for there to be portable H-Alpha solar binoculars?

Here is my 0.3A H-alpha binocular. I made it into a monocular but got to exploit the 15x and image stabilization of the Cannon. Not overly portable, but was fun to put together and view through.

George