Search found 1125 matches

by thesmiths
Tue Jun 11, 2024 2:26 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: proms of june 10th with new curved slit spectro-coro
Replies: 4
Views: 99

Re: proms of june 10th with new curved slit spectro-coro

ChrisHalpha2017 wrote: Tue Jun 11, 2024 4:32 am I was lucky in the afternoon as I had a few space between clouds that allowed me to test my new curved slit.
Is it possible to varying the spacing or is it necessarily a fixed gap? Do you know approximately the spacing?
by thesmiths
Mon Jun 03, 2024 5:51 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Effect of aperture mask on Calcium-K/H images
Replies: 3
Views: 173

Re: Effect of aperture mask on Calcium-K/H images

Do you use the stop at all wavelengths, or just at the Calcium lines? Generally, I only use the stop at the 400nm lines. For H-alpha, you want to use the largest aperture possible. In principle, most systems would benefit slightly from stopping down at H-beta, but I haven't noticed any real differe...
by thesmiths
Sun Jun 02, 2024 9:33 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Effect of aperture mask on Calcium-K/H images
Replies: 3
Views: 173

Re: Effect of aperture mask on Calcium-K/H images

Most optics work better at the wavelength near f/9 or f/10. I generally use 72mm with a 720mm focal length and 67mm at 600mm focal length. The focal ratio of the telescope should be what limits the focal ratio of the collimator. In your setup, a 50mm aperture (f/8.4) will give you 2.0 arcsec resolut...
by thesmiths
Sun Jun 02, 2024 9:18 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Sun FD in Halpha with SHG, 2024-06-02
Replies: 3
Views: 189

Re: Sun FD in Halpha with SHG, 2024-06-02

I like the quadrant. I hadn't seen that before.
by thesmiths
Sun Jun 02, 2024 9:13 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

Doug, maybe you could comment more about the "ideal" camera for a Sol'Ex... since the ASI178mm is no longer made. The real ideal camera for the standard Solex is the ASI 533MM camera. This is because the pixel size of the IMX 178 is actually too small for bin 1x1 and too large in bin 2x2....
by thesmiths
Mon May 20, 2024 10:38 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

I took them in the 9:00 to 9:30 AM local time window. In the summer here, fair-weather cumulus clouds often form around 10:30 to 11:00 AM or so, and I need to beat that! I can record about 24 frames in 6 minutes......and I stacked 20 this time. Same with Calcium. I looked at each image before stack...
by thesmiths
Mon May 20, 2024 4:19 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

Here is the sun in h-alpha and calcium-H from my spectroheliograph today in very good seeing. This is more typical of my summer morning seeing in Kentucky.....and these calm mornings, with the jet stream winds at 0 - 10 knots today and the scope looking over farm fields with moist grass growing, ar...
by thesmiths
Mon May 20, 2024 4:13 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: SHG slits from China: chrome on borosilicate glass, 7 micron by 13mm
Replies: 16
Views: 1379

Re: SHG slits from China: chrome on borosilicate glass, 7 micron by 13mm

If it's only OD4, it might end up being too transparent near H-alpha. The previous slits were very opaque. Also, the blue colour means it will probably absorb a lot of infrared light. The previous ones were highly reflective. Someone would need to test them to see if they are suitable. I found the b...
by thesmiths
Thu May 16, 2024 9:11 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: I emailed Beloptik about UV/IRcut KG3 for Lunt blocking filter.
Replies: 11
Views: 758

Re: I emailed Beloptik about UV/IRcut KG3 for Lunt blocking filter.

Just for the record, here the transmission profile of my Optolong KG3 IR-cut. Transmission on Ha is about 60%. Yes, that's much more reasonable. I have a GSO IR-cut filter that behaves just like that. Roughly speaking, the transmission at Ca-H and H-alpha are fairly similar. When I use it with an S...
by thesmiths
Thu May 16, 2024 2:41 pm
Forum: Commercial Solar Filters/Cameras/Hardware
Topic: I emailed Beloptik about UV/IRcut KG3 for Lunt blocking filter.
Replies: 11
Views: 758

Re: I emailed Beloptik about UV/IRcut KG3 for Lunt blocking filter.

There's also the Optolong UV/IR block on KG3 . One thing I notice about this Optolong filter is the spectral graph they publish with it (I've seen it sold on a few websites) looks like a sharp UV/IR bandpass. In fact, KG3 rolls off quite a bit towards the red and is down around 30% by the time you ...
by thesmiths
Thu May 16, 2024 1:59 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Is it possible to see the Zeeman effect with SGH?
Replies: 2
Views: 177

Re: Is it possible to see the Zeeman effect with SGH?

Yesterday I was curious on how solar magnetograms are made and found out that the Zeeman effect is used. Is far as I understand, the Zeeman effect causes the spectral lines to split when an atom is in a strong magnetic field. Now I am curious if SHGs can detect this splitting of spectral lines. Yes...
by thesmiths
Tue May 14, 2024 9:13 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

Yes, the pixels will be rather large, but I‘m perfectly happy with not ideal results in the beginning. I guess the learning curve will be rather steep anyway so I will not get the best images right away. There is a big learning curve how to just capture and create any image with an SHG. I think Ric...
by thesmiths
Tue May 14, 2024 2:16 pm
Forum: Total Solar Eclipse April 8 2024
Topic: Solar Eclipse Benton Arkansas
Replies: 10
Views: 377

Re: Solar Eclipse Benton Arkansas

christian viladrich wrote: Thu May 09, 2024 3:20 pm Do you have some first results of your Eddington experiment ? Or are you still processing the data ?
We are still analysing data. The data was of lower quality than had been hoped due to non-ideal cloud situation in Mexico. The site in Texas was completely clouded.
by thesmiths
Tue May 14, 2024 2:10 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

I guess starting with a Sol'Ex makes more sense instead of building my own? I have an older Orion Short tube 80 (f/5) scope and a ASI174MM which I could readily use. I would generally recommend starting with the Solex before building something bigger. A 400mm focal length telescope is a good fit fo...
by thesmiths
Tue May 14, 2024 12:49 pm
Forum: SPoD Archive
Topic: May 2024 Solarchat Zoom meeting
Replies: 5
Views: 329

Re: May 2024 Solarchat Zoom meeting

Here are the slides (for the library). I was not able to attend unfortunately (North American Mother's Day commitment) and did not yet have a chance to watch the video in full. I did look through the excellent slides and have one question about what the definition is for "critical sampling&quo...
by thesmiths
Mon May 13, 2024 3:59 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

I can comfortably adjust everything while looking at the monitor because the black plastic grocery bags covering the setup allow me to grab anything I want while still keeping things in darkness. - Grab the rim of the 90mm acrylic disk and rotate the grating while watching the monitor - Recognize t...
by thesmiths
Mon May 13, 2024 1:32 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

Also, I tried SHG-imaging in calcium-H at both full 102mm aperture and stopped down to 72mm (about f/10). In the past, I could see no difference between the two, so I imaged full aperture. But, with very good seeing this morning.....there was definitely an improvement in sharpness stopped down to 7...
by thesmiths
Fri May 10, 2024 4:54 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: SHG slits from China: chrome on borosilicate glass, 7 micron by 13mm
Replies: 16
Views: 1379

Re: SHG slits from China: chrome on borosilicate glass, 7 micron by 13mm

Did you see significant transversalium artifacts in the raw image from this slit? I did not see much more transversalium in the raw data. I can present some quantitative information on this, but I would avoid trying to read too much into it. The charts below show the "transversalium correction...
by thesmiths
Fri May 10, 2024 4:25 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: SHG slits from China: chrome on borosilicate glass, 7 micron by 13mm
Replies: 16
Views: 1379

Re: SHG slits from China: chrome on borosilicate glass, 7 micron by 13mm

Your image also has very little "shearing artifact". Wonder if the fast exposure speed has that effect? By "shearing artefact" I think you mean the jagged edges of the Sun? This tends to be caused by atmospheric turbulence. You're right, there is not so much evidence of this, ev...
by thesmiths
Fri May 10, 2024 2:56 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: SHG slits from China: chrome on borosilicate glass, 7 micron by 13mm
Replies: 16
Views: 1379

Re: SHG slits from China: chrome on borosilicate glass, 7 micron by 13mm

With no attenuation, I was able to use a 1ms exposure at zero gain and could achieve 484fps (the ROI was 3096x100). If you were using 1ms exposure, how fast did you scan? Wouldn't that take something like 64x scan speed? It is the fps that is the important number, not the exposure. Of course 1/expo...
by thesmiths
Fri May 10, 2024 1:10 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: SHG slits from China: chrome on borosilicate glass, 7 micron by 13mm
Replies: 16
Views: 1379

Re: SHG slits from China: chrome on borosilicate glass, 7 micron by 13mm

1. How long is the light mask you used? I can see that the opening is a bit shorter than the slit ? 2. How do you mount the slit, with the face with the chrome coat (and the slit) facing the telescope or the face with the naked glass facing the scope? I looked back at the specifications for the alu...
by thesmiths
Thu May 09, 2024 5:21 pm
Forum: This is SolarChat !!
Topic: 0.10 angstrom Ca-K full-disk images (5 May 2024)
Replies: 12
Views: 579

Re: 0.10 angstrom Ca-K full-disk images (5 May 2024)

cte wrote: Tue May 07, 2024 5:39 am true chromosphere here
Yes, I think that's right. Ca-K is also supposed to be a little higher in the chromosphere than Ca-H.
by thesmiths
Thu May 09, 2024 5:19 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: H-alpha and Ca-H high-resolution SHG images from 7 May 2024
Replies: 4
Views: 320

Re: H-alpha and Ca-H high-resolution SHG images from 7 May 2024

What is the benefit of stopping the aperture at Ca-H? Is the longer focal length beneficial at that wavelength? Generally, most common telescopes work better at f/10 or higher near 400nm. This reduces the spherochromatic aberration. In addition, there is likely not much point in using a larger aper...
by thesmiths
Thu May 09, 2024 5:12 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Calcium 396.8 and 854.2 nm SHG image comparison
Replies: 4
Views: 442

Re: Calcium 396.8 and 854.2 nm SHG image comparison

To give a complete picture of the three spectra (Ca-IR, H-alpha and Ca-H), I used the Spectrum Analyser feature of our SHG software. It's interesting to note that the shape of the IR line is more similar to the H-alpha line than the Ca-H line. You can also see that the Ca-IR line hardly shows any pr...
by thesmiths
Thu May 09, 2024 3:35 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: ND filter and Herschel wedge comparison
Replies: 15
Views: 2255

Re: ND filter and Herschel wedge comparison

Is the Chinese slit more robust due to their thicker chrome coat or due to their increased thickness/substrate material? I had a burned Shelyak slit on a mere 60mm and it appeared that the chrome coating burned rather than the glass substrate. I find that mounting the slit with the uncoated side up...
by thesmiths
Thu May 09, 2024 2:13 pm
Forum: Total Solar Eclipse April 8 2024
Topic: Solar Eclipse Benton Arkansas
Replies: 10
Views: 377

Re: Solar Eclipse Benton Arkansas

The way to test it is to use the Moon and the earthshine. You set to Moon away for the center of the field, and you push massively exposure time. This way, you see whether reflection / diffusion is brighter than the earthshine. This test is relevant since the Moon has about the same luminosity as p...
by thesmiths
Thu May 09, 2024 11:26 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: ND filter and Herschel wedge comparison
Replies: 15
Views: 2255

Re: ND filter and Herschel wedge comparison

That's a really good verification of what I had heard from my friend Jean-Francois Pettit. Hoya are very good filters but I guess they have a fairly significant amount of wavefront error. I took a slightly different approach by making my own slits on a fused quartz substrate which means I don't nee...
by thesmiths
Thu May 09, 2024 12:09 am
Forum: This is SolarChat !!
Topic: Infrared (854.2 nm) and Violet (396.8 nm) Calcium SHG images from May 7
Replies: 3
Views: 374

Infrared (854.2 nm) and Violet (396.8 nm) Calcium SHG images from May 7

I managed to incrementally improve my infrared spectroheliograph technique and a few days ago achieved my best result. I had earlier in the day managed to also image in H-alpha and Ca-H so was able to create a suitable comparison. Below are images taken at the Calcium 854.2 nm and 396.8 nm lines usi...
by thesmiths
Wed May 08, 2024 10:41 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Calcium 396.8 and 854.2 nm SHG image comparison
Replies: 4
Views: 442

Calcium 396.8 and 854.2 nm SHG image comparison

I have occasionally tried to image the Calcium infrared spectral line at 854.2 nm using a spectroheliograph (see https://solarchatforum.com/viewtopic.php?t=41873 ). I incrementally learned a few things. First of all, an APO triplet seems to perform worse than an ED doublet. As you go outside the vis...
by thesmiths
Tue May 07, 2024 9:50 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: H-alpha and Ca-H high-resolution SHG images from 7 May 2024
Replies: 4
Views: 320

H-alpha and Ca-H high-resolution SHG images from 7 May 2024

The seeing this morning in London was quite good and the clouds stayed away for a few hours. I took out my 106mm aperture APO triplet SHG for the first time in 2024. It took me a little while to get it back in full working order but the results were quite pleasing. H-alpha was taken at the full 106m...
by thesmiths
Mon May 06, 2024 10:33 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

I think I fixed my new laptop problem with fps randomly slowing down and speeding back up when using my ASI183mm camera. I had neglected to delete all the programs HP put on the startup menu that I do not use. So, when I did that and restarted the laptop.....and disconnected from the internet.........
by thesmiths
Sun May 05, 2024 11:20 pm
Forum: This is SolarChat !!
Topic: 0.10 angstrom Ca-K full-disk images (5 May 2024)
Replies: 12
Views: 579

0.10 angstrom Ca-K full-disk images (5 May 2024)

Over on the Solar Radio, Magnetometry and Spectroscopy forum I have posted an analysis of very narrow bandwidth (approximately 0.1 angstrom) images taken at the Ca-K and Ca-H wavelengths ( https://solarchatforum.com/viewtopic.php?t=45003 ). This was done with a Skywatcher 80ED telescope masked to 67...
by thesmiths
Sun May 05, 2024 11:06 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Ca-K imaging at 0.10 angstrom bandwidth
Replies: 2
Views: 229

Re: Ca-K imaging at 0.10 angstrom bandwidth

I used the Spectral Analyser function of our SHG software to look at the full Ca-K and Ca-H bands. This corresponds to the full width of the IMX 178 sensor that I used. The program automatically calculates the dispersion of the diffraction system using its inbuilt library of spectral lines. The geom...
by thesmiths
Sun May 05, 2024 10:49 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Ca-K imaging at 0.10 angstrom bandwidth
Replies: 2
Views: 229

Ca-K imaging at 0.10 angstrom bandwidth

I decided to revisit ultra-narrow bandwidth calcium imaging, this time using a 50mm square 3600 l/mm holographic diffraction grating. Previously I had used a 1800 l/mm grating in second order ( https://solarchatforum.com/viewtopic.php?t=42554 ). Using a grating in first order vs second order is more...
by thesmiths
Sun May 05, 2024 9:42 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

Part 7: Image Processing: Step 1: Assuming all your scan videos are in a single folder......create a second folder. Move every other scan to this second folder. That segregates your N-S scans from your S-N scans. Step 2: Create sun images from the spectral line videos using Doug Smith's "TheSm...
by thesmiths
Sun May 05, 2024 6:17 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

On a related note, I just got a new 17-inch HP Windows-11 laptop and had the original small SSD replaced with a new Samsung 2tb PCIe NVMe SSD. But, when I connect the ASI183mm camera to the USB3 port, the frames per second will read 360 for maybe 20 seconds and then drop off to 100 fps.....and then...
by thesmiths
Sun May 05, 2024 11:05 am
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

Part 7: Imaging: Step 4: Immediately start a new recording. As soon as you see the fps hit 360, start moving the mount north at 16X. Then, stop the recording when the h-alpha line disappears. Step 5: Rinse and repeat over and over again. After about 10 minutes you should have 40 SER videos taking u...
by thesmiths
Sat May 04, 2024 2:09 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

Part 6: Component Adjustment: Step 9: Rotate the camera assembly until the spectrum edge is exactly vertical on your monitor. Then, rotate the collimating assembly until the spectral lines are exactly horizontal. Step 10: Move the scope in RA until the spectrum hits the edge of the CMOS chip. Move ...
by thesmiths
Thu May 02, 2024 8:46 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Upgraded 80ED SHG -- H-alpha and Ca-H images
Replies: 5
Views: 368

Re: Upgraded 80ED SHG -- H-alpha and Ca-H images

I have a 462 and also have a 183 now. Would either of them work with a Sol Ex in a Skywatcher Evostar 80 ED Pro? So, if a 462 or 183 would work with Sol Ex in my SW80 then I could fill in the never ending waiting with a Sol Ex project. Either the 462MM or 183MM would work with the Solex. The 462, s...
by thesmiths
Thu May 02, 2024 12:26 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Fulldisk and fulldisk animation from my Sol'Ex
Replies: 9
Views: 493

Re: Fulldisk and fulldisk animation from my Sol'Ex

minhlead wrote: Wed May 01, 2024 11:36 pm I wrote a sharpcap script that automates the capture process.
Did you post the SharpCap script somewhere? Jean-Francois also has a SharpCap script that does some acquisition automation.
by thesmiths
Wed May 01, 2024 1:40 pm
Forum: This is SolarChat !!
Topic: Ca-H and H-alpha full-disk comparison -- 30 April 2024 (SHG)
Replies: 7
Views: 300

Ca-H and H-alpha full-disk comparison -- 30 April 2024 (SHG)

I'll post this mosaic here as more people look at this board than the more specialised "Solar Radio, Magnetometry and Spectroscopy" section. Click on the image to see at higher resolution. For those who want more details on how the images were acquired, see the full post here: https://sola...
by thesmiths
Tue Apr 30, 2024 8:45 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Upgraded 80ED SHG -- H-alpha and Ca-H images
Replies: 5
Views: 368

Re: Upgraded 80ED SHG -- H-alpha and Ca-H images

I have the exact same focuser on my ED80. I used to like how the Feather Touch focuser felt; now I like how easier it is install an EAF. Because the ED80 is quite light, the total weight of the instrument (including camera, EAF and all the dovetail bars) is just 6.7 kg. I only need a single counter...
by thesmiths
Tue Apr 30, 2024 6:46 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Upgraded 80ED SHG -- H-alpha and Ca-H images
Replies: 5
Views: 368

Upgraded 80ED SHG -- H-alpha and Ca-H images

This is my first SHG imaging session of 2024. Clouds, rain and eclipse planning prevented me from doing any solar imaging until today. I decided to revisit the 80ED SHG design I started working on last September: https://solarchatforum.com/viewtopic.php?t=42440 . I installed the 50mm square 2400 l/m...
by thesmiths
Tue Apr 30, 2024 4:06 pm
Forum: This is SolarChat !!
Topic: Today's SUN (20240428) | Good seeing + Sol'Ex
Replies: 21
Views: 751

Re: Today's SUN (20340428) | Good seeing + Sol'Ex

pedro wrote: Sun Apr 28, 2024 3:07 pm Today's SUN (20340428)
Can telescopes look 10 years into the future as well as billions of years into the past?
by thesmiths
Tue Apr 30, 2024 12:10 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

Part 4: Diffraction Grating Assembly: Step 4: The final step is putting the grating assembly together. Drill and tap 1/4x20 center holes in all the Perspex acrylic disks. Drill and countersink a hole in one of the 70mm x 5mm disks at a specific location to attach the ADM mount. Drill and tap a hole...
by thesmiths
Mon Apr 29, 2024 4:21 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Sun full disc with SHG, 2024-04-27
Replies: 8
Views: 377

Re: Sun full disc with SHG, 2024-04-27

The aperture of lens with FL 80mm is 42mm, and FL 90mm is 46mm. I can not found a suited small industrial lens with FL 100mm to 150mm currently. I assume you are using a camera with 2.4 micron pixels? You would actually be a bit better off using a 90mm lens also for the collimator. Generally for pi...
by thesmiths
Mon Apr 29, 2024 2:05 pm
Forum: Total Solar Eclipse April 8 2024
Topic: Eclipse in Totality April 8 2024 from Indiana
Replies: 14
Views: 493

Re: Eclipse in Totality April 8 2024 from Indiana

bgshelton wrote: Sun Apr 21, 2024 1:53 pm Thanks again everyone for your comments
What was the exposure time (or times) that you used to capture this very nice image? And what kind of lens (focal length, aperture)? Which kind of camera did you use and what ISO setting? I would one day like to capture a similarly lovely image.
by thesmiths
Mon Apr 29, 2024 1:45 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

Which F-number the lens should be set ? F4 or small number ? You should keep the collimator wide open (e.g. f/4) to avoid vignetting of the slit. The f-ratio of the collimator is actually set externally by the f-ratio of the telescope (e.g. f/7) I actually typically set the camera lens at f/5.6 sin...
by thesmiths
Mon Apr 29, 2024 1:40 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: New Spectroheliograph construction (based on 102mm refractor)
Replies: 114
Views: 6454

Re: New Spectroheliograph construction (based on 102mm refractor)

Part 2: Collimating Lens Assembly Step 3: Aim the collimating lens assembly into the camera lens assembly (which was previously adjusted to infinity focus). Space the two lenses facing each other about 2 or 3 inches apart, and adjust them straight and horizontal at the same level. This can be trick...
by thesmiths
Mon Apr 29, 2024 12:58 pm
Forum: Solar Radio, Magnetometry and Spectroscopy
Topic: Sun full disc with SHG, 2024-04-27
Replies: 8
Views: 377

Re: Sun full disc with SHG, 2024-04-27

I use two industrial lens instead of glued lens, one 80mm for collimator and another 90mm for camera. The slit is Chinese-made 7um by 13mm, as thesmiths introduce at another post. Your images are very sharp. I think the focal length of your telescope is 600mm? As I mentioned previously, you could p...