SolarChat!

thesmiths

kornfeld wrote: ↑Mon Apr 15, 2024 4:08 pm After scrambling in the final hours to find a cloud-free location in Texas, I got about as good as I could hope for!

Where did your scrambling start and where did it eventually end up?

thesmiths

Which is the most significant factor in improving resolution compared to the original Solex? Telescope aperture, focal length, collimator and camera lens aperture, or grating size? I think the most significant factor is telescope aperture (and also telescope quality, which is a different issue). Yo...

thesmiths

I should mention that the mount Richard used (AP900) seems to work really well for scanning. A lot of mounts don't seem to scan linearly with time, which leads to strange distortions.

thesmiths

I should mention that the mount Richard used (AP900) seems to work really well for scanning. A lot of mounts don't seem to scan linearly with time, which leads to strange distortions.

thesmiths

Hi Richard, that's a great presentation. Your post-acquisition processing looks pretty perfected. One thing that would be useful to see is a comparison with your previously taken Solex images. That would highlight the improvement in resolution that you achieved with your upgrade to the larger system...

thesmiths

Hi Richard, that's a great presentation. Your post-acquisition processing looks pretty perfected. One thing that would be useful to see is a comparison with your previously taken Solex images. That would highlight the improvement in resolution that you achieved with your upgrade to the larger system...

thesmiths

Someone recommend this video that was done by a friend of his. Taken over Franklin, Indiana. Note how the low-lying cumulus clouds disappear as the ground temperature drops. I had never seen a definitive example of this effect.

thesmiths

When I saw the eclipse for the first time in 2017 I couldn't get over how beautiful the proms were. They just don't come out on camera what they look like with the naked eye. Those beautiful ruby sparkles! Did you manage to get any of the data you were after with the bending of starlight? The promi...

thesmiths

The clouds diminished our eclipse viewing considerably, but the whole experience was fun nevertheless. This was taken with an Askar FMA 180 and a Samsung NX 3000 mirrorless camera, mounted on a Vixen Polarie. The bright red prominences were visible with the naked eye, which was something I had not e...

thesmiths

I actually got these slits in order to try the infrared Calcium lines again. I found my slits gave too much background light at wavelengths above H-alpha since the transmission of thin metal layers increases with wavelength.

thesmiths

I have been working with Maurice in Australia on various mounting designs for spectroheliograph slits. We began with the chrome on fused quartz design I had made some time ago. It was mentioned in a post a few months ago that chrome on borosilicate glass slits were available in China https://solarch...

thesmiths

I made a last minute change from the 80mm f/6 LOMO triplet with 0.8x TeleVue reducer/flattener to the the Askar 65PHQ quintuplet. The image quality is significantly better with the Askar, at least for this application. We also managed to get our software working well enough to do analysis of the tel...

thesmiths

I'm planning on taking photos of the eclipse with an Askar FMA 180 (40mm aperture, 180mm focal length) with an APS-C crop sensor. That should give an extremely wide field of view (corona is likely going to be bigger than in 2017). My plan is to put it on a Vixen Polarie. I chose the FMA 180 because ...

thesmiths

To revisit this old topic, I recently got an Askar 65PHQ for another project (eclipse related) and it occurred to me that it is a good choice for SolEx. The focal length is 416mm and the focal ration is f/6.4. Christian Buil has used the similarly designed 80PHQ and 107PHQ (actually the identical ZW...

thesmiths

highfnum wrote: ↑Wed Feb 21, 2024 10:58 pm slew speeds 0.5x 1x 2x 4x 8x 20x 60x 720x 1400x

It would be nice if they could implement the ability to do arbitrary rates (like 10x, 12x, 15x, etc). Even having just 16x would be very useful.

thesmiths

We've continued to improve our gravitational deflection software (hence a recent pause in new releases of our SHG software). I'll include here a link that describes the newest MEE2024 software package: https://groups.io/g/MEE2024/message/1318

thesmiths

I think AM3 is a good choice. What speeds can you can with?

thesmiths

maybe in future versions you can save pre processed image. that gives user to apply his own treatments for weird cases. The intermediate steps can be saved as FITS files. Turn on "Save fits files" and also read the README for how to use the software: https://github.com/thelondonsmiths/Sol...

thesmiths

v4.3 software fails cause it is looking for a dark line, any way out? I'm not exactly sure why you would want to do this, but one easy way out is to simply invert the levels of the SER file. You can do this, for example, with SER Player and then save the processed frames as another SER file. I have...

thesmiths

You can do something similar with a CaK filter to characterise it, or to tune it better if it's a home brew filter. Both Christian Viladrich and I have posted a few examples of using the Solex type of spectrometer for this purpose.

thesmiths

Focus is not easy but eventually you will get better results. Try to focus the spectra lines first and then the scope The video Pedro mentions from C. Buil is a good demonstration how to focus. But I should mention it is now fairly old so I would point out that Christian no longer puts a micrometer...

thesmiths

Here is a rather nice Ca-H image taken from Australia on the morning of 2 Feb. Maurice says: "My best seeing seems to occur around 8am to 9am... My solar scintillation monitor told me my seeing was varying between about 1.9 and 2.6 arcsec." This image is worth opening up in a new tab to ex...

thesmiths

I think I will not be doing any further imaging myself until March. In the meantime, here are some more nice images taken from Australia on the morning (local time) of 27 January. I think the Ca-K looks particularly good. 260124_Ha_am_11frames_full2.jpg 260124_Hb_am_5frames_full.jpg 260124_CaK_6fram...

thesmiths

inhapi wrote: ↑Thu Feb 01, 2024 4:06 pm What slit does he use ?

See the very first sentence of the beginning of this post.

thesmiths

Now that is science!! The equipment is just the start. My son and I have reused some of our SHG image reconstruction code to develop a gravitational defection software suite. We are still in the middle of development but so far the results look quite good. In 2017, using older CCD cameras and with ...

thesmiths

My shot in Wyoming 2017: Montage eclipse 2017-couronne.jpg Hi Daniel, did you post somewhere how you made your montage? If it's not too difficult, I may try to do something like that (from Texas). I was thinking of using an Askar FMA180 with an APS-C mirrorless camera (very light and simple but goo...

thesmiths

I haven't posted to this thread in a long time so I thought I would give an update. Here is my most recent equipment setup that I plan to use: 1821.jpg 1822.jpg I am using a ZWO 294MM camera, along with a ZWO EAF focuser. I also got a Williams Optics Bahtinov mask to aid with focusing on stars (it's...

thesmiths

Here is the latest image from down under. Data collected late in the day between 17:30 and 18:00 local time on January 17.

: Best 16 of 27 frames stacked is AS!3 and processed in Astrosurface.; 170124_Ha_1730 to 1800LT_MPVsml.jpg (1 MiB) Viewed 749 times

thesmiths

The dust is more than desirable but likely the transversalium can be automatically removed in software. As Pedro says, I would just use a Giotto type Rocket air blower (or the Player One cameras come with a nice little blower). I actually find a little dust to be helpful to make sure the collimator ...

thesmiths

Here is a rather spectacular image taken on 31 Dec 2023, showing the very bright X5 solar flare.

: H-alpha SHG. 100mm aperture. Stack of 30 of 50 scans. Data collected between 21:37 and 22:02 UTC.; 311223_Ha_30frames_MPV.jpg (1.02 MiB) Viewed 1049 times

thesmiths

How big a video file size did you have as a result? I watched the YouTube video. The file size used was around 1.8 GB. In FireCapture, the FPS was 15. The number of frames was 2448 (dimensions 2432 x 152 pixels). This means the time for the scan was 163 seconds. Since the Y/X ratio was close to 1.0...

thesmiths

Since we in the northern hemisphere have limited solar visibility (winter Solstice!), I attach a new image from Maurice taken in Australia. Taken in the morning of Christmas Eve, local time. Best 12 of 25 scans stacked in AS!3 then deconvolution with Astrosurface. Seeing was quite good, estimated at...

thesmiths

The H-alpha line is quite broad due to the fine structure splitting of the line. The splitting is equivalent to approximately 0.16 angstrom. This suggests to me that around 0.2 angstrom spectral resolution is about all that you need for normal H-alpha imaging. The imaging of H-alpha Doppler effects ...

thesmiths

Maurice sent me a recent image (21-11-2023) taken with good seeing from Oz. This is 10 frames from 20 scans, stacked with AS!3, then treatment with Astrosurface. It looks quite perfect to me.

: 211223_Ha_comb.jpg (1.78 MiB) Viewed 1759 times

thesmiths

Solarix wrote: ↑Fri Dec 01, 2023 4:37 pm with flawless 80mm F7.5 refractor

Which telescope is that? How do you know it is flawless?

thesmiths

Great suggestion. The thickness of this slit chrome plating is about 400nm. It is made of K9 material, which may be one of the reasons for its low price. Adding UV/IR to the front-end is a good idea, and I will continue to try it next time. I found an eBay seller who would also send me this same sl...

thesmiths

Here is the link to purchase glass slits: https://item.taobao.com/item.htm?spm=a21n57.1.0.0.10a7523c9duhHv&id=700716949946&ns=1&abbucket=18#detail Advantages: The gap is very narrow and the gap is very long. The disadvantage is that the outer size of the glass slit is relatively small. ...

thesmiths

An updated and improved printed version is available from here : https://azur3dprintshop.com/9-solex-base.html The optical parts are available from here : https://www.shelyak.com/produit/kit-optique-solex/?lang=en The improved version from Azur Print is actually not the link above. Go to https://az...

thesmiths

Some more suggestions for your nice design: You can eliminate the guiding part and make an "imaging only" version. For this version, the slit could be mounted perpendicular, which might help to keep the focal plane constant across the whole solar image. It would also be worth changing from...

thesmiths

I use a variant of Sol'ex. See top of this page : http://astrosurf.com/viladrich/astro/instrument/spectro/Solex/Solex.html I use 200 mm focal length collimating and imaging lenses (instead of shorter focal length in the original version) for better spectral resolution in Ca K. It is rather easy to ...

thesmiths

I use a variant of Sol'ex. See top of this page : http://astrosurf.com/viladrich/astro/instrument/spectro/Solex/Solex.html I use 200 mm focal length collimating and imaging lenses (instead of shorter focal length in the original version) for better spectral resolution in Ca K. It is rather easy to ...

thesmiths

yltansg wrote: ↑Sun Dec 10, 2023 1:58 am You mentioned using a spectro. I am guessing it is a professional test instrument. What model is it?

I think for filter testing, Christian now uses a fairly standard Solex spectrometer. It has resolution around 0.2 angstrom.

thesmiths

yltansg wrote: ↑Sun Dec 10, 2023 1:58 am You mentioned using a spectro. I am guessing it is a professional test instrument. What model is it?

I think for filter testing, Christian now uses a fairly standard Solex spectrometer. It has resolution around 0.2 angstrom.

thesmiths

With regards to the solar scintillation monitor: would you say that the images are representative of the minimum values (e.g. 0.54, 0.47, 0.37 arcsec) or more like the average values? The Rayleigh criterion for the 300mm optics is around 0.36 arcsec at 430nm -- do you think you are quite close to th...

thesmiths

Hi Pedro, I think the IMX178 sensor helps. Your files are extremely large considering the spatial resolution possible with the 2-inch aperture. At what speed are you scanning your mount? In FireCapture you can reduce the FPS independent of the exposure time to slow down the acquisition. The ROI is a...

thesmiths

Maurice sent me two new images he took today (in Melbourne, Australia) with his 100mm aperture SHG. He said there were some high clouds but at least he's got some sun (unlike many of us in the northern hemisphere). He's currently testing out the new mounting method for my chrome on quartz slits; so ...

thesmiths

Thank you for posting more photos of your interesting setup. My experience with the C8 SE mount (with the single arm) is that it does not move very smoothly. It is really only for visual use. It was not even possible to use it for taking video images of bright planets like Jupiter because it jumped ...

thesmiths

It looks like a very nice modified design. I agree that having internal helical threads for the lenses is a good idea. The weakness of the Solex is the sliding mechanism for focusing the collimator lens. You say you used the Celestron 8SE. I assume you mean that was the mount (not the telescope). So...

thesmiths

Rodler wrote: ↑Sun Nov 19, 2023 7:05 am I would like to buy such a slit from you. Would it be possible?

All the 9 micron wide slits are now gone. But I will shortly be making a second batch of quartz slits, which will likely be 8 micron wide. You can send me a private message regarding the new batch.

thesmiths

: zwo sale.JPG (16.42 KiB) Viewed 316 times

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