Spectroscope

[dabateman]

@photoni,

To get the lines I really needed to drop my exposure to way under exposed.

For me, I find the Mercury lines more useful than the sunlight fraunhofer lines.

Also there is a 708nm Mercury line that might appear and maybe what you are seeing in the zwb1 and zwb3 images.

This may help or confuse you to what you are seeing: 

https://physics.nist.gov/PhysRefData/Handbook/Tables/mercurytable2.htm

[Alaun]

Did you focus on the slit? An out of focus would not show the lines.

[photoni]

17 hours ago, Nate said:

I can only get lines if I use a home made spectrometer for inside. It's got to be the distance from your camera to the slit, or the distance to the light source. I'm trying to figure this out too, as I'd like to use my camera instead of a FS Webcam for indoor sources. Here's what I made yesterday, kind of works for indoor and outdoor.

 

 

I don't understand where you put the reticle ... directly above the camera?

[photoni]

11 hours ago, dabateman said:

Also there is a 708nm Mercury line that might appear and maybe what you are seeing in the zwb1 and zwb3 images.

where ?

 

this is the first step
then...
understand what my lenses see from 510 to 325 nm
and why some, despite having the same focal length and similar brightness, are better (I have 3 of 300mm)

 

thank you all for your help

Antonio

[Nate]

8 hours ago, photoni said:

where you put the reticle

Sorry I forgot to show that part. It's on the right side of the first pic, the thinner the slit, the tighter the lines generally.

[Nate]

Here's what I got with the R72 and sunlight

@photoni

[Daniel Csati]

The Fraunhofer lines are far too narrow to resolve them with your setup. You would need a echelle grating-prism combination to resolve those. Google "echelle spectrum"

 

Here you can browse the spectra of the sun with extra high resolution: https://bass2000.obspm.fr/solar_spect.php .. wavelength is in angstroms so 630nm = 6300A

[Andy Perrin]

I think the Fraunhofer lines are the main ones? They were the first to be discovered back in the 19th C. I think these probably are the (darkest) Fraunhofer lines unless you can propose an alternative explanation. 

[photoni]

17 hours ago, Andy Perrin said:

I think the Fraunhofer lines are the main ones? They were the first to be discovered back in the 19th C. I think these probably are the (darkest) Fraunhofer lines unless you can propose an alternative explanation. 

I have not yet been able to see a stable spectrum of the sun with Mr. Fraunhofer.
Today a very empirical test of the sun, with Meritar 50 f: 2.9
reflection of the reticle on a sheet of plain photocopying paper (this is wrong ... I think this leads to an excitement of the whitener)

 

I am perplexed and confused XD

 

 

[Andy Perrin]

I see a few lines on yours, Photoni. They are just very blurry. Nate’s is much sharper, and we have many other examples on the forum of people’s diffraction grating photos showing solar lines. 

[Daniel Csati]

On 6/26/2022 at 5:16 AM, Andy Perrin said:

I think the Fraunhofer lines are the main ones? They were the first to be discovered back in the 19th C. I think these probably are the (darkest) Fraunhofer lines unless you can propose an alternative explanation. 

It could be some atmospheric absorption lines, there are a couple in the visible range too. 

 

Edit: maybe it's a group of unresolved Fraunhofer lines

[photoni]

good morning
I changed the lens, I used the Soligor KA 35mm f: 3.5 @f: 8 which should have better UV sensitivity
I used a 3mm thick Teflon board and a scale cut out of paper (the photocopy paper has different colors and spectrum !!!)
I used a tripod and a lower sensitivity (800iso)
I tightened the opening of sunlight, now it is about 2mmx50mm (unfortunately the wind was moving it)
I did the tests with and without cut of the reds and IR
in the last 4 images I believe that on the right there is no IR contamination but I believe a double spectrum

 

looking at the real spectrum it seems to me that the best emulation of the wet plate (325-510nm) is the stack of TSN575 + QB29 2mm thick (~ BG39 + BG25)
The one with QB5 (~ BG28) perhaps a little wider towards the greens also seems interesting to me.

 

I will start from these conclusions to try the Orthochromatic BLACK&WHITE film.

 

Thank you
Antonio

[colinbm]

You are learning something that we didn't learn at school.

[Andy Perrin]

10 hours ago, Daniel Csati said:

It could be some atmospheric absorption lines, there are a couple in the visible range too. 

 

Edit: maybe it's a group of unresolved Fraunhofer lines

They match very well with the known spacings of the major Faunhofer lines. Almost certainly some of them are groups of lines but I have no doubt it’s them. 

[Nate]

Looks great, Can definitely see the lines. I love doing experiments like this. Reminds me of when I had a small hole from a window opening shine onto a dvd I had, and cast the spectrum to the ceiling. Then took pics with different filters.

[photoni]

I've been looking for an easy way to let sunlight through a crack for a long time :)
Today I tried in the studio with flash light
with the traditional method it is impossible, the quartz tube is circular and the parabola is wavy.
I found the solution by projecting the cone of light onto a chrome tube, basically a long line.

... there are no Fraunhofer lines
the lattice is the bad one made in israel 20x30cm
.
now it is necessary to understand where to make the absorption lines coincide.

 

P.S. all filters are from Jason (apart from R72) ... he says 2mm thick.

 

Soligor KA 35mm lens f: 11 - different ISO and power

 

Thanks

Antonio

 

 

 

 

 

 

 

 

NEW

 

 

[colinbm]

I did mention sometime in the beginning of this thread that you can use a needle or pin to reflect the light off.

[photoni]

2 minutes ago, colinbm said:

I did mention sometime in the beginning of this thread that you can use a needle or pin to reflect the light off.

 

sorry ... I had no intuition, I used a 6-9mm tube

[Andy Perrin]

You can see the D pretty well, and I think you need a better reference spectrum for the lines. The one you showed barely labels the UV. The very dark A line at 750nm is also clearly identified in the Hoya spectrum. 

[ulf]

1 hour ago, Andy Perrin said:

You can see the D pretty well, and I think you need a better reference spectrum for the lines. The one you showed barely labels the UV. The very dark A line at 750nm is also clearly identified in the Hoya spectrum. 

 I think the last spectra was created by flash light.

I do not expect the Fraunhofer lines to be present there.

They are a part of spectra from astronomic light sources like the sun and stars.

[Andy Perrin]

42 minutes ago, ulf said:

 I think the last spectra was created by flash light.

I do not expect the Fraunhofer lines to be present there.

They are a part of spectra from astronomic light sources like the sun and stars.

 I know that! I am very confused though, why he would be using a flashlight. I thought he said he was using "sunlight through a crack" but apparently I misread because then he said it was a flashlight.

[photoni]

I repeat, I used 100ΩW Elinchrome Flash light with clear tube.

 

@Andy Perrin I changed the graph and put a more faithful Fraunhofer scale (I have not found others with the UV part marked ... where to look?)
... and I tried to make lines F and A coincide

 

@ulf I believe the flash light somehow works the other way around, the emission peaks are clear not black lines.

 

Infrared also has very strange emission peaks after 850 nm

 

P.S. I forgot to take a modeling light shot (I have one with a shifted set)

 

P.P.S.
I have to look for a light (neon?) With a safe and stable emission with "certified" lines, not the sun that turns :)

[photoni]

or maybe this is the right scale

with ZWB1 and Soligor about 350nm

and R720 peaking at 750nm

 

[Andy Perrin]

Fraunhofer lines ONLY come with sunshine. You can’t match them to a flashlight. This is not a meaningful comparison. I just didn’t understand that it was a flashlight. 

[photoni]

On 6/3/2022 at 9:12 PM, dabateman said:

For me, I find the Mercury lines more useful than the sunlight fraunhofer lines.

what do you mean ?

 

3 hours ago, Andy Perrin said:

Fraunhofer lines ONLY come with sunshine.

I was hoping to have some known "references" for example those peaks in IR what are they?