[Laser] Chucks question continued

Tue May 15 22:53:34 EDT 2018

When I get the spectrometer I will surely let everyone know. Oh, and I 
did order mine direct from the mfr instead of ebay, hopefully get it 
quicker.

Mike C.

On 5/15/2018 5:20 PM, Chuck Hast wrote:
> Found it. Interesting.
>
> On Tue, May 15, 2018 at 9:06 AM, Jim Moss <n9jim-6 at pacbell.net> wrote:
>
>> Mike found a spectrometer on eBay.
>> New they are about $150, and there is a $70 model as well. From a French
>> company Thunder Optics.
>> Jim
>>
>> Sent from my iPhone
>>
>>> On May 14, 2018, at 9:44 PM, Chuck Hast <wchast at gmail.com> wrote:
>>>
>>> Jim,
>>> Looks like I missed something did not see anything from Mike just saw
>>> your response. Is it some sort of spectrograph or spectrometer?
>>>
>>>
>>>> On Mon, May 14, 2018 at 11:32 PM, Jim Moss <n9jim-6 at pacbell.net> wrote:
>>>>
>>>> Mike,
>>>> Looks like that is pretty cheap.
>>>> Looks like it is about 3nm resolution, and about 2 month delay to
>> shipment.
>>>> You have to calibrate it yourself.
>>>> Might be interesting.
>>>> Let us know how it goes.
>>>> Jim
>>>>
>>>>
>>>> Sent from my iPad
>>>>
>>>>> On May 14, 2018, at 8:08 PM, Chuck Hast <wchast at gmail.com> wrote:
>>>>>
>>>>> Jim,
>>>>> That did it. Now to go through it and get it into a stand alone little
>>>>> piece of
>>>>> say python code. A good exercise for me...
>>>>>
>>>>> Then the larger angle was probably what was taking a bite out the
>>>> numbers in
>>>>> the original calculation using the formula that you indicated was doing
>>>> the
>>>>> approximation.
>>>>>
>>>>>
>>>>>> On Mon, May 14, 2018 at 8:21 PM, Jim Moss <n9jim-6 at pacbell.net>
>> wrote:
>>>>>> Chuck,
>>>>>> It looks like we may have sin and tan issues here
>>>>>>
>>>>>> Original cited article:
>>>>>> http://laserclassroom.com/products/measure-wavelength-laser-light/
>>>>>>
>>>>>> The angle based on your data is arctan(627/1000) = 32.08771207 Degrees
>>>>>> That’s diffraction distance (X) / distance to target (L)
>>>>>>
>>>>>> The grating equation is WL = d sin(32.08771207), d=1000/mm
>>>>>> Or 531.2 nM.  That matches your laser source.
>>>>>>
>>>>>> Note that in your original cited article approximates sin = tan.
>>>>>> This is true when the angle is small, but introduces errors at larger
>>>>>> angles.
>>>>>>
>>>>>> Here’s a calculator for the experiment: not using the approximation.
>>>>>> http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/gratcal.html
>>>>>>
>>>>>> Jim
>>>>>>
>>>>>> Sent from my iPad
>>>>>>
>>>>>>> On May 14, 2018, at 5:40 PM, Jim Moss <n9jim-6 at pacbell.net> wrote:
>>>>>>>
>>>>>>> Chuck,
>>>>>>>
>>>>>>> After rereading, I think my statement on d is not correct. It may be
>> as
>>>>>> simple as 1 mm/1000. See link below to Newport.
>>>>>>> Could the error be related to that you are not reflecting directly
>> off
>>>>>> the grating surface? The experiment shows sending the beam thru the
>>>>>> grating? If so, could there be an angle error induced?
>>>>>>> Could it be that the grating is facing the wrong way? Thus creating
>> an
>>>>>> offset due to the medium thickness of the grating material?
>>>>>>> Good summary on defraction gratings.
>>>>>>> https://www.newport.com/t/grating-physics
>>>>>>>
>>>>>>> Jim
>>>>>>>
>>>>>>>
>>>>>>> Sent from my iPad
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>>>>>
>>>>>
>>>>> --
>>>>>
>>>>> Chuck Hast  -- KP4DJT --
>>>>> I can do all things through Christ which strengtheneth me.
>>>>> Ph 4:13 KJV
>>>>> Todo lo puedo en Cristo que me fortalece.
>>>>> Fil 4:13 RVR1960
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>>>
>>>
>>> --
>>>
>>> Chuck Hast  -- KP4DJT --
>>> I can do all things through Christ which strengtheneth me.
>>> Ph 4:13 KJV
>>> Todo lo puedo en Cristo que me fortalece.
>>> Fil 4:13 RVR1960
>>> ______________________________________________________________
>>> Laser mailing list
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