Difference: LogBookAstronomyEntry0106 (1 vs. 4)

Revision 421 Jul 2016 - JosephBayley

Line: 1 to 1
 
META TOPICPARENT name="LogBookAstronomy"

Log Book Entry No.106

Days, Calendar Created: 20 Jul 2016 11:33:11 Days, Calendar Last Revised: 21 Jul 2016 16:58:50 Person JosephBayley Text Alignment and focus of camera and optical fiber
Line: 24 to 24
 
    • Images were then taken of both the spectral line of the laser and the image on the FireWire camera as it was scanned, 40 images were taken.
    • The maximum intensity of the beam and its position were recorded on the FireWire camera and the summed intensity was recorded for the spectrum with removal of backgorund.
    • The intensity on the spectral line was then plotted against the position on the FireWire camera, this gave a plot shown below.
Changed:
<
<
HorScan20th1.png
>
>
HorScan20th1.png
 
  • The peak position on the above plot is then used to set the position of the beam on the camera, which is approximately at a position of 200 pixels.
  • Once the position has been set the process was repeated scanning this time vertically, this gave a plot as shown below.
Changed:
<
<
VerScan20th1.png
>
>
VerScan20th1.png
 
  • The best position for the beam to be on the camera for max intensity at this stage is then at pixel values [200,216].

Focussing the beam

Line: 36 to 36
 
  • Once the beam has been set to the best position as found earlier the camera and optical fiber were adjusted between distances of 220mm-290mm in 2mm intervals to find the best focus.
  • Here the same measurements as before were made. The intensity of the spectral line and the maximum intensity of the FireWire camera are plotted against focal distance.
  • The plot of both the camera and optical fiber is shown below.
Changed:
<
<
BothFocus20th.png
>
>
BothFocus20th.png
 
Changed:
<
<

BothFocus20th2.png
>
>

BothFocus20th2.png
 
  • With this image the approximate best focus was set at 250mm

Repeat of alignment

  • The alignment process was then repeated as before, this gave the below plots.
Changed:
<
<
HorScan20th2.png
>
>
HorScan20th2.png
 
Changed:
<
<

VerScan20th2.png
>
>

VerScan20th2.png
 
  • These gave maxima at a pixel position of [201,217], The image below shows the position of the laser of the camera at this point:
Changed:
<
<
BestAlignment.png
>
>
BestAlignment.png
 

Horizontal Scans at different Focal lengths

  • For 6 different focal lengths, 240,244,248,252,256,260, a horizontal scan of the laser was recored on the camera and the spectrometer. This range was chosen as in the above focus plots, this is where the intensity flattens.
  • For each of these the position of the laser of the FireWire camera was plotted against the total intensity of the fibers.
  • The aim was that the focal length which gives the smallest width of a spectral line is the correct focus.
  • The plot below shows the intensity plot for each of the focal lengths, and the widths of the line.
Changed:
<
<
ScansFull.png
>
>
ScansFull.png
 
  • This shows the widths does not change much in that range, this could be due to the fact that the focus is smaller than the size of the optical fiber, therefore, the integrated amplitude will remain the same in this range.
  • Therefore, by selecting a single fiber to integrate the intensity over, it should be possible to find focus.
  • The below plot shows the same results for a single fiber
Changed:
<
<
ScansSingle.png
>
>
ScansSingle.png
 
  • This shows that the width of the line drops in the range of 252-256 mm .
Added:
>
>
  • by fitting a Gaussian function to both the image on the firewire camera and the plots above, the widths could be plotted against the focal length for both.
    Fiber_Camera_scan.png

  • Each of these were then fit with a hyperbola function,
 \begin{equation} f(x; \mu,a,b) = a\sqrt{1+((x-\mu)^{2} / b^{2})} \end{equation}<br />

  • This gave parameters of,
parameter FireWire Fiber
mean 254.81.2 255.21.1
a 4.280.92 6.121.25
b 4.721.4 4.431.2
 Back to: LogBookAstronomy

META FORM name="%25SYSTEMWEB%25.LogBookForm"
Line: 80 to 94
 
META FILEATTACHMENT attachment="BothFocus20th2.png" attr="h" comment="" date="1469020026" name="BothFocus20th2.png" path="BothFocus20th2.png" size="67217" user="zxap044" version="1"
META FILEATTACHMENT attachment="ScansFull.png" attr="h" comment="" date="1469093730" name="ScansFull.png" path="ScansFull.png" size="139382" user="zxap044" version="3"
META FILEATTACHMENT attachment="ScansSingle.png" attr="h" comment="" date="1469093731" name="ScansSingle.png" path="ScansSingle.png" size="126557" user="zxap044" version="3"
Added:
>
>
META FILEATTACHMENT attachment="Fiber_Camera_scan.png" attr="h" comment="" date="1469116729" name="Fiber_Camera_scan.png" path="Fiber_Camera_scan.png" size="86389" user="zxap044" version="2"
META FILEATTACHMENT attachment="latex994446c3083330402004f6473db66db8.png" attr="h" comment="" date="1469116214" name="latex994446c3083330402004f6473db66db8.png" user="zxap044" version="1"

Revision 321 Jul 2016 - JosephBayley

Line: 1 to 1
 
META TOPICPARENT name="LogBookAstronomy"

Log Book Entry No.106

Days, Calendar Created: 20 Jul 2016 11:33:11 Days, Calendar Last Revised: 21 Jul 2016 16:58:50 Person JosephBayley Text Alignment and focus of camera and optical fiber
Line: 19 to 19
 
  • FireWire Camera:
    • records video at 30fps
    • Exposure: 1/500 s
Changed:
<
<
  • Approximate focus was first found.
>
>
  • Approximate focus was first found. set at 255 mm
 
  • The mirror was adjusted horizontally such that the laser moved horizontally in the camera frame.
    • Images were then taken of both the spectral line of the laser and the image on the FireWire camera as it was scanned, 40 images were taken.
    • The maximum intensity of the beam and its position were recorded on the FireWire camera and the summed intensity was recorded for the spectrum with removal of backgorund.
    • The intensity on the spectral line was then plotted against the position on the FireWire camera, this gave a plot shown below.
Changed:
<
<
HorScan20th1.png
>
>
HorScan20th1.png
 
  • The peak position on the above plot is then used to set the position of the beam on the camera, which is approximately at a position of 200 pixels.
  • Once the position has been set the process was repeated scanning this time vertically, this gave a plot as shown below.
Changed:
<
<
VerScan20th1.png
>
>
VerScan20th1.png
 
  • The best position for the beam to be on the camera for max intensity at this stage is then at pixel values [200,216].

Focussing the beam

Line: 36 to 36
 
  • Once the beam has been set to the best position as found earlier the camera and optical fiber were adjusted between distances of 220mm-290mm in 2mm intervals to find the best focus.
  • Here the same measurements as before were made. The intensity of the spectral line and the maximum intensity of the FireWire camera are plotted against focal distance.
  • The plot of both the camera and optical fiber is shown below.
Changed:
<
<
BothFocus20th.png
>
>
BothFocus20th.png
 
Changed:
<
<

BothFocus20th2.png
>
>

BothFocus20th2.png
 
  • With this image the approximate best focus was set at 250mm

Repeat of alignment

  • The alignment process was then repeated as before, this gave the below plots.
Changed:
<
<
HorScan20th2.png
>
>
HorScan20th2.png
 
Changed:
<
<

VerScan20th2.png
>
>

VerScan20th2.png
 
  • These gave maxima at a pixel position of [201,217], The image below shows the position of the laser of the camera at this point:
Added:
>
>
BestAlignment.png
 
Changed:
<
<

BestAlignment.png
>
>

Horizontal Scans at different Focal lengths

  • For 6 different focal lengths, 240,244,248,252,256,260, a horizontal scan of the laser was recored on the camera and the spectrometer. This range was chosen as in the above focus plots, this is where the intensity flattens.
  • For each of these the position of the laser of the FireWire camera was plotted against the total intensity of the fibers.
  • The aim was that the focal length which gives the smallest width of a spectral line is the correct focus.
  • The plot below shows the intensity plot for each of the focal lengths, and the widths of the line.
ScansFull.png

  • This shows the widths does not change much in that range, this could be due to the fact that the focus is smaller than the size of the optical fiber, therefore, the integrated amplitude will remain the same in this range.
  • Therefore, by selecting a single fiber to integrate the intensity over, it should be possible to find focus.
  • The below plot shows the same results for a single fiber
ScansSingle.png
  • This shows that the width of the line drops in the range of 252-256 mm .
 Back to: LogBookAstronomy
Deleted:
<
<
 
META FORM name="%25SYSTEMWEB%25.LogBookForm"
FORM FIELD Subject Subject Alignment and focus of camera and optical fiber
FORM FIELD Status Status blank
Line: 68 to 78
 
META FILEATTACHMENT attachment="BestAlignment.bmp" attr="h" comment="" date="1469017396" name="BestAlignment.bmp" path="BestAlignment.bmp" size="308278" user="zxap044" version="1"
META FILEATTACHMENT attachment="BestAlignment.png" attr="h" comment="" date="1469017467" name="BestAlignment.png" path="BestAlignment.png" size="308278" user="zxap044" version="1"
META FILEATTACHMENT attachment="BothFocus20th2.png" attr="h" comment="" date="1469020026" name="BothFocus20th2.png" path="BothFocus20th2.png" size="67217" user="zxap044" version="1"
Added:
>
>
META FILEATTACHMENT attachment="ScansFull.png" attr="h" comment="" date="1469093730" name="ScansFull.png" path="ScansFull.png" size="139382" user="zxap044" version="3"
META FILEATTACHMENT attachment="ScansSingle.png" attr="h" comment="" date="1469093731" name="ScansSingle.png" path="ScansSingle.png" size="126557" user="zxap044" version="3"

Revision 220 Jul 2016 - JosephBayley

Line: 1 to 1
 
META TOPICPARENT name="LogBookAstronomy"

Log Book Entry No.106

Days, Calendar Created: 20 Jul 2016 11:33:11 Days, Calendar Last Revised: 21 Jul 2016 16:58:50 Person JosephBayley Text Alignment and focus of camera and optical fiber
Line: 26 to 26
 
    • The intensity on the spectral line was then plotted against the position on the FireWire camera, this gave a plot shown below.
HorScan20th1.png
Changed:
<
<
  • The peak position on the above plot is then used to set the position of the beam on the camera.
>
>
  • The peak position on the above plot is then used to set the position of the beam on the camera, which is approximately at a position of 200 pixels.
 
  • Once the position has been set the process was repeated scanning this time vertically, this gave a plot as shown below.
VerScan20th1.png
Changed:
<
<
  • The best position for the beam to be on the camera for max intensity at this stage is then at pixel values [].
>
>
  • The best position for the beam to be on the camera for max intensity at this stage is then at pixel values [200,216].
 

Focussing the beam

Line: 38 to 38
 
  • The plot of both the camera and optical fiber is shown below.
BothFocus20th.png
Added:
>
>

BothFocus20th2.png

  • With this image the approximate best focus was set at 250mm
 

Repeat of alignment

Added:
>
>
  • The alignment process was then repeated as before, this gave the below plots.
HorScan20th2.png


VerScan20th2.png

  • These gave maxima at a pixel position of [201,217], The image below shows the position of the laser of the camera at this point:


BestAlignment.png

 Back to: LogBookAstronomy
Added:
>
>
 
META FORM name="%25SYSTEMWEB%25.LogBookForm"
FORM FIELD Subject Subject Alignment and focus of camera and optical fiber
FORM FIELD Status Status blank
Line: 47 to 61
 
FORM FIELD Status Status blank
FORM FIELD Author Author JosephBayley
META FILEATTACHMENT attachment="BothFocus20th.png" attr="h" comment="" date="1469010664" name="BothFocus20th.png" path="BothFocus20th.png" size="66252" user="zxap044" version="1"
Changed:
<
<
META FILEATTACHMENT attachment="HorScan20th1.png" attr="h" comment="" date="1469010663" name="HorScan20th1.png" path="HorScan20th1.png" size="62935" user="zxap044" version="1"
META FILEATTACHMENT attachment="VerScan20th1.png" attr="h" comment="" date="1469010663" name="VerScan20th1.png" path="VerScan20th1.png" size="63159" user="zxap044" version="1"
>
>
META FILEATTACHMENT attachment="HorScan20th1.png" attr="h" comment="" date="1469016939" name="HorScan20th1.png" path="HorScan20th1.png" size="83466" user="zxap044" version="2"
META FILEATTACHMENT attachment="VerScan20th1.png" attr="h" comment="" date="1469016938" name="VerScan20th1.png" path="VerScan20th1.png" size="84821" user="zxap044" version="2"
META FILEATTACHMENT attachment="HorScan20th2.png" attr="h" comment="" date="1469016939" name="HorScan20th2.png" path="HorScan20th2.png" size="84652" user="zxap044" version="1"
META FILEATTACHMENT attachment="VerScan20th2.png" attr="h" comment="" date="1469016938" name="VerScan20th2.png" path="VerScan20th2.png" size="84074" user="zxap044" version="1"
META FILEATTACHMENT attachment="BestAlignment.bmp" attr="h" comment="" date="1469017396" name="BestAlignment.bmp" path="BestAlignment.bmp" size="308278" user="zxap044" version="1"
META FILEATTACHMENT attachment="BestAlignment.png" attr="h" comment="" date="1469017467" name="BestAlignment.png" path="BestAlignment.png" size="308278" user="zxap044" version="1"
META FILEATTACHMENT attachment="BothFocus20th2.png" attr="h" comment="" date="1469020026" name="BothFocus20th2.png" path="BothFocus20th2.png" size="67217" user="zxap044" version="1"

Revision 120 Jul 2016 - JosephBayley

Line: 1 to 1
Added:
>
>
META TOPICPARENT name="LogBookAstronomy"

Log Book Entry No.106

Days, Calendar Created: 20 Jul 2016 11:33:11 Days, Calendar Last Revised: 21 Jul 2016 16:58:50 Person JosephBayley Text Alignment and focus of camera and optical fiber

<-- 
Please DO NOT alter or remove the line below this line. 
  • Set EDITMETHOD = wysiwyg
Please DO NOT alter or remove the line above this line. -->

IDEA! Please edit and put your text etc. here

Alignment of fiber horizontally and vertically

  • SBIG camera for spectrometer:
    • Exposure: 0.1s
    • Temp: 10 deg
    • Subframes
  • FireWire Camera:
    • records video at 30fps
    • Exposure: 1/500 s
  • Approximate focus was first found.
  • The mirror was adjusted horizontally such that the laser moved horizontally in the camera frame.
    • Images were then taken of both the spectral line of the laser and the image on the FireWire camera as it was scanned, 40 images were taken.
    • The maximum intensity of the beam and its position were recorded on the FireWire camera and the summed intensity was recorded for the spectrum with removal of backgorund.
    • The intensity on the spectral line was then plotted against the position on the FireWire camera, this gave a plot shown below.
HorScan20th1.png

  • The peak position on the above plot is then used to set the position of the beam on the camera.
  • Once the position has been set the process was repeated scanning this time vertically, this gave a plot as shown below.
VerScan20th1.png
  • The best position for the beam to be on the camera for max intensity at this stage is then at pixel values [].

Focussing the beam

  • Once the beam has been set to the best position as found earlier the camera and optical fiber were adjusted between distances of 220mm-290mm in 2mm intervals to find the best focus.
  • Here the same measurements as before were made. The intensity of the spectral line and the maximum intensity of the FireWire camera are plotted against focal distance.
  • The plot of both the camera and optical fiber is shown below.
BothFocus20th.png

Repeat of alignment

Back to: LogBookAstronomy

META FORM name="%25SYSTEMWEB%25.LogBookForm"
FORM FIELD Subject Subject Alignment and focus of camera and optical fiber
FORM FIELD Status Status blank
FORM FIELD Author Author JosephBayley
META FILEATTACHMENT attachment="BothFocus20th.png" attr="h" comment="" date="1469010664" name="BothFocus20th.png" path="BothFocus20th.png" size="66252" user="zxap044" version="1"
META FILEATTACHMENT attachment="HorScan20th1.png" attr="h" comment="" date="1469010663" name="HorScan20th1.png" path="HorScan20th1.png" size="62935" user="zxap044" version="1"
META FILEATTACHMENT attachment="VerScan20th1.png" attr="h" comment="" date="1469010663" name="VerScan20th1.png" path="VerScan20th1.png" size="63159" user="zxap044" version="1"
 
This site is powered by the TWiki collaboration platform Powered by PerlCopyright © 2008-2021 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding RHUL Physics Department TWiki? Send feedback