Objective Grating for Corona spectrum
Hi,I've made a preliminary test on my setup for spectroscopic observation of the solar corona during the coming total solar eclipse.
Basically, the setup consists of a transmission grating (600 l/mm)attached to the front of my 70-210 mm, f/2.8 lens (photo 1) mounted on a Canon 40D body.The grating is oriented such that the spectrum will align with the longer side of the cmos sensor.
The lens is zoomed so that the whole 1st order spectrum just fits the CMOS.
A spectrum was taken near sunset time yesterday (photo 2 and 3).The setup was also tested on street lamps last week. (photo 4, 5).
PTS A very cost effective setup!:) Good to see that you also do spectroscopic observation.
I also plan the similar observation, I plan to use a monochrome CCD camera...tentatively will be the SKYnx series camera because can record 12 bits video. The analysis of monochrome spectrum is easier compare to color camera.
If got a monochrome DSLR, then will best...I can do a little bit high-res spectrosopic observation... Hi Universe24,
My choice of 40D was mainly due to its larger size.If I use my Imperx 2k x 2k monochrome camera, it is just 15 x 15 mm.I like to have a better spatial resolution.Moreover, I do not plan much scientific measurements with the corona spectrum, except to check the relative intensity distribution of the corona as a function of several elements. I expect the shape of the corona will be different at different wavelengths.
For polarization observation, I'll use the Imperx camera.
For high spectral resolution work, I use a LHRIES III spectrograph.Please refer to:
http://forum.hkas.org.hk/viewthread.php?tid=2066&extra=page%3D9 for my solar spectrum
http://forum.hkas.org.hk/viewthread.php?tid=2159&extra=page%3D8 for my spectrum of Capella
http://forum.hkas.org.hk/forumdisplay.php?fid=8&page=7 for other stellar spectra
http://forum.hkas.org.hk/viewthread.php?tid=2330&extra=page%3D4 for Epsilon Aurigae
PTS If use the 2k x 2k mono camera, the download time for every single image should be ~9s. Thus, you will also loss 9s each time. This is notworth to loss time during solar eclipse.
I am also interested in your polarization observation. I also plan to have this task for my observation team member to do this. Recently I bought a PL photographic filter. Not sure how good with this type of filter which not design for optical experiment application. May I know a little bit more about the Imperx camera? Hi Universe24,
My 2k x 2k Imperx uses the Cameralink interface, and is capable of 15 fps rate at full resolution (at a data rate of some 120 MB per second), limited by the exposure, which has a range of 1 micro-second to 10 s.
Thus if I use 0.1s exposure, I can have 10 fps.
As for the polariser, I have a A4 size polaroid sheet from 3M.I am checking it's characteristics but I believe it will compare well with the photographic PL filters.
PTS Hi PTS,
The Imperx cameras is the type of camera that I looking for. To use it on my flash spectrum observation. 12bits data is just nice to me.
May I know how much it cost? How is the S/N ratio performance?
Imperx camera
Hi Universe24,This camera is expensive.In addition to the camera itself, you need a cameralink interface (mine is a PCMCIA card camerlink interface).
It now comes with TEC cooling to improve noise.
There is also a version using Gigabit ethernet interface that requires no additional card.
Please check the following site:
http://www.imperx.com/megapixel-cameras/ipx-4m15-l
PTS
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