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I am looking into making a hobby out of spectroscopy but don't exactly know where to start.
All I can really go off is a high school education of physics and the various reading that one usually does when looking into something new.
The main questions are, essentially;
1. What is the best spectrometry equipment for an amateur like myself?
I have little to no knowledge on all the necessary equipment, so any recommendations would be very much appreciated. For any suggestions, if you wouldn't mind giving a reason as to why you recommend a said product, I will take this information with great appreciation.
In terms of a camera, I've read that CCD monochrome cameras are the best. How does a DSLR rank against this though?
In terms of a telescope, should I be looking at one with a specific aperture range? If so, are there any other properties I should be looking at?
Is a grating better than a prism? Why?
What software is the most effective and easiest to use?
Do I need some sort of focusing device?
2. How do you collect spectral data using the technology?
Is it as simple as pointing at a star and recording the acquired data?
How long should I view the chosen star? Is it a photo or a video?
I would assume that these questions have been asked plenty of times, so any links to other forums which discuss the same questions and topics I am raising will be very helpful as well.
Any type of reply is welcome. As an amateur, anything is helpful.
Looking forward to discussing this with you all.
I finished observations of the Mizar A spectroscopic binary.
Calibration for the Hα line made on water lines contained in the Earth's atmosphere.
I used LowSpec spectrograph with 1800 grooves/mm reflective holographic grating, APM APO 107/700, QHY163M camera and HEQ5 mount with guiding.
It turned out that the Earth's movement practically compensated for the radial velocity of the Mizar A system.
Based on the analysis, I received the result:
vr = -8.8 km/s
in fact the system is approaching at a radial velocity of -6.3 km/s.
I also determined the phase plot of radial velocities based on my measurements for the Na (together for both lines) and separately for Hα line:
Error is based on half my spectral resolution (0.2 Å/pix corresponds to rv = 10 km/s). Each measurement corresponds to the stack a few images.
The most important purpose of observing this binary system was to record the historical Ca II line (often called as CaK, 3933.66 Å).
The distances in the violet part of the spectrum are almost 2x smaller than the corresponding shifts for the Hα line. This line initiated the discovery of spectroscopically binary systems, and Mizar A was the first discovered system of this type.
These were the spectroscopic observations in the 19th century:
I've made several observations of this line in the last two weeks:
Animation showing the changes in the CaK line based on my observations:
Not only the Ca II is split, but the surrounding lines also, shown below in a wider environment:
Balmer hydrogen lines are becoming more dense as Balmer's gap approaches (3646 Å).
Observation result of the Hα line:
And animation showing the changes in this line:
The Na I doublet was much more difficult to observe, because stars with A spectral type contain very faint lines of this metal:
Animation showing the changes in the sodium doublet:
We received the sodium quartet
This system consists of two yellow giants having types G0III and G8III (some sources give K0III), similar masses and brightness. The orbital period of the components is 104 days.
The fact that one of the stars has a later spectral type is very convenient 😀. It has stronger spectral lines of metals, including sodium.
This allows you to immediately recognize which star is approaching and which is currently moving away.
I made 3 observations so far with using a DIY 3D printed LowSpec spectrograph in the version v2 designed by @Paul Gerlach and a 1800 l/mm holographic grating.
Based on these observations, the spectral spread for both observations for the sodium line is 0.79 Å (0.079 nm) or 4 pixels, which gives a difference of radial velocities of 40 km/s.
Assuming that component A belongs to G8III and component B to G0III:
2019-12-03 component A was moving at relative vr to the barycenter of the system of -20 km/s and component B was moving at a relative vr of +20 km/s.
2020-01-23 component A was moving at a relative vr of +20 km/s and component B was moving at a relative vr of -20 km/s.
I called radial speeds relative, because the radial velocity of the Capella barycenter to the Solar System wasn't included.
I took the radial velocity of the Capella barycenter into account and I received this phase plot:
The background is the plot of radial velocities from paper:
M. Weber, K. G. Strassmeier, 2011, The spectroscopic orbit of Capella revisited
1. Alcyone (Eta Tauri, η Tau, 25 Tau) in the Pleiades open cluster, spectral type B7IIIe+A0V+A0V+F2V.
This star is a multiple system, but my goal of observation was the H-alpha profile of the main component:
Horizontal axis scaled to radial velocity:
2. Pleione (28 Tau, BU Tau) also in M45, spectral type B8Vne, variable star, the brightness changes in range: 4.83 - 5.38 V.
This is the faintest star, which I observed with using APO 107/700 & Low Spec spectrograph 1800 l/mm.
It was difficult, but obervation was positive (high gain, exposure time 4 min):
3. Tianguan (Zeta Tauri, ζ Tau), spectral type B1IVe+G8III: (mark ":" according to the VSX database means uncertainty).
This is an eclipsing binary with variability type E/GS+GCAS, period is 133 d. The brightness changes in range: 2.80 - 3.17 V.
4. Cih, Tsih (γ Cas), spectral type B0.5IVpe, variable star with a magnitude range of 1.6 to 3 V:
5. Alnitak (Zeta Orionis, ζ Ori), spectral type O9.5Ibe+B0III. Variable star with a magnitude range of 1.74 to 1.77 V.
Spectral lines have characteristic P Cygni profile, below H-alpha:
Recently I observed profiles of hydrogen Balmer lines in Sirius spectrum with spectral type A. I used LowSpec spectrograph with 1800 l/mm diffraction grating and APO APM 107/700 on HEQ5 mount.
H-delta & H-epsilon:
I had some problems with stacking, so I used the best single frames in analysis.