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Bajastro

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About Bajastro

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  1. Robin, which stars are the best for RV calibrations? Last time, when I observed some H-alpha profiles in Be stars I used Capella spectra for wavelenght calibration. It isn't very good example, because this star is spectroscopic binary. No spectral lamp used.
  2. Thanks all. I didn't use the calibration lamp. So, now I can only observe splitting of the spectral lines depending on the phase. In this case, movements of Solar System bodies were omitted. But for better measurements precision of spectroscopic binaries with higher eccentricity orbits, I will need a good calibration module soon. My friend is constructing a calibration module for his LowSpec spectrograph.
  3. 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 https://arxiv.org/pdf/1104.0342.pdf
  4. 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:
  5. Thanks. Robin, I had to refocus often. For example I split the solar spectrum in 60 segments to get sharp lines in whole visible range. Only the center of image is sharp, peripheral areas in both sides are defocused. Ken, I tried to stack with using BASS software, but after comparison with single frame I had too big differences. Last night I had 5 good stack and one was wrong. Marius
  6. 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-alpha: H-beta: H-gamma: H-delta & H-epsilon: I had some problems with stacking, so I used the best single frames in analysis.
  7. Looks great, but I've already printed version 2.0. Are you planning to add a calibration module with a spectral lamp in next version?
  8. @Merlin66 your equipment is impressive. Why Spectra L-200 is no longer available. What happened? I can try to add a support from the dovetail.
  9. @Merlin66 I'm a bit afraid of that. My focuser isn't high technology, it is cheap China product. It slightly moves when I change a position of my telescope, but the guiding works well.
  10. @Thalestris24 You and me have a loss of light You can improve parallelism your telescopes during the day with using very far terrestrial objects (over 0.5 km), eventually Moon. It isn't difficult.
  11. Yes, It will be vignette, but Low Spec is optimized for f/10 telescopes. I use f/4 Newtonian telescope and cone of light is cutted on the collimating lens holder. I'm planning to buy a Barlow lens 2x to get the telescope's longer focal length. Maybe in the future I will have SCT, which it should be better for slit spectroscopy.
  12. I think that smaller diameter of aperture will be better and cut peripheral aberrations this achromatic doublet (about f/2.4), for example: This value gives me focal ratio about f/3.5 for guiding lens with diameter 12.5 mm and focal length 30 mm. I will test it soon.
  13. Thanks @drjolo, today I also checked my lens in guiding module, it was... tilted. Unfortunately, I don't have artificial star and I have to wait for clear sky and test it again. I think that focal ratio 2.4 for achromatic lens is too low. I will try to reduce this aperture up to f/3 - f/3.75, external aberrations should be much lower. Guiding lens also was stressed (squeezed).
  14. After the calibration of axis RA in my mount I calibrate GoTO usually with using one star. Next I center first star with visually observation in finderscope 8x. Important is moving on the same side of sky where was calibrated star for GoTo system. Becasue after rotating mount on the opposite side of the sky usually scope isn't pointed on a particular star. I'm using HEQ5 mount with Rowan modification kit.
  15. @Thalestris24 I use built-in Low Spec guide module with achromatic lens with 30 mm focal length and ASI120MM Mini. I don't need any external guide scope.
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