click here for my full review [S&T - May 2000 issue]click below for more spectrometer pages
- minor mods - remote control to spectrometer
- Don Starkey's equipment modifications
- 2nd light - low-res spectra
- Mira [o Ceti] in hi-res
- Saturn & Jupiter Doppler shifts
- Saturn & Jupiter - methane bands
- more emission line stars
- Venus' spectrum in daylight
- some winter stars
- M42 + other emission objects
- SBIG spectrometer own webpage
- my homepage....
These are a few of my 'first light' spectra from the SBIG spectrometer which couples exclusively with the SBIG ST-7/8 cameras and uses the second 'tracking' chip to 'hold' the star on the spectroscopic slit for the duration of the exposure. Both chips view the same on-axis field. A periscope feeds the 'tracking' chip via an inclined mirror whilst a narrow 18 micron gap in the same mirror acts as a spectroscopic slit. This is reimaged onto the main imaging chip via a series of plane and concave mirrors. A reflective grating midway within the system disperses the final light into a spectrum. Two gratings are available via a rotating carousel to give different spectral resolution. Maximum dispersion is quoted as 1.07A/pixel [my estimate ~1.062A/pixel <g>] or 16 times better than the simple Rainbow grating placed before the CCD - assuming 9 micron pixels in each example. Using the lower resolution grating, wider slit [supplied] plus pixel binning increases sensitivity by 2 to 3 stellar magnitudes.The spectrometer is built to SBIG's usual exacting standards and is shown above coupled to my 30cm Meade LX200. For more info contact SBIG.
1999 Oct 6: The following spectra cover the red [Ha] to yellow [D1/D2] region except the Vega spectrum which shows the extended blue sensitivity of the KAF 'E' chip into near UV.
Beta Cyg 1+2 form the double star Albireo; 1 is a cool orange [K3 II] star whilst 2 is a hot Be star with emission lines. Note the relative width of the hydrogen lines [Balmer series] in Vega [AO V] and giant star Deneb [A2 Ia]. The twin sodium emission lines D1+D2 [overlaying beta Cyg - extreme right - centre] originate in the light polluted skies over WPO. The Doppler Shift in the spectrum caused by the earth's orbital motion [30km/s] represents one tenth of the separation of the D1+D2 lines or 0.6A [0.06nm].
1999 Oct 5: this sequence covers the deep red end of the spectrum and includes the 'B' band superimposed by the earth's atmosphere. Note the Doppler broadening of the emission lines of helium and hydrogen in b Lyrae. The spectrum of Jupiter and Saturn is essentially reflected sunlight.
text & images copyright - Maurice Gavin - 1999/2000