robin_astro

I think to be fair it should be pointed out that the ALPY 600 spectrograph is actually ~1400ukp for the equivalent core and guiding module which is similar to the price of the CCDSpec when it was launched, though it may now be discounted. Robin

Thanks for the "heads up" on this. I pointed my low resolution spectrograph at it last night. The spectrum confirms the z=2.4 redshift https://stargazerslounge.com/topic/300597-11-billion-years-ago/ Robin

Hi Louise, Using the video mode is good to start with as it helps with focusing. Choose a main sequence A or B type star to start with (type Av/Bv) There is a list of bright stars with their spectral type in the back of the manual. Check you have the grating orientated with the star on the left and the brightest spectrum horizontal across the field (There are spectra on both sides of the star image, one is much brighter). Focus first on the zero order star image to start with, then reduce the exposure until the spectrum looks on the under exposed side all the way along the spectrum and then wind the focuser in a touch until you see a dark absorption line appear sharpest about 1/3 the way along the spectrum (The Hydrogen beta line) You should then be able to other Hydrogen lines crowding together towards the blue end nearest the zero order. ( It is a good idea to always start an observing session this way as this star can be used to both wavelength calibrate and adjust your spectrum for the response of your instrument.) Once you are in good focus you can move to other targets. Perhaps try a cool M type star for example, noting the broad molecular bands and an emission line star like Gamma Cas for example, looking for the bright spot towards the right hand end of the spectrum which is Hydrogen alpha emission from the disc around this star, or later in the year, P Cygni, a luminous blue variable supergiant which shows Hydrogen and Helium emission lines. Wolf Rayet stars, although fainter show spectacular emission lines too in the stellar wind. You can get an idea of what the raw spectra should look like here. (Yours will be clearer as these were taken with a smaller camera sensor so the spectrum is not very long) http://www.threehillsobservatory.co.uk/astro/spectra_12.htm http://www.threehillsobservatory.co.uk/astro/spectra_14.htm Cheers Robin

Yep, that should work in principle, attached to the telescope in place of the eyepiece, for bright stars. I began my jouney in to astronomical spectroscopy and the development of the Star Analyser http://www.patonhawksley.co.uk/staranalyser.html in much the same way back in 2002 http://www.threehillsobservatory.co.uk/astro/spectra_1.htm (first light) You will need to remove the webcam lens and space the grating around 25-30mm away from the camera sensor to give a decent length spectrum and to explore into the IR, remove the IR block filter Good Luck! Robin www.threehillsobservatory.co.uk