At last out observing again for the first time in nearly 3 weeks. Below is a spectrum of the H-alpha absorption line of Vega. I use this along with a professional reference spectrum of Vega to work out the instrument response. This allows me to then to correct the other spectra I'll be obtaining tonight to remove the effect of my equipment and the Earth's atmosphere.

chi Cyg spectra near to H-alpha. As chi Cyg is on the rise the H-alpha emission is starting up again. This emission line is associated with a hypersonic shock wave that passes through the star once per cycle.

Here is an image through my spectrograph guide camera with V Sge positioned on the spectrograph slit.

Doing a mix of spectroscopy and watching the Olympic tennis final tonight. I already have spectra of the Mira variable chi Cyg and the symbiotic star CH Cyg. Both of these are around 7th-8th mag, so not too much of a challenge.

However, now I've moved onto the unusual binary V Sge. At a little below 11th mag this is a real challenge for more setup. I'm doing a 2 hour run, but even then I expect a very noisy spectrum.

Below is a spectrum of chi Cyg from 8th August compared with a similar spectrum from 2nd June. chi Cyg brightened from just below 10th mag to nearly 7th mag over this time period and is shrinking as it brightens. I am looking for the appearance of the H alpha emission line. This should be appear near maximum light and is related to a hypersonic shock wave that passes through the photosphere.

The peaks and troughs in the spectrum are due to absorption in the relatively cool photosphere of chi Cyg. Many are due to molecules like titanium oxide.

I had my first observing session in a couple of months last night, now it is starting to get dark at a remotely sensible hour. I was pleased to obtain a spectrum of chi Cyg, as well as spotting a bright meteor flashing over the observatory. It looked like my first Perseid of the season.

Trying out the update profile button.. Dominic has used his admin rights to edit this several times... And even James has managed to edit it too... :)

Trying out adding a new post.

My main interests are spectroscopy and variable stars, though I enjoy many aspects of astronomy including observing deep sky objects and travelling to see total solar eclipses.