Andrew’s Astronomy Blog

Friday evening at the Observatory was spent showing some visitors around. As it was clear we were able to look at Venus, Mars, Jupiter and Uranus as well as the Moon through the 20″. Although the planets were all very low and suffering from massive amounts of atmospheric dispersion they went away happy.

After that, it was down to the main business of the night, measuring periodic error on the 20″ drives. This shows that we have some more work to do to stop drift on the altitude drive and also that we have about 7 arc seconds  peak to peak periodic error on the azimuth axis.

By this time, Jupiter was high in the sky so we finished up putting my modified Philips webcam on with a 2.5x PowerMate for some video images. Jupiter is more favourably positioned for Northern hemisphere observers than it has been for many years and it was nice to see it at a decent altitude with lots of detail visible in the eyepiece.

Discovered by Mechain on the 27th March 1781, M103 became the last entry in Messier’s original catalog. Interstellar extinction of about 1.5 magnitudes makes determining the precise distance difficult but it probably lies about 7200 light years away. The cluster diameter is 17 light years and the bright star in the field is Delta Cassiopeia.

This was the first time that I’d tried out a new piece of software, DSLR_Logger from the AstroTrac Yahoo group. It’s main purpose is for determining precise polar alignment of the mount. I will write more about this program when I’ve had a chance to explore it rather more fully.

This was also the first outing for my new Williams Optics Field Flattener 3 on the 70mm.

Looking through the images I collected last night revealed 6 meteors, 2 aircraft & a lot of satellites. I’d taken 10 90 second images of the area around Cassiopeia which were stacked to provide the background. The images with meteors trails were then selected and using painted selection masks superimposed on the background using Photoshop.

Next time I will acquire the images slightly differently.  Downloading them to the laptop results in a considerable time lapse between images. Capturing jpegs directly to the camera flash card with the camera locked on repeat would minimise the chance of missing meteors.

Last night was the peak for this year’s Perseid meteor shower and the weather was reasonably kind with only occasional cloud until 2AM when it clouded over.

I’ve got a lot of photos to sort through but this image came from one of the longer exposures aimed at capturing the star background. A single 90 second exposure at ISO1600, f/3.5, 18mm.