Asteroid Vesta

To start with let's be clear that this is not a great image. In fact it is of very average quality, but I thought it was worth sharing the process by which the image was obtained and cleaned up a bit. As you will see the process is not particularly refined, but clearly shows what can be done in a few minutes with even modest equipment. I write this, therefore, to encourage the amateur to take pictures of the sky with even modest digital cameras - quite often it reveals more than you think

Equipment

I possess an 4 mega-pixel Sony Cybershot camera that is now 7 years old. It is functional, practical and with a bit of effort can be persuaded to take long(ish) exposure images. Actually the maximum it will allow is 8 seconds which is not really enough to get a deep image of the sky - but it does produce some results. Further problems are caused because it is not designed for this kind of work so flat fielding or have dark current subtraction are out of the question. Any long exposure, therefore, becomes inherently noisy and makes it impossible to make any accurate photometric measurements.

Location

I currently live in Holland, one the more densely populated parts of Europe, and even in a small town there are plenty of street lights around. So despite my efforts to use buildings to shield from the direct glare there is little that can be done in terms of changing location when there is a sudden gap in the usually unfavourable winter weather. So one makes the best of every opportunity.

Images

Firstly, you can click on any image to view the full size image. Secondly, you are welcome to use any of the images as long as you put a link back to this page.

As you can see the base image is full of a lovely reddish glow from a street light. In fact I could not have picked a worse location from which to take this picture as the target region of Leo is completely bathed in sodium-based light pollution. Having said that even in this image Vesta is visible

Having captured the image I used photoshop on this occasion to clean up the image. Firstly I applied a deep blue filter to counteract the red from the light pollution...

...and then adjusted the levels to remove some of the background noise.

The outcome is a slightly blue image, but one that clearly shows Vesta as you can see from the image at the top of the page.

The final image shows the mark-up of the constellations and if you look carefully in Cancer you can definitely see three or four star that represent M44 - the Beehive Cluster.