Solar Photography

Most of my recent observing has been at the eyepiece rather than the webcam, but a few crisp winter mornings and some new equipment has tempted me back to photography. The target this time is the Sun, armed with my trusty Phillips SPC900 and my newest piece of kit - a Lunt LS60 solar telescope. I've become fairly proficient with the SPC900 when taking pictures of the Moon, so how hard can it be to take pictures of the Sun? The short answer is 'harder'. Before I get onto my list of problems, here's my first attempt:

It's not a complete disaster but clearly could be a lot better! So what makes taking pictures of the Sun more difficult than taking pictures of the Moon?

1. It's sunny. Sitting with a laptop underneath the Moon is not a problem - set the brightness to a minimum and the picture is clear and easy to focus. Sitting with a laptop underneath the Sun means an umbrella, a towel over the head, a reflecting screen with every last speck of dirt magnified, and a picture that is still a bit washed out. I definitely need a better set-up to keep things darker around the laptop.

2. Focusing. It is much easier to focus upon features on the Moon - the field of view is typically crater sized and it is easy enough to get most things in focus. No such luxury with the Sun where different features are best seen at completely different focal settings. When a sunspot is looking sharp, a nearby prominence is barely even visible. Get the prominence in focus and the sunspot has disappeared.

3. Exposure. Getting the right webcam settings for the Moon is fairly easy - simply increase the exposure rate and decrease the gain. For the Sun things are a little more complicated. The picture above is mostly over-exposed but it's not easy to find suitable settings for both the disk and the limb. This was made even more difficult by not being able to clearly see the laptop screen.

None of these problems is insurmountable but I need to be much better organised. All in all, more practice is needed.