A budget tripod for astrophotography ball-head or 3-way pan-head?

Question

I am currently looking for a tripod for astrophotography, I wonder is there any significant difference between a tripod with a ball-head or one with a 3-way pan-head? Like say in terms of the stability for bulb exposure, say 20 mins. I know ball-head'ed ones are more versatile for other uses, but that is not my main concern.

BTW: My camera is a Canon 30D, it is not very heavy.

Answer 1

Essentially the only long-exposure astro-photograph you can do on a normal tripod/head is star trails. This is usually done with a fairly wide angle lens, so it isn't very demanding about the tripod or head you use.

For essentially any other astrophotography, you need something like a Newtonian mount with a clock drive. This is adjusted to your latitude, and constantly rotates at the same speed, but in the opposite direction, as the earth's rotation. This allows whatever's on the mount (camera or telescope) to remain pointed at the same object in the sky for an extended period of time.

Answer 2

A good ballhead is very stable and so is a good pan head. The key is good. A cheap one of either won't hold and will drift over time. Heavy weight might be more difficult to carry but actually helps with stability.

The advantage of a ballhead is mostly speed in setting it up. For heavy gear and precise positioning people use gear-heads because they constantly support the weight of the gear, but once in place, a high-end ballhead should be as stable.

Look for a head which is rated for the weight of your camera, plus lens, plus star-tracker multiply by two for safety. Actually, you should look at the star tracker first, some do not need a head.