[dreamcompiler]

The conventional wisdom is "Dobbies are not designed for photography" but that assumes tracking is necessary for photography. I'd expect that for untracked photography a Dobbie would work fine provided you could lock it down in alt/az and the whole assembly was robust enough not to vibrate for a few seconds. That might be a tall order.

[labcomputer]

That conventional wisdom is because a Dobsonian is a Newtonian telescope on an altaz mount.

The altaz mount, not lack of tracking, is what makes it difficult for conventional astrophotography because the image rotates as you track the star. That prevents using a single long exposure. Equatorial mounts keep the image stationary.

[dreamcompiler]

That was my point.

1. Long exposures require tracking.

2. Dobbies can't track because they have altaz mounts [0].

3. But short exposures don't require tracking. Therefore a Dobbie might work for short exposures iff you can lock down the altaz axes and sufficiently reduce vibration.

[0] It is possible -- and fairly common -- to track with altaz mounts. Both axes require coordinated, computer-controlled stepper motors. In addition you need a third motor to rotate the tube. This was not possible before digitally-controlled motors. So some Dobbies do track but that kind of defeats the purpose of a Dobbie as a cheap light bucket anybody can afford.

In contrast tracking with an equatorial mount only needs a single motor and that motor doesn't need to be digitally-controlled.

[shmerl]

What about short exposure which is the point of the above post?

[shmerl]

I guess it would need some experimenting. I was thinking of getting something like Apertura AD8 for visual observation, but I was wondering if photography with it is feasible.

[calmbell]

Don't buy a dob to do untracked astrophotography. It will be hard, and you will be disappointed with the results. I would pick between visual observation and astrophotography. They are almost separate hobbies that require separate kits. Get the Apertura AD8 for visual or a smart telescope like the Seestar S50 or S30 for astrophotography. The dob would provide great views of the Moon, Saturn, Jupiter, and decent views of some deep sky objects. The smart telescopes provide decent images of the Moon, Saturn, Jupiter, and great images of many deep-sky objects with image stacking build into the software. The smart telescopes are automated, and the dob requires learning the sky for manual tracking.

[shmerl]

I mostly want it for visual observation, but if photography with it is possible - then why not try it. It's not the primary goal.