While there isnt a general answer ala "Buy X, get pretty space pictures", the next best answer is: The best gear is the one you already have. Pretty much every DSLR made in the last 15 years will suffice. Even a kit lens will be okay for starting out, although a bad lens is much worse than a old camera. If you want to get a new lens, check out used vintage lenses.
While OAT can be used standalone, using a laptop with it will significantly improve your experience. For example: A simple "blind" GoTo may not always be accurate, it will get you in the close area of the target but almost never hit it on spot. Too many factors play into it, how precise the time was entered, how level the mount is, how well aligned the camera is to the DEC axis. By using a computer, you can make use of so called "Plate Solving" which will automatically calculate the coordinates from a picture and correct the position.
Another benefit is that it is much more easy to take images through software on a computer rather than a intervalometer, if your camera supports PC control.
You probably came across the term "Autoguiding". But what is it and whats the benefits?
An Autoguider is a extra camera and scope with high magnification. It uses a PC to watch the position of a single star and if that star moves slightly it will issue a correction to the mounts motors.
This significantly increases the possible focal length and exposure time that can be achieved with OAT, while also increasing the amount of usable images without star trails.
Once you've built your tracker, and have calibrated it (Calibration not necessary with the OAT Kits), the next thing you'll want to do is learn how to set it up and use it.
So you're ready to take pictures! This is the way we recommend that you get started. Remember that the most critical thing is for the mount to be polar-aligned. What this means is that the mount should point at the celestial pole when it is in the Home position.
The polar alignment is relatively easy in the northern hemisphere and the mount can guide you through that setup. For the southern hemisphere it is a little harder.
For more information on different PA methods, see the Polar Alignment page.
Luckily there is a fairly bright star (called Polaris) very close to the celestial north pole. We utilize it to do the alignment.
If you have the LCD only and no laptop or GPS module, you'll need to enter the correct HA manually. You can obtain it from an app like "Simple Astro Tools" or from Stellarium, by clicking on Polaris. Make sure that Stellarium has your correct location and time!
Home the mount
Homing means rotating the RA ring to be centered and the DEC ring rotated such that the camera points out of the RA ring at 90 degrees (see figure below). This adjustment does not need the camera, it is purely physical, using the OAT hardware.
This is how OAT should be aligned to North and South in the Northern Hemisphere. In the Southern Hemisphere, it is turned around.
Align the home marker in the middle of the RA ring with the indicator of the RA motor mount.
Align the two sprockets of the DEC wheel with the RA Ring, so that the DEC assembly points 90° to the RA Ring.
Your OAT is now in it's home position. This is the position you will have to bring it in every time you set it up!
If you are using the LCD, use the four arrows to center the RA and DEC ring like shown and press
Yes to confirm.
If you are using OATControl, use the four directions to center the RA and DEC ring like shown, then click
Next, you will need to Polar Align the mount. See the PolarAlignment page for that.
Polar Align the mount
This requires you to use your camera If you are using OATControl click on
Polar alignment, if you're using the LCD: select
The mount will move for a bit, mostly around RA. After the slew, physically move the mount (via the single back M14 screw and via rotating the whole mount) such that Polaris is in the dead center of your viewfinder. Make sure the front stays level. If you're taking pictures (as opposed to Live View), move the mount in one direction only between pictures to see where the star goes. Repeat until centered. You may need to mark your laptop screen somehow from pic to pic so you can see how the movement of the mount corresponds to the star movement.
If you are using OATControl, confirm that it is centered by clicking
Done, if you're using the LCD press
SELECT to confirm.
You're now polar-aligned.
Since there is no bright star near the southern celestial pole, it is recommended to use Drift Alignment e.g. DARV.
Alternatively, some software can automatically and interactively tell you which direction to adjust the mount by taking 2 or 3 reference images. On Windows, you can use Sharpcap (paid, £10/yr). On Linux, KStars includes an alignment module built in to the Ekos suite (free). Note that these tools work best with a rather long equivalent focal length, e.g. Sharpcap recommends a field of view of 1-2.5 degrees (that's >400mm on APS-C/FF, you will also need to find compatible drivers for a DSLR). An easier option is the OpenAstroGuider Add-On, which seems to works well with Sharpcap, and is a useful upgrade too.