Finding a Target

 Terminology

The EduSnap team has used some confusing marketing language like "smart zenith mirror" to describe the modes and the hardware. Basically, the rear back tube combines a diagonal mirror for an eyepiece with a "One Shot Color" astrophotography camera. A switch flips between using the mirror with the eyepiece or directing the image back to the camera. It has no other logical function. The smart aspect is in the camera software, not in the switch itself.

The scope can be used like a spotting scope or for taking deep space photos of nebulae and star clusters. But in terms of camera operation, the Moon and planets are more like terrestrial targets with short exposures, whereas deep space photos involve long exposures involving stacked images.

Note that focusing a target with the eyepiece is not reliable enough for getting good focus for the camera. To properly focus the image for photography, you must switch into camera mode.

Navigating by hand control using the eyepiece

Switch the mirror box to the eyepiece icon. The picture area in the app will be dark because the scope is now directed to the eyepiece. Use the direction buttons in the app to steer the scope in the direction you want to view. Toggle the number in the middle of the arrows to change the speed from 1 (fine tuning) to 2 (framing an object) to 3 (moving the scope quickly to a new location). Twist the focusing ring to make the object you want to look at more clear.

Navigating by hand control using the camera

Switch the mirror box to the camera icon. The picture area in the app will display whatever the scope is pointed at. Use the direction buttons to steer the scope in the direction you want to view.  Toggle the number in the middle of the arrows to change the speed from 1 (fine tuning) to 2 (framing an object) to 3 (moving the scope quickly to a new location). Twist the focusing ring for best focus of the object you are viewing. The image will appear blurry until you adjust the focus properly.

Navigating by target selection in the Go To mode

This mode works best in very dark skies with no clouds. The telescope takes periodic photos and compares the stars in the field to a sky database to determine where the scope is pointed. Then it calculates a new motion to arrive closer to the target. If there are few stars near the target, or if the sky has  low contrast or clouds, this automated navigation technique cannot succeed and the app will ask you to provide a new target.

Switch the mirror box to camera mode. In camera mode, you can use any of three methods in the app to request automatic navigation to objects:

1. The [Star Map] tab shows the sky so that you can orient with your local horizon to determine whether objects in the map are within your view. If you designate locations below your tree line the mount will try valiantly but fail to close on the hidden object. At default view, the objects it shows as visible should also be bright enough to photograph. As you zoom in, the map shows dimmer objects that can be challenging to photograph.
2. The [Tonight] tab brings up a list of objects that are above the horizon at your local time. Again, not all will be directly visible.
3. The [Sky Objects] tab brings up a catalog of objects sorted by type, such as Solar System, star clusters, etc.

Regardless of how you select your object, the software opens to an explainer for that object and along with a [GoTo] button that starts the "slew" or motorized movement to that object. The camera uses the app's knowledge of your time and location to move the telescope to the approximate vicinity in the sky, then it starts taking photos and comparing stars with a star map of the object's location (also known as "plate solving").

If the process finds many bright stars along the way, it can finish centering the object in about two minutes. If it stays at 97% completion without updates, it is having trouble with not enough stars or with poor skies (streetlights or moonlight, for example). In this case, it will eventually give up and suggest trying a new target. Just go back to any of the finders and try again. Star clusters are usually easy finds. Fainter objects really rely on bright stars near the object to close the search.

A well-located target will have a green circle around the approximate image area of the extended object. If the scope complains that it could not center the object, it might still be in the frame. Use a test exposure with a small stack of about 10 frames just to see if the object is off in a corner. If it is, note the bright stars around it and use the hand control buttons to nudge the stars to the desired new location, and try a new test shot. When you are happy with the framing, remember to change the settings for the full 80 recommended exposures.

Note that your scope camera should be focused as well as you can judge on sky objects (here, the Moon is an excellent focusing target.) If the initial search starts off in bad camera focus, use the moment to refocus the camera on a nearby star, then turn off the power, reorient the mount, and start over.

If you want to try a new object, there is normally no need to reset the scope... if the star tracking method (better known as plate solving) succeeds, things just work.

If plate solving fails, conditions or focus might be sub-optimal. This is a great time to flip the mirror box to visual mode and use the navigation widget to just look around.

Note that if the scope had a clutch, you could just move it by hand to point to a different place. But it relies solely on motor control. Always use the navigation widget to command it to new locations.