Finding your target without a GoTo mount

Every method works the same way. First you get close, by pointing at a bright star or a known patch of sky. Then you refine, by checking what your camera sees against a map, and nudging until the target sits where you want it. The camera is the best finder you have, because a short test shot shows stars the eye cannot.

A wide field of view makes it all easier. A frame two or three degrees across contains plenty of stars to recognize, and a large target is simple to land in the frame. The field-of-view calculator shows what your setup covers.

• Star hopping

  Start at a bright star you can see, then follow a chain of fainter stars to the target, using a sky map for the pattern.

  Good for: Free, needs no electronics, and teaches you the sky. Works for bright targets in rich star fields.

  Limit: Takes practice, and faint galaxies and nebulae are not visible by eye, so the last hop is often taken from a test shot.

• Red-dot finder, Telrad or finder scope

  A finder shows a small circle or crosshair on the sky, lined up with the main scope. You put the finder on the spot where the sky map says the target is.

  Good for: Gets you to within about a degree quickly, especially for wide targets such as Andromeda or Orion's Sword.

  Limit: Needs to be aligned with the camera once, in daylight. Faint targets cannot be seen in it.

• Test shot and compare

  Take a short, high-gain or high-ISO exposure, then compare the stars in the frame with a sky map to see where you are pointed.

  Good for: Uses the camera you already have, and works for targets you cannot see.

  Limit: You need to recognize the star pattern, which is easier with a wide field of view.

• Plate solving

  Software reads the stars in a test shot, matches them to a catalog and tells you exactly where the camera is pointing.

  Good for: Removes the guesswork. Fast and very accurate, even on a dim field.

  Limit: Needs a computer, phone or an app that can do it, and a field with enough stars. Often it works without internet, once the star catalogs are installed.

• Phone sky map

  A sky app uses your phone's sensors to show what is where. Hold it against the tube to read the direction, or use it to find the star pattern to hop from.

  Good for: Quick for finding the target's position and the stars around it. Free ones are fine.

  Limit: Phone compasses are often off by many degrees, and metal gear throws them off more. Use it for the layout, not as a precise pointer.

• Setting circles and a fixed offset

  Some mounts have right ascension and declination circles. Set them on a known star, then turn to the target's coordinates.

  Good for: Works on a polar-aligned mount with no electronics.

  Limit: Only as good as the polar alignment and the circles. Expect to land within a degree or two, then fine tune by hand.

1. 1

   Know where it is before you go out

   Look up the target's constellation, and note which bright star sits nearest it and how high the target is at your start time. Dark Window's planner shows the best targets and when each is above 30 degrees.

2. 2

   Align the finder in daylight

   Point the camera or scope at a distant landmark such as a chimney or a tower, and adjust the finder until it sits on the same spot. Doing this on the first dark night is much harder.

3. 3

   Polar align first

   If your mount tracks, polar align before you hunt for the target, because once the sky stops drifting past, finding things gets easier. See the polar alignment guide.

4. 4

   Aim at a bright star near the target

   Put a bright star in the finder, then center it in the camera. Take a quick test frame to confirm the pointing and focus.

5. 5

   Hop or nudge to the target

   Follow the chain of stars on your sky map, and check with a short test shot after each hop. Use the field of view to judge the distance, because one frame covers a known number of degrees.

6. 6

   Confirm and frame

   Take a longer test exposure, then nudge the target to where you want it in the frame. Check the framing against the field-of-view calculator, and note that the target needs to sit comfortably in the frame.

7. 7

   Fine tune and start

   Make small changes with the mount's slow-motion controls, then recheck focus and start your sequence.

Measuring the sky by hand helps with the hops. At arm’s length, your little finger is about 1 degree wide, three middle fingers are about 5 degrees, and a closed fist is about 10 degrees.

The Andromeda galaxy is a classic first target. Start at a bright star, Mirach, and follow two fainter stars in a line to the galaxy. Each hop is only a few degrees, so you can check it with a test shot.

Plate solving is the shortcut that makes a manual mount feel almost like a GoTo one. You take a test shot, the software tells you exactly where you are pointed, and you nudge the mount and solve again. It needs no cooperation from the mount.

• Stellarium (free)

  A planetarium for the desktop, web and phone. Set your location and time, search for the target, and it shows the star pattern, its altitude and the direction to face. It can also draw your camera's field of view over the sky.

• SkySafari, Sky Guide and similar phone apps

  Point-and-identify apps that are good for finding the star pattern around a target. Their star maps are fine, and their compasses are only roughly right.

• ASTAP and Siril (free)

  Both can plate solve a test image on a computer and report the center coordinates of the field. ASTAP is a small, fast solver, and Siril has a built-in one. Check each program's documentation for the star catalog you need to install.

• Capture apps with plate solving

  Some capture software, such as ASIAIR, NINA and APT, can plate solve and tell you where you are pointed, even if the mount cannot slew itself. What is available varies by program and version, so check yours.

• Printed star charts and a red light

  A paper chart needs no battery, and a red light keeps your eyes adapted. A good chart of your target's neighborhood is worth printing.

Software and menus change from version to version, so check each program’s own documentation for how to solve a test image.

• Hunting for the target before the mount is polar aligned, so the sky drifts while you search.
• Not aligning the finder in daylight, then fighting a finder that points somewhere else.
• Relying on a phone compass. Use the app for the star pattern, and the sky itself for the aim.
• Skipping test shots. A 10 or 15 second frame at high gain shows stars you cannot see by eye and tells you at once where you are.
• Chasing a faint target in a bright, moonlit sky. Pick a bright, easy target first, and save the faint ones for a dark night.
• Forgetting that a small field of view makes hopping hard. A wider lens or a focal reducer makes it much easier.

How do I find a galaxy or nebula without a GoTo mount?

Find a bright star near it with the naked eye or a finder, then follow a chain of fainter stars to the target using a sky map. Take short, high-gain test shots along the way. At the end, the target is often only visible in the test shot, so compare the stars in the frame with your map.

What is star hopping?

A way of navigating the sky by following a path of stars from a bright, easy-to-find star to a faint target. Sky map apps and printed charts show the path, and a finder scope with a known field of view gives you the distance of each hop.

Can I plate solve with a mount that has no GoTo?

Yes. Plate solving only tells you where the camera is pointing. It does not need the mount to do anything. You read the answer, nudge the mount by hand and solve again until you are on target.

Do I need a finder scope for astrophotography?

It helps a lot. A simple red-dot finder or a Telrad is enough for wide fields. Align it with the camera in daylight, so the first dark night is spent imaging and not troubleshooting.

How accurate is my phone compass for finding a target?

Not very. Phone compasses are often off by many degrees, especially near a mount or a tripod made of metal. Use the app to identify the star pattern, and confirm with the stars themselves.

What is the easiest target to find without GoTo?

Large, bright objects near bright stars, such as the Pleiades, the Andromeda galaxy, the Orion Nebula and the Double Cluster in Perseus. A wide field of view makes them much easier to frame.