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StarHopping 101

by Rob Hawley

Finding Your Way in the Skies

When I first started using a telescope about 8 years ago I got lost every time I looked for something in the sky. This was particularly true if I did so from my light polluted back yard in suburban San Jose.  Sure I recognized the bright star patterns I learned as a cub scout like the Big Dipper, but the rest was a mystery.  In frustration I got a GOTO scope, but having it do all the work gave me an experience like watching TV. What I need was a good chart and some instruction of how to use it.

This video is the result of my own journey.  The material began as a chapter in the internet book I produced on the Messier Marathon. Using the medium of video I have been able to greatly expand that brief explanation making it both more entertaining and more informative.

The total run time is 30 minutes. If you want to just get a flavor of what I have done then I suggest you start with section

Section 1

  • The Basics

In this section I discuss the types of finders, introduce the choices for charts, and describe the symbols used in charts

Section 2

  • A Sample Star Hop

This section introduces the process of star hopping in detail.  I use animation to show how each step should be done and what you will experience.

This example is also provided in text version below

Section 3

  • Astronomical Coordinates

  • Using Paper Charts

  • Optical Rotations

This defines the coordinate system used in astronomical charts.  I also discuss how optical rotations in Newtonian telescopes and straight finders affect what you will see.  I include a brief repeat of section 2 to show the difference.

Section 4 -

  • Scopes with Diagonal Mirrors

  • Working Efficiently

  • Selecting a Dark Site

The final section continues the discussion on optical rotations by showing how a diagonal prism or mirror affects what you will see.  I provide some suggestions on how to work efficiently, finally I stress that star hopping is easier if you can see the stars.

Entire Course as YouTube playlist


Finding M38 - Web Example

To find your way around in the sky you need the right kind of finders and a good set of charts.  I use paper charts (Pocket Sky Atlas, Bright Star Atlas, and Uranometria), but most of the time I use a laptop running SkyMap Pro and more recently SkyTools V 3. 

The trick to Star Hopping is first getting your bearings.  Experience has told me that before I get behind the telescope you first have to sit with a visual star chart and acquaint yourself with the stars.  In this example we will find M38 in a November sky.  In November M 38 will be in the east. Click on the picture for a full size view.

We have to first locate the area of interest in the sky.  Using the Naked Eye chart (or high level charts in paper atlases) we can see that the target area is just to the left and above the constellation Orion.

Looking at the more detailed view we can see that M38 is in the middle of the pentagon of Auriga (which actually borrows a star from another constellation).

To star hop we have to pick an obvious starting point and then navigate using easy to recognize patterns.  Anything that is distinctive will do in this case there is a row of stars part way from iota ( ι) Auriga and M38. We place our red dot finder on iota. 

We need to then verify we are really on the right star and determine how the image is rotated.  The fastest way to do this is by star patterns.

Look for patterns of stars around the suspected start point.  The green pattern is fairly bright and should survive even city lights.  The red pattern is distinctive, but dimmer.  We may not be able to see it in all skies. 

One this is done we rotate the chart to agree with the sky.  As you get more experienced you may be able to skip this step, but I strongly recommend beginners always do it.

We now can see we have to move the field of view to the right.  Let's do so until we see the row of stars.

Move that group to the left of the field of view as shown in the chart

Now move the field of view in the 5 o'clock direction until the group just disappears.  We should now be on M38.

Remember that what you will actually see will depend on your time, location, and optics.  The technique will work as shown for all Newtonian telescopes and finders.  See Section 4 above for scopes with diagonals.


Creative Commons License
Copyright 2009,2016 Robert J Hawley Some Rights Reserved StarHopping 101 by Robert J. Hawley is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.
Based on a work at

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However You may not alter, transform, or build upon these works.

rjh 12/15/16