ELBRUS CALIBRATING TUTORIAL


Introduction
Do I need this calibration tutorial ?
Are my images reversed ? Example 1
Are my images reversed ? Example 2
How to have selected stars in my images
Determining my parameters
Now I can solve my images


INTRODUCTION

The most dificult point for new Elbrus users is to calibrate. This is an attempt to help you. It will be very frustrating if you really need Elbrus but you can't use it. So if, despite this tutorial, you still have problems, don't hesitate. Send a mail to the yahoo group StarLocatorElbrus. Everybody there is ready to help you.

Elbrus works by comparing the stars in your image to the database. So the first thing you must have is a set of stars extracted from your image. If Elbrus is not able to extract stars it can do nothing more, and it stops searching. Elbrus searches angular star distances, so it must know how big are your pixels in arcseconds. In order to do the job faster, the orientation of the image is needed, we call it the image angle. It tells us where is the North direction in your images. And to furthermore accelerate the search, we need to know where is the East (or West) relative to the North. This is given by the "reversed image" concept.

So we are going to learn:
-how to know whether or not are your images reversed,
-how to have stars selected in your images,
-how to compute the calibration parameters pixel-size and image-angle for your scope-camera configuration,
-how to apply all this in solving images.

But first we must answer the question:


Do I need this calibration tutorial ?

1.- Run Elbrus, go to the File menu, then to 'A-Image path...' and select your image.
The image must be loaded and displayed.

2-A .- If your image is a FITS file with the coordinates of the image in the header then go to the 'Coordinates' menu and select the ' - from the FITS header' option.

2-B .- If your image is a FITS file without the coordinates in the header, or if the image is a BMP file or a JPG file, then go to the 'Coordinates' menu and select the ' - manually selected...' option. Now introduce the approximate coordinates.

3.- Now press the 'Analyze' button.

4.- If the image is solved with more than 14 sides you probably don't need this tutorial. Nevertheless I think it may be useful to read it.

5.- If you get the 'No solution found' or you get a poor solution with less than 15 sides, or you don't understand what we are speaking about, then probably this tutorial will help you.


You can now proceed with the next step:
Are my images reversed ? Example 1

(Updated November 6, 2008 Alfonso Pulido)