STAR Atlas:PRO frequently asked questions - FAQs

How much of the Sky will I see through my own Telescope, Eyepieces and CCD Camera?

Yes, it is worth using the telescope views if you are planning to use a telescope as you can gain valuable information from Star Atlas: PRO which is directly useful when looking at the sky through your own telescope.

Telescope views allow you to project a circular shaped reticle onto the STAR Atlas: PRO chart that matches the same Field of View that you would see when looking through your own Telescope. STAR Atlas: PRO permits you to add an optical description for an unlimited number of Telescope and Eyepiece combinations. STAR Atlas: PRO can also project a reticle for CCD Cameras and you may add your own CCD Camera details. So when you wish to draw a reticle you need then only selected the combination of Telescope and Eyepiece you are using before the reticle is drawn.

To set up the program so you can use the telescope views you need to have the following information about your telescope before you start. You need: -

1. The diameter of your telescope.
2. The focal length of it.
3. The focal length of each of your eye pieces
4. The apparent field of view of each of your eye pieces.

The person who sold you the telescope should be able to tell you or, if you are lucky, the information will be in the documentation that came with it. You may also check the Internet; some Eyepiece manufacturers have this information available on their web sites.

The diameter (aperture) and focal length of your telescope should be entered in Millimetres (mm). Following are list of common telescope apertures and how you may calculate the Focal Length of your Telescope.

4-inch 101 mm
5-inch 127 mm
6-inch 152 mm
8-inch 203 mm
10-inch 254 mm
12-inch 305 mm

The Focal Length of your telescope can easily be calculated by multiplying the telescope �f/ratio� by the aperture of the telescope.

Using a 4-inch f/9 telescope as an example:

First convert 4-inch to millimetres which equals 101mm. Then multiply the 101mm by 9 (the f/ ratio) and this gives you the Focal Length of your Telescope, 909mm.

To set up the telescope data in Star Atlas: PRO: -

1. Open the Star Atlas: PRO.
2. Right click on the desktop.
3. Click on [Eyepiece FOV].
4. Click on [Add Telescope] at the top.
5. Enter a name e.g. �New Telescope�.
6. Click on [Focal Length] and add the figure e.g. 1200 mm.
7. Click on [Diameter] and add the figure e.g. 254 mm for a 10-inch telescope.
8. Next click on [Add Eyepiece] and give the first a name e.g. �Low Power�.
9. Add the [Focal Length] e.g. 25 mm.
10. Add [Apparent FOV (Degrees)] e.g. 50.
11. Next add any other eyepieces e.g. �High Power� etc.
12. If you are going to use this program with a moving telescope, you need to enable the [Centre and Keep Reticule Enabled] under [Reticle Option] at the bottom of the screen. This allows the screen to refresh every few seconds when moving a telescope but the reticle on the desktop.
13. Now, to use this feature, just right click on the object of interest on the desktop,
14. Click on [Eyepiece FOV],
15. Click on [Draw FOV] and a circular FOV appears at your area of interest.
16. The size of the reticle can be varied by changing the [Eyepiece] from low to high power or vice-versa.

You may wish to adjust the �Field of View� (see FAQ When should I use the Field of View command as this will allow the viewer to obtain images with the reticule of the telescope optimised for that object.

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