Orion STARSHOOT 52085 - Manual (Page 9)

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5. Click the Expose button. You should see the out of focus star in the image.
If you do not see anything, you need to increase the exposure time.
6. Check that the Subframe section at the bottom of the Camera Control
window has both the On and Mouse boxes checked on.
7. Draw a small box around the unfocused star with your mouse (hold-click
and drag the mouse cursor around the star to draw the box, Figure 11).
8. In the Camera Control Window, in the box below the Mode box, select
Focus. Click Expose. The camera will only download the area you previ-
ously selected, which makes each image download significantly faster than
the whole frame.
Note: If the StarShoot Pro is grossly out of focus, no object will appear in the
image, not even a blur. Increase the exposure time if needed and patiently
move through the focus range of your telescope until you see the centered
star come into view.
9. Gradually adjust the telescope’s focuser inward until the star visually
comes to a small point on your computer screen. You have achieved a
rough focus. Some small adjustments remain to get a perfect focus.
10. Click the Stop button.
11. Set Seconds somewhere between 0.002 and 0.1 seconds (or longer for
fainter stars).
12. Click Expose.
13. Carefully watch the FWHM and Max Pixel values in the Camera Control
Window (Figure 12). The FWHM (Full-Width Half Maximum) indicates the
diameter of the star. The Max Val is the brightness value for the bright-
est pixel in the star. The smaller
the FWHM, and the larger the
Max Pixel, the closer you are to
focused.
14. Adjust the focus as needed to
get the smallest FWHM and larg-
est Max Pixel possible. The Max
Pixel should stay well below
65535, as this is the saturation
level for the camera. If the Max
Pixel approaches 65535, reduce
the exposure time or try selecting
a fainter star. Paying attention to
these values will help you get a
very accurate focus, far better
than simply looking at the star
image on your screen.
15. Click Stop once you reach the
best focus and click Reset in the
Subframe section at the bottom
of the Camera Control window
(Figure 13). Before proceeding to
take images, set the Mode box
back to Single.
Note: Due to atmospheric seeing
conditions, you may notice signifi-
cant fluctuation in the
FWHM and Max Pixel values while focusing. You
typically have to take multiple exposures each time you adjust the focuser to
determine the quality of your focus.
Caution: Once you have achieved focus, be sure to click the
Reset button at
the bottom of the camera control window, otherwise the camera will crop all
your images into a small square!
Imaging Deep Sky Objects
Capturing impressive images of deep sky objects, such as galaxies, nebu-
lae, and star clusters, require long exposures. You will take several individual
images and stack them together to form one high-quality resultant image, just
as you would with planetary imaging. But while planetary images are formed
by stacking many exposures of less than 5 seconds, deep space images will
generally be comprised of individual images of a minute or longer!
Note that the StarShoot Pro is also capable of capturing planetary images. To
increase the image scale of the planets, a barlow lens is recommended. See
“Tips – Using Focal Reducers and Barlow Lenses”.
Figure 12. The FWHM and Max Pixel
in the Camera Control Window help
determine the best focus.
Figure 13. Click Reset in the
Subframe box after you have achieved
focus.
Figure 11. Draw a
small box around the
star to focus on with
your mouse. The next
exposure will download
a “subframe”, using
only the small area
you selected which
greatly decreases the
download time.