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Additionally, you will notice the CCD temperature will rise if multiple fast expo‑
sures are taken in succession. This is normal and the temperature will drop back
to your target temperature shortly.
4.3. Imaging Deep Sky Objects
Capturing impressive images of deep sky objects, such as galaxies, nebulae,
and star clusters, require relatively long exposures. You will take several
individual images and stack them together to form one high-quality resultant
image.
Very accurate polar alignment is essential for deep sky imaging. Stars will streak
across the field of view without precise polar alignment and tracking. Longer
exposures of 60 seconds or more also require autoguiding with a separate
camera. The Orion StarShoot AutoGuider (available separately from Orion) can
be operated with the G4 in PHD Guiding.
To start:
1. Acquire and center the deep sky object into the field of view of your
eyepiece. If you are using a mount with an accurate computerized go-to
system, you can keep the camera installed in your telescope’s focuser
without using the eyepiece.
2. Remove the eyepiece and replace it with the G4 camera.
3. Focus the camera as outlined in Section 4.1. If necessary, move the
telescope to a nearby star to determine the best focus.
For best results we recommend selecting
Raw in the pull down menu next to the
Color label in the Capture tab (Figure 6). For StarShoot G4 Monochrome users,
no special selection is needed, all images will be raw.
4. In the
Capture tab, set the Exposure value to around 10-20 seconds and
click
Start. After the image downloads check to see if the deep sky object
is centered well in your camera. Adjust the camera orientation if needed,
keeping in mind that you may have to refocus the camera after making
the adjustment. Reposition the telescope if needed to center the deep sky
object.
5. Click
Sequence and set the Directory save path, and File Name for your
images as well as your exposure details (
Figure 8). For most deep sky
imaging, set:
Run: Always check on
Type: Light 1x1
Exposure: Greater than 30 seconds (to your choosing)
Binning: 1x1,
Repeat: multiple exposures, we recommend more than 5.
6. Click the
Run Sequence and the G4 will immediately begin the sequence
of exposures. A naming convention is assigned to your
File Name. If you
