8
Deep Sky Imaging
Deep sky imaging typically requires longer exposures. Video Mode is limited to 5 second exposures. Trig-
ger Mode is best suited for long exposure astrophotos. The Meade DSI IV’s thermoelectric cooler (TEC)
also suppresses the inherent noise in longer exposure images.
It will take a few minutes for the camera tempera-
ture to stabilize. The TEC “Power” percentage is
displayed so you can monitor how much of the
potential power capacity the TEC is using. When
the temperature is stabilized, the TEC power should
always be well below 100%. If the power remains
at 100%, reduce the Target Temperature.
You can also monitor the current temperature of
the sensor on the lower right corner of SkyCapture.
When the TEC is on, you can monitor this tempera-
ture to know when you have reach the set Target
Temperature.
1. Plug the 12 volt power cord from the AC power adapter into the “DC 12V” port on the DSI IV if you have
not already done so. This is used to power the TEC.
2. Locate the Bit Depth menu on the left menu bar
of SkyCapture and Select “12 Bits”. This setting
captures all of the available information from the
camera which is recommend for deep sky imaging.
3. Locate the Cooling menu on the left menu bar
of SkyCapture. Select “On” under “TEC” and enter
a “Target Temperature ºC” value. The temperature
value should be no more than 40ºC cooler than
the ambient temperature. But to allow for some
temperature fluctuations, keep the temperature to
within about 30ºC of ambient. So, if it’s 20ºC (68ºF)
outside, set the Target Temperature to -10ºC and
click “Apply”.
A Note About the Gain Setting
The Gain Slider is used to adjust the sensitivity of
the DSI IV. Higher gain is more sensitive but con-
tains higher noise. In Video Mode, the gain adjust-
ments can be seen in real-time. In Trigger Mode,
any exposure longer than 5 seconds will require a
higher gain setting, due to the way the DSI IV op-
erates during long exposures. For best results, set
the gain to 10 or higher before toggling to Trigger
Mode. Once Trigger Mode is selected, you will no
longer be able to adjust the gain.