View Single Post
Old 31-05-2016, 10:54 AM
glend (Glen)
Registered User

glend is offline
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 6,417
New Test Images Up

Last night was another great clear one, probably the last for awhile, so I ran some image sequences and can share the results here. What I am trying to do with this image series is dial in the camera settings (Gain and Offset) and learn how to use what combinations on various targets. There is similiar work being done on the CN forum but of course we have the better sky.

For the first series I returned to NGC6188, which I had shot a few days ago and was not happy with the lack of data acquired with the lower gain and offset settings. I ran two series of 10 x 60" Ha subs, one series with the current recommendations by Jon Rista on CN, of Gain = 70, and Offset = 12; the other series used the Unity Preset (Gain 139, and Offset = 21). For this target the Unity preset worked best and really brought out the detail.

Note: All these series were stacked with Darks and Bias frames (shot with the same settings as the lights) in DSS. Camera sensor was maintained at -25C throughout. Processing was limited to only auto levels in Photoshop, as I wanted only a basic treatment. Obviously more processing can improve them all, but that's not the purpose here.

You can see it here on Astrobin:

NGC 6188 Detail Page:

NGC 6188 Full Screen:

Next in the test series I moved over to the Trifud Nebula (M20) and conducted the same two 10 x 60" series using the same Gain and Offset settings as above. The Trifud is a brighter target and in this case the lower settings seem to work better. It would benefit from some additional shadow and highlights processing.

You can see both Trifuds on Astrobin here:

First the lower gain (71) and offset (12) settings:

Detail page:

Full Screen:

Here is the second Trifud using Unity presets:

Detail Page:

Full Screen:

I should add that I also ran OIII and SII series for these targets. It amazes me how much work this camera can get through in just a couple of hours. It took me just 30 minutes to run the entire 10 x 60" Ha, OIII and SII series. And folks this is narrowband I'm talking about.

Since the weather is turning bad I am going to turn now to processing the Ha, OIII, and SII series into false colour images of these targets. I will post them up on Astrobin in due course.
Over to you Ray.

Last edited by glend; 31-05-2016 at 11:06 AM.
Reply With Quote