Cone Nebula

[daverave83]

Hey Guys

After my great success getting 1 min exposures and pushing the Goto 1.10mins, in the right conditions i'm looking to push the boundary further and setting myself a new target.

The Cone/Christmas Tree Nebula.

I need abit of guidance with the subs, particulary when they post RGB subs!?

Are these subs taken using a different RGB filters or is it DSS filtering between the colours?

I know most of you are thinking "you sir are crazy" maybe but i have noticed when you take certain amount of lights that some images trail after 1min and some don't. It seems that it trails when the GOTO is slewing with the object then once it's in the FOV trailing has diminished, out of the 10 images 2 of them have trailing at 1.10. Even at 1.20 field rotation is small  but you do get pear shaped stars however DSS can sort this.

I am looking to do.

ISO 3200 x 40 - 40 Secs - any longer noise comes apparent.

ISO 1600 x 20 - 1min 20 secs

ISO 800 x 20 - 1min 30 Sec!

So how are the RGB Channels done to bring out the nebulosity?

Ta

David

[ollypenrice]

If the GoTo is still slewing the mount during an exposure then naturally you'll get trails.

Once it has settled on its target it will track more or less well just because it isn't perfect. Some subs will trail, some won't. You need an autoguider to make long and consistently reliable subs possible.

DSS won't sort out wrongly shaped stars if they appear on a sub exposure. It can rotate one or more subs to fit another but if, on one sub, you have trailing then it goes into the stack. Nothing to be done unless you reject the trailed sub.

Is yours an alt az or an equatorial mount? If alt-az the length of exposure depends somewhat on the position of your target in the sky.

If you are using a one shot colour camera then all three colour channels are recorded in the data. I don't use DSS but the colour can be released (de-Bayered) in the stack. Someone will come along and tell you haw to do that.

Olly