Holy Space Spiders, Batman!

[AstroViking (Steve)]

Evening all,

I hope you're all taking advantage of the warmth and clear skies we're having at the moment. (In Melbourne, anyway...)

I was out on Friday night (under a 3/4 moon, no less) trying my hand at a big, bright target that was as far away from the moon as I could get. I wanted to try for the Banana Nebula (hey, why not?) but all I got was a spectacular close up of the side of my house when I slewed to it.

So Plan B came into effect (no "Plan 9", thankfully, even if we are dealing with Outer Space) and I pointed the scope at NGC2070 - the Tarantula Nebula.

With all the light pollution and moonlight, I couldn't see much of the sky at all. Even at the zenith, the sky was a pale grey colour. I really need to win the Lotto and buy that bush property I dream of...

Anyway, for a single hour of data, I think the end results came out pretty well. I'm still cursing at the way overblown blue channel, so hopefully the L-Enhance filter will fix that when it arrives...

The first image is a boring Siril stack, with the basic work done (background extraction, colour calibration, remove green noise, histogram stretch) before being dragged into Affinity Photo. I dropped it pretty hard to avoid the splodgy and noise-filled star fields around the Tarantula. (I know the core is blown out. I suspect this is another target for an M42-style "two sets of images" project.)

The second image followed the same Siril process as the first, but I used the"drizzle" feature to double the image dimensions (and quadruple the size of the file on disk). Apparently this helps reduce noise and can tease out fainter detail. All I know is that my computer needs a good rest after using it. I tried to keep the green to a minimum and pushed the blue a bit harder. At least this time I don't appear to have blown the core out as much...

Oh yes - when I was using a gain of 25 I was getting some serious vertical banding in the stacked image. This is a known "bug" with this camera and the easiest solution is to bump the gain to about 50. (You can also try the 'Remove Banding' option in Siril - that works a treat, too.)

Secondly, I took all the calibration frames at the same time, substituting "Dark Flats" for the bias frames. It seems to have worked out OK.

Apologies for the wall of text, I got carried away.

As always, comments and critiques welcome.

Cheers,
V

Details:
EvoStar 72ED @ 420mm / ASI183MC-Pro / HEQ5 / SV165+SV305
Proc: Siril, Affinity Photo
Bortle: 5/6
Gain: 50
Offset: 10
Temp: 0 degrees C
Lights: 360 @ 10 seconds
Darks: 25
Flats: 25
Dark Flats (Bias): 25

[Crater101 (Warren)]

Originally Posted by AstroViking

Oh yes - when I was using a gain of 25 I was getting some serious vertical banding in the stacked image. This is a known "bug" with this camera and the easiest solution is to bump the gain to about 50.

Firstly, a huge Thank You for that bit of information. I've been seeing the vertical banding and wasn't aware of the issue.


Secondly, these are pretty good results. I do like what you've done here, particularly in the second one. You're getting the hang of this much quicker than me.


(And I had to smile at the title - I can still remember watching Adam West and Burt Ward, many years ago... )

[AstroViking (Steve)]

Hi Warren,

You're very welcome! I've done heaps of reading and research on how to make the camera work properly. It's a matter of time and experimenting with settings now. (And remembering to grab darks and flats / dark-flats if required.)

Originally Posted by Crater101

Firstly, a huge Thank You for that bit of information. I've been seeing the vertical banding and wasn't aware of the issue.

Thanks. I'm still not happy with how they turned out - I was trying to get a less-green colour, and to make the nebulosity stand out more from the background. I probably need a lot more data to really make everything work the way I want it to.

Originally Posted by Crater101

Secondly, these are pretty good results. I do like what you've done here, particularly in the second one. You're getting the hang of this much quicker than me.

A bit before my time, but I've seen a few episodes of the dynamic duo.

Originally Posted by Crater101

(And I had to smile at the title - I can still remember watching Adam West and Burt Ward, many years ago... )

Now, when are you going to post up an image??

Cheers,
V

[Crater101 (Warren)]

Originally Posted by AstroViking

Now, when are you going to post up an image??

Cheers,
V

As soon as I get something that doesn't look like a kindergarten drawing...

[oska (John)]

Good one Steve, glad you're setting some star time

[xelasnave]

I enjoyed the wall of text but I am one for brevity as shown in my posts.

You can save that core ..so are you going to try and share the result?

Alex

[AstroViking (Steve)]

Thanks for the kind words John & Alex.

Alex - yep, will have a go at what you suggested tomorrow night.

Cheers,
V