Antares with new G11

[midnight]

Hi All!

I normally don't post in this section as I am still grasping with my technique but I have just become a new owner of a G11 and couldn't help getting the bugger out and taking an image.

Compared to my old LXD55, this thing is a dream. Gemini II is a bit - well - let's not go there as I have come from Autostar. About 1hr in, G11 decided to go from "guide" to "slew" by itself and took off cutting out on the safety limit - I checked the hand controller and it was in "guide" and I disconnected the ST4 cable and then drove it back east and in moved at "slew" speed but still in "guide" on hand controller :screwy:. I changed the speed on the hand controller to "slew" and then it moved at guide speed. I have heard the stories of the Gemini firmware but this is dodgey!

Anyway, several of IIS' members have recommended I post here so here it is. Many thanks for your help!!

Just a quicky but it has turned out better than I thought.:D

40D + 200mmF2.8L @ F3.5
Stack of 11 x 4min @ ISO800
Dark frames = 16 as per lights.
Stacked using DSS. Imported into Photoshop to adjust levels and curves and then saturation adjust. About 5mins of PS as my PS skills are still basic.
I had an opportunity to buy a Celestron Nexguide camera in the US recently and gave this a go and it worked beautifully.

I'm not sure about the colour but the original tiff from DSS was really smooth and reasonably sharp so I'm pretty sure I've got good polar alignment and guiding good. The G11 is much better to polar align than the old Meade.

More than happy to hear what can be improved as this is where I have learnt most.

Cheers,
Darrin...

[atalas]

Darrin,congrats on the mount! I'm sure you'll work the bugs out before too long.

As for your image....wonderful result with very little exposure,nice work.

[Octane]

Signing in from AAIC (thank heavens for 3G tethering) -- just wanted to say well done.

Are you sharpening? The stars seem a bit crunchy.

The important thing is that you have the foundations of good polar alignment in the bag. Did you take flats?

You can use a few more iterations of curves to really bring out the detail in the dust lanes.

Top stuff -- you'll go far, Darrin.

H

[midnight]

thanks very much for your support in the past H!!. I have learnt a fair bit from you and I was very dissappointed I can't be there at AAIC as I really wanted to go (work committments unfortunately).
No sharpening done. No flats - I was too eager to try out the G11 and snap away. When I stretched, the image seemed to get "noisy" quickly. Perhaps not enough exposure time overall.



Louie, thanks very much. I have been closely watching your demonstrations on your site and I am limiting my self to stretching and curves at the moment but as I said to Humayun, the data quickly "blotches" or looks noisy after only 1 interation (and I checked it is indeed RAW). I can only assume there is only so much to do with 40 odd minutes of data at this ISO. But the mount is really a big step up and I just now need the clouds to bugger off.

One question though - how do you know you are "over" stretching? Ie if the image is starting to look rough/ragged after a stretch, is this an indicator you've pretty much hit your budget limit with the exposure/data obtained?

Cheers,
Darrin...

[Octane]

One tell-tale sign of over-stretching, can be seen in the form of highlight clipping (stars blowing out and perhaps the dust immediately around Antares) in the histogram in Photoshop.

Keep it up -- add more data to this one, and you'll have a winner.

H

[atalas]

One question though - how do you know you are "over" stretching? Ie if the image is starting to look rough/ragged after a stretch, is this an indicator you've pretty much hit your budget limit with the exposure/data obtained?

Cheers,
Darrin...

Yes,noise level will limit you but of cause you need to push harder to see what you have to deal with first,then drop back.

Noise reduction techniques will help but nothing is a substitute for more good data and dark skies.

H mentioned flats,(don't skimp on dark's either)most important(even more so for DSLR) so follow this advice to the letter...he knows what his talking about.

I remember H used to spend a lot of time on his dark's straight after lights so this would give him closer temperatures to his lights and had great results.

Like he said mate keep It up,your well on your way.

[Ross G]

Great photo Darrin.

Your skills are racing ahead at a rapid rate.


Ross.

[Hagar]

Very nice Darren. This is a great start to your new mount. Looks like you have most of the critical items under control.

The image could do with a little brightening which will show off the dust in this spectacular image a little. This can be done with a light stretch on the bright areas but to be honest you need a bit more signal eg. exposure to allow much more stretching.
You could also just do a reprocess and during the curves stretch manage the brightness with the curve.

You have done very well in a very difficult section of sky to process just right. Lots of much easier targets up there that don't test your processing bquite as hard but compliments on this. A job well done.

[midnight]

Thanks Doug, Ross, Louie & H!

I'll keep your points in mind for next time. I just had to get out there and click away once the new mount arrived. There are many variations to try and not enough clear nights at the moment ;)

Cheers,
Darrin...