Ngc3324

[allan gould]

I was attempting to see if I could cure the flex I suddenly had in my setup by changing the guidescope ring setup as well as moving the SCT focusser from in to out focus limits several times. Now I can do 10 min exposures with no trailing.
Happy again.
I trialled NGC3324 after seeing Peter_4059's shot and managed to get 7x10min exposures with my QHY8 before the rain came in briefly to end the session.
I also played a bit with my flats and took them down to a mean of 24000ADU and that gave me a far better corrected image than I had seen previously.
Any comments welcomed

[telecasterguru (Frank)]

Allan,
You look like you're getting there.
When you say you took your flats down to a mean of 24000ADU how did you measure that?

Frank

[peter_4059 (Peter)]

Nice shot Allan. Good to hear the flexure is coming under control again.

[gregbradley]

Good result Allan.

I aim for about 20,000 ADU for flats. I read a report that said to go for more as it resulted in lower noise. I tried 50,000 ADU and the flats just completely wrecked the image and overwhelmed it. So not sure what went wrong there or if that approach only works with some setups.

Greg.

[sjastro]

That's a fine image Alan.

Regards

Steven

[allan gould]

Originally Posted by telecasterguru

Allan,
You look like you're getting there.
When you say you took your flats down to a mean of 24000ADU how did you measure that?

Frank

Measured in Nebulosity using the pixel stats function - very usefull.

Originally Posted by peter_4059

Nice shot Allan. Good to hear the flexure is coming under control again.

Thanks Peter, I had visions of what you went through to get rid of focus creep or what ever. Really didnt want to go there.

Originally Posted by gregbradley

Good result Allan.

I aim for about 20,000 ADU for flats. I read a report that said to go for more as it resulted in lower noise. I tried 50,000 ADU and the flats just completely wrecked the image and overwhelmed it. So not sure what went wrong there or if that approach only works with some setups.

Greg.

Greg
Have to agree with you as I was having troubles with flat corrections leaving residue gradients that became worse and worse on stretching the image so I played around with various ADU levels (from 9000 - 50000) and found as you have thatat 20-24000 is optimum for my QHY8. After processing it then gives a very flat frame that doesn't have a gradient in it.

[allan gould]

I re-did the processing of this shot as I realised that it was too harsh and lost a lot of detail due to me being tired last night. A lesson there?
Anyway I redid it so that it was far more subtle in its details and not so contrasty. I think I was trying to bring out the San Gabriel profile too much.
Anyway the repro is at the top of the link.

[allan gould]

Originally Posted by sjastro

That's a fine image Alan.

Regards

Steven

Thanks for that Steven - its an interesting region that with more carefull processing has a lot to offer. Did a Sidonio on it that Im happy with.
See attached and comments welcomed.

[pmrid (Peter)]

Hi Allan. have you ever seen how well the image of Gabriella Mistral - the Chilean poetess after whom this nebula is named - fits over this object.
Here's a rough attempt at showing it.
Peter

[allan gould]

Originally Posted by pmrid

Hi Allan. have you ever seen how well the image of Gabriella Mistral - the Chilean poetess after whom this nebula is named - fits over this object.
Here's a rough attempt at showing it.
Peter

Peter
The first time I saw a photo of it I was stuck by the resemblance but now that Ive processed it for the faint dust etc its beginning to look more like a smiling skull to me.