Horsehead - only 51 minutes of data

[alpal]

Hi Guys,
I finally got my system working after some technical problems
caused by a loose Lodestar connection.
It's fixed now.

I had to discard all my 1x1 binned frames as they were too noisy.
Many other frames were discarded due to clouds.
That left me with only 51 minutes of data.
I think I'll stick to 2x2 binning from now on.
I shot this last night between clouds & a lot of light pollution
from an outer suburb in Melbourne.

8" f6 Newt, QHY9, PHD guiding.

3 x 10 minute Ha for Luminance.
3 x 3 minute Red
2 x 3 minute Green
2 x 3 minute Blue
All binned 2x2.
Darks & bias applied - no flats.

A larger version is on flickr here:

http://www.flickr.com/photos/24719437@N03/11596366876/in/photostream/

[alpal]

I've had a couple of nights of clear weather.
I took the horsehead one night & got a bit of the flame nebula.
I took the flame only the next night & combined them into a mosaic.
They are both a bit noisy even with extra time on the flame.

Cropped from full frame.
12 x 10 minutes Ha as Luminance.
6 x 5 minutes each of GB.
11 x 5 minutes of R.
All binned 2x2 & nearly 4 hours of integration.
8" f6 Newt. QHY9, PHD guiding.
Larger versions on my flickr photos.
Any comments welcome.

[cometcatcher]

Amazing amount of detail for such a short amount of time.

[alpal]

Thanks Kevin,
It's amazing what you can do from the suburbs.


I did a couple of interesting pics.
I use a 1222 mm focal length 8" Newt.
This gives me a 0.91 arc seconds per pixel ratio with my KAF 8300 sensor = 5.4 micron pixels.
The seeing is never that good - typically 2.5 to 6 arc seconds.
On the night these images were taken it was poor at about 5 arc seconds.
Therefore binning at 1x1 was of no use to get more detail.
Also - I chose binning 2x2 after seeing the noise around the horsehead in a 10 minute
sub frame of Ha at binning 1x1.

I produced these pics from the original 10 minute frames.
They were stretched in FITs Liberator & further stretched
in Photoshop to try & give equal justice to them.
There were no: darks, flats or biases applied.
This is raw data at original pixels.
The only conversion is to JPG but they don't look any different to the Tiff files.

Question - should I only image with binning at 2x2 from now on?

What do others think about this question?

cheers
Allan

[Ross G]

Good to see some photos from you Allan.

Nice looking Horse Head.

I like the colours.

Ross.

[alpal]

Thanks Ross,
I re-processed the flame nebula.
I used an extra luminance layer made up of all 33 frames of Ha RGB.
I blurred the noisy RGB before combining the luminance
& did further processing in Fitswork4.
Nearly 4 hours of integration time at binning 2x2.
A larger version is on my flickr photos.

Hopefully it really looks like it's on fire as it's name suggests?

[astronobob]

Nice going Al, I always dig the curtain on horsey's, you have brought it out very well in this, them mono CCD's are advantages in so many ways.
The Flame has come up trumps, dont often see this one worked up seperately, looking rather 3D too, with Alnitak peering in the corner, kinda in the distance to me, not sure if it is back there in reality, but very effective processing there :thumbsup: :thumbsup:

[RickS]

Allan,

I just had another look at these images after your comments on Geoff's Thor's Helmet thread. The 1x1 image has much bigger stars that the 2x2 when you equalize the sizes, either by downsizing the 1x1 or upsizing the 2x2. Dunno whether it was a difference in focus, guiding or something else but I reckon it's not a completely fair comparison.

Cheers,
Rick.

[alpal]

Hi Rick,
I just checked the original frames & yes the stars are larger in the 1x1 RAW data.
The FWHM for the 1x1 frame is just under 6 arc seconds for most stars
& the 2x2 frame is just over 3 arc seconds ( allowing for image scale )

In scientific experiment only one variable should be changed so
you are right - it's not a fair comparison.
However - just looking at the noise it is obvious that the 1x1 frame is more noisy.
This experiment will need to be repeated to confirm.

Also - did you see the graph here?
http://www.microscopyu.com/tutorials/java/digitalimaging/signaltonoise/signaltonoisejavafigure2.jpg

Has anyone else got some better frames that can be checked?

cheers
Allan

[alpal]

Thanks Bob,
I like the way the Flame Nebula came out.
It was nearly 4 hours of data & that made all the difference.

cheers
Allan

[rustigsmed]

Good to see someone has finally managed to take some images in Melbourne!!!

Nice going Allan the reworked Flame looks pretty good to me.

Cheers,

Rusty

[strongmanmike]

Have to agree there, nice job Allan.

As for the 1X1 vs 2X2 and apart from the unfair comparison due star sizes as mentioned...you make a good point :confuse3:

Mike

[telecasterguru]

Very well done from the burbs.

[alpal]

Thanks Rusty,
It was nice to finally get a picture or 2.
The flame came out quite well - a bit noisy but lots of detail.
Melbourne has had about 8 months of mostly cloudy nights.

cheers
Allan

[alpal]

Thanks Mike,
Binning must be considered for everyone's setup especially
when we don't all have sub arc second seeing.
Would you have any pics with the same exposure time
binned 1x1 & 2x2 of the same target for a true comparison?
Hopefully we can see some examples with the same focus
& all other variables identical except for binning.

this graph does say that it increases signal to noise ratio:
http://www.microscopyu.com/tutorials/java/digitalimaging/signaltonoise/signaltonoisejavafigure2.jpg


cheers
Allan

[alpal]

Thanks Frank,
The 2" CLS-CCD filter does help a lot & it's in front of all the 2" filters.

cheers
Allan

[rustigsmed]

Yes ... about the same time since receiving my EQ8 ... :sadeyes: ...i'm sure i'll get to use it one day :(

[alpal]

You poor bloke.
I was going to upgrade my system but these cloudy nights have put me off.
We did have some nice clear nights on 27th, 28th & 29th of December 2013.

Maybe we'll get a week or 2 in a row sometime soon?
I hope so.

cheers
Allan

[strongmanmike]

Actually I haven't imaged binned with the new camera (except for finding and framing) ..or the ProLine for that matter. I'm probably just anal about getting the most resolution possible, even when the seeing looks ordinary..hey, it might improve and then I will have lost time :lol: :rolleyes:

Must try binning, must try binning, must...might have helped with the third shell of NGC 2438 and the jet in NGC 1232 actually :question:

Mike

[alpal]

Well yes Mike,
If it makes the camera 4 times more sensitive than a faint shell might just pop out.
A faint shell doesn't need resolution.
My best FWHM from Melbourne was 2.4 arc seconds.
I am super oversampling on binning 1x1 with my system.

cheers
Allan

[strongmanmike]

Well actually there are some subtle details in that shell too, so I was concerned they might be missed at bin 2X2 but I was again probably over worried :thumbsup:

Mike

[alpal]

Well yes Mike,
your SXVF-H694/ AG12 combo is giving 0.81 arc seconds per pixel
at binning 1x1 & 1.62 arc seconds at binning 2x2.

Are you getting better than 1.6 arc seconds seeing?

[strongmanmike]

Ummm?...probably not often :face:

BUT, let's see?... on good nights like for THIS (http://www.pbase.com/strongmanmike2002/image/151629696/original) and THIS (http://www.pbase.com/strongmanmike2002/image/152595656/original) it may well have been, at least for much of the data collection, but I don't know exact figures..?

Mike

[alpal]

They are magnificent images Mike.

I get some idea by using the information tool in Maxim DL.
I measure the FWHM.
As I said the best I ever measured was 2.4 arc seconds from Melbourne.
Jupiter is just a fuzzy ball with 2 lines through it from Melbourne
but on Mt Baw Baw at 5,000 feet altitude it's as sharp as a tack.
I bet Mt Baw Baw has better than 1 arc second seeing sometimes.
Your site probably has seeing down to 1 arc second on some nights or parts of nights.
I notice that it can change - regardless of focus on the same night -
it can go from 2.8 arc seconds to 5.6 in a matter of 2 hours.

[strongmanmike]

So, now you see why I just stick to Bin 1 X 1...juuust in case :D :lol:

Oh an I also get shocking seeing too by the way :doh:...keeps life interesting I guess :rolleyes: :mad2:

I've posted this before and getting a bit off topic but speaking of seeing

This shows the difference the atmosphere can make even to medium FL deep sky imaging... same object, same site, same scope, same camera, same imager :)

Centaurus A (http://www.pbase.com/strongmanmike2002/image/141800216/original)

[alpal]

Thanks for that comparison pic Mike,
That shows it all.
Seeing is everything - the pics are like chalk & cheese.

Still - you'll be tempted to click 2x2 one night - LOL

cheers
Allan