M83, Southern Pinwheel Galaxy

[Dr Nick]

Hey, all.

On the 10th and 11th of July I had my first clear nights in 1 and a half months!:(

I managed over the two nights to take an image of M83.

Telescope: 8" newtonian f/5 reflector

Camera: DSI Pro II

Mount: EQ-5

Tracking: Yes

Guiding: No

Software: Taken with Envisage, then processed in PS CS2

Location: 5kms away from Glen Innes, NSW, Australia. 1070m above sea level. Perfect skies here...

Exposures:
I took the luminance layer at 7:10pm on the 10th. This consisted of 65 8 second exposures.

The colour was taken on the 11th around 7:20pm. I got 50, 8second exposures for each colour layer.


I have ran the image through paint to reduce the filesize. Please click here (http://users.nsw.chariot.net.au/%7Eduffell/deep/M83%2019-10%20and%2019-20.jpg) to see the original image (http://users.nsw.chariot.net.au/%7Eduffell/deep/M83%2019-10%20and%2019-20.jpg).

Comments and critique welcome.

[ballaratdragons]

Hi Nick,

Great to hear you say more than "Nice Image" :lol:

Your M83 is actually very good. I like the clour balance. The detail is great.

It looks like the DSI Pro II suffers the same problem as the Toucam with the Star Bloat. Annoying isn't it! But you have done well capturing the fine structures in the arms.
Did you use any filters? I am wondering if an IR/UV cut filter might help with the Star Bloat and core burnout.

I like it :thumbsup:

[Dennis]

Very nice Nick. Excellent results for such short exposures.

Chees

Dennis

[Dr Nick]

Thanks.
I would be able to say a bit more than nice image a little more often if you guys didn't take so many wonderful images, i can hardly get through them all. Plus, as I said, I havn't had any clear skies in over a month now, how good it feels to get out in the sub-zero temperatures...

The DSI Pro II does suffer from star bloat, do you know of any ways I can reduce this in PS?

Also, while I'm asking, can anyone tell me how to make diffraction spikes in PS? I have seen them added before and I think if done correctly, they can make an image more wonderful.

Yes, i do use a filter with all of my images, other than the colour filters I need to get coloured images, I also mount an IR filter on the nosepiece of the DSI Pro II for all of my shots (including the colour shots).

Oh, and yes, the core of many deep sky objects burns out when I image. I have gotten quite good at using this technique (http://www.nicksastronomy.com/burns.php) to help but I dont often bother with just small things like this unless I really have some spair time outside on a clear night.

Thanks again. ;)

[Dr Nick]

Thanks, Dennis.

I try to take longer exposures but my tracking isn't that good, I find it would be much better with a $3,000 mount that I can hook yp to my computer and guide as I image, but unfortunately, i dont have one :(

Maybe in 50 years or so when I get my superannuation if I manage to save enough in there... ;)

[ballaratdragons]

As I am only just finding out myself, Nick, there are diiferent rated IR filters. Then there are IR/UV filters. Then there are different methods of IR filtering. Not as Cut & Dry as I thought it would be! IR can be filtered by 2 different methods, reflective or absorbtion. Reflective is the better.

I am at the moment about to order a Baader IR/UV Cut filter as it has an extremely Sharp Cutoff at 690nm (leaves all the visible red, including the important 656nm H-alpha emission line).
and a sharp cutoff below 400nm which eliminates violet halos around bright stars (more effectively than simpler so-called Minus Violet photographic filters). These nm cut-off levels allow colour through, not just Blue, and is reflective, not absorbive.

As for the Star Spikes, may I suggest Noel Carboni's set of Photoshop actions: http://actions.home.att.net/Astronomy_Tools_For_Full_Version.ht ml

One click and many actions are done for you :)

[Ric]

Hi Nick, that's a very nice image, well done.

You have captured some lovely details in the spiral arms, the core is a little cooked but it does not detract from the overall image. In respect to the IR filter I have have found that I have been getting better results after I changed from the Meade IR to an Astronomik IR/UV filter.

I find the star bloat annoying as well with my camera, If I work out how to get rid of it I'll let you know.

That's a great website you have as well.

Cheers

[browndog]

Congratulations Nick this is a great image... I like your colour balance and presentation.:thumbsup:

and with only 8sec exposures..! :eyepop: You should be very happy this.

Keep working on that alignment. If you can get it just right I am sure you will be able to take some longer exposures. The best thing that I did recently was use StarTarg, it not only helped me understand drift alignment it actually works! Try this website for more information: http://www.andysshotglass.com/StarTarg.html

I think that there have been some recent postings about StarTarg and a similar but free executable that was developed by anther ice-in-space member.

[Dennis]

Mate – I’ve got a $7500+ mount (Tak EM200) and I would be very happy to produce with it, what you have done with your mount!

Cheers

Dennis

[jase]

Good work there Dr Nick. You've certainly brought out plenty of detail in the galaxy structure. Longer exposure times will definitely help, but you may need up with worse star bloat. Perhaps a trade off. Well done.:thumbsup:

[sheeny]

Yeah, I know what you mean... and a lot of the time everyone else has stolen your superlatives before you even found the thread!!! I know that happens to me!:lol:

Oh... and BTW... Nice image, Nick! :poke:


I found a tutorial on the web recently about this, but I can't find it again ATM:rolleyes:.

The gist of it though was that you can make your own brush shape to do this like this (roughly):whistle::

Create a new image file say with a black background, pretty square say about 200 to 400 pixels per side.

Draw a white horizontal line across the middle so the length of the line is say 1/2 the length of 1 side of the image. Experiment with different width lines too for different effects - I think 3 pixels wide works well.

I think you use motion blur with the direction of the blur parallel to the line to extend and taper the line. Have a play till it looks good.

Now copy the layer that has the line in it, and then rotate the new layer 90°.

It should look like a pair of square diffraction spikes now.

Flatten the image so it's all in one layer.

Invert the image so it's a black cross on a white background and then save it as a custom brush. Use the [ and ] keys to decrease and increase the brush size.;) I've attached an example of the one I made...

Al.

[ballaratdragons]

Nick,
I had a play with your image in PhotoShop and cleaned the stars up and added a few spikes. Hope you don't mind.

It's a great pic and I wanted to clean the stars up for you.
I couldn't clean the core up, I would need the original raw data for that.

[Dr Nick]

Oh.... Ok... Well, I have no idea what kind of filter mine is, it is just the one that came with tthe Imager, I'll have to look into that further. ;)

[Dr Nick]

Thanks everyone!

Ric - I will have a look at an astronomic filter ;)

Ken - Thanks for touching that touch up, it looks good ;)