NGC253 - my first galaxy image

[iceman]

Ok so Jase's Silver Coin was worth about $100,000, sitting proudly on display at the local museum.. My silver coin is a 5c coin that has been discarded, fallen down the back of the lounge, run over by a car and is now only barely recognisable as legal tender... :)

But it is my first image of a deep space galaxy! So I'm happy with it all the same :)

The main problems with my previous deep-space images were lack of exposure. I couldn't go longer than 30s with those without trailing, and I figured out that most of that was due to inproper balance of the scope/camera on the mount. For this image, balance still wasn't perfect but it was better than before and this image is made up of 90s exposures - which did have slight trailing (60s had very little) but (for me) it wasn't bad enough to detract from the image so I used them anyway.

It was also my first time controlling the camera remotely, via ImagesPlus Camera Control. I didn't use it for focusing or composition (yet), but that will come next. But it was nice to be able to set up a sequence of exposures and just watch it do its thing.

I didn't use ICNR for this image either. While packing up I took dark frames.

So, the image consists of 11x 90s exposures, and 9x 90s darks. No flats or anything else.

Saxon ED80 on EQ6, unguided.
Canon 350D, ISO1600.

The images were calibrated, aligned and stacked in DeepSkyStacker. I still need to work out how to use ImagesPlus for calibration. Post processing in photoshop was just curves, saturation and levels across the image as a whole. No masking or selective processing.

My composition is horrible. I needed to spend more time getting the galaxy composed in the frame properly, but I only had an hour outside and needed to start capturing photons!

Seeing was less than average, and transparency was horrible. No clouds, but a very light sky.

My main problems now are:
1. Still too noisy. I need to Avg the images (rather than Add), but to do that I need enough exposure. (also so I can use a lower ISO)
2. More exposure. I need to go longer than 90s. To do that I need more accurate polar alignment, balance, and ultimately of course auto-guiding.
3. More exposures. I need to spend more time on the object and take more exposures.
4. Composition. You can see why :)
5. Processing. Better calibration, better processing techniques. There must be more to deep space image processing than just levels and curves :)

Anyway, thanks for looking at my rusty 5c piece.

[sheeny]

Looks good to me Mike!

Al.

[h0ughy]

OK did you take flats and bias's? think about doing that. as for the noise - get a cooled DSLR:whistle:, or come back to 800 for a while. Nice image mike, yes composition is king, but I enjoyed your image. I give you 20 cents!!!;):D

[Phil]

wow great shot Mike well done.
Phil

[Garyh]

I don`t mind the framing Mike! with using 1600 iso I find that you need like 20-30 images to stack to smooth out the noise satisfactory. Maybe try some handguiding and drop back to iso 800 like Houghy mentions and 4-5min exposures..
good first galaxy :thumbsup:

[Dennis]

Very nice work Mike, although I'm sure I've seen some Milky Way wide fields from you, so this has to be your 2nd Galaxy.:whistle::whistle:

Joking aside, that is a mighty fine effort for your 1st Galaxy – nice round stars and good detail in the spiral structure. The background looks a little too dull or grey on my LCD display. You've done extremely well to produce such a good result, faced with such a steep learning curve for DSO acquisition and processing.:thumbsup:

Cheers

Dennis

[acropolite]

Have to agree with what Dennis said, a mighty fine effort. It's only upwards from here.:thumbsup:

[jase]

Mike, a fine achievement. I think you've highlighted your deficiencies in original post and agree with them. The longer the integration time the easier the data is to work with and the smoother final image will be. ...and yes, there is a lot more to DSO processing than levels and curves, but don't underestimate the power of these two tools. They play a major part in what you want to display to the viewer. Histograms are your friend, know how they respond to different techniques will ensure you are making the most out of your data. There are of course many more linear and non-linear stretching tools that are suited to different objects. Look forward to seeing more as you develop your style/processing work flow.

[Dr Nick]

Thats your first deep space galaxy?!?! Very well done! ;)

[tornado33]

Well done, great to see youre getting into DSO imaging now :)
Scott

[little col]

:thumbsup::thumbsup: well done on your first deep space galaxy mike , i would be very happy indeed to get such an image myself:)

[leon]

Cant complain about that Mike, pretty good effort i reckon for a first attempt.

Leon

[EzyStyles]

great first galaxy mike! I dont see any issues with it besides you might want to lower the black level a little (just a small bit) to darken the background (not too dark otherwise will clip).

overall excellent image mike. luv it.

[Lee]

I think it looks great - better than my crack at the coin this time last year! Definitely worth a dollar....

[Tamtarn]

Yet to try this Galaxy Mike, but we would be happy to get an image as good as this.

[Bassnut]

Well Mike, im going in hard here, cause I know you can take it ;-).

Not good, and you have told us EXACTLY why already, thats why I recon within a few weeks or mths you will absolutely cream this DSO stuff.

You are one of the best on the planet for planetary (sic) and you are a perfectionist, this is a very short stepping stone to DSO nirvana, stop mucking around dude ;-).

[rat156]

Hi Mike,

Yes, I've come to the conclusion that Galaxies are tough going.

A couple of tips for you;
Try to not saturate you stars when hitting the picture with levels. All your stars are white, very white.
Your grey level is too white, about 90% is what I work with most of the time.
Use layers to get the colour right in one pic and the detail in another, then recombine, you can even fake a luminance from the RGB data.
Don't be tempted to go too long in you exposures, 2 mins is about all I can get without skyglow dominating, even from relatively dark skies.

Lastly, stop pissing about with the DSLR, get a mono CCD, you've got the LRGB thing going in the planetary stuff.

Why don't you use the DMK as a guider?

Cheers
Stuart

[Ric]

A great start Mike. I like the composition and the appearance of it just floating in space.

A fine first effort :thumbsup:

[RB]

What a wonderful image for your first galaxy Mike, I think you've done a marvelous job and the little ED80 is a real performer too.

Excellent work !!

:thumbsup: :) :thumbsup:

[nandopg]

Hi Mike,
Nice wide field image Mike...and it came in a very good time for me: I am starting to image the galaxies in the Sculptor group and a wide field image is always welcome.
Your image actually is looking great to me even more being the first one.

If you don't mind, a couple of suggestions:
1- Use ImagePlus to calibrate, align and stack your images. Always calibrate with darks, flats and bias frames.

2- Use an off-axis device for image composition and coarse focus. I use one carried by Taurus Technologies (www.taurus-tech.com (http://www.taurus-tech.com)). In my opinion this is a must have accessory.

3- For fine focusing I use DSLR Focus. It is much better than the focus resource present in ImagePlus.

4- Fine tune your polar alignment making sure that the mounting is able to track a star for at least 40 minutes. Use a cross hairs eyepiece for that. I use in this case the star's drift method.

5- Don't use ASA 1600 in your camera, use ASA 800 at most.

Congratulations Mike, I hope to see more from you. :thumbsup::thumbsup::thumbsup:

Fernando

[glenc]

Nice shot Mike. You should be able to get the galaxy 253 and the globular 288 in the same 2 degree wide field.
Caroline Herschel found 253 and it was the first galaxy I ever saw with a telescope.

[iceman]

Many thanks for all your feedback and suggestions. I'm away from home on a 33.6k connection, so will respond in detail to your thoughts when I get back.. But just wanted to take the time to say thanks and I appreciate the honesty.

[iceman]

I don't even know what a bias is or how to take it. I'm not going to bother with flats until I get the lights and darks right. I believe (perhaps wrongly?) that taking and calibrating flats will only offer slight improvement to my image, compared to the rest of the things I need to get right first, which will improve the image by much more.


Thanks Dennis, I agree - my processing leaves a lot to be desired. The dull grey background is indicative of the sky that night but I probably could've done more to process it out, or reduce it. Looking at it now (on a proper screen) I could've adjusted the black point more, but I did all the processing on my laptop screen while on the plane over to Perth. In hindsight I should've waited.


Thanks Jase - I appreciate your comments and look forward to your constructive criticism. And you're right - I need to work on my processing workflow - at the moment it's too rushed and I'm not paying enough careful attention to the data I've got. But with better data, the motivation will be there to do it better :)


Thanks Scott - DSO imaging is a different beast, that's for sure. I'm not sure i'll ever take the time needed to do it really well like you and other guys here do. If I've only got a spare hour, you can capture a great planetary image if the seeing is excellent. But in DSO imaging, you need to spend much longer to get a good image. I also need more "tools" to do it properly but maybe I'll build them up over time.


Thanks Fred, I appreciate your honest feedback and I can take it. I know what I need to do to get better at this DSO imaging, it's just a matter of the right tools and techniques, and more time.
I'm happy with this as my first image, but certainly not happy with it as a galaxy image. There's a lot to do!


Thanks for your tips and feedback, Stuart.
You're right about the stars.. There was very little colour in the galaxy and pushing the saturation brought a little colour into the galaxy but most likely to the detriment of the stars. I need to do more masking and selective processing. I really haven't taken the time to learn DSO image processing properly yet. Once I am capturing enough quality data then that'll motivate me to improve my processing routines.
I'll be persisting with the DSLR though - I already have the mono DMK but i'm not planning on using it for DSO imaging, and I can't afford to buy a mono deep space camera.
I do plan on using the DMK to guide with, but I need to set up a guide scope first. I've got a cheapo 80mm refractor which I'll use (with the DMK) to guide the ED80, but I need to get the right mountings to set them up side by side. Guiding is definitely one of the next steps for me.


Hi Fernando, thanks for your comments and suggestions.
1- I tried using IP to calibrate but my dark frames ended up with pixel spots all over the place and when subtracted from the lights, left dark pixel spots. I'm not sure what I did wrong, but I'll give it a go next time.
2- The Taurus device looks interesting - did you get the Mini Tracker or the Tracker III? Do you have to replace it with the camera afterwards?
3- I don't have DSLRFocus - what makes it better than what is in ImagesPlus?
4- Yes, definitely something I need to work on. I've been very lazy and haven't spent any time getting alignment right.
5- I would've liked to use 800, but wanted to capture as much light as possible given my shorter exposures. I was hoping I'd be able to avg the frames (instead of adding) if I got enough exposure at ISO1600, but 90s just wasn't enough.


Thanks Glen, i'll definitely work on the composition next time.

Thanks all for your comments, tips and suggestions. I appreciate your feedback.

[nandopg]

Hi Mike,
1- Did you use "Automatic Processing" in ImagesPlus? "Automatic Processing" is the best way to calibrate the images in IP. If you want I can write a small step by step procedure on how to set it up. At least this method has been working very well for me. Please let me know on that.

2- I have a Tracker III. With this OAG you don't need to take the camera out after focusing, not to mention the nice capability provided by the guiding port.

3- I had some lockups in my computer focusing with IP, I never had one using DSLRFocus. Also the workflow and the presentation of the focusing data in DSLRFocus is much better.

4- According to some papers, the highest dynamic range achievable with an uncooled DSLR is obtained using ASA 400, although ASA 800 is a maximum that should be used. Since I read this paper I've been adopting ASA 800 for galaxies and planetary nebulas and ASA 400 for brighter star clusters.

Best Regards,

Fernando

[xelasnave]

I think you can be proud of that shot Mike well done.
alex

[davidpretorius]

hey hey,

all that processing still sounds a lot easier than planetary.............. that is where the real men are!!!

well done mike!