Tonight's attempt. Best 24 of 30 x 100 second subs. Cheap DSLR through ED80 unguided. Darks, flats and bias applied, stacked in DSS, edited in Lightroom.
Meh... don't like it much.
I think I need to read some books or something. My processing & editing isn't really moving forward because I simply don't know what I'm doing. I feel like there are fundamental things I need to know rather than just doing random or default things in DSS. Feeling a little deflated because it's not really a step forward.
Having said that, it was fairly low in the sky over the brightest part of the horizon from where I live; most previous targets have been a lot closer to the zenith or at least to the east which is out to sea. Maybe I'm not accounting for light pollution and how much that can ruin data, haven't dealt with much before as it's pretty dark here.
Anyway! Any critique, suggestions and book/website recommendations on how to really get a proper grasp on basic processing would be extremely welcome. Thanks in advance.
Last edited by thegableguy; 10-05-2016 at 10:35 PM.
Reason: Added second edit
Hi Chris, I notice that you keep referring to your cheap DSLR. It doesn't
matter whether you paid $350 or $1350, you won't see much difference in your results, although DSLR sensors are getting quieter, so newer models are better. Stunning results can be obtained from any DSLR given enough skill, talent, and commitment.
A damn good book is Photoshop for Astronomy by R. Scott Ireland; it
comes with a CD of tutorials. There are many tutorials on the internet dealing with all the different aspects of processing.
raymo
Hi Chris,
Why not concentrate on the positives rather than the negatives. There's wouldn't be one of us in this game that hasn't felt deflated or frustrated at times but I've never thought that I've not made some progress. It's a learning curve that can be steep at times.
I was told on the weekend that astro-imaging is 40% imaging and 60% processing and I think that's pretty true.
Your image taken under the conditions you mentioned isn't that bad. Considering it was unguided the stars are round and no vignetting that I can see. It's a nice wide field shot and a person more advanced with processing will get more out of it.
As Raymo said have a look at the online tutorials. They'll help a lot.
Keep at it, most of us have probably had more failures than successes but that's the nature of the game.
this is actually a tougher subject than most people think. the dynamic range of the tarantula is pretty extreme. and actually when using an unmodified dslr on the tarantula it is actually difficult to get much colour at all in fact very little red and some green if stretched a lot. I think you are comparing your shots to modified dslrs.
so if there is any improvement I would consider modding the camera to allow more Ha onto the sensor. perhaps try to shoot some galaxies /globs or planetary nebs where the Ha is less important and you'll be able to compare your images more closely and will then notice that your results are consistent with un modded dslrs. (although Justin Tilbrook is the king of the unmodded dslr somehow he manages some fancy processing to punch out some more red).
Not actually comparing my results to any others - I deliberately haven't really looked at many amateur shots of it, which for some reason is how I prefer to do it first time. I like seeing which way the data goes and following it to an aesthetically pleasing result. Unfortunately this particular data didn't really go anywhere...!
Think I need to spend a lot of time on the aforementioned tutorials and reading before getting back out there for more shooting. Ta for the book tip Raymo, I'll see if I can track down a copy.
Re the cheap DSLR, I'm mainly saying that to distinguish it from a CCD or OSC, but I'll be trying a pro DSLR next time I image just to see what difference there is, if any. I'm fairly unimpressed with the D3300 for normal daylight photography - it's noisy as hell and its colour rendition is only so-so, not to mention the lower bitrate NEFs, so it would surprise me somewhat if a better body didn't improve at least some aspects, dynamic range and noise being the main two I'll be testing. Main problem though is losing the crop factor & magnification. Anyway we shall see!
Chris, looks a bit like you're clipping the black end of the histogram as that field has lots and lots of stars, and it should look a bit more like a star field. Nice effort all the same.
The moral of the story, echoing that above, is that it doesn't matter what you use, it's up to your skill to make the most of it. It's all possible.
Regarding crop factor and full frame...your focal length doesn't actually change with crop sensor/full frame, it's just that the FOV is that much larger with full frame. It's not quite the same thing. Assuming pixels of the same size in each camera, the angular resolution is the same with the same scope.
Chris, looks a bit like you're clipping the black end of the histogram as that field has lots and lots of stars, and it should look a bit more like a star field. Nice effort all the same.
The moral of the story, echoing that above, is that it doesn't matter what you use, it's up to your skill to make the most of it. It's all possible.
Regarding crop factor and full frame...your focal length doesn't actually change with crop sensor/full frame, it's just that the FOV is that much larger with full frame. It's not quite the same thing. Assuming pixels of the same size in each camera, the angular resolution is the same with the same scope.
I saw that thread. Very interesting! I can't claim I understand much of what people were saying to be honest, but it was interesting to see the sharpest image come from the cheapest camera.
Yeah the star field thing - all I had at the lower end was light pollution and noise. There was simply no data there. Changing the curve just made the entire sky a wash. I tried stretching it but a) I don't really know how, and b) I honestly don't think there was anything to be stretched anyway.
And yep I understand the difference between focal length and FOV. I had a lengthy argument with my Dad about it recently; he was convinced that they were the same thing and I had to draw diagrams and get various lenses on two different cameras to make my point. But the fact remains that because both cameras are 24MP, on a full frame the fine details will be somewhat smaller.
Totally agree that the challenge is working within your means and exploring the limits of your equipment and abilities rather than bemoaning the lack of some other bit of gear. I guess that means for this particular image I need to explore ways to shoot and process to help eliminate light & atmospheric pollution... just not sure how that can be done with my very basic setup without spending more money. Can't spend any more right now.
Having said that, it's hard to know where to look for further development right now. With 510mm unguided and a stock DSLR it feels like after the usual suspects (Orion, Carina, Tarantula, Lagoon nebulae; Omega Centauri; Southern Pinwheel) I'm kinda just running over the same old ground. I need some sort of guidance as to what I need to do to improve but I'm at a bit of a loss as to what that is. I can do those targets again, and probably will, but I can't expect different results if I keep going about it the same way.
Anyway. This current disappointment notwithstanding, it's still pretty amazing stuff as far as I'm concerned. 600 light years wide, 160,000 light years away, stars over 100 times the mass of the Sun - how can I possibly be bummed for long with those sorts of figures??
Had another shot at stacking without darks, and a completely different edit. Still a bit crap - I can't really decide if it's an improvement. I think it is but the noise is pretty distracting.
I also know that my editing will get better; when I first got into photography I did what everyone did and just crank the contrast / clarity / saturation to silly levels, took years to temper it all to a reasonable level. I'm quite sure that's what I'm doing here so give me a year or two to get over my amateurish tendencies and stop making the background black...!!
Don't second guess yourself Chris, astro image processing is a large
subject. An example of this is that the "Photoshop Astronomy" book
that I mentioned has 308 A4 size pages. Just let it come in it's own
good time while you learn all the other facets of astro imaging.
Your latest effort is the best of the bunch, but with relatively short subs with a small scope and a DSLR
it should be green without the blue centre.
raymo
Last edited by raymo; 11-05-2016 at 11:30 PM.
Reason: more text
Had another shot at stacking without darks, and a completely different edit. Still a bit crap - I can't really decide if it's an improvement. I think it is but the noise is pretty distracting.
I also know that my editing will get better; when I first got into photography I did what everyone did and just crank the contrast / clarity / saturation to silly levels, took years to temper it all to a reasonable level. I'm quite sure that's what I'm doing here so give me a year or two to get over my amateurish tendencies and stop making the background black...!!
I think this is better Chris -, I posted the other one to show a more 'correct' colour balance as it had appeared that you had tried to make the tarantula red in the original - perhaps going for a look seen more with nb or modified dslrs.
Chris, I don't see anything to be disappointed about there
The next step up in capabilities will come from imaging at a dark sky, as it makes it much easier to get good signal. You'll also want to be guiding, as that will then limit what photons you're catching.
One of the take-home points of the thread I linked to was that it's beneficial to match the pixels to the focal length. Even though my angular resolution was pretty high, it's still possible to get good results. The cheapest camera had the edge in sharpness and fine detail as it had the smallest pixels. It was also the noisiest. The other cameras gave cleaner output for the same total exposure time. The workaround for that is just to take more shots
For your ED80, it may work out that the crop chip is better suited from a resolution point of view, but you have to balance that off against the signal to noise ratio somehow. There's also the factor of atmospherics...the atmosphere will only show us what it wants to!
