This is M16, the Eagle Nebula, taken from Palomar Mountain. As usual, I wish I could pick up more colors in my astronomy photos, but the reds usually overwhelm everything else. I'd need to do multiple exposures with four different filters to really pick up all the colors, and that's both expensive and time consuming. Maybe someday.
The second photo is an enlarged (and rotated) view of the center of the nebula. This is the part of the nebula known as the "Pillars of Creation" thanks to a famous Hubble Telescope picture of them. Click the link to see the difference in resolution between the Hubble and my telescope. It's, um, a lot.
The detailed picture also provides a good look at my guiding problem. As you can see, the stars are slightly oblong, which means my telescope isn't following the sky precisely. I'm still not sure why. It's also odd that the stars are so far out of round but the picture itself is fairly sharp. That doesn't make sense to me.
Dude. I'm a professional stargazer and this is really amazing work.
Even small guide errors or a slightly off polar alignment (assuming you're using an equatorial mount) can cause elongation in the stars. My half-asked guess would be that you had some short-lived variation, causing the bright objects to elongate but leaving the fainter stuff OK, e.g., your PSF was off enough to show up for bright objects but is lost in the noise for faint ones. But I'm be curious to hear from others who do astrophotography way more than I do.
Whatever the cause, this looks great.
Hal_10000 is correct on all points. That is a fantastic picture, and the elongated stars are pretty minor, considering the challenges of tracking stars from a movable platform.
I design optics and precision mechanical stuff that goes into space, and yes, the bright stars will record errors due to imperfect gears and/or polar misalignment and/or bad seeing, while the same errors on dimmer extended objects will be lost in the noise, as Hal_10000 said.
Even the best gears have errors, and it doesn't take much of a breeze to shift your scope off axis for a short time. The remedy is to:
1. do away with gears,
2. stiffen your tracking system,
3. track using a guider (preferably off-axis, not a separate telescope, because of the inevitable differential bending between the two scopes), and
4. reduce the wind resistance of your scope.
You probably don't want to fold your refractor, so solution #4 is out.
Solution #3 just costs money. They sell cameras with built-in tracking chips.
Solutions #1 and #2 basically mean buying a better mount.
A good, medium-sized mount that is stiff ideally uses a friction drive. Almost all professional telescopes use direct drive motors, where the drive coupling is a magnetic field with encoder feedback, but there are no good solutions being offered to amateurs in mounts of this type. The ones I have used have not been very stiff. The practical solution is to go to a friction drive.
A very good friction drive mount is made by mesu, but it really isn't portable. It is, though, the ultimate mid-size drive solution, until you win the lottery and can buy a DFM scope. Which also isn't portable.
https://www.dfmengineering.com/news_telescope_gearing.html
In the meantime, your photos really are terrific.
Oh, one other thing. I assume that you are taking multiple images and stacking. If so, you can probably reject the few images with elongated stars.
The last sentence in the linked NASA page sheds some light on the discrepancy in resolution between yours and theirs:
"A large telescope and optimal viewing conditions are necessary to resolve the Pillars of Creation."
I think you shouldn't sweat the difference. Your budget is not quite up to theirs.
Mr. Drum, Ken Rhodes is correct. You are a perfectionist, too hard on yourself, though some people might wrongly assume that you are humble-bragging. Relax & enjoy the compliments for some beautiful results!
A quick calculation puts the size of those "pillars" into perspective.
The outer diameter of the Kuiper Belt surrounding our solar system is about 55 Astronomical Units (AU). A light year equals about 63,000 AU, so the solar system (out to the Kuiper Belt) would be about 1/5,000 of the height of those pillars.
We really are small potatoes in a big pot.
My brain wants to see a dark eagle within the lighted up shining material, but also the whole big shining material can be an eagle, facing right, wings up, legs and feet stretched down as if landing on a branch.
Is the eagle name from the dark eagle, or from the shining eagle, or either/both,I wonder. Google didn’t help much on this.
wow! awesome job!
Round or oval, awesome photo's and I love the colour. Makes me want to enlarge them and put them on my den walls. Good job!
Thanks for sharing with us.
Concur with the others that this is really nice work, Kevin. You probably already know that eccentricity along RA is usually due to periodic error, DEC means polar misalignment. I'd suggest going through the eccentricity numbers and seeing if the problem is common in your subs, or confined to relatively few.
Absolutely spellbinding.
I have a friend who could probably help out. He takes spectacular images.
I don't remember what your are using for image capture, but some cameras pre-scale the raw data. Because the red and blue channels tend to be lower signal, that signal is increased in the raw data.
Try using a SeeStar and see what you get. My friend calls it a gateway drug for astrophotography.
Not the astro camera Kevin is using. Good thought, though.
I won't speak for Kevin, but speaking *of* him, he's way past the SeeStar stage.