This is the recurring nova RS Ophiuchi as seen on August 22, 2021. The nova is the redish star in the middle of the image.
OK. Last night I made yet another attempt at photographing M42. This time I took a series of 90 second exposures, got all the needed flats, darks, and bias frames, and processed them with slightly more understanding of how to manipulate photos. Behold!
The red colors are still very faint, and I had to crop the image more than I wanted because of field rotation artifacts. but the level of detail visible is incredible compared to my earlier attempts. I am quite satisfied with this image!
So earlier this month I took a nice photo of M42, but it was an off the cuff event that I really didn’t plan out. Last night I made a second attempt and I was prepared this time. I bought a Bahtinov mask to help me get sharp focus, I took proper dark frames and flat frames, I tinkered with the ISO and exposure length to try and get sharper stars, and I took a lot more light frames so that I could build up a greater total exposure time. I expected to get an image that showed a lot more detail and color. The result? Well, see for yourself.
Huh. It really doesn’t look that much different, does it? Turns out I was working under a misunderstanding. I thought that the combined exposure time of all images used determined how much detail would be visible. Turns out, that’s not the case. Instead, the exposure of a single frame determines how much detail there is, so if you want to see fainter details you have to do longer exposures, just like in the old days of film. So what does adding more light frames get you? After reading up some more to figure out where I went wrong I found out that more frames just improves the signal to noise ratio in the final image. In other words, the final image is cleaner. Compare the new and old images and you will see that the old image shows a lot of “grain” while the new image is much smoother. So the new image did improve in that way, at least!
Also, adding in the darks and flats got rid of the artifacts from dust on the sensor that show up as dark blotches in the old image, so there’s another improvement!
Where do I go from here? The next attempt will be using longer exposure times. Perhaps I’ll go up to a minute per frame. My reading tonight also tells me that I need to be taking more dark and flat frames, as well as bias frames, so I’ll be sure to do that in my next session.
I have also ordered an equatorial wedge so that my telescope won’t have to operate in alt-az mode. I had always heard this was preferred, but I didn’t realize why until last night when I realized that the sky was rotating, while my telescope was not, which means that the orientation of the stars in the images changed as the series of photos progressed. Deep Sky Stacker is capable of adjusting for that, but in the raw stacked image you can see the result around the edges of the stacked image – they show a series of rotating lines where the edges of each individual frame are. Once I get the wedge delivered I won’t have to worry about that anymore.
Last July I bought a nice new telescope – an 8 inch Meade LX-200 – but since then I’ve only really tinkered with it visually. Tonight was a clear night, and I’ve been meaning for months to observe M42, so I set up the scope on the deck in the back yard and took a gaze.
It was beautiful! I’d never seen so much detail before, and for the first time ever I saw all four stars of the Trapezium. And then I thought, what the heck, I’ll take a photo of it. It ought to at least be better than my previous photos.
So I attached my Canon 50D at prime focus, got the focus as good as I could get it, experimented with exposure times a little and settled on 5 second exposures. I took 25 of them. And I took 5 black frames as well because I knew I would need them for the Deep Sky Syacker image processing program I’d tinkered with a while back.
So after packing up, I downloaded the images from my camera and set Deep Sky Stacker to work. I’ve never tried this before and I really don’t know what I’m doing, but as I played with the image I began to see amazing detail. Behold, my first crude attempt at image processing.
Holy Haleakala! (As the Bad Astronomer would say.)
Compare this to my previous best photo taken with a 500mm lens.
I had no idea my little off the cuff attempt at astrophotography could produce such an amazing result with so little effort! To quote Casablanca, “Louis, I think this is the beginning of a beautiful friendship.”
A Visit From Saint Vanduul
The Night Before Orion
Twas the night before Orion and all through the kingship
Not a creature was stirring, not even AI chips.
The loot sacks were hung by the reactor with care,
In hopes that Saint Vanduul soon would be there.
The hatchlings were nestled all snug in their berths,
While visions of entrails filled them with mirth.
And Mama in her helmet, and I in my space socks
Had just started playing “EVA to the airlock”.
When out in the hangar there arose such a clatter,
I jumped from my bunk to see what was the matter!
Away to the gun rack I flew like a racer
Tore open the doors and grab a big laser!
The emergency lights on the newly patched bulkhead
gave a sheen of fresh blood so beautifully red.
Then what to my vengeful eyes should appear
but a minature Scythe, with eight missiles here.
With a little old pilot, so nimble and cruel
I knew in a moment it was Saint Vanduul.
More rapid than lasers his missiles they came
and he whistled and shouted and called them by name
Now Killer! Now Thriller!
Now Savage and Brutish!
On Vicious! On Ruthless!
Inhuman and Fiendish!
Blow up the porch!
Blow up the wall!
Now breach the hull! Breach the hull!
Blast away all!
As dry leaves that before the wild hurricane fly,
so fell our guards in the blink of an eye!
Then up to the landing deck onward they flew
with the Scythe full of loot and Saint Vanduul too!
Then in a twinkling my heart filled with ire
As crawling and clawing my comrades expired.
I drew up my gun and started to aim,
When out came Saint Vanduul – his knife was aflame!
He was dressed all in armor from his head to his foot,
and his body was covered in guts, blood, and soot.
A bundle of bombs he had flung on his back
and looked like Hell’s maw all gaping and black.
His eyes how they glowered! His cheeks full of fury!
His nose was all crooked just like a rigged jury!
His twisted little mouth was drawn up in a snarl
Exposing his teeth, sharp, pointed and gnarled!
The stump of a hand from the bodies he picked him,
and chewed the remains of his most recent victim.
He had a broad face and little round belly,
but the rest of that corpse had been turned into jelly.
I fired and shot and tried killing that horror
but he dodged and turned and he filled me with terror.
A blink of my eye and a twist of his head
and his knife at my throat filling me with dread.
He spoke not a word but cast me aside
called me a weakling and bade me abide.
He filled all our racks with bombs and explosives
and said we should use some gasses corrosive.
He sprang to his Scythe, his engines he gunned,
and away then he flew, for he knew he had won.
But I heard him exclaim ‘ere he flew out of sight
“Happy slaying to all, and to all a good night!”