Herzy

https://docs.google.com/document/d/1bG-1YK96-D0icRRkbd3xmruZznbGDf7QQu7zbk0_kao/edit I wrote this as a a chapter in a much larger astrophotography guide a while back. It’s a guide to deciding on your optical tube/camera/mount/locations for your imaging session. I created several illustrations to help visualize my explanations. I wanted to share in hopes it helps some other people interested

I wasn’t referring to noise by calling a higher bit depth ADC ‘superior’, I was referring to the color range. Higher bit ADCs have less color banding and less banding between brightness values, giving a smoother overall image. Does it not?

You’re correct about the broadband targets showing up in the green channel, and I should change the wording of that section, but my point was simply that the standard Bayer matrix has 50% green pixels, 25% red pixels, and 25% blue pixels. Later I compared that to a filter wheel over a monochromatic sensor, showing how every pixel is operating at maximum efficiency rather than being constricted by color filters. I don’t claim this to be perfect, and I appreciate the corrections. It’s a very complicated topic.

Pixel non-linearity in a CMOS sensor refers to internal ADC’s performing separate conversions at each pixel site, whereas the CCD performs all operations through a single external ADC. CMOS sensors will have more uncertainty/noise due to this, but they will have lower readout times because not ever charge has to pass through the same ADC. Because the CMOS sensor has built in ADC’s at every pixel they are usually only 12bit, whereas CCD sensors can get away with higher quality 16bit ADCs. Amp glow isn’t exclusive to CMOS, you’re correct. But it is more prevalent, due to the more compacted and complex circuitry at every pixel site. I hope that clears some of it up

The Ultimate Fireworks: In this picture, we see the death-throes of a long-dead star. A star’s core is an environment with pressure and temperatures sufficient to ignite nuclear fusion. Nuclear fusion is a process where atoms are fused into heavier elements, releasing enormous amounts of energy. A star maintains stability between nuclear fusion and gravity with a delicate balance of nature, so vital to our existence. Hydrogen nuclei are fused into Helium, Helium to Lithium, Lithium to Beryllium, and so on down the periodic table until a critical point. After Iron, the fusion process loses efficiency, disrupting the delicate balance between gravity and nuclear fusion. In a fraction of a second, the star implodes, sometimes reaching 25% the speed of light in a spectacular supernova. The energy released from the collapse jets out the star's outer layers - dumping millions of tons of heavy elements into the cosmos. These fireworks often outshine the entire galaxy they live in. A New Chapter: In this picture, we see gas clouds shaped by the ferocious solar wind. Structures like these form from the remnants of countless ancient supernovae who sacrificed their elements and energy. While staring into the core of this nebula, you are seeing heavy elements coalescing into pockets of high density. The heaviest among them can be classified as protostars, kick-starting the life-cycle once again. Once these protostars reach critical pressure, nuclear fusion is again ignited. A new generation of stars are born, each hosting a variety of orbiting planets. I derive a deep sense of connectivity from the fact that every atom other than Hydrogen in your body was forged in the core of long-dead stars. Thanks to these stars, the universe is a fertile environment, brimming with the key ingredients for life. This gives me an almost spiritual sense of harmony with nature. Not only are we in the universe, but the universe is in us. A Snapshot in Time Galaxies are some of the most awe-inspiring and grandiose objects nature has to offer. The Whirlpool Galaxy (M51), seen above, is nearly 23 million light-years from Earth. The light emitted by this galaxy endured 31,000 millennia of a journey across space and through time before coming to a rest on my sensor. When staring into this image, you see a freeze-frame of many million interstellar collisions and explosions, birthing new generations of stars to replace them. You are seeing planets evolving, enormous gas clouds coalescing, black holes devouring, and potentially even civilizations happily living without ever knowing of human existence. When staring into the heart of this galaxy, you glimpse into the life of countless solar systems. You are witnessing cosmic evolution at the most colossal scale - It is a snapshot in time

deleted

Over the years I’ve been collecting my knowledge on Astrophotography. Here is a section I wrote. I hope it is helpful, though I don’t claim it to be perfect. Any corrections are welcome. I also created all of the illustrations myself.

Would you mind posting the stacked file? I had a similar issue last night on my M51. Big dark spot in the middle.

This is what I've been doing recently. I've been filing through the top t-ring, but i can never get all the way through I without damaging the threads of the adapter underneath.

I have already unscrewed the screws for the top part of the t-ring as suggested. It makes it even harder to get a grip on the metal to turn. It has been taking a WD40 bath for the past 12-ish hours. I'm hoping that might help. I tried the heating thing last night, but I only did it once. I'll try that again if the WD40 doesn't work. I don't think it is a left hand thread. When I get it out of the WD40 I will make sure, but I'm almost 100% sure that it isn't. I'm thinking of taking it to some sort of camera repair shop to see what they can do for me.

I've already tried the WD40, but that oven and freezer thing might be a possibility. I've tried freezing them, but they are both made out of the same metal so they will contract at the same rate. Would that method still work if they are made of the same metal?

I think there may be some confusion. The adapters are not connected to the telescope. The adapters screw in to the telescope extension tube like the picture shows. Could you elaborate? I don't think I fully understand. They screw together, so if anything, that method should make it worse. It could mess the threads up and make it impossible to unscrew. Unless I'm missing something? I hope the pics help. Hayden

Just about a year later and I still haven't got these adapters apart. I've literally turned to the point of bleeding. I've tried the shoes approach as well. Celestron doesn't make the scope anymore, so they can't really help me.

You've far surpassed whatever results I can achieve, but I still like to go back on my alt/az every once in a while for the ease of use even though I have an AVX. Good luck!

Has anyone been able to capture the comet out now? It's up in the morning or so I've heard.

Thanks. Ken's images makes the actual nebula look great, and Ian's has great detail in the dust. If I may, I might blend the two together. I did take darks (no bias), but I only took 9 so i thought it wouldn't make a big difference and didn't apply them. Also, I checked out the flats and there is that green gradient in it. I'll try to take another set, although it might be too late.

https://www.dropbox.com/s/30y7o9zhegesrdl/M42 - Stacked (DSS).fts?dl=0 Here is the Stacked fits file. You can layer a stretched version and a less-stretched version to preserve the core. If you want to give it a go, please do.

I think it might be the flats because I took them in a rush (it was freezing out there). I also suspect the masking introduced noise. I will try combining the fully stretched file with one that only stretches the core. That way, there will be less noise.

Don't mind at all! You made the faint dust really pop! It is a little oversaturated, but that's an easy fix. When I get home from school I'll link the full stacked file so you can give it a go. You'll see that the core is way overexposed. The layering helped a lot.

I took this on Saturday with the clubs SE mount and an AT72ED from a dark site. I can't get the core to look right. The nebula was so bright even in 45s subs that it appeared all white. I layered some old pictures I had over it to make it more visible, but it still is blown out. I also don't like the blurred feeling to the image. Seems like the detail is all blurred.

What camera are you using? That's incredible. It looks better than several hours of normal broadband imaging from my house, and it's only a single sub.

Nige, what are you going for? are you going to keep moving towards the pleiades? Great image(s) btw!

As a follow-up of my horse-head questions, I'll show what I managed tonight. There were a TON of wispy clouds, as you can probably see from the light leakage from Altinak. Stars, no matter how bright, never spill out like that for me, so the clouds must have spread the light out. Not only that, but I would guess that the image was blurred significantly from them. Anyways, here is 24 minutes on the HH nebula. My frames from last night (with no clouds) were much crisper, but I didn't take many of them. I'm excited to try this out with a few hours of integration soon, this time with no clouds! BTW, my AVX mount counterweight is nowhere to be found (how in the world did I manage to lose a counterweight.....??????), so I'm back in business with my SLT mount. Surprisingly, it works well with my AT72ED and handles the weight well, which I never thought it could.

Interesting.... I stretched my files and it wasn't at all visible. Not to worry, though! It turns out there were some wispy clouds over where I was imaging because all of my pictures for that 15 minute period (including the only pictures I took of the horsehead) are washed out.