Astrophotography is all about passion, patience, and perseverance. Whether you spend 2 hours capturing multiple shots of the Milky Way, creating a star trail, or spend a whole night integrating 10-12 hours’ worth of the nebula or galaxy, these three things would help you push the boundaries. Jeffrey Horne, an astrophotographer from Nashville, TN, seems to have “a lot” of these virtues. He spent 569 hours over 147 nights to capture one image – an image of the Spaghetti nebula. And he managed to include a guest, the red planet, Mars. In this article, we speak to Jeffrey about his journey and the behind-the-scenes of his image.
1. What made you choose this target of the Spaghetti nebula?
I’ve studied the northern hemisphere sky for years now. I’ve taken some very deep images of some very wide parts of the sky. Out of all of my “exploration”, the Spaghetti Nebula is just my favorite. I love nebulae with wispy filaments, and this one takes the cake for that! It’s really fascinating that this is an exploded star, so what we’re seeing with the nebula is actually a spherical shell that is expanding.
2. What made you decide on this extremely long integration time?
I’ve been doing very long exposure times, in the 200+ hour range. I knew I wanted this one to be at least 300 hours, since I’m so enamored with it. I really wanted to do it justice. Halfway through the first winter of imaging this nebula, I realized that Mars was going to pass through my frame. That kinda changed everything, since Mars would make this an extra-special image. That’s when I knew I was going to make this a three-year-long project. I didn’t have a specific number of hours in mind for this…just “as much as I can get in three winters”.
Keep in mind also that this nebula is very dim. I can’t see it all in a 10-minute sub-exposure. It takes quite a bit of data to even be able to see any of it, especially from my Bortle 8-9 sky.
I did whatever I could to get as much exposure time as possible. I set up my rig on cloudy nights if there was a decent chance that the clouds would clear at all. That meant that some nights I might have only gotten 1-2 hours, and some nights, nothing. Of course, some nights were perfectly clear and I was able to image all night. This persistence was worth it to me. Every little bit adds up!
3. Could you take us through the integration phase? What were the major challenges throughout the 147 nights?
Most of the actual imaging process was fairly methodical. Watch the weather, set up the rig if it might be clear at all that night, bring the rig inside in the morning, sort through my subexposures from the night before, and cull the subexposures that have clouds passing through.
The unpredictable weather in Nashville, TN, was probably the biggest challenge. There can be 0% chance of rain in the forecast, and we still might get a pop-up shower that seemingly appears out of nowhere. Rain and astrophotography gear do NOT mix! I searched for some kind of rain alarm…something that would alert me and wake me up if it detected rain. I couldn’t find anything that suited my needs. Only personal weather stations that basically use the forecast and radar to tell you that it’s about to start raining, which isn’t always accurate.
I happened to find a guy, Brian (Astrolips 2000), who had built his own rain detector…he calls it “The Raininator”. I followed his instructions and built my own. That thing has saved my gear over a dozen times already! If a single drop of rain falls on it, my phone and home speakers start blaring country music, which gets my attention immediately!
4. Could you share the processing experience of such a huge amount of data?
Wow. It was a lot of data to process! 463GB. On my M1 Max computer, it took 58 hours to integrate all of the data.
Pixinsight, one of the programs I used for processing this image, is very flexible, but also quite complicated. It was difficult (for me) to figure out how to integrate multiple years’ of data and still include the correct calibration frames for the data from each respective year (fresh flat frames, flat darks, and dark frames were taken each year, since the imaging train/rotation wasn’t perfectly aligned between years, and since the camera sensor characteristics change over time.)
The solution I came up with, which is quite rudimentary, was to use different subexposure lengths each year. That’s why you see subexposure lengths of 480 seconds, 510 seconds, and 600 seconds in my data. This made it easier to assign the correct calibration frames to their respective light frames.
Another challenge was simply taming my expectations. When you spend three years and get over 500 hours of exposure time on one target, your mind really builds up a mental picture of what you think the image will look like. It’s a bit of a mental struggle to realize that after so much time, the final image doesn’t match up with what you’d imagined. This is offset, though, when you start to realize that there are certain very faint structures that are in the image that you can’t find in other images. They are subtle things, but very rewarding.
5. If you were to go back in time (during the integration and processing phase), what changes would you have made in the whole process? (If any)
I think the only change that I would make is to buy a house outside of the city instead of 3 miles from downtown! 🙂
6. What would be your top three suggestions for other astrophotographers wanting to take up such long projects?
- Have patience. It’s a slow process with nothing but delayed gratification, but it’s worth it.
- Be efficient. Setting up every night, even if there’s just a chance for an hour of clear skies, can test your resolve. Make it easier by streamlining your setup process, including cable management, polar alignment, automation, image acquisition, and data importing/culling. When I first started astrophotography, it would take me 2 hours from the time I started setting up until the first real subexposure rolled in. Now, it takes me about 5 minutes.
- Do test integrations along the way. I usually integrate all of my data quite a few times during the course of acquiring data. It helps to see the progress of the image, and by processing the image several times before you’ve acquired all of your data, it gets you familiar with the data and prepares you for processing the final integration.
7. What are your plans for your next long-term projects? Do you have an “integration-time” goal that you would like to achieve?
I don’t have any integration-time goals. For me, it’s more about capturing the faint details that present themselves with long exposures, rather than trying to reach a certain number of hours. This really varies depending on the target and what faint nebulosity I think is present in the image, waiting to be revealed.
What’s next for me? Longer focal length images!
I’ve been doing widefield images for several years now (180mm focal length). I’ve done quite a few very deep integrations of nebula-filled areas of the sky. This means I’ve spent countless hours studying, very closely, the details of these regions. I’ve found certain areas that I absolutely love, and now I want to “zoom in” on those areas and get long integrations on those areas. I recently bought an Askar 120 APO, and it’s all set up and ready to image this summer when the nebulae come back to the northern-hemisphere sky. This will allow me to image at 672mm and 840mm (this also means that for the first time, I’m going to be imaging at a proper imaging scale, rather than being very undersampled.)
It’s quite a big change for me, but I’m so excited for this next journey!
About the astrophotographer
Jeffrey Horne is a Nashville-based astrophotographer whose passion for the cosmos was ignited in childhood by his father’s love of astronomy. By day, he co-runs a flower company with his wife, and by night, he captures breathtaking deep-sky images from his backyard under light-polluted skies. His work has been featured by NASA, Sky & Telescope, Astronomy Magazine, the BBC, and more.
You can check more of Jeffrey’s images on Astrobin and Instagram.
Clear skies!
[All images in this article are by Jeffrey Horne, used with permission.]
