November 19th, 2021, 2:14 a.m. local time
One of my most "popular" blog posts is of the Orion Nebula that I took in 2018, nearly four years ago. Popular, as in, it gets one or two Internet searches every one to three days. What I wrote back then still applies, that this type of photo represents the limits of my astrophotography equipment. Dobsonian telescopes are intended for observation and not photographing. So when it comes to deep sky objects, like M42, you can start to see noticeable issues, such as the exaggerated star trails, which are difficult to hide with most reasonable exposures (say, in the 0.2 to 0.5 second range).
To take truly good images of nebula, star clusters, and even galaxies, a telescope geared towards astrophotogrphy is needed, along with an equatorial mount that tracks objects with the Earth's rotation. And, of course, a camera designed for long term exposures with thermal cooling.
It is for these reasons that I normally stay away from close-up deep sky images. My equipment is better-suited for wider field views, such as my Orion Nebula image direct from my digital camera in 2020. The wider the view, the sky rotational issues are masked with the correct exposure lengths, which can be calculated from the lens size.
So why did I take this picture? It was on the night (morning) of the Lunar Eclipse. The sky was clear, and though my target was the Moon overhead towards the West, Orion was center-stage from my vantage. At 2 a.m. I did not want to retool my equipment for the entire constellation, but decided that a quick turn of the telescope towards Orion's nebula wouldn't hurt.
The setup for this image is nearly identical to how I took the M42 image in 2018. Same Dobsonian telescope. Same 2-inch eyepiece. The main difference is the phone camera. In early 2018 I still had my Samsung Galaxy S7, and it was much later in 2018 when I got my iPhone XS, which I still have.
I did a variety of touch-ups in PaintShop Pro to tweak the above image's sharpness, brightness, and contrast.
Speaking of my iPhone, that may be a topic for another time. My XS is over three years old now. It still works fine. But the time will inevitably come when I have to upgrade. Because I frequently use my phone for afocal photography at the telescope, I am worried about how the more recent iPhones' camera bulges from the back will impact mounting against an eyepiece. My tentative plan is to get an iPhone 14 late in 2022, so I have a year still to figure out how the purchase may impact my astrophotography.
Telescope and photography settings:
- 254mm Dobsonian (homemade)
- Exposure - not captured by NightCap
- ISO - not captured by NightCap (approximately 800-1600)
- Q70 32mm eyepiece (2.00″)
- iPhone XS with NightCap app on eyepiece mount
- Touchups in PaintShop Pro