Walking in downtown Krakow at 19:00, I couldn’t see more than 30 meters ahead. It was snowing so hard that the street lamps were struggling to cast their light on the walking paths below. It was totally awesome and reminded me of home. This doesn’t exactly set up a post about taking astrophotos, but I know this squall was just the last gas of a storm system holding on for dear life. By midnight, there wouldn’t be a cloud in the sky. It was a really weird night for astrophotography.
I was doubly blessed this evening. I managed to enlist the help of my youngest son. A 10-year-old bundle of pure energy. There isn’t any moment of peaceful silence that can escape his penchant for filling the void. But I love the curiosity and his desire to be involved. I made the decision to test the Bahtinov mask tonight because it was starting to get late and the temperature had already fallen to minus 5 Celcius.
Comfortable Astrophotography
The plan was simple: Set up the tripod on the back porch, connect wirelessly to the camera, dial in the focus using the Bahtinov mask, and then rip off several hundred photos. We’d need to reframe our target every 100 – 150 photos so we set the camera up real close to the back door. Therefore, we could initiate the photo sequence from inside our warm home and reframe the target in between sequences. It was a rather fun and comfortable way to photograph tonight.
We decided to photograph Orion. It was in a nice position in the sky and it’s always a fun target to photograph. The only issue we are going to have is that from our vantage point, we’re photographing Orion when it’s sitting directly behind Krakow. I’m not crazy about shooting directly into the worst of the light pollution I have from our home, but beggars can’t be choosers.
Shooting Configuration
I set the camera up at f/2.8, ISO 6400, and an exposure time of 1 second. Tonight, I want to take both flats and darks to create a good stacked photo. Mainly because it’s my son’s first time out with me and I want him to have something to remember this night.
I popped on the Bahtinov mask and we quickly focused on Procyon which shone brilliantly in the sky tonight. It took no time at all to dial in the focus. One thing I realize now is that the focus photo is a little bit overexposed. I could have dialed the ISO down a little bit for better results. Lesson learned.
With the focus set, we started shooting and ended up taking about 750 light frames. I did pause briefly about halfway through the session to check the focus using the mask again. I found it was still spot on and there was no need for any adjustments. I did let the camera soak in the cold for about 20 minutes before we began so I wasn’t really expecting any issues.
Next, we put the lens cap on the camera and took 50 dark frames. And finally, we used a tablet to take flat frames with the camera in Av mode. Do you know what I didn’t remember to do though? I forgot to take the lens cap off when I took my flat frames. Facepalm. By the time I realized my boneheaded error, I’d probably already compromised my focus as I was putting things away. So I decided to forego stacking with the flats. Oh well.
Processing the Final Image
While it was a rather weird night for astrophotography, we ended up with some decent photos. My son went to bed but I stayed up to go ahead and kick off the stacking and final processing. It took about 2 hours to run through Deep Sky Stacker, and then as usual I did some initial processing in Siril and finished the photo in Gimp.
If I had it to do over again, I probably would have taken the exposure time down a whisker to about 0.8 seconds. Fully zoomed in you can definitely see that the stars are a smidgen oblong. If we can get out again in the coming days that is exactly what I will do.
Next on my list is to get out again with the Lego Star Tracker and tomorrow night should be a good night to try that. Let’s hope the weather doesn’t make it another weird night for astrophotography.