20.08.2018
New aspect: First field trip with the rig
Acquisition:
For this target I met with a good friend of mine right in the middle of nowhere. The goal was to flee from city lights, so we chose what seemed to be a place, right in the middle of german no man’s land. It was the first time I packed the rig into the car and assembled it far away from the known grounds of my own backyard. There are multiple factors involved in doing so: where is flat ground? Where is north? Is the power supply line from the car to the scope long enough? Can we build the rigs right here, or is it property of someone else?
We found a lonesome patch of farmland with a bumpy road, found a flat pace to build the rig onto, found north and Polaris… Then (in the middle of the night) a white van came along. We were like: „What?“ Inside the van was the farmer owning the land we stood on. Seeing us building telescope rigs he was very delighted. He told us that he had suspected strangers to set fires. He encouraged us to carry out our observation as we would thereby watch (and guard?) his property. I… really was surprised that setting fires really is a thing in central Germany. Never heard about that. Never mind. Unfortunately clouds came in and we had to quit the party early around midnight. It was a lot of work for a very short acquisition time. But worth it, because I learned a lot of new procedures while setting up the rig in „unknown territories“.
Was the ride worth it?
No. Despite the cool evening with my dear friend the light conditions weren’t no better than at home. That might surprise you and so it did surprise me. But cities tend to have a very big (!) light dome. We met between two cites. Two domes, one on each side. You really need to drive like 50km to leave the sphere of light of even a medium city. Always check and double check light pollution maps.
Post processing:
The post processing part was interesting. I had (as always) little data to work with. But it was my first globular cluster and a relatively bright target by itself. The main focus was to bring out outer stars of that cluster while not over exposing the core. That target first required the use of masks in GIMP2 to apply changes to the outer stars but not to the core and not to the surrounding background stars.
I did two versions on the first run and later on I tried a third version. I like the third best for it’s natural appearance. The iconic trileg-symbol (Mercedes) can best be seen in the first two versions. Choose you favourite if you wish to.
M13 – 60sec @ ISO800 
M13 – 60sec @ ISO800 M13 – 60sec @ ISO800
Tech data:
- Scope: Skywatcher 750/150 PDS
- Camera: Olympus e3
- Unguided image
- 18 x 60′ lights
- 10 x 60′ darks
- @ ISO 800
Conclusion:
Doing things away from home is challenging. You need to double check everything in order not to forget something important. Check light pollution maps for good places first! Plan your target and… Better ask the owner of the land you want to build your rig onto, whether that’s OK beforehand! 😉 A: „Get off my ground!“ tends to shorten the evening. But an evening in a very dark location must be unforgettable!
Greetings,
Chris