NGC 5139 – Omega Centauri, the largest globular cluster of the night sky, but only visible from the southern hemisphere. Would it be a good target to test new gear?
My new gear
In July I bough a Canon T6i and a field flattener for my Long Perng S400M-C 66mm f/6 refractor . I was so excited with my new gear that I took some pictures, did a basic processing and then totally forgot to publish it.

I choose this one as my first test by two reasons. First one, I have already taken a picture of this globular cluster with my old Nikon D5000, and it would be a good comparison.
Second, this is an easy target, but this field full of stars is a good way to measure focus and focal plane correction. Besides, there are some faint galaxies around NGC 5139 that only a good exposure could solve.
The differences are huge. My Nikon D5000 have 12.3mp, and my new Canon T6i have 24mp. Twice the number of pixels. This mean that now I’m closer from the correct arcsec/pixel ratio for my telescope, but also means that my computer strugles a lot more to pre/pos process the images.
At the same time, now I can use almost all the field of view of the image, thanks to the field flattener.
The night didn’t help
I wanted to make at least 4 hours, with frames of 180 seconds. But I knew the clouds would came fast. Then I stayed with 60s frames.
My bortle 6 skies don’t wan’t to help, and my optolong L-Pro still didn’t arrived.
The results: NGC 5139 – Omega Centauri
Oh my, I love this giant!

Setup:
- Telescope: Long Perng S400M-C 66mm f/6 refractor
- iOptron CEM25P with a 2″ tripod
- Câmera: Canon T6i
- Field Flattener for short refractors
- ZWO 60280 Finder and Guide Scope and QHY5L-ii Color for guiding
EXIF:
- 88x60s
- ISO 1600
- DARKS: 100
- FLAT: 50
- BIAS: 150