Galaxy
NGC 6946
Fireworks Galaxy
|
| Object : | NGC 6946 |
| Coordinates/Direction : | RA: 20h34m, DEC: +60o09' |
| Object size : | 16.2' x 11.2' |
| Apparent magnitude : | 9.6 |
| Distance : | 25.2 Mly |
| No solar mass : | - |
| Type : | SAB |
| Discovered by : | William Herschel, year 1798 |
| Find in constellation : | |
| More to know : |
Wikipedia:
https://en.wikipedia.org/ wiki/ NGC_6946 |
| Exp. time : | 56x120 seconds, 400iso, dithering mode |
| Image process tool : | Siril, GraXpert, Gimp, Irfanview |
| Processing : | flat, photometric color calibration, background, stretch |
| Weather : | Moon Phase 14%, Temperature +4o C, rel Humidity 62% |
| Comment : |
Crop of the inner part of the image.
The galaxy NGC 6946 is very weak and hard to get good contrast on.
I test three different processing methods here.
This one only Gimp for post processing. |
| Date : | 2026-04-13 |
| Image process tool : | Siril, GraXpert, VeraLux, Gimp, Irfanview |
| Processing : | flat, photometric color calibration, background, stretch |
| Comment : |
Here I have used VeraLux which is a script in Siril.
Normally this stretch the image in a good way.
Here it didn't do it better compare to what I did in Gimp. |
| Date : | 2026-04-13 |
| Image process tool : | Siril, GraXpert, SyQon, Gimp, Irfanview |
| Processing : | flat, photometric color calibration, background, stretch |
| Comment : |
More advanced is to separate the stars from the background.
Normally done when the object is a nebula. In this case it's a galaxy, but it's so diffuse that it behave more like a nebula.
I used SyQon which is a script in Siril.
The galaxy is easier to see but very noisy to get a good result.
More exposure needed as always. |
| Exp. time : | 149x60 seconds, iso1600, dithering mode |
| Image process tool : | Siril, Gimp, Irfanview |
| Processing : | synthetic bias, flat, photometric color calibration |
| Weather : | clear, temperature +12o C |
| Comment : |
The galaxy NGC 6946 or Fireworks Galaxy, it isn't far away, 25 millions ly as our other neighbors.
It has some interesting neighbors which can be seen here on the plate solved image:
NGC 6946, plate solved by Astrometry.net.
The open cluster NGC 6939 is one of them.
Great weather this evening and night.
I could get 2.5 hours of exposure.
Maybe this was the last night this season for astrophotography. |
English
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