Nebula
NGC 7000
North America Nebula
|
| Object : | NGC 7000 (Caldwell 20) |
| Coordinates/Direction : | RA: 20h59m, DEC: +44o31' |
| Object size : | 120' x 100' |
| Apparent magnitude : | 4 |
| Distance : | 2.59 kly |
| Discovered by : | William Herschel, year 1829 |
| Find in constellation : | Cygnus |
| More to know : |
Wikipedia:
https://en.wikipedia.org/ wiki/ North America Nebula |
| Exp. time : | 63x60 seconds, iso400, every third dithered |
| Image process tool : | Siril, Gimp, Irfanview |
| Processing : | flat, photometric color calibration |
| Weather : | clear sky, Moon phase 3%, temperature +5o C |
| Date : | 2025-04-25 |
| Image process tool : | Siril, Irfanview |
| Processing : | No Drizzle vs Drizzle x2. |
| Comment : |
No drizzle vs drizzle.
You need a lot of images when using Drizzle technique, 25 to 100 and they must be taken with dithering.
More noise but higher resolution on under sampled images. |
| Exp. time : | 52x240 seconds, iso400, every third dithered |
| Image process tool : | Siril, GraXpert, SyQon, Gimp, Irfanview |
| Processing : | flat, photometric color calibration, Drizzle x1, dark subtraction |
| Weather : | full moon, temperature +5o C |
| Comment : |
So much new toys to play with.
Testing the new 4.1.2 version of Siril.
Includes a new star remover, a tool that remove all the stars and only leave the nebula.
With this I can do much more aggressive image processing.
The fine structure of the nebula can now be seen in more details.
More than 4 hours at a relative dark place let this be done.
Now afterwards I can see that I let the right part of the nebula go away, it's not so easy to see the border between light pollution and the nebula.
The Milky Way is in the background too, which make it even more tricky to separate the nebula.
This time I didn't use the stretch tool VeraLux that have been so popular, the stretch is done in Gimp. |
| Exp. time : | 30x240 seconds, iso400, every third dithered |
| Image process tool : | Siril, Gimp, Irfanview |
| Processing : | flat, photometric color calibration |
| Weather : | clear sky, full moon, temperature +5o C |
| Comment : |
We had a clear sky with a full moon.
Very disturbing but clear skies are not common and we wanted to take more astrophotos, this is a very bright object. |
| Date : | 2024-11-16 |
| Processing : | new flat, photometric color calibration |
| Comment : |
Some problem in the upper part of the photo.
Now I'm sure that is from the off-axis adapter.
I have adjusted the mirror for the off-axis and put on a black tape on the backside to reduce the internal reflections.
Still some problem in the upper part, but better now and even better next time I take a photo. |
NGC 7000, 2024-11-16, VeraLux version
|
| Date : | 2024-11-16 |
| Processing : | Siril and past processing with VeraLux |
| Comment : |
One year later I installed a new version of Siril which included VeraLux.
VeraLux do a Hyper Metric Stretch on the image, something you do at the end of the image processing.
I reprocessed the image with this new tool and I didn't even use Gimp this time, but normally use it for fine adjustment.
Very easy to use VeraLux. |
NGC 7000, 2024-11-07
(Click on image to get one in full resolution in a new window)
|
| Date : | 2024-11-07 |
| Time (UT) : | 19:43 to 21:25 |
| Mount : | SkyWatcher HEQ5, belt modified, low rider |
| Guide : | ASI120 camera with off-axis |
| camera : | Nikon D800, QE=0.56, full frame, 36 Mpixel, 14 bit |
| camera temperature: | - , no temperature sensor |
| Film/CCD : | Raw, NEF |
| Filter : | none |
| Exp. time : | 24x240 seconds, iso400, every third dithered |
| Image process tool : | Siril, Gimp, Irfanview |
| Processing : | flat, photometric color calibration |
| Weather : | clear sky, temperature +3o C |
| Comment : |
Almost a perfect night.
At the upper part of the image can be seen something that shouldn't be there.
I think it's from the off-axis adapter that protrude into the light beam.
It can also be a light leakage, but I think I sealed the optics from that earlier.
I will take better flats to calibrate with later. |
NGC 7000, 2023-03-28
|
| Date : | 2023-03-28 |
| Time (UT) : | 22:57 to 00:08 |
| Mount : | SkyWatcher HEQ5, belt modified, low rider |
| Guide : | QHY5 camera with 200 mm f/3.5 lens |
| Lens/telescope : | Pentax 645 300 mm ED f/4 (set to f/4) |
| Corrector/Barlow : | - |
| Field (FOV) : | 6.8x4.5o (full frame) before crop |
| camera : | Canon 6D, QE=0.5, full frame, 20 Mpixel, 14 bit |
| camera temperature: | About 6o C above surrounding temperature |
| Film/CCD : | Raw, Cr2 |
| Filter : | none |
| Exp. time : | 77x30 seconds, iso1600, dithering mode |
| Image process tool : | Siril, Gimp, Irfanview |
| Processing : | cal dark (const), flatcrop, desaturated, color calibration |
| Weather : | clear |
| Site : | Sweden, Stockholm, Hagsätra.
Bortle 9
Free view Az: 20o to 90o, 165o to 185o, Alt: 20o to 55o |
| Comment : |
It's not many weeks left of this astronomy season.
Desperately I looking fore something exciting to photograph.
In Northeast very low to the horizon I see that the nebula NGC 7000 climbing up.
When I start photographing it it's only 19 degrees above the horizon.
But it's a very big nebula with its 120 x 100 arc min size, bright too with magnitude 4.
Nebulas is almost impossible to photograph when there are heavy light pollution without narrow band filter.
This photo isn't very nice, but I can take a new later when out on a dark place.
This was also the first photo that I processed with desaturate tool in Siril of the over exposed stars and after that color calibrated the stars. |
English
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