| Object : | M13, Globular Cluster |
| Coordinates/Direction : | RA: 16h41m, DEC: +36o27' |
| Object size : | 20' |
| More to know : |
Wikipedia:
https://en.wikipedia.org/ wiki/ Messier 13 |
| Exp. time : | 28x120 seconds = 54 minutes, ISO1600, dithering mode |
| Image process tool : | Siril, Gimp, IrfanView |
| Processing : | bias flat photometric color cal |
| Weather : | clear sky, Moon, -1o C |
| Comment : |
That was a long time ago I took a photo of the M13 globular cluster with my big refractor.
Nice to see it again. |
| Exp. time : | 27x30 seconds, 58x60 seconds, ISO1600, dithering mode |
| Image process tool : | AstroImageJ, Fitswork, IrfanView |
| Processing : | demosaic, synthetic flat calibrated, hot pixel removed by dithering, level |
| Weather : | clear sky |
| Comment : |
Things start to work now with my new used Pentax medium format lens. Motor focus excellent, auto focus some times.
Problems left to solved, there is some tilt of the sensor because of the adapter doesn't fit very well, project Pentax 645 300mm.
When this problem is solved I have a very high performance lens that have low vignetting even at full frame. |
| Exp. time : | 93x60 seconds, ISO1600, dithering mode |
| Image process tool : | AstroImageJ, Fitswork, IrfanView |
| Processing : | demosaic, synthetic flat calibrated, hot pixel removed by dithering, level |
| Weather : | clear with drifting clouds |
| Comment : |
Now in Mars I have the globular cluster M13 in Eastern direction, we had a clear sky this night and I started up the telescope.
I got a total exposure of 93 minutes, the images in the middle are a bit of focus.
This time I flat calibrated the image with the new tool Flatfield.
It make a synthetic flat frame adapted mathematically to the optics vignetting.
No problem with old flat frames that are not updated to a cleaned sensor, and no problem with reflections in the telescope that destroy the flat frame.
Compare with the photos below.
Stains and dust on the sensor is a big problem, you can see here:
'cleaning sensor' how I fight it (only Swedish). |
| Exp. time : | 62x60 seconds, ISO1600, dithering mode |
| Image process tool : | AstroImageJ, Fitswork, IrfanView |
| Processing : | demosaic, flat calibrated, hot pixel removed by dithering, level |
| Weather : | clear, Moon |
| Comment : |
Globular cluster are one of the few objects that you can catch even if the light pollution is high.
This is the first image of M13 where I have the telescope setup for 910 mm focal length.
Compare with the photos below. |
| Date : | 2016-09-03 |
| Time (UT) : | 19:54 to 20:55 |
| Mount : | Star Adventurer |
| Guide : | - |
| Lens/telescope : | Sigma APO 150mm f/2.8 (set to f/4.0) |
| Corrector/Barlow : | - |
| Field (FOV) : | 13.6x9.1 degree, before cropping |
| Filter : | none |
| camera : | Canon 6D, controlled by intervallo meter |
| Film/CCD : | Raw |
| Exp. time : | 29x120 seconds, iso400 |
| Image process tool : | AstroImageJ, Fitswork |
| Processing : | demosaic, flat, hot pixel removed by dithering, level |
| Weather : | clear |
| Comment : |
Wide angle version, at this photo M13 looks like a bright star.
This photo was taken under the Mariestad Starparty, Under the Stars. We got a very dark night almost free from clouds.
It gave me a chance to do more test with different setting.
This time I lowered the iso setting to 400 to achieve more dynamic.
The image is processed in the AstroImageJ software which I have developed macros to.
It need that I have taken the images with dithering, now I didn't had that possibility with this mount,
but polar align was not perfect so I got some kind of dithering, enough to get rid of the hot pixels.
The Sigma 150mm APO 2.8 give me very sharp stars compare to other lenses I have.
And it will be better when I have practice the polar align process better. |
| Exp. time : | 33x120 seconds, iso800, dithering mode |
| Image process tool : | Fitswork, Irfanview |
| Processing : | crop, level, no cal dark&bias, only dithering, crop |
| Weather : | clear |
| Comment : |
A new shot on M13, no calibration, only dithering to get rid of hotpixels. |
| Exp. time : | 60x60 seconds, iso800 |
| Image process tool : | Fitswork, Irfanview |
| Processing : | resize, level, no cal dark&bias, only dithering |
| Weather : | clear, full moon |
| Comment : |
First shot with my Canon 6D on M13. |
| Comment : |
A zoom in to the core of M13, pixel 1:1 relation.
In the future I will use the dithering technique as an alternative to dark&bias calibration.
It doesn't work perfect today, but I will test out the settings to get it to work better.
The sharpness wasn't perfect this time and the full moon also disturb, |
| Exp. time : | 43x60 seconds, iso800 |
| Image process tool : | Fitswork, Irfanview |
| Processing : | resize, level, cal dark&bias |
| Weather : | clear |
| Comment : |
An easy shot even under my light polluted area. |
English
(click on the image to get a full resolution photo in a new window)
(click on the image to get a full resolution photo in a new window)
(click on the image to get a full resolution photo in a new window)
(click on the image to get a full resolution photo in a new window)
