M13
NGC 6205
The M13 globular cluster is one of the largest and brightest in the Milky Way. This ancient, 11.6 billion years old cluster is made up of 100,000 stars and thousands are visible in this picture. It is located 22,200 light-years away from Earth.
In 1974 a radio message was sent towards M13. It will take another 22,150 years for this message to reach its destination.
On two consecutive nights we’ve been imaging M3 and M13. M13 was the primary objective, but we used the early hours of the night when it was not yet in position on the secondary objective, M3.
[pending update]
| Telescope | Skywatcher Esprit 100ED (f/5.5) |
| Filter | Astrodon LRGB Gen2 E-Series |
| Field flattener | Skywatcher Esprit (1x) |
| Camera | QHYCCD 268m, -20°C, Mode 0, Gain 26, Offset 30 |
| Resolution | 3092x2003 (cropped & scaled 50%) |
| Light frames | R: 13/13 (300s), 2/2 (900s) 1:35h total |
| G: 9/13 (300s), 2/2 (900s) 1:15h total | |
| B: 10/13 (300s), 2/2 (900s) 1:20h total | |
| 4h10m total | |
| Flat frames | 16 each (3s) |
| Darkflat frames | 16 |
| Dark frames | 13 |
| Bias frames | - |
| Location | Bolton, UK |
| Local time | 2022-03-26 01:55 - 03:44 (12 light frames used) |
| 2022-03-26 23:59 - 02:57 (26 light frames used) | |
| Image center | 16h41m34s +36°27'31" |
| Field of view | 1°58 x 1°16 (rotation 91°) |
2021 version
We revisited M13 to test some new equipment. This is a pretty raw image; just stacked, some LPC and then stretched, but no Gimp. We could not use an LP filter with this setup (waiting for parts). Technically it was not dark either, only nautical darkness.
In any case, here it is. We are happy with the scope and M13 is spectacular :-D Around the center of M13 there are 1-2 stars in every cubic light-year which is 500x the density of our own neighbourhood. M13 itself is about 22.200 light-years away; while NGC 6207, the bright galaxy to left M13, is around 30 million(!) light-years away.
The image below combines data from two nights.
| Telescope | Skywatcher Esprit 100ED (f/5.5) |
| Filter | - |
| Field flattener | Altair Planostar (0.79x reducer) |
| Camera | Canon 7D Mark II |
| Resolution | 2148 x 1509 (cropped & scaled) |
| Light frames | 169/181, 1m @ ISO 1600, 2h49m in total (out of 3h01m) |
| Dark frames | 30, 30 |
| Bias frames | 24, 28 |
| Flat frames | 29, 32 |
| Location | Bolton, UK |
| Local time | 2021-05-31 00:07 - 02:04 (86 useful frames) |
| 2021-06-05 00:11 - 02:21 (83 useful frames) |
Analyitical results (combined for both sessions)
2020 version
This is a newly published image, taken a year ago with a very different setup; only for comparison.
| Camera | Canon 400D |
| Telescope | Skywatcher 200/1000 Newton |
| Corrector | Vixen R200SS |
| Resolution | 3888 x 2592 (cropped & scaled to 1000 x 654) |
| Light frames | 12, 300s (1h total) @ ISO 400 |
| Dark frames | 10 |
| Bias frames | 10 |
| Flat frames | - |
| Location | Bolton, UK |
| Local time | 2020-05-06 23:13:45 - 00:17:34 |