M57 Remastered

This is an image of Messier 57 nebula obtained using frames captured in the night from 16 to 17 of June 2016 with Canon EOS 600D + Canon EF-S F/4-5.6 55-250mm IS II lens (@ 250mm; F/7) fixed at EQ5 motorized mount.

The nebula is a remnant of a star, which ended active life and expelled its outer layers. A core of the dead star -- a white dwarf -- could be hardly distinguished in the center of the nebula.

Greenish color of the nebula is caused by double-ionized oxygen; a reddish color of outer layers corresponds to hydrogen and ionized nitrogen. A density of glowing gas is very small yet many times denser than interstellar medium.

Estimated size of the nebula is about a light-year, a distance to it is ~2300 light-years.

The previous image was made using DeepSkyStacker: good yet not perfect program. This picture (which is definitely more realistic) is a result of stacking of 40 frames (30s exposure each) using FITStacker program. Images were calibrated and aligned using IRIS (15 offsets, 15 darks, and 15 flats were used for calibration).

M51 "Whirlpool" Remastered

A double-galaxy in Canis Venatici

This is a result of stacking frames captured during two nights: from 8 to 9 of Jul + from 13 to 14 of Jul. Signal-to-Noise ratio is somewhat better than in the previous image.

A pair of intensively interacting galaxies are in the image; it is supposed that the main galaxy and its smaller companion have already passed by or through each other. The smaller galaxy (which probably was an ordinary spiral) has lost its arms and is significantly disrupted.

Canon EOS 600D + EF-S 55-250 f/4-5.6 55-250mm IS II + EQ5

102 light frames in total (98*30sec + 4*120sec)

Last edition on 2016-07-16; IRIS: calibration, stacking using FITStacker12; postprocessing: FITSwork4, RawTherapee; noise reducing: Noiseware Community Edition

The galaxy is located near star Alkaid of Ursa Major. Borders of the picture are depicted in the following photo (which I captured in Spring of 2014):

M51 "Whirlpool" Galaxy

M51 "Whirlpool" Galaxy in Canes Venatici, at a distance of about 30 million light years from us, is swallowing its smaller companion.
The companion probably was an ordinary spiral galaxy before the clash, now it's lost many of its stars and interstellar clouds (a portion of them created a faint bridge between galaxies).
The main galaxy is smaller than our own Milky Way (is about 2/3 of it) while it is brighter because of many hot young stars have been forming as a result of the collision.

Canon EOS 600D + EF-S 55-250 f/4-5.6 55-250mm IS II + EQ5.

49 frames by 60sec, f/7, ISO 800; 15 darks, 15 bias, 15 flats. The picture is cropped. Processed with IRIS, FITSwork4, RawTherapee.

M101 "Pinwheel" Galaxy

Messier 101 "Pinwheel" Galaxy in Ursa Major

This is one of so-called "grand-design spiral galaxies" with well-defined spiral arms. The galaxy is located at a distance of about 20 million light years, it is somewhat bigger than our Milky Way. An estimated number of stars it M101 is about 1 trillion.

Two dwarf galaxies are also seen in the photo: NGC 5474 in the upper-left corner and quite dimmed NGC 5477 to the upper-right from the M101 (see an annotated picture beneath). They are both gravitationally-bound satellites of Pinwheel.

The image was obtained using Canon EOS 600D camera with EF-S f/4-5.6 55-250mm II IS lens @250mm and f/6.4. The camera was fixed on an EQ5 motorized mount.
52 individual frames (60sec each) were calibrated and stacked using IRIS (13 offsets, 13 darks, and 13 flats were used). FITSwork4 and RawTherapee were also used. The image is cropped.

M13 Globular Cluster in Hercules

Globular cluster M13 captured using Canon EOS 600D + EF-S F/4-5.6 55-250mm @250mm and F/7. The camera was put on EQ5 motorized mount.

The cluster's diameter is about 145 light years; it is composed of about half million stars and is distanced more than 25000 light years from Earth (according to Wikipedia).