Archive for Rebel XSi

Milky Way Time Lapse with Canon EOS 450d

Posted in Astrophotography with tags , , , on 2012/06/18 by computerphysicslab

Milky Way rises by the East. Sagittarius on the left and Scorpius on the right.


Bright nebulae at Milky Way core

Posted in Astrophotography with tags , , , , , , , , , , , , on 2011/07/04 by computerphysicslab

Summer views of Milky Way are spectacular because the galaxy bulge is brighter and broader than its spiral arms visible the rest of the year. Located near Sagittarius and Scorpius constellations, the bright nebulae and dark lanes of the area creates a beautiful contrast in brightness and colors.

This picture is a 4-pane mosaic ensambled with free software Fitswork 4.40. Every pane is a 10 minutes exposition through a 55mm lens attached to a Canon EOS 450d (Rebel XSi) DSLR camera, mounted over a motorized equatorial mount, Sky Watcher EQ6.

Mosaic - Sagittarius Scorpius - Milky Way core

A full resolution picture is available at AweSky

EQ6 periodic error

Posted in Astrophotography with tags , , , , , , , , , , , , , on 2011/04/06 by computerphysicslab

I took a bunch of 30 seconds shots aiming M42 nebula as regular, in order to stack them later. Polar alignment was also regular, using EQ6 polar scope, probably not perfect.

I think M42 is a good target to measure periodic error in RA movement due to its near 0 degrees declination.

In order to show the drift, I stacked the shots without drift correction using a free software called startrails that gets the brightest pixels per shot, obtaining that way the best startrail you can achieve.

To measure the length of the drift, I requested a single shot solved plate from They provide an exact width in arcminutes of the field. Then, I divide the width field by the width in pixels of my DSLR camera sensor, obtaining the resolution per pixel in arcseconds (a number close to 1 arcsecond/pixel for a 1,200 mm effective focal length telescope).

Then I measure the height of RA drift pattern with my regular post-processing free software, Fitswork4, and multiply that value by the previous resolution.

That is the way I have found that my EQ6 mount drifts around 40 arcseconds in RA movement. Dividing total exposure by the number of cycles (top peak to lower peak) I got the elapsed time needed to fulfill the periodic error: around 6 minutes long.

Mare Crisium and Palus Somni

Posted in Astrophotography with tags , , , , , , , , , , , , on 2011/02/28 by computerphysicslab

Mare Crisium is one of my favorite Moon areas. There is a lot of details inside Crisium, but it is not easy to detect, because it is very fine. High aperture telescopes are needed to spot the small impact craters inside this maria, because its typical lengths are 1 or 2 kilometers wide.

Near Mare Crisium there is another big area called Palus Somni (below), that is visible in this picture made with an amateur telescope. The big and bright crater in the middle is Proclus:

The telescope used is a Celestron Nexstar 5SE and the camera is a Canon EOS 450d (Rebel XSi) DSLR. The picture actually is a mosaic made of two panes.

Sharing raw footage of Jupiter and Saturn

Posted in Astrophotography with tags , , , , , , , , , , , on 2011/02/11 by computerphysicslab

On 2011-02-06 I  took some videos of Jupiter and Saturn through a (4 inch) 102mm apochromatic refractor telescope. Applying Registax I got the results of the picture.

I’d like to share these two videos with anybody interested in playing with them:

Capella, the brightest star in Auriga

Posted in Astrophotography with tags , , , , , , , , on 2010/10/02 by computerphysicslab

Capella is the brightest star in Auriga constellation. It is very easy to spot in the Northern hemisphere. It is a circumpolar star, very bright one. The picture has been taken through a 300mm telephoto lens and Canon EOS 450d over a Sky Watcher EQ6 equatorial mount.

Here it is the full frame, with a lot of stars in the field and great detail:

M57, the Ring Nebula

Posted in Astrophotography with tags , , , , , , , , , , , on 2010/09/21 by computerphysicslab

The Ring Nebula (also known as the Planetary Nebula M57, Messier 57, M57 or NGC 6720) is a prototypical planetary nebula in the constellation of Lyra. This is one of the most famous nebulae often used as an example of this type of astronomical objects. It is located at 0.7 kpc (2300 light years) from Earth and was discovered by Antoine Darquier de Pellepoix in 1779.

Their joint magnitude V-band (green filter) is equal to 8.80. Its real form is possibly a bipolar nebula seen with an inclination of 30 ° from its axis, and calculated that it has been expanding around 1600 years.

From their radial velocity, -19.2 km/s, it follows that approaches Earth more than 69120 km/h: this rate is caused by the combination of the sun’s orbital speed around the nucleus of the Milky Way and the speed of the Earth itself.

M57 is illuminated by a white dwarf at its center of visual magnitude 15.8.

This picture is a single shot of 30 seconds exposition through a SkyWatcher 6 inches refractor telescope at prime focus. Fitsworks4 was used to remove a bit the background noise.