Saturn through amateur telescope

Posted in Astrophotography on 2011/07/10 by computerphysicslab

In reply to your video “White storm on Saturn through amateur telescope near 2011 opposition”

Hi!

I’m really impressed by your video here. I want to do the same this weekend and was a little bit disappointed on how poor DSLRs are for planets compared to webcams, or cams like DMK41 etc. But your video shows me that it’s possible to take good pictures/videos 馃檪

I have a few quick questions please 馃檪 – you’ve done this on a altazimuth mount? like the 8 inch Newton (Dobson) I have?

What were the settings for the video? I have a Canon EOS 600D – which would be better – more resolution (full hd) but less fps or lower resolution and more fps? I hope that it’s not a problem that my cam records mov files instead of avi files.

did you use eyepice projection or a barlow? and how long was your source video for registax? sooo many questions 馃檪

But when I see some images in Internet I always hope that the 600D was not a mistake to buy.

Thanks in advance :-), Best regards, Michael

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Hi Michael,

A DSLR camera can also take good high quality videos like a DMK camera, at least in the case of my Canon EOS 450d using a free software called eos_movrec you will find in Internet. This software makes AVI files.

I guess Canon EOS 600d also lets you apply this technique.

This video Saturn video was recorded using a robotic altazimuth mount, that comes with Celestron C5 Nextstar telescope.

Sometimes I use a barlow, and other times eyepiece projection if barlow is not enough. Barlow is good for lunar pictures but not eyepiece projection, only useful at planets, due to its wild field curvature, spoiling the borders of the image.

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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

Aristarchus crater (Moon) with Meade Lightbridge 16 inch

Posted in Astrophotography with tags , , , , , , , on 2011/04/17 by computerphysicslab

Aristarchus crater (Moon) with Meade Lightbridge 16 inch:

Aristarchus is a large impact crater on the Moon, is in the northwest of the nearside of the Moon. It is considered the brightest of the large formations on the lunar surface, its albedo is nearly double that of most other geographical spots. The crater is bright enough to be visible to the naked eye and is stunning when viewed through a large telescope. It is also easy to identify when most of the lunar surface is illuminated by reflection of light on Earth.

The crater is located on the southeast edge of the Aristarchus Plateau, an area that contains several high volcanic features, such as wrinkling rimes. This area is known for it have been detected in a significant number of transient lunar phenomena of nature as well as by recent emissions gas radon to be measured by the spacecraft Lunar Prospector.

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 astrometry.net. 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.

Moons of Saturn through telescope

Posted in Astrophotography with tags , , , , , , , , , , , , , , , , , , , on 2011/03/09 by computerphysicslab

Titan, Tethys, Rhea, Dione, Iapetus are five bright moons of Saturn, the ring planet in our Solar system. They can be observed through amateur telescopes with at least 100mm (4 inches) of aperture. The following picture was taken through a 5 inch telescope, a Celestron NexStar 5 SE XLT. It is an image composed of 84 single subframes of 1 second of exposition each one.

It was taken on 2011-03-06 02h10mUT using a DBK 21AU04.AS Imaging Source CCD camera. Planet was recorded in a different exposition through a video stacked (shift and add) using Registax free software.

Check out the JPL simulation matching the picture above.

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.

Celestron NexStar 5SE vs Takahashi FS102

Posted in Astrophotography with tags , , , , , , , , , , , , , , on 2011/02/19 by computerphysicslab

This week I had the chance to test a Takahashi FS102 refractor apochromatic fluorite telescope and also a Celestron NexStar 5SE Schmidt-Cassegrain catadioptric telescope. First one has an aperture of 102mm and second one of 125mm plus a central obstruction. Their light gathering power is similar and also their theoretical resolution. Nevertheless I wanted to check by myself the mythical optical quality of FS102 in contrast to the well-known Celestron.

Tests were made using the same camera to capture video and similar weather conditions both nights. I took in both cases a video of the planet Saturn when reaching the meridian, its maximum altitude. Celestron C5 perform flawlessly because I could get a sharp view of Saturn and its ring at 500x magnification. Takahashi also let me reach that high powers with a crisp result. C5’s focuser is very precise, but Takahashi’s is even more being a rack and pinion system. Focusing the FS 102 was very pleasant due to its smoothness and accuracy. Probably a better contrast in visual images delivered by refractor telescopes also gave it an advantage here.

Trying to resolve fine details, in both telescopes I could see the shadow of Saturn over the rings clearly. Here it is the final picture after applying Registax and Fitswork4 to both videos.

Probably FS102 performs better on wide field astrophotography, but on planetary imaging this picture above is my conclusion.