Archive for 150/750

Mare Tranquillitatis in color

Posted in Astrophotography with tags , , , , , , , , , , , , , , on 2009/09/11 by computerphysicslab

Color contrasts in the Moon are interesting even beautiful. The following picture shows Mare Tranquillitatis area and the southern part of Mare Serenitatis in full color. It was taken 4 days after full moon. The shadows in the terminator show the orography of the landscape. Mare Tranquillitatis seems to be mainly blue. This is due to its peculiar chemical composition.

Mare-Tranquillitatis-sat_filtered

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Pitiscus

Posted in Astrophotography with tags , , , , , , , , , , , , , , , , , , , on 2009/09/09 by computerphysicslab

Pitiscus, Hommel, Ideler and Spallanzani are the only four craters of the picture with proper name. The rest of them are named by letter surnames like Ideler R or Ideler L. They are located in the South-East area of the Moon. The picture was taken on 2009-09-09 05h 20m U.T. and the terminator was passing across Pitiscus, Hommel, the two big and shadowed craters. Pitiscus is 85 km wide and Hommel is 129 km (76 miles). The smallest craters of the image are 7 km wide, that is 3.5 arcseconds, 1.75 arcseconds for the bright spot and 1.75 arcseconds for the shadow spot. Image detail could then be better for a 6-inch telescope (this is the equipment used to take the image, an scope capable up to 0.7 arcseconds of resolution). 622 subframes were recorded with the Manual-Crazy-Tracking system and stacked in Registax 5.

150mm-Pitiscus-622_labeled

Posidonius

Posted in Astrophotography with tags , , , , , , , , , , , , , on 2009/09/08 by computerphysicslab

Posidonius is a big crater of the Moon on Mare Serenitatis. There is a lot of interesting details to observe inside: peaks, ridges, craterlets, … In the following image taken yesterday night, 4 km wide craters can be spot as small white points in the smooth surface of Mare Serenitatis.

Posidonius measures 95 km in diameter. The second biggest crater (a bit ghostly) in the picture is Chacornac, just below Posidonius. Inside it is visible a small craterlet called Chacornac A (it measures 5 km in diameter).

The third biggest crater of the picture is Daniell (31 km wide) located in the upper middle side. Its shape is not circular, but oval. This is the cause of a strange effect in perspective when comparing it with the craters nearby.

Posidonius

PosidoniusPosidonius is a lunar impact crater that is located on the western edge of Mare Serenitatis

Dorsum Oppel

Posted in Astrophotography with tags , , , , , , , , , , , , , , , on 2009/09/07 by computerphysicslab

Dorsum Oppel is a wrinkle ridge of the Moon in Mare Crisium. 2 days after full moon is the best moment to observe it. It is a very large formation and the landscape along is quite impressive, full of small craters, tiny mountains and the smooth floor of Mare Crisium. It is important to reach a high magnification to enjoy the view (150x at least).

My setup is a 6-inch telescope, but I bet it is possible to observe it comfortably with a 4-inch refractor.

Dorsum Oppel

The bright and overexposed crater is Proclus. I have to work harder the dynamic range issue next time.

Swift and Peirce are the pair of craters in the upper side of the picture, near the lunar terminator. Below Peirce should be visible a 2 kms wide craterlet, but unfortunately my picture cannot yield such a resolution. According to a quick calculation, 3 kms is the smallest visible feature in theis image, and that corresponds to 1.5 arcseconds. A bit far still to the maximum theoretical resolution of a 6-inch telescope (that is around 0.7 arcseconds)

Yerkes is the big ghostly crater in the right side. Apparently there is a central peak in its center. I have been looking for a confirmation of the existence of that peak, but I haven’t found any reliable source where it is mentioned. Any hint here, I would be thankful…

Manual Crazy Tracking

Posted in Astrophotography with tags , , , , , , , , , on 2009/09/01 by computerphysicslab

Lacking of an equatorial mount I have built myself a kind of manual tracking system that keeps into the field of view of a webcam a planet like Jupiter, for 3 minutes. This is long enough to record useful data and then post-process it with aggressive wavelets.

The resulting tracking is not at all perfect. You may see Jupiter swinging around the screen. It is important to capture the data at a fast shutter speed (1/100 sec.) to avoid motion blur in every frame because the planet is always dancing.

In spite of this movement, the results after stacking are very good. Here I show this really simple system and the resulting yesterday’s Jupiter with the webcam:

Manual-Crazy-Tracking-01

Manual-Crazy-Tracking-02

Manual-Crazy-Tracking-03

As you can see the Manual-Crazy-Tracking is a very simple system that consists in a rubber band attached to the tripod handle. If you try to track manually directly pushing the tripod handle, the shaking is excessive and you would need a very very fast shutter speed to get some useful data. The rubber band is necessary to reduce vibrations and increase the shift movement control.

At beginning Jupiter is located in the center of the field of view with no need to any corrections. As long as it drifts due to its sidereal movement you will have to pull using the rubber band in order to keep it in the center of the screen (it is supposed you have a laptop there capturing and showing images from the webcam). This way you may have Jupiter centered in the screen for a long time. You will have time to focus (left hand pulling the rubber band and right hand tweaking the focuser) and time to expose.

Jupiter, Io & Wesley impact scar

Posted in Astrophotography with tags , , , , , , , , , , , , , on 2009/08/28 by computerphysicslab

Good seeing yesterday too (2009-08-27 23h05m UT). Wesley impact scar is fading day after day, but it is still there. I made an animation that shows Io approaching Jupiter’s limb: http://www.youtube.com/watch?v=78zJtv569y4

Jupiter-Io-Wesley-impact-2009-08-27-23h05m-UT

Big Jupo

Posted in Astrophotography with tags , , , , , , , , , , , , , , , , , on 2009/08/27 by computerphysicslab

I have a good seeing last night. So I got my best Jupiter yet. Here it is:

Jupiter 2009-08-26 Sharp

It is 4x resampled via Registax Mitchell and PS. After resampled I can spot more details in bands and polar zones.

As always I used the 6-inch no-EQ mounted newtonian reflector, the 14mm eyepiece doing afocal projection over the Canon EOS 450d (Rebel XTi) body and recording video using “EOS Camera Movie Record” free software. Three times Jupiter crossed over the field of view. Registax and VirtualDub added and stacked the footage properly.