Archive for Meade Lightbridge 16″

Moon scratched by the claw of a bear

Posted in Astrophotography with tags , , , , , , , , , , , , on 2011/08/31 by computerphysicslab

Near Bullialdus crater (at top-right side of the picture) there is a quite interesting region called Rimae Hippalus. Hippalus crater is the big one (left-center side of the picture). It is a big crater. In this image, shadows in this crater due to a low altitude sunlight creates a visual effect, as if a great creature had stamped his bare footprint in lunar soil. Do you see it?

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.

A very fast Lightbridge 16 review

Posted in Astrophotography with tags , , , on 2009/11/06 by computerphysicslab

Hello, Id like to ask a question about your experience with the 16″ Lightbridge. I’ve read some good reviews and bad reviews about it. I’ve read that it is very hard to collimate and that the focuser may not come perfectly perpendicular to the tube assembly from the factory and may need shimming to properly align it.

I’d like to know your opinion on these things and also the quality of the focuser. Is there much flex in the trusses? Have you been able to attain crisp clear focus? Would you recommend this scope, or to rather spend an extra $1000 to get a similar sized Discovery scope?

Thanks!

-Joey

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Collimation is an important issue when observing through Meade Lightbridge 16″. Mainly for planets and Moon, because a good collimation gives much better images at high magnification. When moving the telescope, it is usual to get discollimation, so every time you move it, you firstly have to collimate it before observing.

Another disadvantage of this telescope is its weight. It weights a lot and it is not easy to move from one place to another.

Nevertheless starfield views are incredible due to its high aperture, mainly under dark skies. It becomes very easy to observe deep sky objects. It is impressive to observe Dumbell nebula at 200x.

To attain crisp clear focus is very difficult when observing planets or the Moon due to atmospheric turbulence. 16 inches of aperture are very sensitive to turbulence.

I would recommend the telescope if you are planing to be observing always at the same place. It is a very cheap telescope taking into account its aperture.

I cannot talk about Discovery telescope, because I have never watched through one of them.

Regards,

 

Lightbridge-16

Bullialdus area

Posted in Astrophotography with tags , , , , , , , , , , on 2009/07/18 by computerphysicslab

A lot of features are located in this area of the Moon. Some of them are: Rupes Recta, Pitatus, Promontorium Taenarium, Bullialdus. It corresponds to the area covered by the Rükl plates 53 & 54.

Moon-Bullialdus-Area

Bullialdus is the big crater at upper left side, in the shadows. Pitatus is centered in the lower side. Inside several details are visible: a peak and an inner rim. Rupus Recta is the large straight wall on the right side.

This picture was obtained after stacking (with Registax 5) 20 single frames taken with Casio Exilim pocket digital camera in afocal projection through an eyepiece using a Meade Lightbridge 16-inch dobsonian telescope.

Mare Crisium

Posted in Astrophotography with tags , , , , , , , , , , , on 2009/07/03 by computerphysicslab

Mare Crisium is a big and round dark spot in the face of the Moon. It is easily visible through the naked eye on the right side (East) of the Moon. Inside Mare Crisium there are some interesting features, like small craters as Picard or Peirce. Proclus is the bright crater on the left (West) beyond the Crisium border. Some bright rays emerge from it crossing part of Mare Crisium. At north-east of Crisium (above right) there is a small and dark surface called Mare Anguis (the “serpent sea”). A big crater is visible at its left (West) known as crater Eimmart.

This picture was taken as the integration of 30 subframes stacked in Registax 5, from a video made with Casio Exilim EX-Z80 afocal on Meade Lightbridge 16-inches big Dobsonian, with no tracking.

moon-mare-crisium

DSLR to a LightBridge

Posted in Astrophotography with tags , , , , , on 2009/05/18 by computerphysicslab

Someone asked: “Has anyone had difficulty focusing a DSLR to a LightBridge? I bought the appropriate adapters but cannot focus on any subject. It would seem that the LightBridge focuser extends too far away from the secondary. It seems the obvious answer is to install a focuser with less length. ”

Yesterday I was also trying to focus my DSLR Canon EOS Rebel XTi (EOS 450d) through my Meade Lightbridge 16″, but it was not possible. I haven’t still bought any T-adapter, because I was not sure it could reach the focus. Indeed it doesn’t reach it even without any adapter.

Maybe changing the focuser to a zero profile one could work. Or maybe not.

There is a trick to find out where the focal plane is exactly. When seeing the Moon, remove any eyepiece from the focuser and project the light into a cardboard perpendicular to the focuser axis. When the Moon gets clear and focused, there it is exactly located the focal plane at prime focus.

Knowing the distance from the CCD camera to the T-adapter it is possible to find out if a low profile focuser could reach the focus for prime focus astrophotography.

A bit better Saturn

Posted in Astrophotography with tags , , , , , , , , , , on 2009/05/16 by computerphysicslab

Fortunately, yesterday was not cloudy and I could do further experiments with Saturn. Using a Barlow 2x and Casio Exilim EX-FS10 camera I filmed some videos at highest resolution through the big dobsonian telescope Meade Lightbridge 16-inch. Weather conditions were good. I did a better collimation than previous days, getting sharp focus from time to time. Stacking the frames with Registax 5 I got this resulting image:

Saturn & Titan Meade Lightbridge 16-inch

In the left side of the image, it is visible a satellite of Saturn. It is Titan, with 9 magnitude. Over it, a bit at right there is almost visible another one, Rhea of magnitude 10. Visually it was observable another one aligned to Titan and Rhea, but it is not visible in the image. It was Dione with 11 magnitude.

Luckily this image shows the gap between foreside ring and its rear part. The image effective resolution according to my calculations is 1 arcsecond. Two cloud bands are visible one in the north hemisphere and the other in the south.

I would like to break the 1 arcsecond resolution barrier, but I don’t know if it is possible with this telescope. Theoretically it delivers a 0.3 arcsecond resolution because it has 400mm of mirror diameter.