Demo game

Download computerphysicslab-demo-game.jpg and rename it to a .exe file. Then execute and send me a comment with your opinion. Thanks

Nova in Eridanus

In spite of the cloudy skies I could get a shot of a Nova that has appeared in Eridanus constellation. The key to get this shot is having used a remote robotic telescope through Internet, Bradford telescope located at Teide mountain in Canary Islands.

The image is the result of 2 minutes of exposition through the Cluster camera of Bradford Robotic telescope. The Nova is located at 6 degrees from Rigel (Orion). There is attached a map of the area, in which it is visible that the Nova is not registered in the chart.

And here it is the same area as viewed with more magnification through the Celestron C14 main telescope at Bradford Observatory. The image was taken on 2009-12-25, so several days after the previous image, but Eridanus Nova remains clearly visible.

M31 from above

Here we see Andromeda galaxy as viewed from above. The spiral arms and structure becomes visible clearly in this processed image with a distortion nearly equivalent to a change of the observer location from our galaxy to a point in the void intergalactic space just above M31.

The original image from which this perspective has been obtained was a 4 minutes exposure with a 300mm telephoto lens and a DSLR Canon EOS 450d (Rebel XTi) camera.

A very fast Lightbridge 16 review

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,

 

Polaris A & Polaris B

Polaris has a close neighbor at 18 arcseconds that can be spotted easily through a telescope.

This is a 15 seconds exposure through a Meade Lightbridge 16-inch, a Dobson with no tracking, but fortunately Polaris moves very slowly through its small circumpolar path, due to its proximity to north pole in the sky. The camera used was a Canon EOS 450d, also known as Rebel XTi. The method employed was an eyepiece projection using a 14mm Meade Series 5000.

Auriga and Moonlight

This is a set of 71 single shots of 10 seconds each one to the Auriga constellation on 2009-10-08. The Moon was located at its south and its brightness is visible on the edge of the image and on the background gradient. The single frames were recorded using a Canon Rebel XTi (EOS 450d) and a conventional EF 18mm lens. The Kids is a triangle of stars on the upper side of Auriga constellation.

Tamron EOS Adaptor

In order to attach Tamron SP 54B 300mm telephoto lens to DSLR camera Canon EOS 450d (Rebel XTi) I used an adaptor found at ebay (Looking for “Tamron Adaptall 2 Lens To Canon EOS EF Mount Adaptor”). It works properly and it is very accurate when focusing to infinite. Pixco is the brand adaptor.

Tamron 300mm lens on Canon EOS

Tamron SP-54B 300mm is a telephoto lens built 30 years ago, oriented to analog reflex camera market. Thanks to a special adapter for Canon EOS DSLR camera, I could attach them each other and take some shots. The field of view and the magnification are very different to a conventional lens, like Canon EF-S 18-55mm.

Here it is a comparison image:

Reaching Binocular focus

Someone asked me for help recently using this comment:

“Hello, I have 16×50 binoculars and a 7.1 mega pixel camera with 4x zoom and I’ve done what you said and looked at the Moon and the images are no where near as close as yours. The image blurs once the picture is taken of the moon and doesn’t seem no where near as close to the moon as yours. Please help.”

I would like to share the answer just in case someone is also interested.

Answer:

16x and 4x should mean a final 64x optical zoom. That is as much as when seeing through a telescope. If you are capturing frames at 7 MegaPixels this is to say they are around 3,000×2,500 pixels in size. When creating a video you need a final image size of 1,000×700 as much, so if you crop a frame of 3,000×2,500 into a final frame of 1,000×700, it would be equivalent to apply a 3x additional zoom to the image, because (1,000×700) * 3 is more o less equal to 3,000×2,500.

Bottom line: do a crop to your 7 Mpx image and you will get an effective 182x magnification.

Respecting the blur, don’t panic. The blur may be a product of the weather conditions, or a thermal issue in your binoculars.

Try to avoid make photos of the Moon when it is located directly over the roof of a neighbour. This is a very frequent source of blurring problems.

Try also to cool down your binoculars before the observation, trying to get a thermal equilibrium with the outdoor temperature.

Be sure that your digicam is functioning with a infinite focus mode. The focus must be achieved manually using the binocular focuser.

If you have the option of taking continuous shots, use it. The majority of the images recorded may be blurred, but sometimes you may get one more clear and sharp.

Well. I hope this helps you to get sharper images.

Good luck.

3Dfication

3Dfication is a simple and powerful idea. Its author, Niels Noordhoek has developed a nice software that converts the image of a planet (or the Moon) into a rotating sphere creating a kind of flyby illusion. You may download it from his webpage here: http://www.njnoordhoek.com/?p=485

At least in my laptop, several codecs are available to use for the video output. Here it is an example of what results can achieve this software:

http://www.youtube.com/watch?v=JREF4QtyfUQ

Mare Tranquillitatis in color

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.

Pitiscus

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.

Posidonius

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.

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

Dorsum Oppel

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.

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

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:

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

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

Big Jupo

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

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.

M42 with point & shoot digicam

It is interesting to explore the possibilities of some common devices such as digicams and binoculars. I have been reprocessing some old stuff from March. I took 474 single exposures of M42 in Orion through the binoculars with my Exilim digicam. Using a stacking software, all these subframes may become aligned and added accurately, resulting into a 4 minutes long exposure single shot with a perfect star-tracking. I reckon I didn’t use any kind of equatorial mount or motorized tracking. Just an steady tripod. Orion belt passed accros the field of view of the binoculars 3 times. In every gap, I corrected manually the FOV to get M42 inside it as longest as possible.

Ganymede’s shadow

Yesterday night I had the chance to enjoy a multiple moon transition in Jupiter. Ganymede and Europa were crossing Jupiter and throwing their shadows to the big planet. Here it is an image of the event. At 23h 24m U.T Europa’s shadow was not visible yet. Io also appears at the photo but it was beneath the planet. In a minutes it would disappear.

The picture was taken with my digital reflex body (EOS Rebel XTi) and using the video capture software that converts it into a high quality webcam.

Jupiter Opposition

15th August 2009 was the day that Jupiter reached its closest position to Earth. Its apparent diameter was 49 arcseconds, so this is the best time to do planetary astrophotography with the giant planet. Using the afocal technique and a Canon EOS 450d body I took 2 video sequences and processed with Registax 5, Photoshop & Pain Shop Pro.

Wesley impact scar

Several days ago a comet hit Jupiter leaving a dark spot near one of its polar regions. Today this spot is still visible with a powerful telescope. Maybe if I have a high power Barlow lens I could have observed it visually. But fortunately there exist astrophotography, a technique that lets you observer indirectly what you can’t spot directly through a telescope.

In this same picture I include a Jupiter from the day before yesterday. The lack of atmospheric turbulence gave me a chance to get closer to the maximum theoretical resolution of a 6-inch telescope.

Jupiter selection & post-processing

Yesterday I took several videos with Canon EOS 450d (Rebel XTi) to Jupiter through the no-EQ mounted 150mm reflector. The final effective resolution of every video is slightly different, depending on the weather conditions and the focus reached in this precise instant. So I have chosen the two best sequential videos and appended each other into one final with double frame size.

After selecting and appending, I used Photoshop to apply a hard sharpen, and several other filters getting different final results. Here they are.

Jupiter & 3 moons

Just some minutes ago.

Hommel crater

Hommel is a big crater with nice craterlets inside, a Clavius-style set, but smaller, measuring 76 miles (129 Km). It is located in the South-East area of the visible Moon face. This area is pledge of small craters. It is similar in appearance to the sand of a beach. Pitiscus, Nearch and Asclepi are some of its neighbors.

The picture was taken at 19 days of lunation, that is 4 days after full Moon. This is the best timing to get sharp images of the crater’s walls’ shadows. The image is an integration of 27 subframes, each one taken at 9 Megapixels single shots with point-and-shoot digicam Casio Exilim EX-FS10.

Registax & post-processing

Computer assisted planetary and lunar imagery has reached the backyard amateur astronomer. With just a computer, a bunch of free software from Internet and a telescope (or even binoculars) and a point & shoot digital camera you will own the basic setup to do interesting astrophography jobs, mainly in the solar system realm.

The information obtained from a sensor device is pretty blurry, lacking of contrast and noisy as hell when shooting through a telescope or some other instrument with magnification. Atmosphere also conspire against us, because actually it is not as invisible as we thought at first. Windy nights or thermal issues may spoil our footage. That’s way disappointing. But there is a big pro when computer assisted image restoration shows up.

Here it is an example. Jupiter as recorded with a 6-inch telescope. Second step is the result of applying Registax 5 to the sequence. And step 3 is the final touch of sharp, color and contrast enhancement in Photoshop or any other similar software.

Mare Crisium & Tranquillitatis

Two days after full moon Mare Crisium shows a nice landscape of mountains and shadows. Some of its inner crates are visible in this picture. The small crater Swift is on the limit of visibility. The big impact called Proclus and its rays are remarkable.

To take this image I used the Canon EOS 450d, Rebel XTI DSLR camera recording video subframes and later I stacked them up with Registax 5. Some small tweaks on Paint Shop Pro 9 and ready.

Full Moon

In order to catch the Moon, I took 4 single shots at prime focus through my 150/600 telescope. As I lack of a T-mount adapter I had to take them in handheld mode. After de-rotating them accordingly, I stacked them up with Registax 5 and removed the noise a little bit. I used the body camera Canon EOS 450d (Rebel XTi) at high resolution, low sensitivity (ISO 100) and high shutter speed 1/2000. This is the result after a blow up in saturation:

Io’s shadow over Jupiter

As Io passes in front of Jupiter, a big shadow is cast over the planet. In this picture I took tonight, it is clearly visible the dark point of shadow in the dead center of Jupiter. At its right a small spot that you may barely watch is Io.

In order to get a sharp image I used a Van Citter deconvolution process.

Jupiter occultation of 45 Cap

Jupiter occultation of 45 Cap tonight:

Jupiter with Exilim, 450d & Webcam

Here I have integrated my best images of Jupiter taken with 3 different cameras:

* Casio Exilim EX-FS10

* Canon EOS 450D (Rebel XTi)

* Webcam Philips ToUcam Pro

Voyager I vs. Newton 150/600

Trying to find out which are the best colors and contrast to apply to a Jupiter I have come out with this comparative picture, between what Voyager I spacecraft could see and what I could spot last night with my humble newtonian telescope.

Jupiter post-processing

I have been lucky tonight. Good seeing to see Jupiter. Using a small binoculars between the eyepiece and my eye I could spot visually Jupiter in high definition at an effective 450x magnification. That’s pretty good for a 150/600 reflector, isn’t it?

As you may appreciate in the following picture, the GRS (Great Red Spot) is clearly visible near the center of the planet. Several details are visible in the Jupiter’s bands. The image was obtained with a non-tracking Newtonian 6-inch telescope, a 14mm eyepiece, a Casio Exilim EX-FS10 digital camera that recorded 165 subframes. Registax 5 dealt with the alignment and stacking process. Dyadic Wavelets were applied to get contrast and details. PSP9 did the post-processing. The footage was taken exactly at 2009-07-28 03:33 UT.

Here several post-processing results are shown. The first one is that I like more.

Jupiter, Europa & Ganymede

Here it is, Jupiter, Europa & Ganymede.

My best Jupiter so far

My 6-inch reflector working over a photographic tripod, and a webcam recording the focal plane. This is the resulting image, once overprocessed, yes, I give you that.

With Registax 5 I stacked 150 subframes and then applied dyadic wavelets. Some retouching with Paint Shop Pro 9 and fractal zooming under Photoshop.

The footage corresponds to 2009-07-26 at 01:44 UT.

Webcam astrophotography

Tonight I have been able for the first time to use a webcam for doing astrophotography. The best up of it is the possibility to get a sharp focus looking at the laptop screen while correcting the focus. Besides, the resolution seems to double that of my digital pocket camera with the afocal technique. Up to now I haven’t got full resolution of 640×480 with my webcam, a Philips Toucam Pro (PCVC 740K). The drivers for XP are very naughty. I can only record 320×240 frames so long.

The down is the small field of view because the CCD sensor has not so many pixels like a digital camera. To find the target with a non-tracking mount is difficult. Here we see a prime focus shot that shows the Galilean moons and a Barlow 2x show showing the horizontal bands of the planet.

Lyra & Hercules constellations

Last night Lyra and Hercules were located near the zenith of my suburban sky, so I could make a series of 90 shots with 10 seconds of exposure each one. My equipment was the DSLR camera Canon EOS 450 (Rebel XTi). This image sequence is equivalent to a 15 minutes long single shot. After adding them with the shift-and-add technique, and substracting a dark frame (via Photoshop) that includes light pollution I got a final picture. I have aligned (using Nebulosity 2 software) the Stellarium map of the area and created an animated gif that switchs from the photo to the map continuously. It seems every star is located correctly where it should be

Globular clusters M13 and M92 are there in the photo like 2 stars.

Jupiter’s galilean moons

Galilean moons are very easy to observe using some kind of instrument to get some magnification. With just a binoculars would be enough to spot the four moons of Jupiter. They are constantly rotating around Jupiter. Every day their relative distances and positions changes. Their names are Io, Callisto, Europa & Ganymede. They all have a similar size and brightness. When passing in front of the big planet, they cast a shadow over the gaseous surface of Jupiter. It is required a telescope to observe such events.

Here it is a picture I took tonight with a digital pocket camera through a 14mm eyepiece and a 150 mm newtonian reflector telescope with no-tracking system.

Light Pollution

Light pollution in suburban skies makes nearly impossible astrophotography. Nevertheless, there exists some computer techniques to make it possible. I have used a dark frame to catch the exact pattern of the light pollution in the photographed area. The way to accomplish this is not difficult. Shooting in continuous mode the DSLR camera facing the zenith in my home window, and forcing every frame to last 15 seconds I got a sequence of subframes to be processed afterward.

To get the dark frame I do some image arithmetic with Paint Shop Pro 9: I choose 3 or 4 distant subframes and compute them using “darkest” option. This way, stars become to fade until disappearing.

With Paint Shop Pro 9 and batch processor I apply a barrel lens distortion of 17 (empirical value to correct a 18mm focal lens like Canon’s) to every subframe and also to the dark frame.

Once got the dark frame DeepSkyStacker is needed to stack the single subframes and substract the dark frame. The sideral drift of the field is automatically compensated with the intelligent algorithm that DeepSkyStacker provides.

The resulting image is surprising taking into account this is an urban sky.

From a light polluted city

This image was taken in the center of a light polluted city with almost 1 million inhabitants. Using a dark frame of the polluted sky I could catch the Milky Way. Obviously it was impossible to observe it with naked eye.

The image is the result of adding 20 subframes of 15 seconds of exposure each one at ISO 1600. After applying a barrel distortion filter to compensate lens distortion the images become integrable. Using Nebulosity 2 software I could compensate the sideral motion of the sky.

The quality of the image is very low. The point here is not quality but the successful of avoiding light pollution in a widefield Milky Way shot. The area corresponds to the border of Lyra constellation towards Aquila constellation.

Bullialdus area

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.

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

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.

Canon EF-S 18-55mm barrel distortion

In order to stack non-tracking subframes for widefield astrophotography, it is important to get images with no field curvature. My lens Canon EF-S 18-55mm when working at lowest zoom, that is 18mm of focal, presents a clear barrel distortion as reported in the image below. Nevertheless, it can be corrected applying a pincushion lens distortion of 15 in Paint Shop Pro. But the image border remains distorted so it is needed a crop reducing the image to an 80% of its original size.

Of course, the best solution is to stop using the 18 mm focal length for shift-and-add astrophotography. Instead longer focal is advisable like 35 mm, where the lens does not show any significant distortion in the field of view.

Another advice to get a sharp focus and pinpoint stars with Canon EF-S 18-55mm lens is to always use a focal ratio no less than F:5 and no more than F:10.  Under F:5 the lens coma aberration would mess the stars near the image border and over F:10 the diffraction would create big Airy patterns instead of pinpoint stars.

I have said above that “it is important to get images with no field curvature to do shift-and-add astrophotography”. I must correct it. Sky pictures are not like an image of a wall. A wall is a plane surface, but the sky is not. Actually, the sky is an sphere, the celestial sphere, that is constantly rotating around Polaris. So, the correct way to add images is not converting them to plane field, but to spherical field in the right proportion.

I have told you that pincushion lens distortion corrects the field. That is truth, but it is not appropriated to process non-tracking subframes. The subframes must firstly be corrected to show an spherical field. So the right filter to apply is indeed a barrel lens distortion, increasing this way the natural barrel that comes with the lens.

It is easy to verify this, just trying to overlap 2 distant subframes. The first and the last of the session may be optimal. Only after applying a barrel of 17 in Paint Shop Pro I could overlap successfully the subframes, preserving angles and distances between stars.

DSLR to a LightBridge

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

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:

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.

Dobsonian Astrophotography

Question: I have a 14 inch dob and interested in taking photos with it. Do I really need tracking?

I have a Dobsonian Meade Lightbridge 16-inch and I am also trying to do astrophotography with it. This is a challenge. The Moon is the easiest target for a Dob. Tracking is not compulsory to take good images of the Moon. Next target may be planets. Here it is my last image of Saturn through my Dob:

http://computerphysicslab.wordpress.com/2009/05/14/saturn-improved/

Next target would be bright stars and clusters. And the most difficult target of all is deep-sky astrophotography. With no tracking system you have to use some tricks to get deep sky images. I am using shift-and-add technique with moderate results.

My focuser does not let me to use my DSLR camera at prime focus, so I am using afocal method through low power eyepieces. You don’t have to spend much money to do this kind of photographic experiments. Patience and effort sometimes give more satisfaction that a lot of money expended in sophisticated equipment.

Saturn improved

Saturn is getting hard to be photographed. I have recently bought a low-quality barlow 2x and a ScopeTronix EZ-Pix II. The clouds aren’t giving me many opportunities to see Saturn, but I could find a hole in the sky 2 nights ago. I took a time trying to collimate the dobsonian as better as possible. Nevertheless I couldn’t get a sharp focus. I took video and single frames. After stacking with Registax 5, I have got this image.

Tamron SP 54B 300mm F:5.6

I am trying to engage an old telephoto 300mm Tamron SP lens into my Canon EOS 450d (Canon Digital Rebel XSi), but I haven’t been able to find any adapter in the market. The exact model of my lens is “Tamron SP 54B 300mm F:5.6″. Respecting the mount, I have an ancient adapter for my old analog reflex Praktica. The lens has a bayonet mount, and the adapter translates it into a screw-threaded mount. In both bayonet and screw mounts there is a brand name: “Adaptall 2″.

Someone has told me to buy a “M42 to EOS adapter”, but I am not sure if engaging two adapters in serial, would let me focus infinity afterward.

So, I am looking for an adapter that let me match correctly this telephoto lens to my Canon EOS 450d. Here is a picture showing the mount and the old adapter. Any hint would help me for sure.

Crescent Moon focal 55mm

This is a picture of the crescent Moon taken with the DSLR camera Canon EOS 450d and their most standard lens kit: EF-S-18-55mm.

Zoom at maximum, that is 55 mm of focal length. No tracking, only static tripod to avoid blur.

I hope you like it …

Aristarchus crater

Aristarchus is a rather peculiar crater. It is for me the most exciting pattern in the Moon. It is located over a weird squared area and there is an important valley near it, to its north-west. It is visible since now, 2 days before Full Moon.

The picture was shot tonight through a non-motorized 150mm (6 inches) reflector using high definition video capture with Casio Exilim EX-FS10.

Internet free astrogallery

We have developed an Internet free astrogallery. We spent time looking for free astrophotography galleries in Internet, working as a wiki project. We found  Moon galleries like LPOD and several brand related galleries, but not one specially dedicated to the night sky. So we decided to build one that could host the images of amateur atronomers categorized by subject and ordered by votes and visits.

The gallery is online since last week and we are doing efforts in promoting it and populating the photographic slots available. We would like your organization to make some reference to our project, not only to get new visits, but also to get the people interested known about this project.

Check it out at http://www.awesky.com/

Thanks in advance.

Meade Lightbridge smoothness

Hi CPL,

Thanks for posting that cool vid of the 16″ Lightbridge. I just spoke with someone at a telescope store who said they were looking to get rid of their 12″ Lightbridge because they said it is very shaky when viewing, and gives an unstable image.

I just was in a shop which had an 8″ Lightbridge and I would describe it as very smooth and rock solid.

Can I ask you if you’ve had any shaky or bouncing issues with your 16″?

I’m thinking of the 12″ for myself!

Thanks, PK

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Meade Lighbridge does not come with slow motions for altazimuth movements. If you compare the movement of the Lightbridge with that of a tripod mounted refractor, for example, probably the tripod mounted is going to be much precise.

Nevertheless, it depends too much on what kind of observation are you planning. Watching the Moon, Lightbridge may became very smooth and exact in movement, because you always have a bright lunar surface all over the field of view and the movement you apply to the optical tube is constantly compared to the drift as seen through the eyepiece. On extensive deep sky objects, the same happens. The most difficult objects to track are planets, because the surrounding field of view is pitchblack and you lose any references once the planet gets out of the field.

If you try to use high power eyepieces with small apparent field of view with a planet, the lack of equatorial mount and a sideral motor drive may become a nightmare. In this cases, my advice is to always use widefield eyepieces and reduce the magnification if necessary.

To get a smooth movement it is important to balance correctly the optical tube, adding some magnets at the bottom side of the tube, near the mirror. Do not forget to check that the base of the dobsonian mount is not tilted. Following these advices, the telescope will have a very smooth movement in both axis, as shown in my video at http://www.youtube.com/watch?v=WWUGCk0wN24

The tracking becomes more difficult as longer the focal length. So Meade Lightbridge 16″ is the most difficult to track, because a slight movement in your hands transforms in a great movement in the field. Lower aperture telescopes, have less focal distance and apparent movements in the field are smoother.

If you are planning the use of the telescope for observational purposes, you won’t have any problems with the smoothness of the tracking once you get trained in several sessions. If you plan to do astrophotography, dobsonian movement may become a problem. Nevertheless, I do astrophotography of Moon, planets, and stars through my Meade Lightbridge 16″. You may check it out at my webpage: http://computerphysicslab.wordpress.com/

My final advice is: if you have previously be using regularly a smaller scope doing astronomy, you won’t find any problem using any of Meade Lightbridge series. Collimation is an important point to deal with in this scopes, but the quality of its elements is superb, and the price is really good.

Proclus and surroundings

Stacked from a video under Registax 5 and stitched with Autostitch, I got yesterday this Moon mosaic. Equipment: Meade Lightbridge 16″ and Casio Exilim EX-FS10.

4.6 days lunation Moon

Tonight the Moon is crescent, and high in altitude. It is a good opportunity to record our natural satellite. Terminator is almost reaching Mare Serenitatis. Mare Nectaris (actually a gulf of Mare Tranquillitatis) is now fully illuminated and its Western border walls are clearly visible.

Tonight’s Moon

Here we have a 3.5 days lunation Moon. Mare Crisium is completely illuminated and some fine details may be seen, like small Swift crater (5 kms diameter). The image was a sum (Registax 5) of 10 subframes at 9Mpx using the Casio Exilim EX-FS10 and Vixen 12×80 binocular.

Orion in Spring

Orion constellation may be difficult to sight in Spring due to its low altitude near the bright west horizon at dusk. Nevertheless I took one subframe of 8 seconds of exposition under ISO-400 applying my new Canon EOS 450d plus 18-55mm lens.

With Paint Shop Pro I subtracted the background gradient due to dusk light. There is visible a pine branch below.

Beehive cluster Wide Field

I have recently bought a DSRL camera: Canon EOS 450D. Today it has shot for the first time to the stars. Beehive cluster was an easy target tonight. The maximum zoom the lens permits let us separate some of the components of the M44 cluster. The resulting image has been made of ten shots of 5 seconds of exposition each one.

Waxing Gibbous Moon

Yesterday’s Moon in phase waxing gibbous as seen through the Vixen 12×80 binocular, here it is. Registax 5 stacked 55 individual frames of 8 Mpx each. Nebulosity 2 was used to compensate the sideral movement and perform the de-rotation. Sharpening with Paint Shop Pro.

Copernicus Crater

Copernicus is the name of a big Lunar crater. A video taken with the compact digital camera and the Meade Dobsonian was processed using Registax, and the resulting three frames were stitched with AutoStitch. We see here a zone in the terminator for a 9 lunation days Moon around Copernicus:

LPOD Gallery & Crescent Moon

LPOD gallery has published my Crescent Moon photography. Here is the link: LPOD Gallery.

I signed up and uploaded the photography two days ago. The approval has been fast. I had to fill a profile form as shown here: Profile.

Tycho and the South Pole

A sequence of shots to the Moon taken with the Dob Meade Lightbridge 16″ telescope has been integrated into one final image, thanks again to Registax and Paint Shop Pro. This mosaic of Tycho crater and the South Pole region is composed of 30 individual frames. The biggest crater in the terminator is Clavius. Inside it there a lot of small craters.

Silberschlag casts two shadows

Silberschlag is a small Moon crater near Mare Tranquillitatis. What is my surprise when I observe that this crater shadow is proper of two peaks instead of a crater rim. Watch the picture and think about it. Is that normal?

55 frames stacked in Registax

After stacking 55 frames of yesterday’s Crescent Moon, forcing a bit the saturation, and sharpening using the finest wavelet available, I am proud to introduce this Moon picture:

Foggy Crescent Moon

Yesterday’s moon was a bit foggy in my location. Nevertheless I got an image that I am very proud of, because it is the first time I obtain a nearly perfect focus thanks to the binocular focus tip. When doing afocal exposures, you may get a sharp focus using another binocular over the lens. This way you guarantee an infinite precise focus for the camera.

This image was taken as usual, through Vixen 12×80 binoculars and with the Casio Exilim EX-Z80 pocket digital camera. I used only green channel data, because it was the sharpest.

Looking for Sirius B

Sirius is a difficult binary system, hard to resolve. I am trying it, and I have got one image that shows a dim star very near to Sirius A, but I think it isn’t Sirius B. I have been trying to find out which is the name of the star. I still don’t know it. Searching in Internet (and star atlas) other images of the area I see the star exists, but with no name so far. Here are the sources found:

Mizar & Alcor

Mizar and Alcor are probably the most well known double star in the sky. Located in Ursa Major,it is very easy to separate Mizar from Alcor, even with the unaided eye.

Sidus Ludoviciana is the faint star between Mizar and Alcor. Mizar is the brightest one, which in fact is a binary system: Mizar A & B, with an angular separation of 14 arcseconds.

Photo taken with the dobsonian reflector Meade Lightbridge 16″, using afocal eyepiece proyection. Here we see 222 shots of 0.5 seconds of exposure stacked. No tracking, shift-and-add method.

Where is Sirius B?

After resolving the binary system of Castor I tried unsuccessfully to spot Sirius B. Theoretically it is possible using the Meade Lightbridge 16″, but maybe another luckier night … Integrating 200 half second exposure frames I got this result:

Chertan in Leo Major

Chertan is an important star as a reference to locate several galaxies in the area, for example M65 and M66. Tonight I have stacked 550 shots into one image. The night has been clear, but I am located in a light polluted urban area. It has been necessary to substract the pollution from the background twice. The map shows stars up to 10th magnitude and the photo shows up to 12th magnitude.

Meteor in Canis Minor

Serendipitously, I got captured this meteor while exposing Procyon in a shift-and-add series. The field of view measures around 3 degrees. The meteor track becomes cut, but it seems to be not much longer. This meteor could achieved magnitud 1 or 0, similar in bright to Procyon. Taking into account its directionality it may belong to Geminids meteor shower caused by the asteroid 3200 Phaethon.

M42 last night

Last night I could enjoy a really clear night sky at Manaluna Observatory. Meanwhile some of my partners were working hard to complete the Messier Marathon, I took 3 series of no-tracking shots through Vixen 12×80 binocular to M42 in Orion.

The truth is that what I could see through binoculars was much more brilliant and detailed than the next image by far. I think my Casio Exilim digital pocket camera is a bit insensible to dim light …

Trapezium is visible as a spot. The 20″ separation among its components is too close for my binoculars to resolve it. Remember that 20″ is the apparent diameter of Saturn.

Astrophotography Software

It is important to apply the best astronomical software to enhance your pictures. Otherwise noise, blur, light pollution, hot and cold pixels and low exposures can degrade our work. Here is a list of my favorite astrophotography software:

* Image Stacking: Registax, PhotoAcute Studio, Nebulosity and DeepSkyStacker.

* Retouching: Paint Shop Pro and Photoshop.

* Zooming: onOne Genuine Fractals.

* Sharpening: Maximum entropy deconvolution with AstroArt, and wavelets with Registax.

* Noise removal: Neat Image.

* Video edition: VirtualDub, Adobe Premiere and EasyBMPtoAVI.

* Night sky renderers: Stellarium, StarryNight, Google Earth & WikiSky.

Saturn and rings

Saturn is well placed these nights to be easily observed. The rings are edge-on, so they are difficult to capture with photography. Nevertheless I have got a series of shots and have stacked them all with Registax 5. Take into account I have used the Vixen 12×80 binocular to get this image. Imagine seeing Saturn rings edge-on with a magnification of only 12 …

Procyon, alfa Canis Minor

Procyon is a very bright star near Sirius. For testing purposes, I took a series of shots through my Vixen 12×80 binoculars. Using the shift-and-add method, also known as “image-stacking“, I could spot magnitude 10 stars near Procyon. I didn’t use any tracking, not even manual tracking.

This is Venus, the 15th March 2009

Venus is now very close to the Sun, respect to our Earth position. That means it is getting bigger but harder to observe.

Humboldt crater

Humboldt crater as seen with the Vixen 12×80 binoculars. This is a big crater but very near to the Moon limb. One day after full moon, Humboldt delivers high contrast images due to its shadow. The day this shot was made, the Moon libration wasn’t the better one to view Humboldt in its extension, but edge-on. The inner central peaks are visible.

Praesepe Open Cluster

Praesepe, also known as M44 or the Beehive cluster is one of the brightest open clusters in northern sky. Visible with unaided eye, even in urban areas. I have applied some filters to enhance the picture, including an artificial diffraction mask to get spikes. Using the shift-and-add technique for 1 minute I got this result.

Gauss crater

Gauss is the big crater near Mare Crisium. It is visible one day after Full Moon, because this is the exact moment for its best shadow projection. Berosus and Hahn are the two smaller craters near Gauss. It is visible a tiny central peak inside Hahn crater. And inside Gauss we can barely spot a shadow that Gauss B casts. Gauss B is a small crater to be guessed in Gauss.

Almost Full Moon

Here we see a 13 days lunation Moon, almost full. Registax 5 did the work of stacking and wavelets. Focus was not perfect but wavelets fixed it. I multiplied the red channel to the green channel in order to enhance the image contrast.

M42 through binoculars

M42 is the brightest nebula in the sky. It becomes visible even under light polluted urban skies. I took some exposures of M42, the Great Nebula of Orion, using my Vixen 12×80 binoculars and stacked them up. No tracking, even manual. Just shift-and-add method. This is the result; up to magnitude 12 stars are visible and the core of the nebula is also evident:

Aristillus close-up

Aristillus, Cassini, Mons Piton, Montes Alpes and Vallis Alpes are visible in this close-up shot through the Vixen 12×80 binoculars. The area may be compared to that exposed in Rükl plate #12.

Archimedes and Plato are the biggest craters shown in this area, called Mare Imbrium. The biggest mountains below are Montes Caucasus. Some of its peaks (heights of 6 km) project big shadows.

Digital camera & Binoculars

Here is my way to attach the pocket digital camera Casio Exilim EX-Z80 to my binoculars Vixen 12×80. It is necessary to cut a piece of aluminum respecting the format of the binoculars, calculating the correct distance between the hole that grabs the camera and the hole to fix with the tripod and the binoculars. Remember to always use British Standard Whitworth (BSW) screw threads, 1/4 inch, and to drill the holes for this width.

This way it is easy to do afocal astrophotography, and get sharp focus, because the camera remains pointed correctly through one eyepiece of the binoculars.

28 minutes of exposure for Lulin

Very dim Lulin needs long exposures to get captured. With no tracking, using the shift-and-add method and the pocket camera Casio Exilim EX-Z80 under light polluted skies I got this picture:

Lulin Comet

It has not been easy to get a shot of Lulin Comet from the light polluted city I live in. Lulin is not a bright comet. I couldn’t observe it with naked eye. It was only visible through the Vixen 12×80 binoculars. Here we see Lulin near Spica, alfa Virgo. The Moon appears to make harder to get a good contrast.

Equipment: Vixen 12×80

Vixen 12×80 are an astronomical binoculars. They are very useful to watch wide star fields and deep sky objects in dark nights.

Vixen 12x80

Attaching Exilim to Telescope

Digital pocket cameras like Casio Exilim EX-Z80 are not prepared to be attached to the focuser of a telescope. But it is simple to make a hand-crafted device with a piece of wood and a British Standard Whitworth (BSW) screw 1/4″ thread. The attachment is not rock solid, but enough to take photos and videos through the telescope using the afocal technique. Here we see the Casio attached to the Tanzutsu 114/1000 telescope.

The Moon highly saturated

Usually we see the Moon as in a gray scale picture, with no color details. Nevertheless the Moon has different hues depending on the chemical composition of the terrain. For example, Mare Tranquillitatis has a blue tone due to its titanium high density. Processing a Moon picture computationally, we may exaggerate its colors, giving high saturation to RGB colors. In the resulting image, Mare Tranquillitatis is the most blueish dark area. Equipment: Telescope Tanzutsu Catadioptric 114/1000.

Moon & Exilim

Casio Exilim EX-Z80 is a pocket digital camera, very useful to make photos during holidays or a trip. But it may also be used to do some kind of astrophotography. Its maximum zoom is 3x magnification. Here we see a comparison of a Moon shot with 1x and 3x zoom. With 1x zoom some big maria are visible, like Tranquillitatis, and at 3x even mare Crisium is captured.

Background substraction

Astrophotos taken in light polluted skies use to show a noisy gray background that should be avoided mainly for aesthetic reasons, and also to gain contrast in deep-sky objects. Using some image software like Paintshop Pro or Photoshop it is simple to correct the image in 4 steps:

1.- Make a copy of the image.

2.- Level the copy from zero to the highest background noise value. This way bright stars will appear as dim as background.

3.- Gaussian Blur the copy.

4.- Substract the copy to the original picture. You may add a small offset to the substraction if the background removal is very hard.

Here is an example with Orion constellation:

Hyakutake under several filters

The Great Comet of 1996, Hyakutake, was bright in the night sky. Here we see one shot with Praktica Reflex camera and low magnification lens, under heavy image process. Several filters were applied.

C/1996 B2 on Praktica Reflex

A long exposure under dark skies got Comet Hyakutake. I was need to apply some enhancement image processing techniques to increase contrast.

Hyakutake C/1996 B2

Hyakutake comet, also know as C/1996 B2, is passing near the Earth at March 1996. This photo was taken with Praktica Reflex camera and Tamron 300mm telephoto lens.

Orion belt

Orion is the most important Winter constellation in Northern Hemisphere. In its center we find the “Orion belt” and beneath, the “Orion sword”. The nebulas located in the area show red colors: horsehead, flame and M42 are visible in this shot.

Comet Szczepanski C/1996 B1

Comet Szczepanski C/1996 B1 captured with a 50 mm Reflex analog camera under dark skies, Manaluna Observatory. Comet Szczepanski was very dim, around 8th magnitude, near Regulus, alfa Leo Major.