Moon under the microscope

On the left you see a photograph of the moon taken with a DigiMicro Mobile digital microscope . This is a picture of the real moon, not a re-shot film or a slide. I used a rather unusual solution - I connected the microscope to the telescope. How and why I did this is described in detail in the article Microscope + Telescope =? .

If you have not read that article, I recommend that you view it at least diagonally to understand what is happening under the cut. In it I talked about the principles of operation of a telescope, a microscope and the theoretical possibility of combining their optical schemes. He described the manufacture of a telescope microscope adapter using 3D printing. The first test of the structure was carried out in the afternoon, at remote ground facilities. Go to astronomical observations failed due to adverse weather conditions. Judging by the results of the survey, the idea of ​​many people was interested (406 votes for continuation, 92 against), therefore I publish the continuation with the real Moon under the lens of a microscope.

Consider it an entertaining experiment with optics and photographic equipment, like macro photography through a drop of waterrather than a serious guide to astrophotography. For high-quality shooting of the moon through a telescope, it is better to use a special astro camera or a SLR with a T-adapter in direct focus.

About the process of shooting with a microscope

Before you start shooting the moon, I’ll tell you in more detail about some important points not mentioned in the previous article. About 0.3-0.4 seconds elapses between pressing the shutter release and the actual shooting (I found out by taking a running stopwatch), which allows us to avoid “stirring” when using the microscope for its intended purpose. When shooting in conjunction with a telescope, such a delay is clearly not enough. My budget mount CG3 mount trembles like an aspen sheet from the slightest touch, the vibrations die out for a few seconds, even if you don't spread your legs to their full length.



At first, I had the idea to solder the reed switch parallel to the shutter button and remove the magnet, but then I found the Time Lapse mode in the microscope settings.



No, in this mode, the microscope does not record accelerated video, it just automatically takes a specified number of frames at a specified interval (from a second or more). The video must then be collected from individual frames on the computer. I tried this mode by filming crystallization of sodium chloride from a solution at a speed of 1 frame per minute. The crystals slowly grow at the bottom of the plate with the solution, the minimum increase, the size of the largest cubes is slightly less than a millimeter.



Another experiment is with soda. Unlike cubic crystals of sodium chloride, sodium bicarbonate settles with beautiful needle-shaped snowflakes. Here I take off a small drying droplet, because of which the crystals grow much faster and turn out very small. Therefore, the increase is maximum, the shooting speed is 1 frame per second.



The “Time Lapse” mode is very useful when working with a telescope, to avoid shaking when shooting. I started burst shooting with a second interval, while in the meantime I was aiming at the object, changing the magnification, adjusting the focus, periodically removing my hands from the telescope with the microscope so that the greased frames were preserved.

Shooting a young moon with a microscope + telescope

A few days after the new moon (which, incidentally, was accompanied by a total solar eclipse ), the weather finally finally established. The phase of the moon was approaching the first quarter, which meant favorable conditions for observations in the evening. I connected the microscope to the telescope and waited for the darkness.



There was one more reason for excitement. The fact is that in the microscope chamber there is no possibility of manual exposure control. For a microscope, this does not matter, as there is an adjustable backlight. In the case of the moon, backlighting is useless. The logic of the "machine" will focus on the average brightness of the frame and try to stretch nonexistent details of the black background. As a result, the surface of the moon will be hopelessly overexposed. Therefore, I decided not to wait for complete darkness, but started shooting shortly after sunset. I counted on the fact that the light sky background, which usually interferes with daytime observations , will play into my hands. Here is one of the first test shots:



As it turned out, it was necessary to start shooting even earlier, the sky is not light enough. When it got darker even more and the sky background in frames became almost black, the details on the Moon became even less, everything was lit up. And then I remembered about the adjustable backlight. Of course, it will not help make the sky brighter. But I can put in sight something that will be illuminated! This will affect the average brightness of the frame, which in turn will lead to a decrease in shutter speed "automatic". From a piece of baking foil and a strip of masking tape, I quickly built just such a diaphragm. The hole in the center is punched by an office punch. We insert the product inside the adapter, so that the foil surface is in the focal plane of the telescope:











Putting it all back. Now you can adjust the shutter speed with the wheel of the brightness of the backlight, sacrificing part of the useful area of ​​the frame. The result was a funny shot. Under the microscope lens is a piece of aluminum foil with an opening about 6 mm in diameter. In this hole, “suspended in the air” is an image of the Moon with a width of almost three and a half thousand kilometers, formed by a telescope mirror. And everything is in focus! Well, not quite everything, the foil is wrinkled a little :-) The moon still didn’t crawl a bit into the hole from the hole punch. I decided so far not to mess with fitting the holes, but to try to shoot with a larger increase. In this case, the moon will no longer fit in the frame, but the area of ​​the black sky will decrease, and the correct shutter speed will be obtained without additional tricks.







The only problem is that you have to glue the panorama to get a picture of the whole moon. The title photo of the article is glued from these three frames, and rotated so that the north is on top: It’s bad that the microscope does not have autofocus. In order not to miss the focus, you can make a mask Bakhtinov .

What was the increase?

The question is interesting, but not entirely correct. When we talk about increasing the optical telescope or microscope during visual observations, we compare the angle at which the object is visible with the armed and unaided eye. For example, my telescope with a focal length of a mirror of 650 mm gives a magnification of 65 times using a 10 mm eyepiece. If the matrix is ​​the light receiver, then how do you compare the sizes? The angular magnification will depend on the image output device and viewing distance.

You can approach the issue on the other hand and compare the dimensions of the details of the surface of the moon - visible to the naked eye (or through an optical device with a known magnification), and distinguishable in my pictures. The most characteristic details of the lunar relief are craters. True, they are not visible to the naked eye (at least mine). They were not known at all before Galileo Galilei discovered them with his first telescope with a triple magnification (and coined the term “crater”). The craters on the visible side of the moon that Galileo observed and sketched have diameters of 100-200 kilometers: Craters up to 10-20 km in diameter are visible under the microscope in photographs of the moon (for example, Swift and Pierce ).







It turns out that in my photographs details are visible 10 times smaller than Galileo saw in his triple tube. Therefore, the increase can be roughly estimated as thirty-fold. In visual observations with a 65x magnification, much more details are visible through the same telescope, which is consistent with the estimate.

It would seem, nothing outstanding, the result is only an order of magnitude better than that of Galileo. But, as the galaxy suggests in a nearby post , it’s impossible to make out surface details smaller than 1 kilometer with any ground-based telescope due to atmospheric effects. So the result is in some ways the most average - 10 times better than the first telescope of the 17th century, and 10 times worse than the theoretical limit of modern telescopes.

What about stacking?

In a previous article, I promised to touch on this topic, but all of the above frames are single. Astronomy lovers, when shooting celestial objects, in most cases use the stacking technique - they shoot a series of many frames (or a video clip), and then combine them into one. This allows you to get rid of matrix noise, atmospheric distortion, and significantly improve the quality of the result. This trick didn’t work with a microscope - my telescope doesn’t have a motor for tracking the Moon; it runs too fast out of frame. When shooting at a second interval, the Moon manages to shift significantly between frames and there is a problem with alignment of the series. But it works when shooting an iPhone through an eyepiece ( I shot an eclipse like that) Instead of burst shooting, you can record HD video at 30 frames per second, the moon shifts little between frames and Registax does an excellent job of alignment. In addition, the phone has autofocus which corrects focusing errors.

Original video (I still did it, I shot and published a vertical video from an iPhone) :



After stacking:



For comparison, I put a frame with a microscope next to it, a single frame from an iPhone and a stacking result of 100 frames from an iPhone.

Technical details

All photographs of the moon under the microscope are clickable, you can view them larger. Note that Habrastorage automatically reduces all uploaded images to 1920 pixels in width. Unprocessed original images from a microscope with a resolution of 2560x1920 and video from a phone 1080x1920 can be downloaded here: https://goo.gl/Q5czXj ; surely some of the readers will get better processing results. The resolution of the images is close to the withered 5 megapixels and apparently corresponds to the native resolution of the microscope matrix. There are more options in the settings, but it will already be upscaling. Digital zoom has not been used anywhere.

Conclusion

As a result of the described optical experiments, the microscope was not damaged at all and it can be continued to be used for its intended purpose. You can buy the same microscope in the online store Dadget .


My other articles with the tag " abnormal astronomy ":

• Daytime astronomy
• How to see stars and planets near the sun?
• Anchorage-Honolulu flight delayed for 25 minutes to please the Umbrails on board