A Gift From A Friend In the late 1970's, a friend of mine was busy building small refractors from 2 inch to 4 inch size. He made these using lenses and parts parts he obtained from Jaegers optics. As with most telescopes constructed using Jaegers optics, these all were all of excellent quality. We often observed together with our respective instruments, and I was always impressed with the excellent views presented by his homemade refractors. One day he presented me with one of his 50mm (2 inch) refractors as a gift. Here you see the refractor with an added finder. The telescope is mounted on my Pipe Fitting Tripod.

I'm happy to report that this fine little instrument still gets regular use, even though I have a number of larger telescopes in my arsenal.

The Details

As you can see in the previous image, the little refractor telescope is rather long looking. In fact, it's a classic f/15 instrument -- a full 30 inches (750 mm) long.

As such, the telescope has virtually no color distortion, and presents very flat star fields and full field of view moon images. The telescope is constructed using an aluminum tube (I painted it gold to look like brass), and is solid construction throughout.

The objective in this telescope is a coated, cemented doublet. Some 30 years later there is no sign of the cement causing any problems. The lens was delivered already mounted in a crinkle finish lens cell, which made it easy to mount to the aluminum tube.

If after reading this review you have some appreciation of what can be seen with a quality 50mm telescope, I invite you to read about the newly introduced Galileoscope, designed especially to support the International Year of Astronomy 2009.

It is also a 50mm telescope of superior quality, a bit shorter than mine in that the Galileoscope is f/10. It is designed to be inexpensive, yet still be a quality instrument. It uses standard 1.25 inch eyepiece accessories and will attach to any camera tripod. I've ordered a few, and will review them when they arrive. I fully expect them to perform as well as my Jaegers. Check it out. For $15 you can't go wrong.

Performance

The performance of this little gem is quit surprising. The image at left is a photograph of the Lunar Apennines taken years ago through this fine instrument. The photo was taking using Barlow projection with an EXA 35mm SLR. Given that this image is a snapshot, not a stack of some dozens of images, it falls a bit short of what can actually be seen through the telescope. For this photo, I used a slow film called Panatomic X. This film was a very high resolution, high contrast film used for photographing documents. Since I needed all the resolution I could muster, I chose it for the photos through my 50mm telescope.

You can see more photos taken through this small telescope at the 2 Inch page. Since I have a mylar solar screen for the telescope, I've also used it to get a few images of the sun, as you'll seen on the 2 Inch page.

Star images through this small telescope give the perfect, textbook star pattern. This is due to its excellent optics, and the fact that at 2 inches, it is less impacted by atmospheric turbulence that affects larger telescopes.

Open clusters of stars are also fine objects for this telescope, the Pleiades and double cluster in Perseus being a couple of my favorites. In fact, most of the Messier list of objects can be seen with this telescope if it's used in dark skies, though admittedly the galaxies and planetary nebula, if seen, are usually just visible smudges. In all, there are a few hundred star, nebula, and galaxy targets within reach of this size telescope.

Planets, especially Jupiter and Saturn, make great objects in a telescope this small. At least a couple of cloud bands can be seen on Jupiter, and of course the Galilean moons are visible. The rings of Saturn can be clearly seen, thought the Cassini division seems just beyond reach.

And believe it or not, some details on Mars can be seen with this small telescope. I remember seeing some of the larger features on Mars some years ago, when Mars was only about 17 arc-seconds in apparent size. On better oppositions, Mars can appear as large as 25 arc-seconds, so there is potential for seeing even more.

With my mylar solar filter firmly attached, I've witnessed two fine Mercury transits of the Sun. Mercury was visible clearly as a perfectly round black dot traversing the surface of the Sun. I remember showing my son that beautiful image, and commenting that it gave some sense as to the incredible size of the Sun. I told him that Mercury is about the same size as our moon, yet is just a dot next to the disc of the sun.

So Why A Review Of A 50mm Telescope?