- Rebuilding my CGE Pro
- COUNTING SUNSPOTS WITH A $10 OPTICAL TUBE ASSEMBLY
- Hubble Optics 14 inch Dobsonian - Part 2: The SiTech GoTo system
- iStar Optical’s Phantom FCL 140-6.5 review
- Who’s Afraid of a Phantom: Istar Phantom 140mm F/6.5, that is?
- SHARPSTAR 94EDPH APOCHROMATIC REFRACTOR
- My Losmandy G11T review
- FIELD TEST: THE NOH CT-20 ALT-AZ MOUNT
- SkyTee-2 Alt/Az Mount Review
- SharpStar Askar ACL200 200-mm f/4 astrographic telephoto lens
- A review of the Unistellar EVscope
- Astrotrac 360 tracking platform – first impression
- FIELD TEST: CARL ZEISS APOCHROMATIC & SHARPEST (CZAS) BINOVIEWER
- Omegon 32mm 70º SWA eyepiece review
- Review of iPolar hardware and software for polar alignment
CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.
If you're like me, you have probably seen Jupiter, Saturn, the Orion Nebula, and all of the sky's showpiece objects more times than you can count. And while they are truly spectacular and well worth revisiting, you may be looking for something new, something challenging to observe.
Ask an amateur astronomer to name binary stars that are difficult to resolve and one of the most common responses will probably be Sirius, in Canis Major. While there are more difficult targets, Sirius is always a perennial favorite. The challenge comes not from the close separation of the two stars in the system, however. Rather, the challenge here is from the extreme difference in the two stars' magnitude.
Let's kick off the new year with what many consider to be one of the most difficult visual challenges in the sky. If you listen carefully, you might even hear the strains of the "Mission: Impossible" theme song playing in the background. Of all the deep-sky objects in the winter sky, none carries the mystique of the dark nebula Barnard 33, better known as the Horsehead Nebula.
Nestled in the southeast corner of the dim late-fall/early-winter constellation Fornax, adjacent to the distinctive triangle formed by 6th-magnitude Chi-1 (χ-1), Chi-2 (χ-2), and Chi-3 (χ-3) Fornacis, is an attractive cluster of galaxies known as Abell Galaxy Cluster - Southern Supplement (AGCS) 373.
Have you ever heard of NGC 300, the Southern Pinwheel Galaxy? Were it positioned high in our autumn sky in a prominent constellation, you certainly would have. In fact, NGC 300, an Sc spiral tilted nearly face-on to our view, would be one of the season's showpieces, especially through large backyard telescopes. Because it lies in the far southern sky, nestled among the faint stars of Sculptor, it remains the purview of diehard deep-sky fanatics only.
Take a look at just about any star atlas and you will find a huge, irregular cloud of ionized hydrogen suspended to the south of Mu (μ) Cephei, Herschel's Garnet Star. That's IC 1396, one of the largest nebulae in the night sky. Even from a distance of about 2,450 light years, this complex cocktail of bright glowing gas mixed with dark dust clouds spans 3° of our sky. At that distance, 3° translates to a linear diameter of nearly 160 light years, more than three times greater than the Orion Nebula, M42.
How close can two stars appear and still be resolvable as two? The single most important factor that influences the result is a telescope's aperture. All other things being equal, the larger the aperture, the finer the level of detail resolved. Of the many observational experiments that have been conducted to determine the resolution limits of telescopes, the two most often cited are the Rayleigh Criterion and the Dawes Limit.
What is your favorite globular cluster? Apart from those two southern hemisphere beauties, Omega (ω) Centauri and 47 Tucanae, my answer has to be M22 in Sagittarius. Admittedly, the star chains and "propeller" formation within M13 in Hercules (profiled in the July 2017 Cosmic Challenge) are visually intriguing. But there is just something about the remarkable richness of M22 and its surrounding star field that calls to me.
Fifty years ago this month, on July 30, 1971, Commander David Scott and Pilot James Irwin navigated their Apollo 15 lunar module, nicknamed Falcon, to land among the lunar Apennine mountains, while Alfred Worden remained in orbit aboard the command module, Endeavor. Scott and Irwin guided Falcon to a soft landing between the edge of a deep precipice and the base of a tall mountain to establish Hadley Base, as the landing site became known.
Is there any constellation in the sky more universally known than Ursa Major, the Great Bear? Most of us learned of it as a child, perhaps from a relative or friend, or possibly as a Scout working our way toward a merit badge in astronomy. The seven brightest stars in the group, known in North America as the Big Dipper or in England as the Plough, always draw our attention, especially in the spring when they ride highest in our sky.
Aim your telescope anywhere in the large, seemingly empty gap between the stars Denebola [Beta (β) Leonis] and Vindemiatrix [Epsilon (ε) Virginis] and, given sharp eyes and a dark sky, you are bound to see one or more faint splotches of light somewhere in the eyepiece's field of view. You've entered the Coma-Virgo Realm of Galaxies, a collection of upwards