Astronomy RSS

You've probably seen a very bright yellow-orange star rising from the East as the sun sets. That's Mars! October 13th is the Mars opposition—the best and brightest Mars will be for two more years. Don't worry if you can't get out to see Mars on the 13th though—it will still be extremely bright and brilliant for the next several weeks, through mid-November, when it will begin gradually dimming as the planet moves further away again in its orbit.  How Big Will Mars Be? This tends to get exaggerated every opposition. As we perceive them, Mars and the other planets are all tiny compared...

July is bringing us some hot days, and a hot new target for amateur astronomers! Comet 2020 F3 NEOWISE is now a naked eye comet, presently visible in the pre-dawn sky! How to See It You'll need a clear North-Eastern horizon to make out the comet. By 4:AM, it's several degrees up, and with a good horizon, is clearly visible by the unaided eye. You'll note Venus shinning brightly off to the right, and the bright star Capella above the comet itself, providing a good location aid. The below chart reflects 4:30 AM on July 9th. The best window for...

When you’re selecting a new eyepiece, the first and most important consideration should be how it fits in with the eyepieces you already have – particularly, your magnification scheme.  To figure out the magnification of your eyepieces, you take the focal length of your telescope (1200mm for an f/6 8-inch dob) and divide it by the focal length of the eyepiece.  For example, if you have, say, 25mm and 10mm Plossls that came with your 8-inch dob, they’re giving you 48x and 120x respectively. So, the first analysis is to fill in magnification “gaps” you have – like a high-powered eyepiece,...

It’s fall in Colorado, and that means more humidity in the air, and, if you aren’t mindful, dew on the telescope. This is particularly important for refractors and Cassegrain telescopes - SCTs and Maks, which have a large lens at the front that is highly susceptible to dew buildup. Here are some tips to prevent and in the worst case, remove that dew.  Passive Prevention Lens Hoods and Dew Shields Dew shields are the first line of defense. These work well when you keep your objective pointing far enough towards the horizon that the lens isn’t exposed to the dew coming down...

Celestron last year introduced a fast f/2.2 11" RASA Astrograph, and this year follows that up with the new 8" f/2.0 RASA, a high performance Astrograph for $1699. (They are also making the larger 36mm / 14" RASA available to the public after filling initial institutional orders.) The 8" RASA is an exciting product for astro-imagers - basically a hyperstar system with a 22mm flat field imaging circle, expanding to 32mm. This means it will work for mirrorless APS-C cameras (adapters are available for Canon EOS-M and Sony Mirrorless cameras) but is optimized for astronomical cameras. (Full-frame imagers will want to step...