![]() High-resolution solar imaging with a long-focal-length optic becomes affordable with the addition of a full-aperture, white-light filter. I found the addition of a fan on my 9.25 Edge HD made it usable as much as two hours earlier in my warm Florida climate. Look for telescopes with vents and fans to pull air through, which will accelerate the cooldown, or consider investing in a cooling fan accessory. The drawback of both SCT and MC designs is that they take a lot longer to cool off than a Newtonian reflector, and a warm telescope will produce very blurry images. ![]() But these scopes still require frequent collimation, and MCs tend to stay collimated longer in my experience. Some telescope manufacturers produce modified SCT designs, such as Celestron's Edge HD or Meade's Advanced Coma-Free (ACF) designs, which produce a wider corrected field. You might still find that 2× tele-extender useful for taking advantage of nights when the seeing is exquisite and supports your highest resolution. An MC in the 7- to 10-inch range is a perfect option for this kind of work. The Moon and Sun are brilliant compared to the planets, and a smaller aperture makes for a more portable scope. Maksutov-Cassegrain Telescopes A Maksutov-Cassegrain is a great portable long focal length option.įor high-resolution lunar imaging or solar imaging in white light, an SCT can also serve you well, but I prefer the larger, corrected-image field of a Maksutov-Cassegrain (MC). I prefer the simplicity of a dedicated Powermate or a high-quality Barlow, as neither require additional adapters to connect a video camera. While it's true that it’s better to have a longer native focal length optic, since additional glass can scatter light, modern optical coatings have made this concern a non-issue.Īnother option is eyepiece projection, in which a camera is placed above an eyepiece to provide the additional magnification, but this technique requires a custom adapter. These come in various powers 2×, 4×, even 5× and are an essential part of your long-focal-length imaging toolkit. There are two primary flavors: the time-honored Barlow and the telecentric amplifier popularized by Tele Vue in its Powermate devices. A tele-extender is an optic that increases the focal length of your telescope, giving you more magnification. A large SCT (say, 10 inches and up) will enable you to take closeups of lunar craters and sunspots (again, with the addition of a safe solar filter).Ī smaller, more portable SCT might better suit your needs, though, and you can easily increase its focal length using a tele-extender. What's more, these telescopes provide a well-corrected image in the center of the field of view - right where you are going to place your target planet - without any additional optics. Optically speaking, such a telescope has the focal length you want and bigger apertures are more affordable. For the planets, nothing beats the value of a large Schmidt-Cassegrain telescope (SCT). There are a few optics to choose from for long focal length–imaging. Schmidt-Cassegrain Telescopes Long-focal-length scopes are ideal for imaging the Moon, planets, and the Sun (with an additional solar filter). In fact, most lucky imaging (the technique we use for these targets) is done with small video cameras that pop into the same adapters we use for our eyepieces. In addition, unlike with deep-sky astrophotography with its lengthy exposure times, a telescope setup for high-powered visual observing is often best suited for solar system imaging as well. In fact, they require as much magnification as local seeing conditions allow. The Moon and the Sun (with a proper filter), not to mention the major planets, are bright in comparison and don't require fast optics to image. ![]() But there's more in the sky than just faint fuzzies. The problem with this advice is that it assumes that everyone wants to take photos of galaxies, nebula, star clusters, etc. ![]() It seems everyone in astrophotography (including me!) always gives the same advice to newcomers: Start with a short-focal-length, wide-field telescope.
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