Is That Telescope Really Suitable for Astrophotography? A No-Bullsh*t Guide
The Bitter Truth Surrounding Novice Telescopes in Astroimaging
In today's world, where social media and camera technology advancements are everywhere, it's not uncommon to find telescopes marketed as being ideal for astrophotography. But alas, not all of them deliver on their promises. Let me share my personal experiences and the truth behind these claims.
My initial voyage into the cosmos began with a Celestron NexStar 4SE. This telescope, matched with a clunky, oversized, and disappointingly outdated alt-azimuth GoTo mount, was a pretty decent scope for observing the universe visually. However, when it comes to deep-sky astrophotography – long exposures – my 4SE was far from perfect.
Many telescopes, including the notorious NexStar SE lineup and others like it, are sold as astrophotography-friendly simply because they can track the sky automatically and a camera can be attached. Don't let this mislead you, as I certainly did with my 4SE.
The Smartphone Astrophotography Trap
One of the most common accessories manufacturers attempt to lure you into purchasing their telescope or package is a simple smartphone adapter. Smartphone astrophotography can catch your eye with some impressive planet and Moon shots if you know what you're doing, but it can also require comparable effort and cost to a top-notch dedicated astrophotography camera.
Deep-sky astrophotography using smartphones is improving, but it's more of an intriguing curiosity than a reliable method for taking high-quality, repeatable images. To achieve decent results, you must have a sturdy telescope and adapter, but most smartphone adapters provided with beginner telescopes are questionable at best, especially when it comes to holding your most prized possession securely.
Unless you invest in a quality adapter like a Celestron NexYZ adapter, the cheap suction cups, straps, or flimsy spring clamps that usually come with these adapters can easily drop your phone at any moment. Furthermore, the added weight of the smartphone and adapter can unbalance your telescope, making it difficult to photograph your intended target accurately.
The Ruse of DSLR/Mirrorless Camera Attachments for Astrophotography
Manufacturers often boast about Barlow lenses or telescope eyepiece holder ends with T threads for attaching a DSLR or mirrorless camera to your telescope with a compatible T-ring mount. Failure to mention is that either camera type usually underperforms for planetary astrophotography and creates balance issues in many cases when attached to your telescope.
Many telescopes will simply not be able to focus properly with a DSLR or mirrorless camera at all, without modifying or removing some hardware or the use of a Barlow lens to shift the focus point. Doing so, however, doubles the telescope's f-stop, making long-exposure astrophotography nearly impossible. So even if you can physically attach a camera to your telescope, it doesn't amount to much in the grand scheme of astrophotography.
The Myth of Alt-Azimuth Mounts for Serious Astrophotography
Many beginners invest in complex mounts, be it computerized, a German equatorial, or a combination of both, for their first telescope. While those sophisticated mounts are unnecessary for visual observation, what about for photography?
For long-exposure astrophotography, the NEED is a dedicated equatorial mount, preferably with GoTo (computerized locating and tracking) capabilities.
Automated tracking mounts, including GoTo telescopes, make imaging the Moon and planets less of a struggle than trying to track by hand. However, if you prioritize aperture to enhance planetary imaging performance, non-GoTo solutions such as a motor-driven equatorial mount or an equatorial platform offer better value and are more cost-effective than a fully GoTo telescope.
Most GoTo telescope packages you'll come across as a beginner are alt-azimuth mounted. When it comes to photographing nebulae, stars, and galaxies, that's a problem. All alt-azimuth telescope mount designs suffer from "field rotation," a blurring effect in long exposure images caused by the mount's stair-step motion as it tracks objects in the sky, which combined with less accurate tracking accuracy compared to an equatorial mount and the inability to make real-time corrections with autoguiding limits alt-azimuth astrophotography setups to exposures of no more than a few tens of seconds.
In some cases, cameras are sensitive enough now to compose an image from many hundreds or thousands of frames, each as short as a few seconds of exposure. However, larger dedicated astrophotography setups still require a true equatorial mount.
The Deception of Offering Sub-par Telescope Designs for Astrophotography
Any telescope intended for deep-sky astrophotography should primarily focus on being astrophotography-friendly, offering a fast f-stop (preferably <f/7), a well-illuminated frame without vignetting, and a sharp, flat image across the entire camera sensor for optimal performance.
Creating an astrograph telescope is difficult and expensive, which is why dedicated astrophotography optical tubes tend to cost a pretty penny, even after pairing them with devices like a coma corrector, field flattener, and/or focal reducer for optimal results.
Moreover, most astrophotography-oriented telescopes won't work for visual observation through an eyepiece or offer mediocre visual capabilities compared to less expensive visual telescopes. To ensure a quality astrophotography setup, your telescope needs to have excellent mechanical qualities as well, so it doesn't require frequent collimation adjustments or struggle to reach focus when moving around the sky while maintaining balance.
- For astrophotography, the Celestron NexStar 4SE, while decent for visual observations, fell short when it came to deep-sky astrophotography, particularly long exposures.
- The NexStar SE lineup, like many others, is marketed as astrophotography-friendly due to its automatic sky tracking and camera attachment capabilities, but don't be misled.
- Smartphone astrophotography, though impressive with planet and Moon shots, can be comparable in effort and cost to high-quality dedicated astrophotography cameras.
- Deep-sky astrophotography using smartphones is more of an intriguing curiosity than a reliable method for taking high-quality, repeatable images.
- To achieve decent smartphone astrophotography results, one needs a sturdy telescope and adapter, but the adapters provided with beginner telescopes are often questionable.
- A quality adapter like the Celestron NexYZ adapter is necessary to prevent dropping the smartphone and to balance the telescope for accurate targeting.
- DSLR or mirrorless camera attachments to telescopes may appear attractive due to Barlow lenses and T threads, but they often underperform for planetary astrophotography and create balance issues.
- Many telescopes cannot focus properly with a DSLR or mirrorless camera without modifying hardware or using a Barlow lens, which doubles the telescope's f-stop, making long-exposure astrophotography nearly impossible.
- For serious astrophotography, a dedicated equatorial mount with GoTo capabilities is needed, especially for long-exposure deep-sky photography.
- Most beginner telescopes are alt-azimuth mounted, which is problematic for photographing nebulae, stars, and galaxies due to the 'field rotation' effect in long exposure images.
- Offering sub-par telescope designs for astrophotography that fail to meet essential requirements like fast f-stops, well-illuminated frames, and sharp, flat images is a deception that deserves attention when considering a telescope for astrophotography.
