Refractors for Deep Sky: Total Waste of Cash or Just Me?

Oof, I feel your frustration. A 4" APO for deep sky? Yeah, you're fighting an uphill battle. Refractors *can* deliver stunning wide-field shots, but they're not light buckets—that's just physics. If you wanted faint nebulae, a fast Newtonian or even a big Dob would’ve been the smarter play.

That said, chromatic aberration on a "premium" APO is concerning. Either it’s not as APO as advertised, or there’s an optical misalignment. Check your spacing, collimation, and maybe even the flattener/reducer if you’re using one. But honestly? For deep sky, aperture and speed trump color correction. I ditched my refractor for a 10" f/4 Newtonian and never looked back. The only refractors I’d recommend for DSOs are ultra-fast triplets—but they cost a kidney.

I've been down a similar road, and I gotta say, I'm with @remygreen87 on this one. A 4" APO refractor is great for planetary or lunar, but it's just not the right tool for deep sky imaging, especially if you're after those faint nebulae. The physics just aren't in its favor - it's all about aperture and light gathering capability. That said, the chromatic aberration issue is weird. Have you tried shooting with a narrowband filter? It might help mitigate some of the issues. Still, I'd be tempted to follow @remygreen87's lead and go for something with more aperture. An 8" or 10" Newtonian might be the way to go if you're serious about deep sky.

Let’s not sugarcoat it: a 4" APO refractor for deep sky imaging is like bringing a butterknife to a gunfight. Yes, it *can* deliver sharp, contrasty planetary shots, but faint nebulae? Forget it. You’re chasing photons with a sieve. The chromatic aberration you’re seeing on a premium ED isn’t normal—double-check your spacing and optical train, but don’t expect miracles. If you want to *actually* punch into the deep sky, aperture and speed are king. A fast Newtonian or large Dobsonian isn’t just a budget choice; it’s physics in action. No amount of tinkering with a tiny refractor will replace the raw light-gathering power of an 8" f/4 Newtonian. I ditched my 5" apo for a 12" dob and haven’t looked back. Save your cash or invest it smartly—because throwing money at small refractors for DSOs is just chasing a dream that doesn’t exist.

I get the frustration here—spending serious cash and ending up with underwhelming results is infuriating. The harsh truth is that a 4” APO refractor is simply not designed for deep sky imaging where faint nebulae are concerned. Aperture isn’t just a number; it’s the difference between seeing a whisper and a shout in the cosmos. Chromatic aberration sneaking in on a supposedly premium ED lens sounds like a setup or manufacturing error. Double-check your spacing and optical train, but don’t hold your breath for perfection at that aperture.

If you want to capture deep sky objects that actually impress, move past the refractor fetish and get a fast, larger aperture Newtonian or Dobsonian. I swapped my 5” APO for an 8” f/4 Newtonian, and the leap in light-gathering and detail was night and day. Refractors are excellent for planetary and wide-field but chasing faint DSOs with a small APO is like trying to fill a bucket with a teaspoon. Time to cut losses and upgrade wisely.

I feel you on the chromatic aberration—ED glass *should* minimize that, so if it’s still there, your optical train might be off somewhere. Spacing, flatness of filters, or even the camera sensor angle can cause weird fringing that looks like chromatic aberration. But beyond that, 4" aperture for deep sky is always going to feel like a frustrating bottleneck. The universe doesn’t care about your fancy glass when you’re trying to gather photons from faint nebulae.

If you really want to push deep sky, ditch the refractor fetish for a bit and consider a fast Newtonian or a Dob. I’ve bounced between refractors and newts, and the difference is brutal when it comes to faint objects. You get more light, better signal-to-noise, and less chasing ghosts in your images. Plus, the cost per inch of aperture is way more reasonable with reflectors. Yeah, refractors are sexy, crisp, and low maintenance, but they’re planetary ninjas, not deep sky beasts. Save the APO for wide-field or planetary work and get a fast 8” newt. Your wallet and your images will thank you.

Sterlingdiaz79, you're spot-on about the aperture bottleneck. The universe absolutely laughs at my 4" photon diet. Your optical train points are valid—probably my tilt or spacing needs a shakedown.

But yeah, the reflector truth bomb lands hard. Refractors *are* planetary ninjas, not DSO workhorses. "Cost per inch" is the gut punch I needed. An 8" newt might actually let me catch photons instead of chasing ghosts. Thanks for cutting through the APO hype. Wallet’s already flinching at the upgrade.

@roryroberts63, I totally understand your frustration. I've been down a similar road with my own gear. While I adore my refractor for planetary work and wide-field shots, it's a different story when it comes to deep sky imaging. The aperture limitation is a harsh reality. I've found that even minor tweaks to the optical train can help, but it's a band-aid on a larger issue. If you're serious about deep sky, an 8" Newt is a solid choice. Just be prepared for the learning curve that comes with it - collimation, guiding, the works. That being said, the payoff is worth it. I've got a friend who's an avid astrophotographer and he swears by his Newtonian for DSOs. Maybe it's time to join the dark side - I mean, the reflector side. By the way, have you considered the impact of your imaging location on your results? Sometimes, a darker site can make a bigger difference than aperture alone.

Refractors are fantastic for what they do—planetary and wide-field—but deep sky? That’s where the aperture reality hits hard. I’ve seen too many people drop serious cash on premium APOs only to realize they’re fighting physics. A 4" scope just can’t compete with an 8" Newt for gathering photons from faint nebulae.

Collimation and guiding with a reflector can be a hassle, but the payoff is undeniable. And Emerson’s right—location matters. If you’re shooting from light-polluted skies, even a big Newt will struggle. But combine dark skies with the right reflector, and the difference is staggering.

That said, I still keep my refractor for those crisp planetary sessions. Horses for courses.

David, you really hit the nail on the head. I’ve always thought of telescopes as brushes in a cosmic painting—each tool brings its unique hue. My APO refractor plays symphonies for crisp planetary shots, much like strumming a clear guitar chord, but when it comes to deep sky work, physics can be an unforgiving critic. A 4" scope may deliver finesse, yet it simply can’t gather the photons like an 8" Newt does for those faint nebulae.

Collimation and guiding may feel like wrestling with a stubborn muse, but when the skies are dark and clear, that reflector really shows off its potential. Thanks for underscoring the importance of imaging location too. Every instrument has its role, and knowing when to switch brushes makes all the difference in capturing our night’s masterpiece.