Explainer · Buying Gear · Intermediate
Seestar S50 vs Nikon D5300 vs ASI533MC Pro
The East Veil Nebula, shot three times in one month as the setup actually evolved — a Seestar S50, then a Nikon D5300 and a ZWO ASI533MC Pro through the same manual telescope — and what really changed between each.
12 September 2026 · 4 min read
One target, shot three times in a single month, as the setup behind it actually changed. The East Veil Nebula (Caldwell 33 / NGC 6992) went from the Seestar S50's own optics, to an old Nikon D5300 bolted onto a new manual telescope with a T-ring adapter, to that same telescope's camera being upgraded to a dedicated cooled ASI533MC Pro three weeks later. This isn't three cameras picked to compare — it's the real order this site's gear actually arrived in.
Three Cameras, One Setup's Evolution
Two of these three shots came from the exact same telescope. Only the Seestar has its own separate optics — the D5300 and the ASI533MC Pro were both shot through the same Askar 71F (full review), 486mm and 488mm focal length respectively — near enough identical. That matters: it means the D5300-versus-ASI533MC-Pro pair isolates the camera alone, with the glass held constant, while the Seestar comparison is a genuinely different optical train as well as a different camera.
| Seestar S50 | Nikon D5300 | ASI533MC Pro | |
|---|---|---|---|
| Sensor | Sony IMX462, 1/2.8" | APS-C CMOS, 23.5×15.6mm | Sony IMX533, 1" |
| Native resolution | 1920 × 1080 (2.1MP) | 6000 × 4000 (24MP) | 3008 × 3008 (9.2MP) |
| Cooling | None | None | TEC, to ≈35°C below ambient |
| IR/UV filtering | Built-in LP filter | Stock IR-cut (blocks red) | None fitted for this shot |
| Optics | Built-in 50mm, f/5 (250mm) | Askar 71F, 71mm APO (486mm) | Askar 71F, 71mm APO (488mm) |
| Setup | Automatic goto & plate-solving | Manual — mount, guiding, ASIAIR | Manual — mount, guiding, ASIAIR |
| Typical cost | ≈£550 all-in | Whatever DSLR you already own | £800+ camera alone, plus scope & mount |
The Same Target, Three Times
None of these three are equal-length exposures, and they're each processed and cropped as their own finished photo rather than identical test frames — so this is three real results, not a controlled experiment. Seestar: 597 × 10s subs, ≈99 minutes. D5300: 42 × 120s subs, ≈84 minutes. ASI533MC Pro: 40 × 180s subs, ≈120 minutes.
What Actually Changed Between Them
The most visible difference isn't noise or resolution at all — it's colour. The D5300's stock IR-cut filter blocks much of the exact red light the Veil Nebula emits most strongly in (see the full D5300 review), which is why that shot leans hard toward blue and loses most of the nebula's red filaments — a real optical limitation of an un-modified DSLR on this specific kind of target, nothing to do with exposure time or noise.
Aperture sets a hard ceiling on resolving power no matter how long a scope stacks for — the same Rayleigh-limit point covered in more depth in the Seestar-vs-ASI533MC-Pro comparison. That ceiling is roughly 2.8 arcseconds for the Seestar's 50mm and about 1.9 for the Askar 71F's 71mm. What's worth noticing here is that this ceiling explains the Seestar's shortfall against both of the other two shots, but it says nothing about the difference between the D5300 and the ASI533MC Pro — those two share the exact same 71mm aperture, so whatever separates their results is down to the camera alone.
And what separates them is mainly noise control. The ASI533MC Pro's sensor is thermoelectrically cooled and has no amp glow to correct for; the D5300's sensor has neither, so heat-generated noise builds up more over 120-second subs than it does on the ASI533MC Pro's 180-second ones. The two sensors are physically different sizes too — the D5300's APS-C chip has nearly three times the surface area of the ASI533's 1" sensor, gathering more total light and covering a wider field at the same focal length, which is exactly why it was worth trying before buying anything new.
Which One Should You Actually Buy
If you're just starting out, the Seestar S50 is still the easiest and cheapest way in — see the full Seestar S50 review. If you already own a DSLR, it's worth bolting onto a telescope before buying a dedicated astro camera at all — a T-ring adapter is a small outlay against a purchase you may not need, and the D5300 review covers what that actually looks like in practice. Once a DSLR's noise floor and stock filter start holding a target back, a cooled camera like the ASI533MC Pro is the real next step. For a closer look at the Seestar-versus-dedicated-camera side of this on its own, see the Seestar S50 vs ASI533MC Pro comparison.