Guides / Comparison

Two little doublets. One images flat out of the box. One asks for a flattener.

The Evostar 72ED and Askar 71F are both ~72mm ED doublets — the classic “first astrophotography refractor.” They're close on paper, but they answer one question differently: do you want the proven scope everyone learned on and add a field flattener yourself, or one built to deliver a flat, camera-ready field with nothing bolted on?

Both ~72 mm ED doublets·$599 vs $501·8 min read · updated Jul 2026
The 20-second verdict

Which sentence sounds more like you?

Flat out of the box
Askar 71F Flat-Field Refractor

“I want to screw on my camera and get round stars to the corner — done.”

Built-in flat field — no separate flattener to buy or space
Best when you want fewer parts and fewer things to get wrong
$599typical street price
vs
The proven classic
Sky-Watcher Evostar 72ED

“Give me the scope everyone learned on — I’ll add the flattener myself.”

A battle-tested first imaging scope with huge community support
Best when you want the lowest entry price and don’t mind one add-on
$501typical street price

Both take gorgeous widefield images. You’re really choosing between the lowest price and the fewest moving parts.

Askar 71F Flat-Field Refractor
Askar

Askar 71F Flat-Field Refractor

A flat-field imaging doublet designed to hit a flat, corrected field with no extra corrector.

Sky-Watcher Evostar 72ED
Sky-Watcher

Sky-Watcher Evostar 72ED

The beloved starter ED doublet — superb value, with a flattener as a known next step.

What owning each is like

Picture your first imaging setup.

Imaging with the Askar 71F

You thread your camera straight onto the back, dial in backfocus once, and shoot. Because the flat field is designed in, stars stay round and tight from the center all the way to the corners without a separate corrector hanging off the drawtube. There's less to buy, less to balance, and less to blame when something's soft — the field is either right or your spacing is off, and that's a short list. For a first system, fewer variables is a real gift.

Imaging with the Evostar 72ED

You're standing on a decade of other people's hard-won knowledge: every spacing number, every flattener pairing, every quirk has been posted, solved, and screenshotted somewhere. Bare, it's a lovely visual and lunar scope; add the matched flattener and it becomes a proven widefield astrograph that has trained thousands of beginners. It costs the least to get started — as long as you're comfortable that the flattener is a when, not an if.

Side by side

Close on paper. Different out of the box.

Askar 71F
Evostar 72ED
Identical on paper
Optical designED Doublet RefractorED Refractor
Both are compact ED doublet refractors in the ~72mm class — the sweet spot for a first widefield imaging scope. The real split is whether a flat imaging field is included or added later.
Where they actually differ
Aperture71 mm72 mm
Focal length490 mm420 mm
Focal ratiof/f/6.9f/f/5.8
Field flattenerFlat field built in — none neededAdd a matched flattener (extra cost)
Ready to imageCamera on, dial backfocus, shootAfter you buy + space the flattener
Parts to manageFewer — one integrated opticMore — OTA plus corrector
Community knowledgeNewer, growingVast — the classic beginner scope
Price$599$501
Find yourself

Which one is you?

The Askar 71F is you if…

You want the shortest path from unboxing to round-star subs
You'd rather not research and buy a separate flattener
Fewer parts to space, balance, and troubleshoot appeals to you
A slightly higher sticker is worth a simpler, complete system

The Evostar 72ED is you if…

You want the lowest possible entry price into imaging
You like leaning on a huge community for every setting
You'll also use it visually and for the Moon, not just imaging
Adding a flattener later feels like a normal next step, not a chore

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Start guide →

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Lowest price, or fewest parts?

Go a level deeper on whichever fits how you like to build a rig — full details, what it images, and today’s price.

See Askar 71F details →See Evostar 72ED details →
View Askar 71F deal at Agena AstroProducts →