connect Late 2009 iMac 10.3.6 (21.5" display)with mac mini

From Luna's website, in their own words:

❝ Like any product, Luna Display does have limitations and it’s not recommended for high-motion content. For example, I wouldn’t recommend using Luna Display for gaming or video editing. ❞

Save yourself the headache and buy a monitor for your Mac mini. They don't have to be expensive. You can find an okay monitor starting at ~ $125.

Target display mode is old tech and now dead to Apple.

Yes, both of you make some good points… D.I.Johnson especially , Luna/Duet display may work…**,BUT*** limitations , … even if you buy the pro version… limitations… Hey Daniel, could you do a half step— like a refurbished M2 pro iMac… or a refurbished Mac pro from 2019+ monitor , bear in mind though, that if you replace your 2009 iMac with an Apple silicon Mac, all your old apps/software eon’t work at all… and that in general Apple Silicon Macs are NOT upgradeable after purchase ( for everything ) … they are all made built-to-order.. so maybe look at an Apple certified refurbished Mac of some kind… 2009 IS pretty old though… I’m amazed to hear that yours is still running, albeit slowly… I wouldn’t bother spending any money to upgrade a 2009 iMac or get it fixed if it broke down, I’d definitely recommend having and doing a regular backup of your iMac ( Time Machine will do you fine and it’s free— just add an HD of the same size or bigger than the one in your iMac and there you go)

john B

Sorry, DF71, but it’s natively impossible to do so… what you were hoping to do is called Target Display Mode ( TDM) and it did exist a long time ago, but it’s been dead for many years.. about the only thing that might work is “Luna/Duet Display”, but you have to pay for/buy that..

John B

No.

That iMac does not support Target Display Mode. Of the 2009 models, only the 24" and 27" ones did. In addition, Apple placed restrictions on Target Display Mode such that no current Mac will support using any iMac as a Target Display.

A 21.5" iMac would have a resolution of 1920x1080 pixels.

You can find 24" 1920x1080 monitors for anywhere from about $80 (ones with lousy color accuracy) to $150 (ones with IPS panels and near-100% coverage of sRGB). For about $300 – $350, you could find a basic 27" 2560x1440 or 27" 3840x2160 (4K) monitor with an IPS panel and near-100% coverage of sRGB that would be a huge upgrade on that old iMac, would be more convenient to use, and would take less electricity, besides.