u/tallpsmith

M17 10 minutes in Bortle 8.9. Just finally happy the skies are clear here in Melbourne, Australia winter finally!! It’s been ages.

My backyard is a shocker. A neighbour's willow eats most of the south-west and the rooflines take everything low, so there's a fair chunk of sky I just can't use. I was spending more time working out whether something would finally clear that willow than I was actually imaging.

So I built an iPhone app for it, which I've called Caelo. You hold the phone up and shuffle around in one place, and it helps you map your real trees and rooflines off the phone's sensors. Everything after that gets filtered through your own personal skyline: what's worth pointing at tonight, how long you've actually got before the trees block it, and which months a target is worth chasing at all given your own backyard horizon. It's quite willing to tell you tonight isn't worth it.

I've included the DWARF 3 and the DWARF Mini as built-in scope presets (full disclosure: I own a Seestar S50 myself, but I want to support as many smart scopes as I can), so the app works to a 15 to 75 degree practical alt-az band rather than a generic one. Fair warning on that band: DwarfLab don't publish a mount limit anywhere in the manual, and the closest thing is their advice to aim above 30 degrees, which their app draws as a red zone on the altitude curve. I've gone lower than that on the floor because a suburban horizon doesn't leave you much choice, and I've capped the top at 75 because of the stacking trouble people report up near the zenith in alt-az. Both ends are my call, not a spec, so tell me if I've got them wrong.

The bit I'd most like some folks to test doesn't need a clear night. Mapping your horizon works in daylight, only takes a few minutes using your iPhone, and gives you a usable-sky percentage at the end. If you're up for trying it, give it a go and tell me what your yard scored and whether the shape it drew matches what you can actually see out there. That's the single most useful thing anyone can send me, and you don't have to wait on the weather for it.

A few apps do versions of this now, some of them free. I'd rather you tried them all and told me where mine falls short than take my word for it.

The details: iPhone only, iOS 18 or later, no LiDAR needed. No ads, no tracking, no account to create, and the horizon map never leaves your phone. It'll be free with a one-time unlock for the looking-ahead bits (core app functions are free), no subscription, and everything's unlocked during the beta.

Comment here or DM me and I can send you a TestFlight invite via email.

Surveying all of his domain.

Cold Melbourne winter, Gas fire running. Snooze fest.

My backyard is a shocker. A neighbour's willow tree eats most of the south-west, the rooflines take everything low; there's a decent chunk of sky I just can't use. So I'm curious how everyone else goes: what's your worst obstruction, and what's the best thing you've pulled out of the sky in spite of it? I'll go first (pics).

I ask because I got sick of the guesswork myself. I was spending more time working out whether something would finally clear that willow than I was imaging, so I built an iPhone app for it, which I've called Caelo. You hold the phone up and shuffle around, and it maps your actual tree and rooflines using the phone's sensors. Weather and moon go in like you'd expect. The bit I actually wanted is that everything then gets filtered through your own backyard context: what's worth pointing at tonight, how long you've really got before the trees take it, and which months a target is worth chasing at all. And Caelo is quite willing to tell you tonight isn't worth it.

I know there are a few apps popping up with this concept now, some of them free, and I'd rather you tried them all and told me where mine falls short than take my word for it. What I will say is I've tried really hard to make Caelo as nice an experience as possible. I hate ads and I hate being tracked, so there's neither; there's no account to create, and the sky mapping never leaves your phone.

It's in TestFlight now and I'm after a handful of testers before it goes out properly. It'll be free, with a one-time unlock if you want the looking-ahead bits, no subscription. Everything's unlocked during the beta. iPhone only, on iOS 18 or later, and you don't need LiDAR for the sky mapping.

If you're keen, comment or DM me and I'll send you an invite. Feedback very much appreciated

(but be nice! :) ).

thanks,

Paul