Choosing between two dark sky locations: Bortle 1 in a busy area vs. Bortle 2 in a more private area

Dark Site Light Pollution Request for feedback
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Bluetooth1989 avatar
Bluetooth1989 avatar

I have some time off work this new moon phase and I thought It might be a good time to actually go see some proper dark Skies. I currently live in bortle 5.

I have found 2 different properties that seem reasonable but I am stuck on the bortle rating of them.

Both are just over 3 hours drive away and both cost roughly the same.

One is just listed as a getaway retreat style thing… there are 2 chalets next to each other. At the moment both chalets are empty so with a bit of luck it would only be myself and my partner there. According to the light polution map it is on the edge of bortle 1… but comes in a small pocket of lighter skies at bortle 2.1-2.6.

The other property actually states that they are in an astrotourism region etc and it actually falls in the middle of a bortle 1…. they advertise it a little for that. However there are around 5 cottages to stay in and another building with a few rooms etc. In the photos people have put in reviews of the night sky you can see that there is outdoor lights on … and a campfire place etc, so I think the actual site itself could well be lit up a bit.

Which site would you personally go for? Would the local light polution from the bortle 1 accomidation make it a worse site through an astrophotgraphy set up? Or would the bortle 1 rating of the actual area still make it better for astrophotgraphy if I can point away from the lights of the other accomidation?

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Don avatar
Don avatar

I would get a Sky Quality Meter, and actually measure conditions before making any decisions. I travel quite a bit, and carry a meter where ever I go. Bortle 1 is a high bar to clear. I’ve been to many claimed Bortle 1-2 sites, that were actually 3 or even 4, depending on the scale you use. Elevation makes a difference too. Generally, the higher the better.

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Quinn Groessl avatar
Quinn Groessl avatar

The more private one. You can’t control what other people are doing. I’d rather slightly brighter skies overall than have some idiot with a campfire and spotlights next door.

Tobiasz avatar
Tobiasz avatar

Don · Feb 23, 2026, 11:54 AM

I would get a Sky Quality Meter, and actually measure conditions before making any decisions. I travel quite a bit, and carry a meter where ever I go. Bortle 1 is a high bar to clear. I’ve been to many claimed Bortle 1-2 sites, that were actually 3 or even 4, depending on the scale you use. Elevation makes a difference too. Generally, the higher the better.

I agree. Once I had my SQM-L, my “dark site” was not much darker than the village I am living in. Saves a lot of time and gas.

I was comparing light pollution maps in the search of darker spots and the differences are astonishing. For now I only use this map from David Lorenz, because it seems to be the most accurate one (at least for my locations).

My village: 21 mag/arcs at best. Measurement with SQM-L was 20.9-20.99 depending on the weather.

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Tony Gondola avatar
Tony Gondola avatar

Go with the private site. It would be awful to have a B1 site degraded by what people nearby are doing.

Patrick Graham avatar
Patrick Graham avatar

My vote goes for the more private site as well.

AstroRBA avatar
AstroRBA avatar

I’ve been to B1 sites that have multiple cottages with outdoor lights and firepits etc. BUT those are usually only used during full moon periods. An astro designated site “should” have others on site that respect the purpose so it may be just fine (yahoos could wreck it but probably not)

Tony Gondola avatar
Tony Gondola avatar

If you’re looking to buy it might be best to get something large enough that even if you do have houses nearby, the impact will be minimal. I had 40 acres near Pie Town NM for awhile which was just that situation and it worked well. I suppose someone could install a spotlight but normal outdoor lighting had no impact.

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SonnyE avatar
SonnyE avatar

I just filter out the BS.

When we moved in it was darker here. But then LED’s got popular, and neighbors changed (often on the down stream side). So the best thing was to filter out the BS around me.

If you want to buy property, buy a hole where nobody can build near you. Because just as soon as you get comfy some A’ hole will put up a streetlight on a Barn or pole right in the damned way. It is guaranteed and inevitable.

I’d never go by what somebody sez. My DIL realtor sez, “Buyers are liars.” But if someone is telling you they have a Bortle anything property you can bet they are full of crap. Ask them to prove it.

And don’t use your B-meter during a power outage….

A moderator will review this post shortly. Cute.

Rick Krejci avatar
Rick Krejci avatar

If a property is in a managed area with CC&Rs, see if there are any mentions of lighting. My neighborhood enforces that all lighting should be downward facing, which would give me some leverage if a neighbor puts up a bright security light that blares in all directions. If not, then your best best is larger acreage or up on a hill so neighbor’s direct light impact would be minimized.

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Oscar H. avatar
Oscar H. avatar
+1 for private site
Bluetooth1989 avatar
Bluetooth1989 avatar

Cheers guys. Sounds like the bortle 2 zone is the better choice. Just for the record, sorry if my post was a bit misleading, I am only on about going away for a few days to the dark site. It’s holiday accomidation so I am not purchasing anything, I just wanted to go and experience a proper dark sky site as I think i’ve only really seen bortle 3-4 before and do some imaging for a few nights while i’m there

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Rick Veregin avatar
Rick Veregin avatar

I’m a bit late to reply, but I just wanted to make the point that in low Bortle you are likely limited by read noise in your camera, not the sky conditions. Look up Robin Glover’s wonderful analysis—it is not the background signal that matters so much, but background noise, the square root of the background signal.

So for your CMOS mono camera at F/7, you will be mostly limited by read noise, until maybe 4 minute sub exposures in either Bortle. For less than a 4 minute or so sub length, Bortle background will contribute some to the background noise, but read noise will nearly level the differences. You need to be at 5 to 6 minute exposures in these zones to get to the sky dominating your noise. This assumes you are not using narrow band filters, if you are, read noise will totally dominate in these zones, unless you are taking 60 minute or more subs!

To take advantage of the lowest Bortle you need a very low noise CMOS mono camera at long sub exposure and or low f/ratio!

CS

Rick

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