What's the point - Bortle?

[mikeDnight]

  Have you ever wondered - What's the point of the Bortle scale?

  The only reason I'm asking is that our local skies are what our local skies are, and there's little we can do about it. So does knowing where you are on the Bortle scale put you off trying? Does knowing have a negative psychological effect that affects your zeal and your potential?

 I'm a purely visual observer, so the Bortal scale may not be anywhere near as important to me as it might be to an imager, but for decades I've just assessed the night on the night. On most clear nights I can see the milkyway with the naked eye from my doorstep so I'm happy. I've seen IC434 and the tiny notch of the horse head through my 4" refractor  from my site, but that's because I largely ignore the general consensus about what can and what can't be done. So do scales such as Bortle bother you, slow you down, or stop you in your tracks?

I believe I'm a Bortle 5 spot!

Edited February 26 by mikeDnight

[wookie1965]

It made me get rid of my 10" Celestron Starsense as I couldn't see anything. 

Stick to my refractors at least they can punch through and I can get doubles and triples. 

Edited February 27 by wookie1965

[M40]

I suppose it's just a piece of local knowledge. We moved from a bortle 6 to a bortle 4 and I did check all places that we searched, no way was I moving somewhere brighter, it was one of the very few things on my wish list.

[michael.h.f.wilkinson]

It helps me select which objects to chase on the night. I live in a Bortle 4-5 (6 on a bad night) suburban setting, with Bortle 2-3 skies fairly close by.  I use my biggest scopes (Celestron C8 and Meade SN-6) on planets and moon on bad nights, but gun for fuzzies on good nights. I have visited Bortle 1 and 2 sites on holidays, and everything performs better there.

Regarding the usefulness of the Bortle scale for imagers: I can punch through much of the light pollution with narrow-band filters, and capture stuff that is terribly hard to spot visually, so it seems to affect my observing more.

Even without narrow-band filters, I can subtract the sky background in ways an observer could never do, so the horsey is an easy target for my 80 mm in imaging. You do need much longer integration times to reduce the photon noise of the sky background, but long exposures can get neat results.

13 h 2 min 30 s total integration time on the Dumbbell Nebula

[DirkSteele]

Nothing puts me off as I live in central London so short of perhaps Tokyo or Beijing I live in the worst place in the world to pursue astronomy. Buy I do it anyway.

What the Bortle scale does for me is provide a quick check on what I can expect when I travel and as such whether it is worth packing a scope. Though saying that, I almost always a take a scope anyway.

Certainly, when I finally leave the big smog for a more rural location, the Bortle scale will help me eliminate a few places as if I make the move I want some significant incremental gain on sky darkness.

[Mr Spock]

It feels like I'm in Bortle 95 minimum...

[Ouroboros]

2 minutes ago, Mr Spock said:

It feels like I'm in Bortle 95 minimum...

I think you should try observing after the sun goes down.  

[Mr Spock]

The sky at night is so bright here I need SPF 30 

[carastro]

It is most important to me to know the Bortle scale of other locations seeing that l live in Bortle 8.   If l want to travel to darker skies l need to know the Bortle scale so l know if it the right place to go.  

Edited February 26 by carastro

[michael.h.f.wilkinson]

5 minutes ago, Ouroboros said:

I think you should try observing after the sun goes down.  

Or take up solar astronomy

[ONIKKINEN]

6 minutes ago, carastro said:

It is most important to me to know the Bortle scale of other locations seeing that l live in Bortle 8.   If l want to travel to darker skies l need to know the Bortle scale so l know if it the right place to go.  

This is the case for me as well. I am always driving to a location rather than setting up at home, so knowing what to expect there is important.

[paulastro]

46 minutes ago, mikeDnight said:

  Have you ever wondered - What's the point of the Bortle scale?

  The only reason I'm asking is that our local skies are what our local skies are, and there's little we can do about it. So does knowing where you are on the Bortle scale put you off trying? Does knowing have a negative psychological effect that affects your zeal and your potential?

 I'm a purely visual observer, so the Bortal scale may not be anywhere near as important to me as it might be to an imager, but for decades I've just assessed the night on the night. On most clear nights I can see the milkyway with the naked eye from my doorstep so I'm happy. I've seen IC434 and the tiny notch of the horse head through my 4" refractor  from my site, but that's because I largely ignore the general consensus about what can and what can't be done. So do scales such as Bortle bother you, slow you down, or stop you in your tracks?

I believe I'm a Bortle 5 spot!

Mike  there is an obvious use of the Bortle Scale to anyone who doesn't always choose to observe from home. 

Observers who wish to, can go to a better area for a clearer  view of  fainter deep sky objects inparticular, and more transient objects like brighter comets, aurora displays and meteor showers etc etc. 

It's not the case people go elsewhere because they don't try to get the best of their home conditions, but because its sometimes good to travel somewhere the conditions are better to obtain a better view, or an image.  For this use the Bortle Scale is very useful.  

Of course for your main interests of lunar or planetary work this is not so important.  However, even your excellent deep sky drawings would show more detail if you did them from skies with a better Bortle rating if you wished to - or even a bigger telescope 😅

Its not a weakness or admiting defeat to sometimes seek darker skies.  That's why I've been going to Kelling for about twenty or so years .  Unkind people might say I need to with my aging eyes 😊.

 

 

[badhex]

Basically what everyone else said about travel, and house buying options. Finding out that Nisyros in Greece was a Bortle 3 was a reason for going there on island hopping travels. Similarly knowing it would be worth taking a scope to Ponza as it is a 4 (and it was a good 4 at that!). It's not the most accurate scale, but it's a good finger in the air for what to expect. 

[cajen2]

In my case, it isn't so much the skyglow which is the problem (my skies are supposed to be B5). It's all the local lights - mainly street lights, which are all sodium, but also the usual insecurity, garden and just pointless lights which people seem addicted to ATM. Put it this way, I can normally pick out the brightest stars in U. Major or Orion but that's about it. So it's planets, the Moon or doubles/multiples only for me.

[tomato]

The Bortle scale at least in the UK, pales into insignificance compared to where you are on the Okta scale…

[John]

The darkness and transparency of my sky (supposedly Bortle 5) varies hugely depending on the direction I look in because of LP glows from nearby cities (Bristol, Bath, Newport and Cardiff). To the S and W and overhead it can pe pretty dark. To the N and E, it's not worth trying to hunt for anything faint unless it's 45 degrees or more above the horizon.

I have to be patient and wait for targets to get to the more favourable parts of the sky. It could be worse though - I have seen the Horsehead Nebula a couple of times from my back garden. I can usually see M31 with the naked eye when it's decently placed and quite a lot of the milky way on a good night.

 

Edited February 26 by John

[Elp]

35 minutes ago, tomato said:

The Bortle scale at least in the UK, pales into insignificance compared to where you are on the Okta scale…

I think 7 goes hand in hand with my bortle.

[Zermelo]

For buying my next house.

[JOC]

I've always been vaguely interested in the figure as before I logged onto SGL I thought I lived somewhere fairly dark (notwithstanding four socking great big security lights that appeared about 4 years ago on an industrial estate about 1/4 mile away which didn't do much for my horizon view south).  However, although I saw lots of stars I was amazed to see the views of the milky way that some folks get, I don't think I am that aware of the Milky Way here.  Then I discovered that I was under Bortle 4 skies - about at the halfway point on the scale and assumed that all you wonderful telescope people were probably taking your photos under much darker skies than I have and since discovering I was only Bortle 4 I have been less satisfied with my views of the stars.

[Ags]

The Bortle Scale doesn't put me off observing from my city site, but it helps explain what I see to others, and to understand what others see from their locations.

[Guest]

It definitely helped decide my land buying for sure, but it's not entirely reliable imho.  You really need to be at the land over night on a clear new moon to really know what you've got.

And of course as everyone else mentioned, deciding where to travel sometimes, especially camping.  

 

But as I mentioned in another thread, the bortle scale is very subjective.  It depends on the sky transparency from night to night and also our own eyes.  I know mine are bad enough that what I actually see with my own eyes is at least one number worse than what it actually is.

[Sunshine]

Did I ever mention how much I hate the word "bortle" sounds so ridiculous, out of rebellion I invented Nortle, close enough to bortle and at least for me it sounds better.

[niallk]

With a short drive, I can get to a darker spot, maybe Bortle 4 bordering on 3.

I've noticed nights of exceptional transparency - I'm guessing less back scatter of light pollution being an important factor (?) - and wow: noticeably much better contrast on DSOs.  Unfortunately, such nights have been rare for me, but the memories of what can be possible locally keep me trying!!

One needs a helluva lot of patience & tenacity in this hobby for so many factors & conditions to align for the best views - some of which we can influence,  most we can't.  But that thrill when you know things are looking much better than usual... 😎

Edited February 27 by niallk

[Steve Ward]

4 hours ago, Sunshine said:

Did I ever mention how much I hate the word "bortle" sounds so ridiculous, out of rebellion I invented Nortle, close enough to bortle and at least for me it sounds better.

Well as it's somebody's name I think that's rather petty and schoolyard-like , how would you like folk to start referring to something related to you as Jabba or Neddie rather than your real name ...  😄

Edited February 27 by Steve Ward

[Nigella Bryant]

I'm living in a Bortle 4 bordering 3 so it's important to me too, especially when I move house one day to be nearer my family. My sky at the moment I think is pretty amazing so anything less when I move won't cut the mustard, lol. 

It won't be an immediate move, lol. A few years time when I'm nearer 70, lol.