How dark is your not dark site?

[Size9Hex]

6 hours ago, domstar said:

With winter being too cold to stray far from HQ, I wondered what was considered good darkness for a garden...

Anyway, what is good or poor darkness without getting in a car?

It depends!

From home, I can see stars down to about mag 5.5 inaverted vision near the zenith on a good night if I make a bit of an effort. Near the horizon, and particularly to the south sadly, it's an awful lot brighter. But, 5.5 at zenith is dark enough for the Milky Way to be faintly visible. Having the Milky Way visible means there should be enough darkness/contrast in the sky for other galaxies to also be visible, which really opens up the number of targets you can hunt for. Good/poor is subjective of course, but because of this, seeing the Milky Way is a reasonable line to draw between good/poor I think. Brighter than this, clusters can still be good targets. For nebula hunting, it need to be darker still and I'll happily travel 30 minutes to get to a mag 6 and a bit site (with every type of DSO benefiting from the darker sky and better contrast, not just the nebulae). For double stars, planets and lunar, any site (within reason) can be good.

[Mr Spock]

I can see 5.0 in UMi on a good night. looking to the south or east is much worse though, especially on football nights.

[JOC]

Now I have no idea how to explain how 'not dark' we are, or at least I didn't until I just went outside tonight.  Now tonight we are far too cloudy to make it worth getting the telescope out, but as I was feeing the sheep Orion made an appearance.  Now there is another recent thread where it was mentioned that multiple stars could be found and one of these was in Orion's 'head' - between his shoulders, but a bit higher.  At the time I though how did I miss that, as the other night as an exercise I was working around Orion's key points to practice moving and focussing the telescope.  Since then I've been thinking Orion's head???  Tonight I confirmed my suspicions I looked up and Orion has no head, or does he................we did have lights on as we fed the animals, but as I looked by eye a faint cluster of stars was just about visible in the location where Stellarium had put the 'head'.  In my opinion it was quite a lot fainter that the smudge of stars that is M42 which I could also see.  So there you are, that's how much I can see, Orion's head is just about visible to the naked eye. 

I don't know if that is good, bad or indifferent, but at least it explained why I was so puzzled that I'd never found the stars previously - if I hadn't been told they were there I would not have looked for them, but even with lights on at ground level I could just about make out the cluster that should contain these multiple stars if I look for them next time I get the telescope out. 

[recceranger]

I live in Crickhowell just in the Brecon Beacons NP so I need Night Viewing Goggles just to find my EP!?☘??

[bejay1957]

As with others, it kinda depends on the direction one is looking.  Despite having no streetlights in the village (yes, there are multiple security lights all over), my northern horizon is severely affected by the combined LP from Didcot, Abingdon and Oxford;  I have no western horizon due to the gable end of the house in the next estate, and the roofline of my bungalow obscures part of my eastern horizon view; my southwestern view is slowly being lost as trees in the estate continue to grow...  My better views are looking up to the zenith, with good seeing I can just get M31.

I can go up to the hillfort for better horizons, the northern horizon is still lost in LP, but the eastern horizon is then affected by the LP from Reading and all the lighting from the conurbations up along the M4 corridor to London.

[SilverAstro]

2 hours ago, JOC said:

Orion's head is just about visible to the naked eye.

I don't know if that is good, bad or indifferent,

Pretty fair I'd say, in the presence of lights.

My CdC says they are mag3.4, 4.0 and 4.4,  my Stellarium says mag4, 4 and 4.35m  so a bit of googling for authority needed there.

EDIT wiki says visual magnitude 3.5 for lambda Orion.

 

[Bart]

18 hours ago, Stu said:

Why confused Barry? 5.5 is pretty good, and I would expect to be able to see the Milky Way quite well at that level?

 

18 hours ago, Stu said:

Why confused Barry? 5.5 is pretty good, and I would expect to be able to see the Milky Way quite well at that level?

Well Stu

 A previous poster stated they can't get the Milky Way and yet have a nelm of 4. The Milky Way is good in my garden yet 5.5 is my best I think. Might it be my vision?

edit: don't know how reliable it is, but the DSM app on the iPhone quotes my sky from 20.3 to 21.3. Many/most readings abour 20.9 ish. 

[JOC]

Hi SilverAstro, that's great - thanks for looking things up in terms of which I can see by naked I wouldn't want to commit to that, but it sounds like I must be down to around Mag 4 or so.  From what I understand that's not too bad is it?  However, I suspect that it does depend to some extent on which direction I look.  At the moment during the evening, when I view, Orion drifts nicely from East to South which are my two best directions, I suspect I'd lose a bit once things get round to West and North. 

Mind you from what read here and looking at some of the photos that people have posted of their set-ups I think I am probably luckier than a lot of people in terms of what I have in my own back yard. :-)

[kev]

Im about 4.5 during the evenings. Late at night 5 easy. Milky way visible in the sky but not near horizons and my south is not great (the town is south of me)

On a really good clear night turned midnight about 5.5 and milky way to horizon.  (Lights go off mostly at midnight)  On those occasions ive been known to grab the bins, a jumper dressing gown and coffee and creep out v the house

 

 

[Stu]

3 hours ago, JOC said:

Now I have no idea how to explain how 'not dark' we are, or at least I didn't until I just went outside tonight.  Now tonight we are far too cloudy to make it worth getting the telescope out, but as I was feeing the sheep Orion made an appearance.  Now there is another recent thread where it was mentioned that multiple stars could be found and one of these was in Orion's 'head' - between his shoulders, but a bit higher.  At the time I though how did I miss that, as the other night as an exercise I was working around Orion's key points to practice moving and focussing the telescope.  Since then I've been thinking Orion's head???  Tonight I confirmed my suspicions I looked up and Orion has no head, or does he................we did have lights on as we fed the animals, but as I looked by eye a faint cluster of stars was just about visible in the location where Stellarium had put the 'head'.  In my opinion it was quite a lot fainter that the smudge of stars that is M42 which I could also see.  So there you are, that's how much I can see, Orion's head is just about visible to the naked eye. 

I don't know if that is good, bad or indifferent, but at least it explained why I was so puzzled that I'd never found the stars previously - if I hadn't been told they were there I would not have looked for them, but even with lights on at ground level I could just about make out the cluster that should contain these multiple stars if I look for them next time I get the telescope out. 

So, Orion's head is apparently an open Cluster called Collinder 69, magnitude 2.8. The stars in it are mag 3.4 and below. Quite bright anyway so it seems your skies are not so good

[JOC]

Hi Stu, so not so good eh?  That's a pity and a slight surprise as I had expected my rural location to fairly reasonable for viewing.  So what is considered good?  As aI noted above, this cluster of stars is only just about visible and without knowledge of its existence I would never have realised it was thete to view.  I doubt I could see much brighter.

[Hawksmoor]

Generally from our backyard on the edge of Lowestoft we can see the Milky Way summer and winter after astronomical darkness and before the street lights are turned off at midnight. When the street lights are extinguished observing closer to the horizon becomes much improved and widefield imaging  becomes significantly easier.  With no moon I have been able to see M31 with the naked eye and M33 with binoculars. The double cluster is easy to spot and some stars are visible within the square of Pegasus.  Generally, I consider my location reasonably darkish.  Not as good as the Sahara but better than Greater London.

George

 

[Hawksmoor]

Generally from our backyard on the edge of Lowestoft we can see the Milky Way summer and winter after astronomical darkness and before the street lights are turned off at midnight. When the street lights are extinguished observing closer to the horizon becomes much improved and widefield imaging  becomes significantly easier.  With no moon I have been able to see M31 with the naked eye and M33 with binoculars. The double cluster is easy to spot and some stars are visible within the square of Pegasus.  Generally, I consider my location reasonably darkish.  Not as good as the Sahara but better than Greater London.

George

 

[Hawksmoor]

Oh dear!  old age and chubby fingers on a small screen have caused me to repeat myself repeatedly !

Embarrassed of Lowestoft.

[Stu]

Just now, JOC said:

Hi Stu, so not so good eh?  That's a pity and a slight surprise as I had expected my rural location to fairly reasonable for viewing.  So what is considered good?  As aI noted above, this cluster of stars is only just about visible and without knowledge of its existence I would never have realised it was thete to view.  I doubt I could see much brighter.

I would consider anything better than mag 5.5 to be good, and over 6 is getting properly dark.

Have you checked out Ursa Minor? This has a range of stars down to mag 5. If you can see all seven then your skies are at least mag 5 in that direction.

Don't forget that atmospheric extinction will reduce what you can see as you head down towards the Horizon, as well as light domes from surrounding towns.

[SilverAstro]

1 hour ago, JOC said:

so not so good eh?  That's a pity and a slight surprise

I would say dont be dissappointed by one observation, given the conditions (casual view whilst doing other things with lights - feeding sheep ) were not ideal for an intensive/extensive evaluation, I would think "good , has possibilities".  Had you been more relaxed, rested, dark adapted (no lights nearby) for a good few mins. ( ideally more than 15 ) and selected your night of good seeing I think you will be pleasently surprised ! For example - can you estimate how much haze/moisture was in the air at the time of your obs. did you shine a beam from your torch up into the sky, how much of it could you see ?

Get a few more obs. NE under your belt with known constellations higher and lower in the sky,. you'll soon begin to see the difference

Actually it doesent really matter what your sky is like compared to others, if you can see what you want to and are having fun

 

[niallk]

I reckon that where I go locally is about Bortle 4/5, though I've never properly tried to assess it.  I do head 10mins away to the coast, where at least there are no light domes looking south.  I hope to get further away to darker skies more often, but it's not always feasible with young family/work etc.

I used to observe from my back garden but there is now too much light intruding from neighbours and glaringly bright village streetlights.  I wish they'd turn them off at midnight like how it seems to be done in several places in the UK!

Down the tips of the peninsulae in West Cork/Kerry must be at least Bortle 2 - just stunning naked eye

http://www.skyandtelescope.com/astronomy-resources/light-pollution-and-astronomy-the-bortle-dark-sky-scale/

[DaveS]

On a good night mag 4.2 at the zenith. Normally only 3 stars in UMi but I have glimpsed 4-5 on a very "good" night. Unfortunately my southern view is wrecked by LP from a big retail park. The west isn't too bad as Harrow has fitted well directed LEDs, I've seen it get get better since I moved in. South imaging is really NB only, my efforts on M33 having made that very clear.

NELM 5.5 is, I think, Bortle 5 which is classified as "suburban" . I wish .

[SilverAstro]

4 hours ago, DaveS said:

Bortle 5 which is classified as "suburban" . I wish .

 

Ha! Bortle!! Yes, I know he has been around a while (almost as long as me ) and is an experienced observer, but it is a useless scale, I could write reams on where it goes wrong and how it is not self-consistent - if I add - wrong for THE UK ? This latter bit is only an assumption but Bortle may well be ok for suberbs of a city in the Atacama dessert, or Mojave or wherever it is that John lives. It does not work in our maritime (moisture laden )  atmosphere.

The only scale that matters is the scale on ones eyes and how one can lift it to describe what one can see. Which, for this NE discussion means stars ( planet observers will have other considerations ) If you can see eta Ursa Minor (insert star of choice) you can look forward to a good session

end Bortle diatribe

[mikeDnight]

I can often see 6th mag in the zenith and the milkyway is easy to see from my garden, so i suppose I'm better off than many. I do have flood lights not too far away, but after a word with the council, they turned some lights out on the triple head lighting and aimed the remaining two single lights away from me.  My 8 foot by 7 foot observatory has walls high enough to cut off the direct view of the flood lighting so they rarely affect me. 

I live about 300 yards from a river and I'm situated quite low in the valley of my town, so the air is often steady but can be misty. My site is great for planetary, and when transparent, I get descent views of brighter DSO's. M31 is not hard to see with the naked eye!

Mike 

[DaveS]

Ha yes! I think Bortle wss working in the American south-west and tailered his scale to what he knew. One example being "The Sagitarius star clouds cast shadows" for Bortle 1. Ha ha, they barely rise from here, let alone anywhere further north.

/rant.

[Nyctimene]

Rather good conditions here in Germany, in the rural Odenwald region (between Frankfurt and Heidelberg, 15 km SW of Erbach/Michelstadt). After midnight, when street lights in my small village (450 inhabitants) are switched off completely, in average nights the NELM is between 5.6 mag and 6.0 mag (UMi), and SQM-L readings range from 20.9 to 21.2 (outside the Milky Way). M 31 is visible most of the time naked eye, as is the  Milky Way. The really good nights with NELM of 6.2 or more (SQM-L 21.35 and better), when M 13 can be spotted naked eye, have become rather rare here. Nevertheless, a really dark area near the  light- flooded Rhein-Main- and Rhein-Neckar regions. I've added a picture below; my location  is represented by the blue-green dot (Mossautal, SW of Michelstadt).

Like SilverAstro and others, I never could get on with the Bortle Scale. The aspect, that it was developed by an observer in the dry South-West American regions might really explain, why it seems to be of little use here in the humid Western and Central Europe regions. For 25 years I've lived and observed literally "in the woods" (next village 7km!), and the site, according to Bortle, would have had to be rated as Bortle 4 to 5 ---"rural to suburban sky". Never seen the Zodiacal light or M 33 naked eye. (End rant).

Stephan

[Paz]

At home I can usually see naked eye to magnitude 4.5 sometimes a bit better give or take a little bit. If I stay up really late until more of the artificial lights have gone out it improves but only slightly.

[Arbennek]

I get a consistent NELM of about 4.8, with many nights hitting 5. I get hints of the milky way and M31 is visible with averted vision. The sky to the north is my worst, but it's blocked by the house so I don't observe that way anyway.  I've seen M33, M1, M81/82 amongst others through my binoculars.

So, pretty good I would say, although they could also be better.

[popeye85]

Have just stumbled across this

https://scistarter.com/project/801-Loss-of-the-Night

Seems like a great way to measure how dark it skies is and also help fight LP-win win!!

Downloaded the app but not had a chance to try it out yet.