Can you really see +7 magnitude stars with your eyes in bortle 1 or 2 skies?

[jetstream]

12 hours ago, DanyalAG said:

I have seen it naked eye on a couple of occasions, but it requires dark skies.However, in my opinion Mizar and Alcor is a finer test of visual acuity(at least for me).

Ok, I was puzzled by your answer that Mizar and Alcor are harder to split than the Double Double Epsilon Lyrae.

I just went outside not dark adapted in avg skies and find this extremely easy, but I had to check. It is nowhere near as hard as splitting Epsilon Lyrae into "2" stars.

Did you mean the Double Cluster in Perseus by chance?

[Sunshine]

I really wish they would replace the word bortle, I refuse to say it. 

[jetstream]

1 minute ago, Sunshine said:

I really wish they would replace the word bortle, I refuse to say it. 

I really wish the Bortle scale is scrapped- I just can't relate to it. Bortle 1, Bortle 2 ... I can see M33 naked eye here but some of the parameters don't jive IMHO.

[DanyalAG]

6 minutes ago, jetstream said:

Ok, I was puzzled by your answer that Mizar and Alcor are harder to split than the Double Double Epsilon Lyrae.

I just went outside not dark adapted in avg skies and find this extremely easy, but I had to check. It is nowhere near as hard as splitting Epsilon Lyrae into "2" stars.

Did you mean the Double Cluster in Perseus by chance?

In dark skies, I think Mizar and Alcor would be easier. However from my light-polluted skies, Mizar's glare makes it nearly impossible to see Alcor. On the other hand, the components of Epsilon Lyrae are almost equal magnitude. I find them much easier to focus on both of them.( I live in NELM 4 -4.5 skies )

[jetstream]

3 minutes ago, DanyalAG said:

In dark skies, I think Mizar and Alcor would be easier. However from my light-polluted skies, Mizar's glare makes it nearly impossible to see Alcor. On the other hand, the components of Epsilon Lyrae are almost equal magnitude. I find them much easier to focus on both of them.( I live in NELM 4 -4.5 skies )

Could be, not sure about how your skies affect this.

[alan potts]

I recall Olly who has a place down in southern France has said in the past that one of his visitors can and did 7th mag stars. Though he openly admits he couldn't see these stars the guest could, Olly's site is very dark. I too have seen very difficult objects from here in Bulgaria , many times seeing M33, it's almost overhead in Autumn.

Alan

[Mr Spock]

I remember when... back in the '70s when we had power cuts and there was zero light from anywhere, I had some incredible views of Orion. I remember three faint stars near Betelgeuse which I see in CdC listed as 6.8, 6.9 and 7.2.

I was younger back then and was known for seeing faint stars through my scope. Not so now 

[Barry-W-Fenner]

My wife and I were watching a nature program on Namibia not so long ago. It was about how difficult hunting was for lions when the moon was growing fat.  I couldn't stop looking at the pitch black sky and all the stars, even the narrator mentioned the views of distant galaxys. It looks the perfect place for observing, as long as you don't get eaten..

[Barry-W-Fenner]

On 20/03/2020 at 08:28, Ships and Stars said:

I'd love to visit Namibia. That's been on my list for a few years now. Did you take binoculars or did your lodgings have a scope?

Toyota Land Cruisers (especially old ones and any of the 70 series) are my other weak spot besides astronomy, so I'd imagine there are a few kicking about there.

I to have a soft spot for most things Toyota. My dad has been an employee of them for over 40 years. I have had  many of there model range from the more mundane but extremely reliable corolla., corolla GTI's to MR2's and Celicas. The Land cruiser is legendary and a real no nonsense off road vehicle.

[Barry-W-Fenner]

I really need to get to a decent dark site to see what the Dob can do. My research as to what is available in Kent has only come up with a bortle 5 location so far... 😞

[Ships and Stars]

59 minutes ago, Barry-W-Fenner said:

I really need to get to a decent dark site to see what the Dob can do. My research as to what is available in Kent has only come up with a bortle 5 location so far... 😞

Hi Barry, I had a quick look and there's a little place called Stelling Minnis that the LP Maps says a small area just to the north is 21.15. 

Still in Kent I think, the LP map shows another slighter darker band from near Newchurch running SW towards East Guildford, with the darkest patch about three miles ENE of East Guildford running south down to the coast and a 'Neath Road' in particular. 

Above all, look around Lydd MOD Ranges and/or Dungeness, Romny Marsh and Rye Bay near the coast - that should be the best bet by far for anyone in Kent if you can find a place around there to park?

There's an MOD rifle range near me, and you can walk on it when no training is taking place, and most importantly for us, you can use the car park (it's unlit I believe), but I've no idea about Lydd.

LP Map says that area is a 21.42-21.48, which is Bortle 4 going on Bortle 3, roughly the equivalent of my nearest dark sky spot here in NE Scotland, which is pretty decent, really. 

https://en.wikipedia.org/wiki/Lydd_Ranges

https://en.wikipedia.org/wiki/Dungeness,_Romney_Marsh_and_Rye_Bay

Good luck!

PS try to toggle the transparency slider (top right corner on a desktop/laptop PC) on LightPollutionMap back and forth and it will show the darkest areas more easily👍

 

 

 

Edited March 21, 2020 by Ships and Stars

[Barry-W-Fenner]

40 minutes ago, Ships and Stars said:

Hi Barry, I had a quick look and there's a little place called Stelling Minnis that the LP Maps says a small area just to the north is 21.15. 

Still in Kent I think, the LP map shows another slighter darker band from near Newchurch running SW towards East Guildford, with the darkest patch about three miles ENE of East Guildford running south down to the coast and a 'Neath Road' in particular. 

Above all, look around Lydd MOD Ranges and/or Dungeness, Romny Marsh and Rye Bay near the coast - that should be the best bet by far for anyone in Kent if you can find a place around there to park?

There's an MOD rifle range near me, and you can walk on it when no training is taking place, and most importantly for us, you can use the car park (it's unlit I believe), but I've no idea about Lydd.

LP Map says that area is a 21.42-21.48, which is Bortle 4 going on Bortle 3, roughly the equivalent of my nearest dark sky spot here in NE Scotland, which is pretty decent, really. 

https://en.wikipedia.org/wiki/Lydd_Ranges

https://en.wikipedia.org/wiki/Dungeness,_Romney_Marsh_and_Rye_Bay

Good luck!

PS try to toggle the transparency slider (top right corner on a desktop/laptop PC) on LightPollutionMap back and forth and it will show the darkest areas more easily👍

 

 

 

Thanks SAS, your a gent! I will have a read through this and play around with various locations.  I did read about Lydd and Romney Marsh being dark. They are both about an 45-60 mins  from my location so will be worth checking out.
 

I find it quite amazing how you can have a high bortle area which has the odd pocket of dark sky running through it. Hopefully I can search out a few of these sky's and see what the 8" dob can do in better conditions.

Baz

 

[JTEC]

It’s certainly possible to see darker the mag 7 given the necessary sky quality and eyesight. I know because 20 or so years ago I estimated 7.8-9 from a high quality site in the Canaries. I’ve always had very good eyes. However, neither my eyes nor, I suspect, with the spread of light pollution, the quality of the site are what they were then. I was already an experienced observer at the time and not at all delusional. That said, I would expect there to be some error in the estimate but significantly fainter than mag 7, no question.

With regard to dark skies in Kent, I lived most of my life in Kent and still go there frequently. There were some decent dark skies in Kent back in the 80s but that all started to go away once work started on Eurotunnel and with the consequent growth of Ashford, Canterbury, Medway towns, etc most dark places have been lost and the sky quality is overall quite polluted. I know Stelling Minnis very well - it’s not particularly dark. Dark sky maps are not all completely informative in locating the best observing sites.  The (excellent) CPRE Night Blight interactive map, like most others now, shows light shining upwards as recorded in satellite imagery.  It doesn’t show you what the sky and horizon would look like if you were standing in what shows as a ‘dark’ place on the map. From Stelling, for example, there will be significant horizon light from Folkestone and Dover and perhaps Ashford as well.  I think the darkest places in Kent nowadays are probably to be found around the Romney Marsh. I also had some good observing some years ago from sea horizons on the East Coast.

[Ships and Stars]

2 minutes ago, Barry-W-Fenner said:

Thanks SAS, your a gent! I will have a read through this and play around with various locations.  I did read about Lydd and Romney Marsh being dark. They are both about an 45-60 mins  from my location so will be worth checking out.
 

I find it quite amazing how you can have a high bortle area which has the odd pocket of dark sky running through it. Hopefully I can search out a few of these sky's and see what the 8" dob can do in better conditions.

Baz

 

Good luck there! LP map looks promising for that area,  even north of the firing range. If there are any farms, you might even be able to ask a farmer if you could set your telescope up on one of his tracks. All they can do is say no thanks!

[alacant]

On 19/03/2020 at 14:13, DanyalAG said:

see better than 7

Hi

Interesting point about this is that it's difficult to know where you're looking because when there's no moon or light pollution, you can't see constellation outlines. If you can, that means there's haze and the magnitude will be cut below 7. Nice problem to have:)

Cheers, clear skies and keep safe.

[ollypenrice]

6 hours ago, Sunshine said:

I really wish they would replace the word bortle, I refuse to say it. 

Yes!  It really conjures up the worst kind of gastric disorder, some mortifying internal malfunction occurring in a public place...

🤣lly

[Ships and Stars]

3 hours ago, Mr Spock said:

I remember when... back in the '70s when we had power cuts and there was zero light from anywhere, I had some incredible views of Orion. I remember three faint stars near Betelgeuse which I see in CdC listed as 6.8, 6.9 and 7.2.

I was younger back then and was known for seeing faint stars through my scope. Not so now 

As long as no one suffers or their food spoils, I love a good power cut!

[Mr Spock]

2 minutes ago, Ships and Stars said:

As long as no one suffers or their food spoils, I love a good power cut!

It wasn't fun. Spending the evening in the cold with just a candle...

[Ships and Stars]

13 minutes ago, Mr Spock said:

It wasn't fun. Spending the evening in the cold with just a candle...

Ouch, that qualifies as suffering in my book. I used to live in a flat with a gas/electric card meter (total rip-off!) and it would always run out unexpectedly about five minutes after the local shops shut. Woke up several mornings able to see my frosty breath. I was so happy to get to work because they had heat! 

[DaveL59]

8 minutes ago, Ships and Stars said:

Ouch, that qualifies as suffering in my book. I used to live in a flat with a gas/electric card meter (total rip-off!) and it would always run out unexpectedly about five minutes after the local shops shut. Woke up several mornings able to see my frosty breath. I was so happy to get to work because they had heat! 

the old coin meters were a pain sometimes too, if not emptied then you'd have coin but the meter was full and... clonk - no power

Edited March 21, 2020 by DaveL59

[JTEC]

JJust a couple more points. Our eyes are so different and not just in the obviously quantifiable ways. I’m completely confident about my 7.8-9 estimate back then, at least within an error of maybe 0.3 of a mag. Epsilon Lyr has always just looked like two stars - though it doesn’t nowadays without a slight tweak from specs. But friends have been better at discerning subtle planetary detail, and it’s not for want of experience, appropriate instrumentation or looking.  O’Meara has seen the Galilean satellites with unaided eye, which he confirmed to me in an email. I’ve never met anyone else who has, though there are various tantalising stories. I guess glare from the primary has a lot to do with this because afaik angular separation/resolution should not be an issue for ordinary good human vision. 

Sky background is obviously a big factor all round: natural sky glow, aurora, zodiacal light, etc before you even think about light pollution that travels far from source to pollute remotely what once was illuminated only by natural light. Like many ‘developed’ countries, we have forgotten what an unspoiled natural sky looks like.  Even some of the designated dark sky reserves in the UK are nothing like as dark as ordinary rural places routinely were 50 years ago. Light pollution in the UK is now so ubiquitous and normalised that we have slipped into defining as ‘dark’ places that are just not quite as desecrated as everywhere else around them, and we’re in real danger of congratulating ourselves on securing patches of mediocrity. 

Edited March 21, 2020 by JTEC

[Second Time Around]

I live in a hamlet East Kent and according to Clear Outside my estimated sky quality is mag 20.83 and Bortle 4.  However, as I posted earlier on this topic, this seems optimistic.

From looking at www.lightpollutionmap.info I'm guessing those figures are based on the World Atlas 2015.  The VIIRS 2019 doesn't appear as good.  If you look at the FAQs on the light pollution map it explains the differences between the maps plus lots of other useful information.

I used to live just a few miles away from Stelling Minnis and one of the advantages is that there's public access to the nearby Common, although it's not as good as you might think as JTEC pointed out.  However it's certainly better than just about any of the villages.  

I've just received a package that hopefully contains a secondhand Unihedron Sky Quality meter.  I got it for £35 + £5 postage from UK Astronomy Buy and Sell, and there were 8 available from a finished project.

I'm looking forward to using it and will be checking out lots of locations within an hour of home - as JTEC posted Romney March looks promising.  I'd already started investigating here, but the meter will make it easier to compare.

[jetstream]

8 hours ago, jetstream said:

I really wish the Bortle scale is scrapped- I just can't relate to it. Bortle 1, Bortle 2 ... I can see M33 naked eye here but some of the parameters don't jive IMHO.

Again, the Bortle scale says M33 is visible in Bortle 3 and 4 ..... yeah right. I often wonder if some mistake NGC 752 for it.

 

[Ships and Stars]

1 hour ago, Second Time Around said:

I live in a hamlet East Kent and according to Clear Outside my estimated sky quality is mag 20.83 and Bortle 4.  However, as I posted earlier on this topic, this seems optimistic.

Yes, take the LP map with a lorry-load of salt, especially in built up areas. In really dark rural areas, probably not a great deal has changed except increased distant LP low on the horizon from major cities and the relentless pace of development in general. 

A lot has to do with your 'micro-environment'. I can get an SQM reading of at least 20.3 or 20.4 from home and have seen the Flame Nebula from here with a 20" dob and all of the S&T Pocket Atlas galaxies in Leo except three of them with a 12" dob on an exceptional night. As I'm surrounded by relatively tall (and currently unlit) buildings, this makes an awesome light baffle, despite the greatly restricted sky views, and there is only LP coming from <180 deg around me.

A mere 100m away, it's a completely different story. I took a reading of 7.07 SQM a few nights ago. Not 17.07sqm, but 7.07SQM near some streetlights where the LP map shows 20.4! I didn't even know it went that low.

I've been using my SQM meter a lot this past week, but clouds or trees reflecting light back will skew the reading, think a totally clear night in an open field works best.

[PeterW]

It’d be great for more people to get SQM and go surveying, only places looking for dark sky status have done any, providing some great places, but not giveing much UK coverage. As more places install lighting with better cut-off, we can hope for the lateral spread of LP from towns to diminish, darkening the dark spots and making darker skies closer. 
for faintest star you’ll want to stock up on Vitamin A, avoid bright light in the day, wait a good long time to get adapted and maybe use a tube to help shield “straylight” from nearby stars. The eye sensitivity can increase hugely with adaption and training.

 

Peter