Has anyone observed under Bortle 1 conditions?

[Ships and Stars]

Hi all,

Planning my upcoming astronomy trip here in Scotland, hopefully have a week plus to roam around in the van. I do visual only. I have a Bortle 2 spot just over an hour away at a familiar camping spot, but if its hols and I have the time, I can drove over to the west coast and experience Bortle 1, assuming the weather cooperates.🙄

Of course the darker the better, but wondering if it is worth a lot more in fuel and time to chase Bortle 1, or just relax at a known spot fairly close to home that's still a really good Bortle 2? 21.94sqm, no lights for miles and no traffic. I've not taken my scope there before, only been under Bortle 3/4 right by home, which was pretty good actually. Just thinking the Bortle 1 could be mind-blowing. Viewing through a 20" dob. 

Any thoughts?

Clear skies all.

Edited August 16, 2019 by Ships and Stars
typo

[omo]

Bortle 2 an hour away would be Glen Clova for me, need a car license before i can take some gear there or over to the NW. Would be something to behold when it was actually dark later in the year, compared to the limitations of being in town

[Ships and Stars]

Yep Glen Clova/Glen Doll/Glen Lethnot is wonderful. I've been camping there, no scope though, but it's on my list. A lot of people overlook the eastern glens for both tourism in general and astronomy. Away from Perth/Dundee there is a nice belt of darkness up in the glens running NE. 

At home it's a struggle, the business next to me keeps their rear light on 24/7. I made a cardboard and gaffer tape blinder that hang on their gutters, very lightweight, maybe 50g and doesn't touch the lights or get warm, and I remove it when I put the scope up for the night. Makes a big difference! No fuss, no mess😁 Tarfside would be a great spot, that's where the red pin is dropped at top centre of pic. I'm thinking about hosting a star party in NE Scotland within reasonable distance of Glasgow/Edinburgh this year. No one seems to host one up this way.

Edited August 16, 2019 by Ships and Stars
add info

[Mr niall]

52 minutes ago, Ships and Stars said:

Yep Glen Clova/Glen Doll/Glen Lethnot is wonderful. I've been camping there, no scope though, but it's on my list. A lot of people overlook the eastern glens for both tourism in general and astronomy. Away from Perth/Dundee there is a nice belt of darkness up in the glens running NE. 

At home it's a struggle, the business next to me keeps their rear light on 24/7. I made a cardboard and gaffer tape blinder that hang on their gutters, very lightweight, maybe 50g and doesn't touch the lights or get warm, and I remove it when I put the scope up for the night. Makes a big difference! No fuss, no mess😁 Tarfside would be a great spot, that's where the red pin is dropped at top centre of pic. I'm thinking about hosting a star party in NE Scotland within reasonable distance of Glasgow/Edinburgh this year. No one seems to host one up this way.

Wow, Bortle maps of where I live look like a badly sunburned goldfish...

[Mr niall]

oh no its worse than I thought, it got so red that they changed it back to white...

I suppose the moral of the story is that I would kill for 3/4 skies 😉

[Ships and Stars]

Are you near the Peak District/Edale? Can catch a train to Edale I believe.  I lived in the midlands for many years, I feel your pain. Forgot what night skies should look like. 

[scarp15]

Perhaps the weather forecasting, which we are all of course hopelessly at the mercy of, will indicate if to consider chancing being located either east or west. The convenience of your reachable dark sky 'scratching ground' might therefore be more reasonably attractive, as east may tend to favour slightly more clear sky periods perhaps. Incidentally could be very worth while investing in a Unihedron SQM-L device to take along to any dark sky observing session. If transparency is good, a frequency of (correctly taken) readings, will convey an accurate assessment for actual sky brightness as determined by the time you are actively observing. Also useful for gauging comparisons at different locations. 

[Ships and Stars]

3 hours ago, omo said:

Bortle 2 an hour away would be Glen Clova for me, need a car license before i can take some gear there or over to the NW. Would be something to behold when it was actually dark later in the year, compared to the limitations of being in town

Are you around Dundee or Montrose? Get a pass on your test when you can, it opens things up a lot. City lights are hard going!

[viewer]

Nice to read this! I have Bortle 3-4 on a driving distance, extraordinary views, accustomed to Bortle 7-8. Took a good view on the dark site finder. Better Bortles are more or less pipe dreams. Though I'd be very interested in how Bortle 1 differs from 2, please report. I'd say go for it, then you can decide if you choose 2 for convenience 😉

Edited August 17, 2019 by viewer

[pete_l]

11 hours ago, Ships and Stars said:

 Just thinking the Bortle 1 could be mind-blowing.

Hmmm.

At my location the degree of sky darkness varies from around 21.5 up to "Bortle 1" (to the point where I thought my Unihedron SQM was broken ). The quality of the sky can vary due to many factors, including sunspot activity, prevailing winds and what seems to me to be the most important: atmospheric transparency due to dust and water content. On the best nights I can have an SQM better than 21.8 (see some captures of SQM meter readings from my garden) and on the next night it is lower.

Whether you can make use of great skies is determined primarily by your eyesight.  As a 60-something, I do not have either the acuity or the dilated pupils of a 20 y/o. Which must knock at least a magnitude off my personal NELM. As such, I take the Bortle descriptions with a large pinch of salt.

Having said that, using SQM measurements as a proxy for seeing and transparency does provide some great views on the darkest nights. Though it bears reminding that under a full moon everywhere is Bortle 6!

 

Edited August 17, 2019 by pete_l

[DirkSteele]

I have been fortunate to observe under both Bortle 1 and Bortle 2 skies many times. While near the zenith there is usually little to separate them, I have found that conditions can deviate (but not always) the closer you get to the horizon. I have certainly been under class 2 where small light domes from distant settlements are visible, but under class 1, at least the ones I have observed from, it is that dark all the way to the horizon.

[Ships and Stars]

12 hours ago, viewer said:

Nice to read this! I have Bortle 3-4 on a driving distance, extraordinary views, accustomed to Bortle 7-8. Took a good view on the dark site finder. Better Bortles are more or less pipe dreams. Though I'd be very interested in how Bortle 1 differs from 2, please report. I'd say go for it, then you can decide if you choose 2 for convenience 😉

Good idea! I wouldn't know unless I try. Bortle 1 the first few days if I can get a clear night on the west coast, then bortle 2 on the way home on the same target. Great idea actually, cheers!

[Ships and Stars]

 

1 hour ago, DirkSteele said:

I have been fortunate to observe under both Bortle 1 and Bortle 2 skies many times. While near the zenith there is usually little to separate them, I have found that conditions can deviate (but not always) the closer you get to the horizon. I have certainly been under class 2 where small light domes from distant settlements are visible, but under class 1, at least the ones I have observed from, it is that dark all the way to the horizon.

That makes sense at zenith as you say. My bortle two spot in the NE has a strong light dome on the horizon. I couldn't figure out where it was coming from, until I realised it was Dundee and surroundings, some 50 miles away bouncing off the atmosphere! 

[Ships and Stars]

8 hours ago, pete_l said:

Hmmm.

At my location the degree of sky darkness varies from around 21.5 up to "Bortle 1" (to the point where I thought my Unihedron SQM was broken ). The quality of the sky can vary due to many factors, including sunspot activity, prevailing winds and what seems to me to be the most important: atmospheric transparency due to dust and water content. On the best nights I can have an SQM better than 21.8 (see some captures of SQM meter readings from my garden) and on the next night it is lower.

Whether you can make use of great skies is determined primarily by your eyesight.  As a 60-something, I do not have either the acuity or the dilated pupils of a 20 y/o. Which must knock at least a magnitude off my personal NELM. As such, I take the Bortle descriptions with a large pinch of salt.

Having said that, using SQM measurements as a proxy for seeing and transparency does provide some great views on the darkest nights. Though it bears reminding that under a full moon everywhere is Bortle 6!

 

 

 

 

Oh wow, that's some very useful information. Thank you! I'd like an SQM meter but fear I'd only need it a few times, so will see of one pops up on ebay or ABS and then I can sell it on and break even. I would really like to have on though, that's just the sort of thing that would let me know if I'm tricking myself into thinking some of my spots are darker than I imagine. 

There is quite a good article available online that touches on other factor besides sheer darkness - I had not realised the various factors involved when taking the fuller picture into account- http://adsabs.harvard.edu/full/1984ESOC...18....3W

Like you my eyes are not as good as they used to be, that's also partially down to some welding flashes as well I suspect, but generally speaking, am ok besides some astigmatism which I might try and correct with a TV dioptrx so I can enjoy the full field of view of some of my nicer eyepieces.

I didn't realise the moon can bump everything to Bortle 6! No wonder I was struggling to see the ring nebula a few nights ago!

Many thanks again for the information, I shall have to chase down an SQM meter.

Clear skies.

 

 

[Ships and Stars]

Thanks everyone, if I'm lucky enough to make the west coast and Bortle 1, I'll note the humidity and conditions and compare it to a 2/3/4 as I get closer to home!

[omo]

18 hours ago, Ships and Stars said:

Are you around Dundee or Montrose? Get a pass on your test when you can, it opens things up a lot. City lights are hard going!

Dundee. The comparisons could be interesting.

[Ships and Stars]

29 minutes ago, omo said:

Dundee. The comparisons could be interesting.

Yep, where I live it's quite bright actually. I can just make out the ring nebula with my 130pds when the moon is down. My 200p will do it when the moon's up, but it's not very contrasty. You don't have to go too far from Dundee though to get some really good conditions I've noticed!

[estwing]

Isles of Skye...fantastic. 

[devdusty]

Out of interest where do you find those detailed light pollution maps of the UK ?

Chris P

[Geoff Barnes]

11 hours ago, devdusty said:

Out of interest where do you find those detailed light pollution maps of the UK ?

Chris P

Here you go Chris, just type in or zoom in to your location....

  https://www.lightpollutionmap.info/#zoom=4&lat=6589541&lon=582262&layers=B0FFFFFTFFFFF  

Edited August 21, 2019 by Geoff Barnes

[jetstream]

On 16/08/2019 at 15:44, Ships and Stars said:

Just thinking the Bortle 1 could be mind-blowing. Viewing through a 20" dob. 

Any thoughts?

I live in Bortle 1 skies and was just observing with the 24".

Personally I don't like the Bortle scale- it says M33 is visible naked eye under Bortle 4 skies... skies are variable as is darkness levels for a given site depending on time of year etc. These days I judge the sky by the look of the Milky Way- under my best skies it casts its glow, brightly reflecting off the lake and shows sharp jagged structure along its course and will extend from horizon to horizon. Many objects such as the Lagoon neb are brightly lit among the billowing bright clouds in the split.

The ability to see M33 naked eye is a superb, tough test of sky conditions and I do see it here.

I can't wait to hear your 20" reports from dark skies! Get that sucker on the Veil!

ps if you observe in truly dark skies your 20" will chew the Little Veil up no problem.. (Sh2-91), give it a whirl with the OIII.

[Ships and Stars]

Thanks Jetstream! Your post has me ready to do some proper viewing. The long term weather forecast for the next few weeks is not looking great, but at least it's changeable. Your comments on the milky way and little veil have me itching to get out! Fingers crossed, I've waited since April to get the big dob back out, and have picked up some nice eyepieces over the summer. Thanks very much!

[Uplooker]

The location of the Dumfries and Galloway SP is a great location and if the skies play ball is excellent

[Ships and Stars]

Thanks Ian! I like that part of the world as well. Worked for a short while near Luce Bay, lovely part of the world, must return. Mull of Galloway is pretty spectacular as well. Not been there with a scope, though I imagine it has excellent skies.

[jetstream]

19 hours ago, Ships and Stars said:

Thanks Jetstream! Your post has me ready to do some proper viewing. The long term weather forecast for the next few weeks is not looking great, but at least it's changeable. Your comments on the milky way and little veil have me itching to get out! Fingers crossed, I've waited since April to get the big dob back out, and have picked up some nice eyepieces over the summer. Thanks very much!

Your welcome and pursuing dark skies is fun in itself. Reading reports elsewhere I've noticed that when the term "Bortle" is used by some as a static label- I even did when I said I live in Bortle 1 skies.  My skies vary as do others and to say that most any location is always "Bortle1" is very misleading.

I read a report where the observer described a Bortle 2 sky as 22mag with high 7's NELM.....and then the site was then labelled Bortle 2.

What I did in the pursuit of dark skies is to find a few dark sites that I could travel to and avoid cloud etc- it might be in your best interest to find sites such as this. I'll take a super transparent 21.4 sky over a 21.6 sky with lower trans. My best views come near zenith and I try to pick objects up high, like the Veil is now. The other night M81/M82 were nice in the 24" but no where near as good as they will be higher up.

As far as the Little Veil, try many times after warming up the eyes but don't waste too much valuable dark sky time on it IMHO- too many better objects to see lol! Normally one challenge object is included in each serious obs session here, thats it.

 

Edited August 22, 2019 by jetstream