scarp15

You do simply need a SQM - L. I have just checked the actual coordinates on the light pollution map based on a dark sky session last Saturday: 55' 13' SQM 21.73. The reality is that for this session based upon a frequency of readings, periodically taken throughout, the average reading and repeated log concluded decisively at 20.96, the top reading on this particular night was 21.1. This is based on the circumstance for that given night, which was very cold with snow and ice, its probable that a combination of ice crystals, some moisture resulted in good but not excellent transparency. It is not the darkest area I could get to, but this particular location is convenient, being less than an hours drive from home, visited frequently over a number of years when occasionally gaining readings of 21.3. A SQM-L will record readings at a 40 degree point of sky you observe in. Logging the variations becomes quite addictive, it is not a chore more so a pleasurable task that is complementary to the outcome of your deep sky observing session. The online map resource as said, is just about OK as a rough guide indicator, but it is on a specific night that counts, we should each of us have a Unihedron SQM-L in our tool box.

Possibly Shane but I do not think that even the optimum conditions will necessarily accomplish matching some of the stated map readings in certain locations. It could as you say, convey a decent idea though, as to where is worth while travelling in which case if intent on repeated journeys, a SQM and monitoring readings becomes quite integral to the activity. I do feel that Sky Quality Meters get quite overlooked as a non requirement, and yet compared to say eyepieces for example, offer good value and taking a frequency of readings is purposeful to the experience of your session. I feel that gathering data in this way - as individuals, collectively gathering a pool of statistic monitoring, with coordinates (perhaps starting as a new link on SGL), could be useful perhaps assisting with preservation of supposive dark sky parks which of course are under continued and increased threat from development.

It does concern me that I will venture to a place that according to the map has a reading of 21.8, when the actual measurement is quite off at least during an average circumstance. I do agree that the map could be of assistance as a rough guide if looking for somewhere potentially darker and that a Sky Quality Meter becomes more applicable for those that travel between different locations enabling comparisons to be made.

Yep a Sky Quality Meter should only be used when circumstances are applicable, i.e. periods of good transparency, no stray light etc and in the correct way. The science in this mapping is perhaps impressive, for an actual circumstance concerning an amateur astronomer on a given night, a real time sky brightness reading is more accurate and relevant. Early on when I first began to go dark sky stargazing, I would head out west from Newcastle and become situated in the middle of Hadrian's Wall. Up at zenith and across north it would be completely dark. Due east was a glow from Tyneside and due west would be a glow from Carlisle. I currently like to venture north into a Northumberland valley or else onto higher ground. North and north east is completely dark, yet south east there is still a glow from the coastal towns and Tyneside. Even at Kielder you cannot fully escape it, although there are verifiable SQM readings taken on exceptional nights of 21.7. Perhaps FLO could stockpile Unihedron Sky Quality Meter - L models (that read sky brightness at and near to zenith) and perhaps everyone ought save up for one (especially before Brexit kicks in) and this could stimulate interesting data and debate.

Cheers Gerry, I find the map to be overly simplistic, other than perhaps being a rough guide. I have learnt that readings can vary so much with the best, often within the early hours of the morning assuming that transparency is very good. Equally going to the same location on two different nights results in yet further varied readings. For anyone that does stray from their backyard / garden, you quickly become aware and sensitive to the creep of light pollution, not least through expanding towns, villages and roads. It can be quite depressing, so any good pockets of potential dark sky quality are highly valued that will hopefully gain in awareness and protection. Yep using a SQM-L to seek darker places along the edges of Urban areas is useful and a good indicator for determining sky brightness is quite firmly dark adaption and naked eye observing.

That online mapping resource is misleading, inaccurate and delusional and certainly should not be used for quoting as a reference in any observers reports. If I was to quote from this map based upon locations I go observing within then I would be implying SQM 21.88. Whilst I gain 21+ mag skies, this particular reading is quite simply - at least so far - untrue. A Unihedron SQM-L (check FLO) is a highly useful tool for measuring / assessing an average and monitoring sky brightness over a given period during your observing session. Anything else is quite simply for the birds, at least in my opinion.

It has been a very worth while upgrade and currently use it with some regularity to secure to the mount a TV-85.

Wouldn't it be great if all star parties, allowing for conditions to be applicable, place emphasis towards collecting SQM-L reading data and publish on forums or else where. Interesting links, a dedicated website or maybe to begin Twitter space, would provide good, meaningful, actual accounts for gauging sky brightness in different locations / regions, if enough people could become involved. Approaching autumn, I will channel this information to various backpacking forums and through Twitter, such as influential writers i.e. Robert Macfarlane (The Wild Places, Mountains of the Mind) and outdoor writer, photographer Chris Townsend. What I have absolutely not done is bother to take a reading from my back yard. There are two street lights in the adjoining lane, been there a few years, fluorescent tube fittings. Instead of being replaced with the modern led type down light, they now have ultra bright led fluorescent tube lights projecting yet brighter light into a portion of the yard, hopeless.

Yes as Mark, Peter, Gerry and Stu have already remarked Damian, the SQM-L Unihedron model is quite suitable. It does seem initially like quite a cost at £129, it will become habit forming and provide relevant monitoring data for assessing dark sky quality conditions for each of your sessions. I would be interested to learn of readings for Galloway in the autumn. Definitely going to look into that Peter, it will open this up to a new community of people.

Said with passion, which is what its all about really. Life is unpredictable - great scope that's the main thing, also look forward to observing reports Richard / 25585.

I get that completely Damian, concentration is a core reason for observing, whether solo or with like minded people. I think that for presenting reports on here, it really would be good to see a reliable reference to SQM readings, without being too specific in terms of where your location actually is. I also have two minds regarding how much location information to make transparent on the forum. Some time ago I was traveling to reach a dark sky location that I have used many times, on the backroad approach and pulled in pretty much just by a farmers gate, I was very surprised, nay startled to see a white skywatcher dobsonion stand out in the car head lights, the occupant probably in their car. At that time I felt that I should have pulled over and invite the person to put the dob in the car and follow me to a much better site. However I had my own agenda and did not, probably would have frightened the life out of him / her anyway just by pulling up in what is a remote place. I am not completely sure that disclosing a little too much detail would suddenly unleash a wave of interest and enthusiasm by members on here to invade a special place. If you up-load on YouTube or Twitter maybe, I understand though that it is best to be cautious. The locations I use are also based on research, although at least the approximate vicinity is publicised within Northumberland dark sky park data and at some places I have occasionally seen night scape photographers. My plans to go wild camping though will rouse little attention other than perhaps a curious passing sheep. This debate for monitoring sky brightness I intend to widen, to include folk who go backpacking / wild camping in particular, as many of these people are primarily located to include as part of their wild camping experience, appreciation of a dark sky and therefore could extend this to be monitoring the Bortle Scale for their remote night sky.

I think though Calvin that there is the what if, that many will reckon with. When the forecast emerges as anything but the promise of clear sky, if with a group, sure you might drift off to a pub or whatever, or accept defeat and head home if on your own, questioning your sanity and motivation as you do. Then, soon after, only becoming yet more determined to go back for more - as next time it will be clear and great (of course it will). This is what marks it differently to anything else, you require that extra drive and stubborn determination that just might become rewarding and memorable, not the same if your out for the day mountain biking for example, don't matter if turns out wet and muddy.

With so many factors to consider, it would be nice to perhaps learn of, if from a reliable reading, someone actually did register above 21.6 within the British Isles, based upon a successful dark sky trip.

Readings are valid as a personal reference and for informing others, monitoring sites for club meets, as has been mentioned. They could historically be helpful to monitor if an area has deteriorated over time, or by dark sky protective awareness measures, even improved. If there is to be an inappropriate development proposal, meter readings could assist a pressure group, not least where natural habitat is threatened by excessive light distortion. Quite understand that if you have a secluded place and if conditions are good potentially 21.6 mag sky, you will wish to just enjoy those periods of clear sky. However the relevance is not between chasing assumed 21.6 to become 21.8, more so based upon a location that could achieve mag 21.1 - 21.2, compared to exploring somewhere another twenty minutes journey away and gain readings of 21.5, this then becomes significant for observations.

What is apparent and others who venture to find a darker sky than home, will understand, is the extent you may have to go to erase any trace of light dome. At home, sky glow is familiar and it is easy to become complacent. I still find it quite shocking that an hours distance or more from the city and to arrive at a purported dark venue, is still infected to a greater or lesser extent by a light dome in one direction. What I have equally become aware of though is how dark the other (usually north) direction can be. A SQM is an asset to be able to monitor each time you visit a place and perhaps evaluate if there could be somewhere else near by to explore as a potentially darker zone. Also if on the Isle of Skye and you happen to encounter great dark sky conditions (Aurora aside of course), I personally would be eagerly wiping out the meter to take those readings.

Hi Stu, the last time I got to observe at the Breamish Valley and took some final readings, the meter response time to calibrate each reading was prolonged, registering between Mag 21.49 to 21.53. In comparison, on my recent wild camp trip and with average, poor transparency (thin haze, not thick cloud), I used the meter for one brief attempt of readings, the time it took to calibrate was very quick, almost immediate, I think approx mag 19. If the Milky Way was high, the narrow cone of the SQM-L will produce a lower reading, and equally if there is moisture in the air, picking up light. Of course it should not be used at a dark site in thick cloud as this will give an inaccurate / misleading high reading.

Getting out to a dark sky location in the UK can become a real sense of occasion. Not least because of the probable infrequency and quite committed effort involved and more specifically if fortunate enough to be able to enjoy lengthy periods of good transparency. To collect data to validate the sky darkness can be relevant information to include in an account for if a particular enhanced observation, such as for example, the Crescent Nebula is achieved. The SQM model option provides a wider angular reading, that will detect any light dome impacting the vicinity and will give a variable reading compared to the SQM-L model. If located in a more enclosed environment, such as close hillsides, it will though give a more distorted and inaccurate reading. For UK skies, it is the dark patches at or within a few degrees to zenith that are most intriguing to gain a reading, the narrower SQM-L serves this purpose.

I would like this topic to raise the profile and awareness for using a Sky Quality Meter aimed at dark sky seeking, DSO observers. A sky quality meter, is a hand held device that reads in magnitude per square arc second, night sky brightness. A popular model, and one that I use myself, is a Unihedron SQM-L. This device has an angular sensitivity response of 42 degrees, which is used to take readings at zenith and can also be used to aim at other angles towards an intended target. Observers using this device will take a frequency of readings throughout an observing period, when transparency is good and will log the lowest, highest and average reading. A SQM is also handy to make comparisons if you travel to varied sites. A few years ago, when I made the decision that travel to explore varied dark sky locations was to be my primary aim as a visual astronomy, I purchased a Unihedron Sky Quality Meter from FLO. The first time I took it out, I had been at the time a member of a regional astro society and attended their dark sky site. I was so pre-occupied that it never occurred to me, that is until I'd packed up, to take a reading with my new meter. Following this I made a conscious effort to ensure that taking readings was to be integral to a dark sky session, yet even then it was still almost an after thought late on in the session. However this was to change as gradually I began to place value and priority upon taking a frequency of readings intermittently during the course of the night. It steadily occurred to me that much of my time at a dark sky location was actually occupied just looking up, becoming increasing dark adapted and taking SQM readings. Each of my dark sky trips has to be within an hours drive, perhaps a little more, from home, as factoring in the return journey is essential. There are many locations to explore and I have discovered some quite special places gained within this time frame. For each though, there are still light domes, to get away from this scourge will involve traveling further, deeper. On a recent backpacking, wild camp trip in the Cheviots, Northumberland, I took along my trusty, compact SQM. Unfortunately, whilst there was a great sunset, transparency deteriorated somewhat and it was not required (though great views were had of Jupiter, Venus Moon). My plan for the autumn is to go, further and deeper, wild camping and taking with me my Sky Quality Meter. I do not have aperture fever, what I do have is a strong desire to experience gaining high quality dark sky places and take along what ever optical equipment I am able to carry. Observing in the UK is challenging as the night sky fades and diminishes due to excessive lighting and constant pressures for development. The Green Belt is severely under threat, villages are being transformed into small Towns. Valuing our pockets of sky quality is crucial and measuring, recording on here in reports helpful. One final point, there are on-line map resources that convey magnitude readings for any location. This might be useful as a very general guide, but is as far as I am concerned highly inaccurate and ought not be quoted and included in reports, or other forum accounts. For example I like to go stargazing in the Breamish Valley in Northumberland. The map reading for this location is 21.84 mag, my own readings have never improved - so far, at just over 21.5, it may be slightly darker deeper within the valley but the map reading is still an exaggeration. It will be interesting to learn if you use a SQM or intend to use one.

Shedding a few layers is good, here, the down jacket is replaced with a down vest, late summer nights can become chilly.

Yep I'm looking forward to that aspect to, short sleeved cycling jersey, etc. Having other interests and hobbies ensures that you are kept occupied.

You have to get what you can, when you can, how you can. Been on a family visit to Fylde coast Lancashire. Astronomy was not on the agenda as the forecast looked not so great as usual. As an after thought I took along my binoculars, monopod. Glad I did as last night became lovely and clear, so enjoyed touring the clusters around Auriga, Gemini, Cancer, concluding with the Beehive Cluster, a perfect binocular object. The ISS cruised overhead before my Dad came out to remind me that the Sky at Night was due to start. So quite satisfying after a lengthy period of no activity. Patience, going with the flow with the familiar forecast disappointment, keep on planning and aspiring and retain options in terms of approach.

Quite a spectacle that truly benefits appointing an OIII filter.

New kid on the block

Interesting point John concerning the clarity of M1, For my Friday session, M1 was quite astonishingly defined, without a filter.

Excellent, detailed and vivid account John, very enjoyable to read congratulations. Great to hear of these exploits, taking advantage of some exceptional conditions.