Sky Quality Meter

[mapstar]

Which SQM would be advisable to get as I'm sure there are a few about? Is the Unihedron SQM-L what everyone uses Scarp? 

Edited May 29, 2018 by mapstar

[Mark at Beaufort]

Damian I thought we were generally discussing the Unihedron SQM-L which at £129 from FLO was not a unreasonable amount

[mapstar]

Scarp mentioned using SQM meters in general but said he was using the Unihedron SQM-L. 

I can't seem to find any others? Rother valley sell one called the Geoptik? Looks the exact same but made in Italy? 

Edited May 29, 2018 by mapstar

[25585]

6 hours ago, Demonperformer said:

You want to know what's really sad ... there are occasions (I'm not going to say how many, but just think of a number and increase it) when it's a clear sky and I can't even make the effort to set up at home. Must be getting old!

Me too

[PeterW]

The L version from unihedron is the one we all use. Interesting to see there might be another option... be interesting to calibrate them together!

Maybe we could look to provide binocular advice to those in wild camping communities... show them great skies and hope they can help in the fight against light pollution.  More people getting access to good skies can only be a good thing, if we can get useful data from them then even better!

Peter

[PeterW]

The Geoptik meter looks like the older mom-L unihedron... even days unihedron on the box in this image...  https://www.astroshop.eu/miscellaneous/geoptik-sky-quality-meter/p,8850 looks like Geoptik are resellers of the Unihedron and people assume it is made by them. If the box has the clear raised plastic button protector then I believe it is the wide angle unit (not the narrower angle L version). Anyone else have other information??

 

PEter

[jetstream]

The wider SQM will provide more of a sky "average" than the narrower SQM-L IMHO.

[PeterW]

4 minutes ago, jetstream said:

The wider SQM will provide more of a sky "average" than the narrower SQM-L IMHO.

But with the -L you can move it about tomsample light domes and avoid/sample the milky-way. Both have advantages.

PEter

[Stu]

1 hour ago, PeterW said:

But with the -L you can move it about tomsample light domes and avoid/sample the milky-way. Both have advantages.

PEter

Yes, I actually prefer the L and to be able to sample different areas of sky as I tend to be in areas where there are big variations across the sky. 

As you say, both have their uses, I think in darker areas with more consistency across the sky the wider version might be more useful.

[jetstream]

2 hours ago, PeterW said:

But with the -L you can move it about tomsample light domes and avoid/sample the milky-way. Both have advantages.

PEter

I don't find the standard SQM to offer an advantage personally and especially when trying to find dark holes in between light domes. The SQM-L (which I have) offers the ability to get true zenith sky darkness between the domes and also to measure the brightness of the Milky Way which here is a .3 mag (avg) difference under the best conditions.

There are a few occasions where the sky gets 21.9 consistently over an evening but the overall best is 21.8 mag, season dependent.

The SQM-L is a powerful tool...

[scarp15]

8 hours ago, mapstar said:

Scarp mentioned using SQM meters in general but said he was using the Unihedron SQM-L. 

I can't seem to find any others? Rother valley sell one called the Geoptik? Looks the exact same but made in Italy? 

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.

 

8 hours ago, PeterW said:

The L version from unihedron is the one we all use. Interesting to see there might be another option... be interesting to calibrate them together!

Maybe we could look to provide binocular advice to those in wild camping communities... show them great skies and hope they can help in the fight against light pollution.  More people getting access to good skies can only be a good thing, if we can get useful data from them then even better!

Peter

Definitely going to look into that Peter, it will open this up to a new community of people. 

Edited May 29, 2018 by scarp15
typo

[Demonperformer]

I have the standard one, but would go for the -L if I were puchasing now. Not only useful for really dark sites, but also for directional measurements in more 'urban' sites. Even with the standard one, I get a drop of nearly 2 magnitudes as I drop it towards streetlight level (even with the new 'directed' streetlights), but I think the extra-narrowness of the -L version would provide mroe useable readings at lower altitudes.

[mapstar]

10 hours ago, scarp15 said:

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.

I have thought about getting one several times so it's about time I sorted one out.

The cost isn't really of concern as it will be as you say more productive in the long run saving time and fuel trailing to poor viewing locations. 

I'll be interested about Galloway although I'm not sure I'll be there this year as I think it's going to clash with the Skye mob trip.

Edited May 30, 2018 by mapstar

[Physopto]

On 30/05/2018 at 07:20, mapstar said:

I have thought about getting one several times so it's about time I sorted one out.

The cost isn't really of concern as it will be as you say more productive in the long run saving time and fuel trailing to poor viewing locations. 

I'll be interested about Galloway although I'm not sure I'll be there this year as I think it's going to clash with the Skye mob trip.

Shock and horror !

[mapstar]

46 minutes ago, Physopto said:

Shock and horror !

Be the first I've missed in 5 years 

[Physopto]

On 31/05/2018 at 13:45, mapstar said:

Be the first I've missed in 5 years 

Looks like I will miss them all for the forseable future. Ugg!

 

[scarp15]

On ‎28‎/‎05‎/‎2018 at 09:29, Mark at Beaufort said:

What would be good if someone that is attending the SGL star party in October takes a measurement at Lucksall. Assuming its clear ever night ?

 

On ‎28‎/‎05‎/‎2018 at 11:19, Beulah said:

Good idea and there could be a 'guess the MPSAS' competition...

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.

On ‎27‎/‎05‎/‎2018 at 19:09, PeterW said:

 The more SQM readings of different good sites the better, there used to be a website/map to log them,, but it seems to have vanished.

 

 

 

 

On ‎27‎/‎05‎/‎2018 at 19:17, Beulah said:

I think I remember that site, it was a user created one. Didn't know it vanished.

I use this:

https://www.globeatnight.org/maps.php

2018 map: https://www.globeatnight.org/map/

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.   

 

[laser_jock99]

On 28/05/2018 at 17:09, estwing said:

unless that pesky Aurora is about again...?....

.....or it's summer time!!

[PeterW]

We should also be looking for other camping sites (especially ones with roofed accomodation) in very fark locations for new star party locations....

 

PEterW

[clarkpm4242]

Enjoyed reading this thread.

Being a DSO observer it seems to match much of my musings and varying enthusiams over the years!

Its not just me then!!!

Cheers All!

Paul 

 

[Nyctimene]

On 27/05/2018 at 20:09, PeterW said:

The more SQM readings of different good sites the better, there used to be a website/map to log them,, but it seems to have vanished.

Peter,

I guess, you have this in mind (and it still exists):

https://www.lightpollutionmap.info/#zoom=11&lat=6387596&lon=998499&layers=B0FFTFFFFFT

With the toggle menu function (right top corner), you can enable the "SQM/SQC overlay and filters" menu, to find a lot of SQM/L measurements for Europe (and worldwide). You can also add your own SQM/SQM-L values by clicking the "tool" icon in the left top corner. The "+ SQM" box of the extended toolbar changes the cursor symbol; you then direct it to the measured area and click again. The menu that opens now lets you choose between SQM and SQM-L entries. Name, date, value and comment are asked for, followed by a verification. IIRC, it will last a few days, before the new measurement point will appear on the map.

The SQM "down-up" way of sky brightness evaluation is a very useful tool, as it complements the satellite's "up-down" view displayed on the map.

Hope this helps.

Stephan

[Captain Scarlet]

On 07/06/2018 at 16:04, Nyctimene said:

Peter,

I guess, you have this in mind (and it still exists):

https://www.lightpollutionmap.info/#zoom=11&lat=6387596&lon=998499&layers=B0FFTFFFFFT

With the toggle menu function (right top corner), you can enable the "SQM/SQC overlay and filters" menu, to find a lot of SQM/L measurements for Europe (and worldwide). You can also add your own SQM/SQM-L values by clicking the "tool" icon in the left top corner. The "+ SQM" box of the extended toolbar changes the cursor symbol; you then direct it to the measured area and click again. The menu that opens now lets you choose between SQM and SQM-L entries. Name, date, value and comment are asked for, followed by a verification. IIRC, it will last a few days, before the new measurement point will appear on the map.

The SQM "down-up" way of sky brightness evaluation is a very useful tool, as it complements the satellite's "up-down" view displayed on the map.

Hope this helps.

Stephan

Very useful to note - I'm familar with that site, it's v good imho but I hadn't been aware of the user-data bit. Just added my own bit of data using my SQM-L. (holy thread-revival, batman!).

I think I've just contributed the very first data for the whole of Ireland. Wo-Hoo.

Cheers, Magnus

Edited May 5, 2019 by Captain Magenta

[Nyctimene]

On 06/05/2019 at 00:39, Captain Magenta said:

I think I've just contributed the very first data for the whole of Ireland. Wo-Hoo.

Just looked it up - SQM 21.9 cannot be beaten! Congrats to your outstanding location; have fun with all the DSO's. My observing site is between 21.0 and 21.4 SQM-L values; and I'm quite content with this.

Stephan