Jump to content

stargazine_ep34_banner.thumb.jpg.28dd32d9305c7de9b6591e6bf6600b27.jpg

How dark is your sky on a moonless night?


Recommended Posts

@Stub Mandrel Yes, the website provide by Cinco is the one I used. :) I don't know how precise it is, but it can combine user's SQM-meter readings. For my uses, it is well sufficient.

@Cinco Sauces Thanks! Yeah, the sky over here is pretty good and not too severely light polluted. Anyway, where the "X" is, I measured ~21 mag. In the middle of the white segment it's ~20.3-20.4mag. In the orange area it is ~19.5 mag. So it seems to me that the overlay legend is quite overestimating the quality of the sky. Compared to many other skies, I cannot really complain though. :)  Bins are great under dark skies, particularly if the Milky Way is visible!  Very portable too! 

How about your skies? 

Edited by Piero
  • Like 2
Link to post
Share on other sites
  • Replies 83
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Dark enough to see andromeda naked eye, but not so light that neighbours can see me naked with their eye John 

There are times that the conditions here just come together and last night was one of them unexpectedly. There are many that know the SQM can be affected by transparency- and it can go either way a bi

21.6    (6.4 NELM) http://www.unihedron.com/projects/darksky/NELM2BCalc.html

Posted Images

Just now, Piero said:

@Stub Mandrel Yes, the website provide by Cinco is the one I used. :) I don't know how precise it is, but it can combine user's SQM-meter readings. For my uses, it is well sufficient.

@Cinco Sauces Thanks! Yeah, the sky over here is pretty good and not too severely light polluted. Anyway, where the "X" is, I measured ~21 mag. In the middle of the white segment it's ~20.3-20.4mag. In the orange area it is ~19.5 mag. So it seems to me that the overlay legend is quite overestimating the quality of the sky. Compared to many other skies, I cannot really complain though. :) 

How about your skies? 

The skies I can cycle to are nothing to be jealous about but are somehow ok. See the circle in this map, this is where I cycle to. The red dot to the SE is a SQM measurement from 2012, it reports about 18. I live in the red zone to the East of that point with a NELM of 4 or perhaps 4.5 in good nights. Taking myself to darker sites involves driving many tens of kilometers away from Stockholm. As I do not have a car I seldom do that, except when hanging up with some astro friends that offer a me ride :happy10:.

screenshot.png

  • Like 2
Link to post
Share on other sites

That's proper commitment! Well done! And yeah, using the children van is a very good idea for trips like that. 

Edited by Piero
  • Like 1
Link to post
Share on other sites
17 hours ago, Size9Hex said:

Now that we're getting proper darkness again, I'm wondering whether I can fit my Startravel and AZ3 on the bicycle somehow. :icon_biggrin:

There's a definite appeal in going by bike rather than car as it gives you a lot more options on observing spots (within the distance you're preparing to pedal of course). Wouldn't fancy a mechanical issue late at night in the middle of winter though...

I put my 120ST in a large backpack - this is reasonably easy to transport cycling having testing all this out lugging it out to my normal site.  I have a good camera tripod which is just short enough to put cross-ways across the two pannier bags and tie down.

I've only just really got this setup and waiting for an opportunity to lug this grab and go setup to the countryside where there will be a significant difference.  My normal site is approx mag 5 NELM.  I can see the 7 stars in UMi easily enough and the Milky Way with some detail.  M44 is a pretty clear naked eye object.  I have to wait for M31 to get higher to see if I can see this naked eye though as the East is hitting Oxford's light pollution directly.  I've found a great site out of the way and zero local light pollution and sufficiently away from Oxford so I'm hoping this will be closer to mag 6 NELM.

Just a little bit further from my normal site and away from further local light pollution I've had a reading of 20 using the iPhone Dark Sky meter app.  This seems reasonably consistent with readings elsewhere so I think it's pretty accurate. 

  • Like 3
Link to post
Share on other sites

Excellent to see that we've gone off on a cycling tangent :-)

Sterling effort @Cinco Sauces ! I am properly impressed! Probably a touch too hilly near me to cycle with a Dob on a trailer :-)

Thanks @Davesellars , that's definitely inspired me to give it a go.

My usual approach (with binos and camera tripod so far) has been to take an oversized backpack full of warm clothes to put on when I arrive. Decent bike lights and a mini tool box essential...

  • Like 2
Link to post
Share on other sites

Yep, I occasionally put my Horizon tripod and 10x50s in the Meade tripod bag that came with my long departed ETX 70, and ride to my local golf course. Sometimes I feel adventurous and go a bit further- the Chiltern Hills , but only if it's a guaranteed clear night and the Mrs is out for the evening.

I don't worry too much about mechanicals, as a long time cyclist, I'm always fully prepped. Often, the ride is half the fun...:icon_biggrin:

 

  • Like 3
Link to post
Share on other sites

Belgrade city center 18 SQM-L. Avala mountain 19.90 (close to Belgrade and really just 500 m high). My parents house in a semi-rural area away in the south 20.50 but usually very humid (close to a river and in a valley). 

This summer I was treated to 21.45 in the Greek mountains and that was lovely. Milky way structure, but very humid. Now I am in Serbian mountains (southeast), and it is less humid. I realized the shortcomings of the SQM measurements - last night I arrived a bit tired, but the weather forecast was that that tonight and tomorrow will be overcast. Not knowing the surroundings, I set up immediately in the vicinity of the hotel. Now, hotel is the only source of the LP for 30 km, this is a very remote mountain. SQM reading was only 20.05, but in the eyepiece (once I accommodated under a dark cloth) it was pretty good, and probably better on Veil and Lagoon and Trifid than under 21.45 humid sky. Transparency was really nice.

Link to post
Share on other sites
On 04/08/2016 at 12:27, Piero said:

@Stub Mandrel Yes, the website provide by Cinco is the one I used. :) I don't know how precise it is, but it can combine user's SQM-meter readings. For my uses, it is well sufficient.

@Cinco Sauces Thanks! Yeah, the sky over here is pretty good and not too severely light polluted. Anyway, where the "X" is, I measured ~21 mag. In the middle of the white segment it's ~20.3-20.4mag. In the orange area it is ~19.5 mag. So it seems to me that the overlay legend is quite overestimating the quality of the sky. Compared to many other skies, I cannot really complain though. :)  Bins are great under dark skies, particularly if the Milky Way is visible!  Very portable too! 

How about your skies? 

When it comes to Stare's map, I found it pretty consistent with my SQM-L readings. Of course, while the zenith reading might be more in accord with the map, the overall surroundings and horizon will also have to be taken into account. 

With such patchwork of VIIRS data you might use 'area' feature of the map to measure radiance for a bigger area...that might be a better approximation of what to expect at a particular location.

  • Like 1
Link to post
Share on other sites
  • 3 months later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.