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Dark Sky Meter for iPhone available now!

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#76 Nop

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Posted 22 April 2014 - 07:31 AM

During dark Sky week the app is only $0.99. Thats a steal for a light pollution meter :)

#77 GeneT

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Posted 22 April 2014 - 03:49 PM

When is the Android version coming?

#78 Nop

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Posted 23 April 2014 - 02:25 AM

There will be no Android version.
There are a lot of different Android devices, more than 4000 in total (2013). Most with different camera’s. With so many camera types on the market, it is impossible to make a decent Android port of our software.

But there is a nice and free alternative: the free app is called Loss of the Night https://play.google....lux.welovestars

This cool app is (very) different from our app (you have to use your eyes in stead of a camera), but it has the same goal: raising awareness for dark skies.

#79 RAKing

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Posted 25 April 2014 - 07:05 AM

During dark Sky week the app is only $0.99. Thats a steal for a light pollution meter :)


Yes it is - and I downloaded it to my 5S. Thanks!

The meter seems to work very well and I submitted my first reading last night.

Take care,

Ron


#80 Psion

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Posted 25 April 2014 - 10:32 AM

I tested it 5 months ago (iPhone 4), it works very bad compared with SQM Meter from Unihedron.

#81 Doug Culbertson

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Posted 25 April 2014 - 10:38 AM

Just downloaded it to my 5S, and look forward to trying it out once the clouds clear out.

#82 stevetaylor199

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Posted 25 April 2014 - 02:20 PM

I tested it 5 months ago (iPhone 4), it works very bad compared with SQM Meter from Unihedron.


I have the app installed on the iPhone 4 as well, and frankly I haven't used it to measure the skies because the vendor has explained that model isn't up to the task.

I do love how this app has created maps of readings that any iPhone 4+ user can enjoy. (Or internet user, for that matter.)

I think a 5S is in my near future, so if anything I'd be curious to see how that model would compare to a Unihedron. (And for only five bucks!) :cool:

#83 Joe Bergeron

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Posted 25 April 2014 - 08:04 PM

I tested it 5 months ago (iPhone 4), it works very bad compared with SQM Meter from Unihedron.


That's because the iPhone 4 camera was never up to the task, and was only supported at all because Apple demanded it of the developer.

#84 Psion

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Posted 26 April 2014 - 07:00 AM

Sorry I have iPhone 4s.

#85 drollere

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Posted 05 July 2014 - 11:15 AM

norbert,

congratulations on a very useful and very well designed app. i'm glad you're applying new technology to solve a very "old technology" problem (throw carbon into the sky in as many different forms of carbon as possible, including carbon as photons).

a question and some design suggestions:

Question. what is the reliability of the measurement? i took some readings last night at my mountain house and they varied from about 19.5 up to "SQM > 22. Too dark!" (maybe you should replace "too dark" with "lucky guy!") anyway, have you tested the app to determine the error intervals around SQM estimates? is the error greater as the sky gets darker, or in newer iphone versions? (i currently have an iphone 5 and will get a 6 when it comes out.)

1. on the meter screen, i'd suggest swapping the position of "darkness start" to be on the same line as "sunset" and "darkness end" to be on the same line as "sunrise", and place the "sunrise" and "sunset" vertically and the two "darkness" times vertically. this makes comparisons explicit.

2. i would add a fixed screen (like the Help screen) that interprets SQM values, for example as done here:

http://cleardarksky.com/csk/faq/2.html

3. there is no explanation, on the "settings page" as to what "calibration 0-21 (0=default)" or "calibration 21-up (0=default)" means, or why the calibration numbers would be changed, or what they should be changed to, etc.

4. once you get into "map", the only way to exit is to leave the app entirely. that is awkward.

thanks again, and good luck!

#86 drollere

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Posted 06 July 2014 - 11:07 AM

postscript ... i was up at 3am this morning, after the quarter moon had set, to test the system. cygnus/milky way directly overhead.

phone was placed camera down (screen up) on a wood deck railing and covered with both hands to perform "dark".

phone was always pointed upward toward zenith, held while i was facing toward the northeast. 16 measurements were taken.

perhaps five or six readings were SQM > 22! the rest were were 21.65, 21.80, 21.70. so it is difficult to interpret the multiple readings. should i just discard the > 22, and average the rest?

i also obtained about 8 "invalid" readouts. the software does not inform how to resolve this issue. i rebooted the phone and this may have solved the problem. however, if a reading is "invalid" because the phone is not pointed near enough to the zenith, then it would be helpful if the phone gave this information -- "phone not pointed at zenith" or "zenith angle 20º" etc. to aid the user to obtain more reliable readings.

there is a "device angle" reading at the bottom of the "meter" screen but it is quite small and difficult to read. if it is a critical sampling requirement it should be displayed in a very large font in the center of the screen between the "dark" and "sky" operations.

good luck!

#87 Nop

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Posted 16 July 2014 - 05:51 AM

Hi Bruce,
Thanks for your feedback! It's useful. I will start working on a new version soon.
To respond to some of your questions.
A reading of > 22 (or 'invalid') means that the sensor didn't capture any light. (The difference between dark and light is to small). As of iOS 8 (expected this fall) programmers are able to modify exposure times, so hopefully i will be able to capture more light. Always remember that an iPhone isn't a dedicated light measurement device and therefore i had to make some clever workarounds.
The calibration and other settings are explained on the www.darkskymeter.com website. We are working on a nice manual which can be downloaded from the site as a PDF file.
Good skies (like yours!) are always challenging. The app tries to get as many photons as possible. Mike Weasner has been testing and comparing on his very good and dark site.
In next versions we will try to largen the FOV to gather more light, but that involves some risks: a large FOV (like 22 degrees ) can result in inconsistensies like horizon glow, reflections and milky way averages.
If you get a lot of 'invalids' try to cover the camera as good as possible (eg inside a pocket).
The device angle is not a very important metric, just a rough indication (some folks do point at the floor ;) ). Just point the back camera towards the zenit.

You can always go back to the main menu by clicking on the top left corner ('hamburger menu' ) and choose meter.

Hope this helps and again thanks for your feedback.

#88 drollere

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Posted 11 August 2014 - 10:01 AM

norbert, i tried the meter a few days ago when the moon was gibbous and about 1/3 way to meridian.

 

i got 18.41, 18.43 and 18.42, a nice tight cluster of readings. the app seems very reliable as a measure of light pollution.

 

the spread was much wider, from about 20.8 to 21.5, when i measured at the same location on a moonless midnight. i averaged many readings to get an SQM of 21.2. it seems that somewhere around SQM 20 the variability (noise) goes up when measuring a dark sky.

 

do you have any guidance as to the SQM level where the error bars start to get really large?



#89 Nop

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Posted 22 August 2014 - 07:02 AM

Hi Bruce

The error gets bigger when the skies get darker or the user takes 'bad' darks. 

A series of 3-4 measurements reduces the error a lot.

The iPhone has no dedicated light collection hardware and Apple doesn't allow developers to make long exposures or modify relevant settings.

This will change after release of iOS 8, but i will have to test a lot.



#90 Nop

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Posted 22 August 2014 - 07:07 AM

There is a new version available for all iOS 7 users. The 'readings' panel is improved. If you select a submitted reading, you can click on it and the app shows you where you took the reading on a map.

I've also made a whole new live map. The map, with almost 10.000 measurements is here : http://www.darkskymeter.com/map



#91 Nop

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Posted 25 October 2014 - 12:41 AM

Dark Sky Meter 2.0 is finally available. It supports iOS 8 and iPhone 6 and 6+ (experimental).

And we've made a feature that updates the formulas for all the supported devices over the air. 

And because its Oct 25 (An important date for Dutch LP awareness called 'De nacht van de Nacht' )  the app will be FREE today. Grab it while you can!

https://itunes.apple...89060?ls=1&mt=8

Regards

Norbert


Edited by Nop, 25 October 2014 - 12:50 AM.


#92 Nop

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Posted 28 October 2014 - 08:03 AM

Version 2.0.1 will be available soon. It contains a quick fix for the weather panel, which is fed by 7Timer, but that service isn't always reliable. I'm looking for alternatives.



#93 johnpd

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Posted 24 November 2014 - 01:41 AM

I finally tried the latest Dark Sky Meter 2.0.1 on my new iPhone 6+. I got mixed results. These are the numbers:

 

   21.04, 20.70, 20.34, 20.53, 20.53, 20.29, 19.86, 20.18, 21.39, 20.34, 20.24, 20.53, 20.29, 20.34.  (Avg=20.47)

 

I also received a number of "Invalid, try again" messages as well as two "Too Dark for Device" errors. My SQM meter was consistently giving me numbers in the 20.70s and low 20.80s. Four times I got 20.76 from the SQM. No Moon although the winter Milky Way was getting close to the zenith. Temperature was in the upper 40's. I am wondering if temperature has any affect on the camera? I kept the phone in my pocket for a bit and when I retried DSM, I got the 21.39 (maybe just a coincidence), but the numbers quickly dropped back to the lower 20's as I tried more.

 

JohnD



#94 Nop

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Posted 26 November 2014 - 01:04 PM

Thanks John,

The temperature has influence on the iPhone sensor noise. The 6+ is not tested (as i don't own one) and i hope to get my hands on it and do a round of calibatrions. It has an image stabilization feature which could influence readings). 

Regards

Norbert








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