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Unihedron Sky Quality Meter with Lens - Narrow Field of View # SQM-L
| Brand | Unihedron |
| Part Number | SQM-L |
| Availability | available |
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Product Info
Manufacturer Description
An affordable meter for measuring sky brightness for astronomers! The "Sky Quality Meter" measures the brightness of the night sky in magnitudes per square arcsecond. Designed by Dr. Doug Welch and Anthony Tekatch, the Unihedron Sky Quality Meter offers unprecedented sensitivity in a handheld meter.
Uses:
- Find out how good the night or site REALLY is.
- Compare the sky brightness at different sites quantitatively.
- Document the evolution of light pollution in your area.
- Set planetarium dome illumination to mimic the skies people are likely to experience elsewhere in the city.
- Monitor sky brightness through the night, night-to-night, and year-to-year.
- Determine which nights show the greatest promise for finding the 'faintest fuzzies'!
- Calibrate the effect of sky brightness on qualitative measures such as the Bortle Scale.
- Investigate how sky brightness correlates with the solar cycle and month-to-month sunspot activity.
- Help provide local ground truth for future sky brightness prediction with the Clear Sky Clock
- CCD users can make a correlation between the SQM reading and when the background reaches some ADC level.
Features:
- Audible signal while measurement is in progress.
- Sky brightness displayed in visual magnitudes per square arcsecond.
- Infrared blocking filter restricts measurement to visual bandpass.
- Temperature in both Celsius and Fahrenheit as well as model number and serial number can be displayed with different button press sequence.
- Precision readings at even the darkest sites.
- Power-saving features designed in for maximum battery life.
- Reverse battery protection.
Specifications:
- The Half Width Half Maximum (HWHM) of the angular sensitivity is ~10°. The Full Width Half Maximum (FWHM) is then ~20°. The sensitivity to a point source ~19° off-axis is a factor of 10 lower than on-axis. A point source ~20° and ~40° off-axis would register 3.0 and 5.0 magnitudes fainter, respectively. (See photo 2)
- Operates from 9V battery (included).
- Size 3.6 x 2.6 x 1.1 in.
- Maximum light sampling time: 80 seconds.
- Specifications are subject to change without notice.
Reviews
-
astrobob1940 New Member
- Skill Level
- Unknown
- Time with Product
- Unknown
- User Notes:
- Review by Robert S.
Nov 13, 2018Sky Quality Meter
Pros: Cons: Comments:I've always wondered about the sky brightness above my home observatory and now I know. My sky quality on a clear Moonless night is 20.45. Decent for astrophotography.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Sep 5, 2018Unihedron Sky Quality Meter with Lens - # SQM-L
Pros: Cons: Comments:This SQM operates wonderfully. Ive experienced very reproducible results that are consistent when compared to published ‘dark sky’ maps for my urban location in Arizona. I will be traveling to a Bortle 1 dark sky location in NM in October and will test the SQM there. So far a great addition to my astronomy toolbox and highly recommend the Unihedron Sky Quality Meter with Lens - Narrow Field of View # SQM-L.
Bottom Line: Would you recommend this item? Yes
JAS in ArizonaThis review was provided courtesy of AgenaAstro.com
Aug 14, 2018Nice item for measuring sky brightness
Pros: Cons: Comments:This is a handy device for measuring sky brightness at different locations, or even the same location under different conditions. I'm using it for some research that I'm doing on astrophotography. The device registers quickly, and also gives temperature.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Feb 21, 2018Sky Quality Meter
Pros: Cons: Comments:Seems to do the job it was built to do. The display is bright and easy to read. Simple to operate, only one button. There is no built in memory to store readings, date, time, etc. It displays the light reading and temperature only. I have only had a couple of clear nights since I got it and I do not have another meter to compare the results to but I got consistent readings in the range I expected when I did get a chance to use it.
Bottom Line: Would you recommend this item? Yes
The case is rather lightweight and probably not waterproof but with reasonable care it should hold up OK. I keep mine in an old compact camera case.
As far as I know, this is the only device that provides a standardized sky brightness measurement at a reasonable price.This review was provided courtesy of AgenaAstro.com
Jan 1, 2018Simple, Inexpensive, and Accurate
Pros: Cons: Comments:There's not a lot to say about this product: it's Simple to use (just point it upwards at the sky overhead), Inexpensive (I think that I paid about $ 125.00 for it), and Accurate (from my experience it does an outstanding job of metering the darkness of the sky based upon the various locations where I have used it). I wish that I had purchased one of these many years ago. I don't know why I waited so long!
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Dec 28, 2017Nice addition to my imaging activities
Pros: Cons: Comments:I image both from a red zone at home and white zone in NYC, and I am particularly interested in refining techniques for dealing with light pollution. This meter allows me to be much more precise regarding what works and what doesn't. It is certainly easy to use (point up and press button duh) and arrived quickly and in perfect working order.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Oct 28, 2017El viejo in Oregon
Pros: Cons: Comments:Wonderful instrument to compare dark sites. Very steady, quick, and point-able to not get a false reading from trees or overhangs. I found out that the skies over my house aren't so bad after all.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 6, 2017Unihedron Narrow Field Sky Quality Meter
Pros: Cons: Comments:The meter arrived promptly and well packaged. Agena Astro consistently delivers superb service. I haven't had a chance to use the meter under dark skies yet, but I look forward to taking quantitative measurements of sky quality (darkness) at some of my favorite observation sites.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Mar 25, 2017Sky Quality Meter
Pros: Cons: Comments:This well-built instrument is simple to use and provides accurate, informative readings to help decide when and where to observe.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Sep 30, 2016Convenient for monitoring the sky
Pros:Strong Construction,Lightweight,Easy to Use,Compact
Cons: Comments:I use this to monitor sky conditions during astrophotography. By taking a reading every couple hours I can see if the sky is starting to go bad or is getting better.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Sep 30, 2016Excellent sky quality meter
Pros:Compact,Accurate,Lightweight,Easy to Use
Cons: Comments:I am an avid visual observer who likes to monitor sky brightness to understand which deep space objects are likely to be detected under the current conditions. This is a solidly-built, compact, and accurate light meter. I recommend it highly.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 13, 2016Better than nothing
Pros:Easy to Use,Compact,Lightweight
Cons: Comments:I mounted mine on a lightweight camera tripod and leave it set up through the night so I am consistently measuring the same area of sky. A friend also has one and when we put them side by side we find about .3 difference in readings so I am a little dubious as to their accuracy however I consider the reading to be relative and it certainly is better than nothing and keeps me aware of changing conditions throughout the evening and even from one evening to the next. I think this ability to monitor the sky condition is worth this modest investment, especially when imaging.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jun 28, 2015A great tool, and fun too
Pros:Easy to Use,Long battery life,Accurate,Small
Cons:Girlfriend Demands High
Comments:I'd wanted one of these for a while to see how my conditions changed from night to night, and from site to site. This gizmo doesn't disappoint. I chose the narrow angle meter for it's ability to spot check different areas of the sky, and due to the fact that trees at my home would prevent good readings with the wide angle model.
Bottom Line: Would you recommend this item? Yes
This box is very easy to use, and a lot of fun as you gradually calibrate what you see in the sky against what the box tells you. I've had it for 4 months now, the best reading I've hit yet is 21.65 magarcs from the back yard. At the girlfriends place near Portland, OR, I see about 20 on a good night, better than I expected. This tool will allow me to check and see if the night is imaging worthy for faint fuzzies as well if I want the best high contrast conditions for photography.
The one drawback is, now the girlfriend is getting picky and won't come out unless I can prove we're at 20.5 or better!This review was provided courtesy of AgenaAstro.com
Mar 27, 2015Comments Unihedron SQM-L
Pros:Lightweight,Compact,Easy to Use
Cons: Comments:I use my SQM-L most nights that I observe the night sky. It is light and fits in my pocket nicely. I like to use it to confirm my suspicions about the sky's darkness. Over time I expect to be able to detect any degradation or improvement of my seeing. Since my vision isn't as sharp as it was when I was younger, I can't speak directly to the meter's accuracy, but the numbers are certainly reasonable. In addition, the meter is sensitive enough to detect the difference between my front yard, where I am plagued by a couple annoying, neighboring porch lights, and the back yard, which is shielded for the most part. Although the meter is not "built like a tank", I believe it will withstand a drop better than many eyepieces or your laptop computer. I would not let its construction keep you from buying this item. I'm certainly glad I did.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Feb 21, 2015Satisfied User
Pros:Easy to Use,Compact,Accurate,Lightweight
Cons: Comments:Excellent service from seller.
Bottom Line: Would you recommend this item? Yes
Very helpful in obtaining consistent measurements of sky darkness when searching for an astronomical observing site.This review was provided courtesy of AgenaAstro.com
May 30, 2013Sky Quality Meter
Pros:Lightweight,Compact,Accurate,Easy to Use
Cons: Comments:This meter confirmed what I had suspected about the night sky at my location being much better than expected.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 30, 2013Use it every cloudless night
Pros:Lightweight,Accurate,Strong Construction,Easy to Use,Compact,Quality Lenses
Cons: Comments:Gives me a yardstick to measure my visual performance under a skies of varying darkness.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Dec 20, 2011Keeping Watch on the Dark
Pros:Easy to Use,Compact,Lightweight
Cons: Comments:This is a very useful tool for measuring and monitoring naked eye limiting magnitude (NELM) at my various dark sites or to monitor the sky conditions over the course of a night's observing session. I've had mine now for several weeks and have used it every time I've been out. If you're a well-seasoned observer and can pretty much call the NELM as you see it, then its value is diminished. An observing buddy of mine guessed that a new site we tried was about 5.5 mag. After checking with the SQM I got a 5.63 reading. Other members of my club have different versions of the SQM and a log is being kept of readings from all of our dark sites. By keeping logs of our readings we can monitor light pollution encroachment of our sites. Another club member has a permanent observatory on his property and has one set up to read the sky continually throughout the night with the results posted on his website. Mine has worked flawlessly and is a helpful tool for reporting more objectively on my observations. It's far from "built like a tank" quality, so one must be careful with storage and handling.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Nov 4, 2011A Fun Gadget
Pros:Lightweight,Compact,Easy to Use
Cons: Comments:Like the weather, I can't do anything about the sky conditions but it is fun to know how they compare, e.g., about 20 in my back yard vs. 21+ at Eldorado Star Party. Also gives temperature in degrees C and F. I prefer the narrow angle model over the wider angle version.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Oct 30, 2011Excellent Astro Accessory!!
Pros:Compact,Easy to Use,Accurate,Lightweight
Cons:Compact,Easy to Use,Accurate,Lightweight
Comments:Very repeatable and reliable readings, also very consistent with visual observation at the time.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
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