DaveS Posted December 18, 2021 Share Posted December 18, 2021 I know I have wonky eyes, with probably the beginnings of cataracts, a few years ago my then optician said there were pinhead cataracts. I find extended objects are visible to a fainter level than stars, possibly because point source stars are being "fuzzed" slightly so losing brightness compared to, eg, the milky way which is already "fuzzed", if that makes sense. 1 Link to comment Share on other sites More sharing options...
gorann Posted December 18, 2021 Share Posted December 18, 2021 7 hours ago, vlaiv said: I always thought that this is relevant: Translating SQM(mag/arcsec2) to Bortle has become quite confusing to me. Where I am my SQM meter goes from 21.1 on some nights to 21.7 on the best. According to the scale you posted it is Bortle 2-3 but now in Wikipedia it is Bortle 4: https://en.wikipedia.org/wiki/Bortle_scale Link to comment Share on other sites More sharing options...
vlaiv Posted December 18, 2021 Share Posted December 18, 2021 42 minutes ago, gorann said: Translating SQM(mag/arcsec2) to Bortle has become quite confusing to me. Where I am my SQM meter goes from 21.1 on some nights to 21.7 on the best. According to the scale you posted it is Bortle 2-3 but now in Wikipedia it is Bortle 4: I think wiki is more accurate. Check lightpollutionmap.info as well - it also gives both values (I think). In any case - Bortle scale is not really with hard limits as it is descriptive in nature, so there is bound to be some difference in interpretation unless we take some values to be standard - like Bortle 4 goes between SQM A and B. Link to comment Share on other sites More sharing options...
niallk Posted December 18, 2021 Share Posted December 18, 2021 The skies can be very variable where I am - perhaps moisture content in the atmosphere (?). When I go to the coast to be as far from light domes as I can get, there has only been 1 night I can remember when the Flame neb was in-your-face very detailed. A real treat! I had one outstandingly magnificent night on the Omega neb - wow the detail. And one really extra special night on the Orion neb where it was even way more detailed than usual offering a curiously 'scooped out' 3D appearance, and tinges of pink - I always see green. So I think transparency and reflection of light pollution is a big and variable factor for me locally. Some nights it can be moonless, no jetstream, etc - but still not as rewarding as you'd hope. I do always strive to allow the mirror cool for a few hrs for DSOs. 1 Link to comment Share on other sites More sharing options...
Ags Posted December 19, 2021 Share Posted December 19, 2021 I think intense light pollution multiplies any variability in the sky quality - a little haze will reflect the city lights back at me very strongly, but the same haze in the middle of nowhere has nothing to reflect. 1 Link to comment Share on other sites More sharing options...
DaveS Posted December 19, 2021 Share Posted December 19, 2021 According to CO (Using the LP map data) I am 21.66 and the dark end of Bortle 4. On the "Good To Stargaze" app I have on my 'phone it's 21.7 (Rounded up) and Bortle 2.8. From the appearance of the Milky Way plus visibility of several nebulae / clusters I would put it mid Bortle 3, certainly not into the Bortle 2-3 range. I don't go by limiting magnitude for the reasons I posted above. Link to comment Share on other sites More sharing options...
Ags Posted December 19, 2021 Share Posted December 19, 2021 Just installed Good to Stargaze. It says I am in Bortle 7.4, not too far from my estimate of Bortle 8++. Link to comment Share on other sites More sharing options...
Dave scutt Posted December 19, 2021 Share Posted December 19, 2021 17 minutes ago, Ags said: Just installed Good to Stargaze. It says I am in Bortle 7.4, not too far from my estimate of Bortle 8++. Thanks I didn't know about this app so I downloaded it aswell, it's says SQM 21.8 and Bortle 2.4 Link to comment Share on other sites More sharing options...
Mr Spock Posted December 19, 2021 Share Posted December 19, 2021 You get the same information with Clear Outside Link to comment Share on other sites More sharing options...
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