59 replies to this topic

[daveb2022]

I bought one of these but what is that small ring for?

Activates the power switch...it pushes the momentary power switch so it stays on.

[MrsM75]

Maybe you have higher expectation, you will NEVER see astrophotography images. Not even in an Obsession Dob.

 

And there is a difference between a short focal length scope and a long focal length scope. Saying the view of 200x Mak is same as a 85x view of a Refractor, is sorry, there is a difference. Maybe you expecting Astrophotography images.

 

If money is not an issue for you, then please get Night Vision, guarantee you love it.

 

Night Vision will solve it for you.

Edited by MrsM75, 23 June 2025 - 10:38 PM.

[MrsM75]

Thank you for the site https://www.darkskysites.com/

 

If the new Lightpollution Map of 2025 should be use as the latest map, I click that link, then I got Bortle 7 in my city of 34,000 population. Not bad. Better than I thought. I thought I was like in Bortle 11, lol.

 

Edited by MrsM75, 23 June 2025 - 10:26 PM.

[Dave Mitsky]

The figure for my home on David Lorenz's map is close to what I typically measure with my SQM-L.  It's not accurate for some of the other locations from which I observe.

[MrsM75]

Is David Lorenz map same as the https://www.darkskysites.com/ map?

 

I just know Bortle can be subjective from one person to one person, you put 2 people under the same sky, and one person can have better eyesight than another. 2 people will not see the exact same thing even in the same sky. Not everyone retina is the same.

Edited by MrsM75, 23 June 2025 - 10:32 PM.

[Starman1]

Old Light pollution maps:

https://www.lightpol...2l0eSI6Ijg1In0=

 

David Lorenz' LP site:

https://djlorenz.git...erlay/dark.html

 

Current LP site being constantly improved to more closely resemble reality:

https://www.darkskysites.com/

[daveb2022]

The darkskysites is the closest to my readings. However it shows 18.71 and is what I get on a premium night which is rare. But that is very close. 

[Bearcub]

Some factors:

 

Viewer experience

Eyes health

minimum magnification to separate quality between telescopes should be higher until differences are noticed

atmospheric abberation, pickering scale should be looked at to gauge the nights sky..

 

And of course, the telescopes just might be what they are and as a small coincidence they deliver similar performance in a certain night. But do they give similar performance majority of nights? There could be measured how many nights it took for telescopes to show significant difference i quality.

[Tony Flanders]

Look!
A new light pollution map with up to date info and FAR more accurate light pollution figures than previous attempts, even David Lorenz's 2024 one.
It is very close to my actual measurements at my dark sites and uses current satellite data.
The best I've seen so far:
https://www.cloudyni...lculations-etc/
 
https://www.darkskysites.com/

I find the forecast SQM values from darkskysites.com to be much worse than I obtain with my SQM and SQM-L. It forecasts my country home to be 20.80, whereas last night I obtained 21.1 on both devices, and was disappointed that it didn't read better. On a really transparent autumn night before the leaves fall, I can get as dark as 21.3 around midnight.

 

David Lorenz's 2024 map says 21.2, which seems spot-on.

Edited by Tony Flanders, 30 June 2025 - 01:54 PM.

[Starman1]

I find the forecast SQM values from darkskysites.com to be much worse than I obtain with my SQM and SQM-L. It forecasts my country home to be 20.80, whereas last night I obtained 21.1 on both devices, and was disappointed that it didn't read better. On a really transparent autumn night before the leaves fall, I can get as dark as 21.3 around midnight.

 

David Lorenz's 2024 map says 21.2, which seems spot-on.

Must still be some tweaking needed.

Earlier LP maps predicted 21.56 at my favorite site.

Lorenz' site predicts 21.35 at the site.

DarkSkySites predicts 21.25 at that site.

Recent measurements at new moon range from 21.17-21.22

 

At my second most-frequented site, the figures are 21.35, 21.22, and 21.17 and recent measurements have been 20.96-21.10

 

You're getting pessimistic numbers, I'm getting optimistic numbers.

 

The annoying thing isn't the accuracy of the numbers for me, it's that the first site mentioned averaged 21.47 from 2005-2017.

LED conversion, solar activity, population growth in the vicinity, volcanic eruptions, and much higher humidity in the air at 8000' has brightened the site.

Unfortunately for me, if I want a darker site, it's a 4.5 hour drive each way and untenable in the summer months due to heat in the desert.

Edited by Starman1, 30 June 2025 - 03:54 PM.