Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Astronomical Seeing in Big Bear Lake, CA

  • Please log in to reply
8 replies to this topic

#1 MountainAir

MountainAir

    Mariner 2

  • *****
  • topic starter
  • Posts: 231
  • Joined: 02 Oct 2019

Posted 22 July 2021 - 11:56 AM

Does anyone have any useful experience to share regarding the ground-perspective astronomical seeing in Big Bear Lake, CA?

 

Three times I was able to bring my 2350mm SCT to Big Bear, but I have no real experience with the seeing.

  • Once I managed to get just a few minutes in with Jupiter and Saturn before the clouds rolled in.  I didn't capture enough data for a lucky imaging stack.
  • Another time I had it there for 4 days but couldn't get a clear view of the sky around the hotel (and it was Valentine's Day weekend, so no trip off into the wilderness for me).
  • This last time I rented a cabin for a week, but the entire time it was windy (10+ mph winds, though by the sound of the trees I think it was faster at higher elevation) that affected seeing enough to make focusing unreliable.

In short, I've been there three times and have not been able to take one usable photo or assess the seeing conditions at all.

 

I can see the seeing scores in arcsec on MeteoBlue, but I believe these are calculated from satellite/weather data and are not actual ground observation conditions (which are probably 2" seeing or worse).

https://www.meteoblu...america_5328163

 

I am just wondering how the mountain compares to the desert (e.g. East San Diego County).  The mountain certainly perturbs the laminar flow off the coast, but there's less atmosphere to worry about at 7200ft vs 3000 ft.

 

Any experience to share?  Maybe comparison photos of Jupiter from the two locations?

 

Thanks in advance.


Edited by MountainAir, 22 July 2021 - 11:57 AM.


#2 MarMax

MarMax

    Apollo

  • *****
  • Posts: 1,249
  • Joined: 27 May 2020
  • Loc: Los Angeles

Posted 22 July 2021 - 01:02 PM

I've made about four trips to the Moonridge area of Big Bear Lake during the past year. I only brought the C11 up twice. For comparison, I also have a friend that lives in Yucca Valley. Here are the posted numbers for the two locations:

 

Big Bear

- SQM: 21.20 
- Bortle: Class 4
- Elevation: 2217 meters (7270 ft)

 

Yucca Valley

-  SQM: 21.60 
-  Bortle: Class 4
-  Elevation: 1039 meters (3400 ft)

 

To be honest, I can't really say there is a significant difference between the two locations. The differences are more subtle and I've not measured actual SQM with my meter. But there does seem to be less light pollution in general at the Yucca Valley location. Yucca Valley is generally better for lower Alt and both locations are about equal with high Alt objects. And of course conditions matter.


  • MountainAir likes this

#3 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 93,570
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 22 July 2021 - 05:29 PM

Just a comment:

 

If seeing is important, coastal San Diego is better than the mountains or the desert.

 

Jon


  • vdog likes this

#4 MountainAir

MountainAir

    Mariner 2

  • *****
  • topic starter
  • Posts: 231
  • Joined: 02 Oct 2019

Posted 22 July 2021 - 05:52 PM

Just a comment:

 

If seeing is important, coastal San Diego is better than the mountains or the desert.

 

Jon

Any of the laminar flow along the coast would be better, but it's at the expense of light pollution:  I don't know anywhere in coastal San Diego that isn't at least a Bottle 6.  Besides, the family always wants to go to Big Bear for hiking.

 

Side note, I tried the iOS app "Dark Sky Meter" the last time I was in the outskirts of Big Bear and I got an SQM of 21.4.  I'm not sure how accurate it is (I don't have an SQM meter myself), but ClearOutside said 21.45. It's pretty cool -- you take a dark frame by covering the lens, then just hold the camera up to the zenith.



#5 Starman1

Starman1

    Vendor (EyepiecesEtc.com)

  • *****
  • Vendors
  • Posts: 51,156
  • Joined: 23 Jun 2003
  • Loc: Los Angeles

Posted 22 July 2021 - 06:03 PM

Does anyone have any useful experience to share regarding the ground-perspective astronomical seeing in Big Bear Lake, CA?

 

Three times I was able to bring my 2350mm SCT to Big Bear, but I have no real experience with the seeing.

  • Once I managed to get just a few minutes in with Jupiter and Saturn before the clouds rolled in.  I didn't capture enough data for a lucky imaging stack.
  • Another time I had it there for 4 days but couldn't get a clear view of the sky around the hotel (and it was Valentine's Day weekend, so no trip off into the wilderness for me).
  • This last time I rented a cabin for a week, but the entire time it was windy (10+ mph winds, though by the sound of the trees I think it was faster at higher elevation) that affected seeing enough to make focusing unreliable.

In short, I've been there three times and have not been able to take one usable photo or assess the seeing conditions at all.

 

I can see the seeing scores in arcsec on MeteoBlue, but I believe these are calculated from satellite/weather data and are not actual ground observation conditions (which are probably 2" seeing or worse).

https://www.meteoblu...america_5328163

 

I am just wondering how the mountain compares to the desert (e.g. East San Diego County).  The mountain certainly perturbs the laminar flow off the coast, but there's less atmosphere to worry about at 7200ft vs 3000 ft.

 

Any experience to share?  Maybe comparison photos of Jupiter from the two locations?

 

Thanks in advance.

Seeing is good by the lake, but LP from Los Angeles is egregious.

Darkness is good in the desert, but seeing is often poor.

Want both?  Find a high mountain top far from the city, like White Mountain.

As for BigBear, the farther you get away from the lake, the poorer seeing is.

The lake seems to keep the atmosphere quiet (It's why the solar observatory is out in the lake on a promontory).


  • MountainAir and MarMax like this

#6 MikeHC8

MikeHC8

    Vostok 1

  • -----
  • Posts: 150
  • Joined: 09 Dec 2018
  • Loc: San Diego

Posted 22 July 2021 - 07:50 PM

Holcomb valley is good place, has areas that are away homes.  Follow the trail to arrow lake and go to rattlesnake canyon which is heading to the desert is good also.  I would agree that San Diego county is better and one other spot is Banner, very dark skies. 


  • MountainAir likes this

#7 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 93,570
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 22 July 2021 - 07:55 PM

Any of the laminar flow along the coast would be better, but it's at the expense of light pollution:  I don't know anywhere in coastal San Diego that isn't at least a Bottle 6.  Besides, the family always wants to go to Big Bear for hiking.

 

Side note, I tried the iOS app "Dark Sky Meter" the last time I was in the outskirts of Big Bear and I got an SQM of 21.4.  I'm not sure how accurate it is (I don't have an SQM meter myself), but ClearOutside said 21.45. It's pretty cool -- you take a dark frame by covering the lens, then just hold the camera up to the zenith.

 

You mentioned photos of Jupiter.. What are your photographic goals?

 

I have an SQM and a SQM-L.  In general, I find they read about 0.3 magnitudes brighter than the light pollution maps.

 

Jon



#8 Chucke

Chucke

    Viking 1

  • *****
  • Posts: 829
  • Joined: 12 Mar 2010
  • Loc: AZ

Posted 23 July 2021 - 02:09 PM

Back when I used to go to RTMC the seeing at Camp Oaks was ususally quite poor.  On occasion it would be ok but not often.  As Don said there is a reason they built the solar observatory in the lake.

 

If it is convenient to you try Palomar.  They put the observatory there for good reason.  Also, OCA's Anza site often has decent seeing.  It is about 10 miles from Palomar and has facilities.  Unfortuantely, it is affected by the OC and Temecula light domes.


Edited by Chucke, 23 July 2021 - 02:10 PM.


#9 MountainAir

MountainAir

    Mariner 2

  • *****
  • topic starter
  • Posts: 231
  • Joined: 02 Oct 2019

Posted 23 July 2021 - 11:00 PM

Good commentary, thank you.  I'll need to fire up the SharpCap seeing monitor at various sites to see how well they rank from the ground.

 

A great Sky & Telescope article on seeing:  https://skyandtelesc...ing-the-seeing/


  • Symui likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics