Author Topic: Lake Sonoma or Dino Point or Pinnacles  (Read 392 times)

dnsmiley

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Lake Sonoma or Dino Point or Pinnacles
« on: October 19, 2017, 12:42:39 PM »
Hi,

For those who have been to all three sites how do they compare in terms of darkness and horizons? I've looked at dark sky maps and read ORs on TAC. My impression is Lake Sonoma and Pinnacles might be darker than Dino Point but of course local conditions matter. Trying to decide where to go Saturday the 21st, I've only been to Lake Sonoma which is the closest to me, and hoping the predicted rain will clear it up, but if not will travel south.

Thanks.
« Last Edit: October 19, 2017, 07:43:33 PM by dnsmiley »

Marko

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Re: Lake Sonoma vs Dino Point vs Pinnacles
« Reply #1 on: October 19, 2017, 01:06:37 PM »
There are 2 Pinnacles so I would like to hear the reply on this thread as well perhaps for both Pinnacles.

As for Dino the horizons themselves are very low with SQM in ballpark of Lake Sonoma but a little brighter at Dino.  The far away but bright light on the Damn does make the east horizon the highest and one tends to put scope on west side of car to minimize darn light distraction when looking into eyepiece.

11 ORs of mine from 2007 through 2012 yield SQM values between 21.0 through 21.3 with 21.15 area being most common  (my sqm broke around then so not sure on recent numbers there).   Only at Lake Sonoma once.

I publish a map of common sites and typical SQMs here:  http://astrospotter.com/BayAreaAstronomySites.jpg   Has not been updated for a few years.
Let me roam the deep skies and I'll be content.

Peter Natscher

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Re: Lake Sonoma vs Dino Point vs Pinnacles
« Reply #2 on: October 19, 2017, 03:55:57 PM »
I was observing from Pinnacles West last December 21st.  Had clear skies with a SQM of 21.45.  Another evening at Pinnacles East parked way west into the park towards the mountain ridges near end of road at last parking lot was definitely darker overhead vs. Pinnacles Westr but has poor horizons.  The light domes of the West parking area are not visible at the East location – the surrounding mountains block the light domes and possibly darkening the area. At Pinnacles East, Sagittarius at the meridian was not completely clearing the south mountain tops.  At Dino Pint, I get SQM 21.1-21.3 on different nights.   CalStar gave readings of 21.38-21.57 last month, darker after midnight.  GSSP gave 21.6-21.9 but my SQM device is the narrow angle model and could be reading a bit high.  At GSSP, it gave me a 22.09 reading while pointing overhead into the dark Pegasus square one early morning hour at GSSP after most people had gone to bed!

Marko

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Re: Lake Sonoma vs Dino Point vs Pinnacles
« Reply #3 on: October 19, 2017, 04:21:40 PM »
Peter:  Suggest you verify your SQM against 2 other people.   I found with two units so far that they tend to get better and better readings till I realized they were out of cal.   Also note that any dirt or partially blocked sensor gets you 'better' skies.   So I keep black tape over mine and now I always have 22+ readings.   YEAH!
Let me roam the deep skies and I'll be content.

DDK

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Re: Lake Sonoma vs Dino Point vs Pinnacles
« Reply #4 on: October 19, 2017, 06:39:23 PM »
Dan, why say vs? The better conjunction here is or.
I've been to all 3 places you mention, and they're all fine observing sites. You can just pick according to your mood. Especially driving mood in this case, living in Mill Valley.

And please let's not get off into squirrelmeters on this thread, and you know I mean it, Marko.
Plus, limiting magnitude counts, while taking a little effort, more than pointing upward, have a built-in reliability.
And those darksky maps are hooey, many of them are generated in Italy and based on population numbers, not at all on actual conditions.

Have been to your default spot, Lake Sonoma, once. It was dark and lovely. Angie and Doug Traeger, Steve Gottlieb and Carter Scholz were all there that night. Each of them has praised that spot over years. You have quite serious skies off to the West there, as you know.

Just did a quick scan of my observing logs, and I've been to Dinosaur Point over 3 dozen times since 2001. Conditions can be excellent there. Did a whole exploration of the Fornax Cluster there, where you need a good southern sky. Also did a good part of a serious mini-project at Dinosaur Point, combing the Bowl of the Dipper for galaxies. Those little Ursa Major galaxies take a good sky to tease out. And it's gorgeous there along San Luis Reservoir.

The Pinnacles also is a spectacular area. I'd mentioned to you that the east side would be a very long drive from Mill Valley. We have a choice of 3 observing spots on the west side, all with various strengths, I've observed at all 3 repeatedly, with fine results.

You want numbers? Both at Dinosaur Point and at Pinnacles, I've seen limiting magnitudes of 6.5. That's world class dark, up there with Lassen and Anderson Mesa south of Flagstaff. I've only gotten 6.6 twice, from Fremont Peak on nights when the marine layer was covering the towns. Now there's a selection effect there, as I've been to the Peak more than anywhere else.

So rather than vs I'd say plus. Of course every night is different, but that's part of the fun.
Seriously though Smiley, if I lived in Mill Valley I'd haunt Lake Sonoma and forget all those freeways to the south.
TAC - astro anarchy at work <*>

dnsmiley

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Re: Lake Sonoma or Dino Point or Pinnacles
« Reply #5 on: October 19, 2017, 07:49:02 PM »
Thanks all for the input. Yes, “or” would be better than “vs” so I modified it! The rain is falling now, I shall hope for fires to go away and clear, clean dark skies to arrive.