Showing posts with label dark sky. Show all posts
Showing posts with label dark sky. Show all posts

Thursday, April 25, 2024

Getting Out of Town, but to Where?


This post is going to be an exercise in overthinking a simple task like combining imaging and camping, much like the many posts I've made about batteries and such. Wander in at your own risk. 

🌲🌳🌲🌳🌲🌳🌲

Last time I said this post would be about some parks I visited in the hope of finding a nice dark place at which to image and camp. Here are the results of that little jaunt and the realization it forced upon me. 
  • Cedar Hanson County Park near Trimont: Very nice for campers, but too many trees
  • Sands Country Cove campground southwest of St. James: High density, packed even in April, which is not the nicest month to tour Minnesota. Reservations will be tight, just like how it packs the RVs together. It looks like it caters to families with big RVs. On the other hand, no trees.
  • Eagle's Nest County Park east of St. James: Needs a variance to park away from trees in an open pasture that's probably dedicated to horse riders. I've written to the county parks person about that variance, but this is a "light green" light pollution area so not much darker than a local site.
  • Voss Park, Butterfield: A large area of trees was removed and sites added since my last visit. It's also not much darker than a non-camping site I use now.
  • Lake Hanska County Park, north of La Salle: Too many trees.
Yes, that's correct, none of these were suitable.

Related: An article by the Dyrt.com reports on a poll of 7000 campers. One result was

"In 2023, 45.5% of campers reported difficulty booking a site because a campground was sold out. It was four-times harder to find an available campsite to book than it was in 2019, when just 10.6% of campers reported difficulty."

Here is the realization: Campground reservations are a necessity. Sure, some campgrounds say they are first-come, first-serve. Theoretically you can see a good forecast in the morning, hop in the car and drive three hours to one of those campgrounds hoping there's an available spot for the night. But the chances are that spot will be gone by the time you get there, meaning you have to turn around and drive three hours back home. Not good. Minnesota state parks do allow same-day reservations, but your chance of that working in your favor seems particularly small if you want more than one consecutive night.
 
The problem with advance reservations is the same as that with multi-day star parties: the weather. You can't know what you're going to get.  But unlike star parties with registration fees and associated travel expenses, camping reservations do give you an out. You can cancel the reservation and get some (or most) of your money back, and then complain about the clouds from the comfort of your own home.

🌲🌳🌲🌳🌲🌳🌲

The Hunt for Darkness


Let's say you enjoy camping and want to combine that with dark-sky imaging as an alternative to attending distant star parties.

Choosing when to camp is easy, just mesh your personal schedule with any time the moon isn't a bother. Then match that to campground availability. 

Deciding Where to camp is a little tougher. If you live in a light-polluted city you'll probably need to drive one to three hours to find dark sky.  That means you should think about what your daily safe driving range is. That's the amount of time you can stay alert and your back won't punish you the next day. For me, old and decrepit as I am, that range is about six hours. For the rest of this post I'll assume a driving range of half that -- three hours -- because that permits turning around and returning home if a crucial item was forgotten ("OMG I forgot the counterweight!"). 

With your driving range decided you can start your hunt for campsites that are reasonably dark, accept reservations, and have open sky. And I do mean hunt because campgrounds satisfying all three conditions seem to be rather rare. Some camp sites may be dark enough overhead but have troublesome horizon light domes from nearby cities in the direction you want to image. Many camps are full of shade trees that block the sky. Some like to maximize land usage by packing large RVs so tightly together that they obstruct the sky. Some are near major highways and almost impossible to book. Some are rather primitive. Will you need power and water? Flush toilets? A shower? Everyone has a particular set of requirements.  If you need to run a generator after 10 P.M. you may have issues with a campground's quiet time. And some smaller parks are just sort of unkempt or creepy, making you wonder if they're a "party park" for locals (see for example, Pine Ridge Park north of Herman). Your hunt is for a camp where you can securely image and enjoy yourself while doing so.

It's almost May now and places are taking reservations: it's time to get site hunting. For this post I used Google search, Google Earth, Google Maps, and Light Pollution Atlas 2006 (selecting the 2022 overlay). Google Earth showed me if the locations are infested with trees, Google Maps provided directions and drive times, and the Light Pollution Atlas was great for figuring out how dark a site is and what the horizon situation might be.

Other online resources that were helpful included Minnesota's state park finder and a map of Minnesota's counties. Googling a county name will point you to the county's home page, and from there you can see what it has for parks. A few counties structure their web sites as if they don't want anyone to know they have parks, so be ready to dig.

There are a lot of campground finders on the internet, two that seemed useful are Hipcamp for smaller private camps and The Dyrt for pretty much everything else.

My personal site hunt was limited to the south and west of the Twin Cities because I enjoy that part of the state and it's less tree-infested than elsewhere. You're free to hunt wherever you want. But first we should think about just how dark we want it to be.


☆★✨🌟✨★☆

What is Dark Enough, and What is Too Dark?


I know, I know, there's no such thing as "too dark."  But there can be a dark so dark that it can't be reached within your driving time limit.

My very subjective take on "dark enough" is based mainly on my past imaging at different sites. 

First a bit of terminology: the Light Pollution Ratio, or LPR. LPR is the ratio of light pollution to natural sky brightness; an LPR of 1.0 means that the light pollution is equal to the natural sky brightness. The smaller the LPR the darker the sky. (The Light Pollution Atlas gives you the LPR when you click on its map.)

The diagram below shows an LPR diagram from the Light Pollution Atlas 2022 overlay. The area covered is from near the South Dakota border at left to a bit past Eau Claire WI at right, and just south of Duluth at top to Albert Lea at bottom. Color indicates LPR value with light green being between 0.6 and 1.0; dark green is 0.33 to 0.6. I've changed all areas with LPR greater than 3 to black.

Light pollution map of southern Minnesota. Click to enlarge! 

My back yard has an LPR of 24.5 (!), which is emphatically awful. If I want to image emission nebulae it's narrowband filter time. LRGB imaging (my preference) works well from Eagle Lake (LPR 2.34, EL on the diagram) and Starhome (a friend's back yard, LPR 2.9, SH on the diagram). They're both on the fringe of the Metro and suffer from its huge light dome. Cherry Grove (LPR 1.08, CG on the diagram) is located south of the cities and is very good overhead but less so northward and to the southeast. A person I corresponded with during my Astronomical League Bright Nebula imaging years was using LRGB from a Missouri site with an LPR of 0.6 and his images were nothing less than excellent. I've also imaged from locations where the LPR is under 0.2 and can attest to their excellence.

My take is that an LPR > 7 or so will push you to use narrowband or at least multiband filters. An LPR < 7 is probably dark enough for LRGB imaging of most targets, and an LPR < 0.6 is great for almost any DSO. If you're planning to go super deep, like imaging IFN, then you probably want it as dark as possible to reduce your total exposure time.

My hunting goal will be to find locations where the LPR is 0.6 or less; my motto will be "Go Dark Green or Stay Home." You may be willing to accept something brighter, or demand even darker based on your imaging gear and targets.

Once I determined my personal "dark enough" I could perform my hunt. What follows is the result. See the summary at the end of this post for campground LPR values, links to the individual parks/campgrounds, and other comments.

Minnesota State Parks


Minnesota state parks are widely regarded as some of the nicest in the country. The facilities are well maintained and staffed by knowledgeable outdoor enthusiasts. And lucky for us there are two parks that may be particularly suitable for imagers!

Not suitable -- either too bright or blocked sky: Big Stone Lake, Blue Mounds, Camden, Flandrau, Fort Ridgely, Glacial Lakes, Kilen Woods (probably), Lake Maria, Minneopa, Minnesota Valley, Monson Lake, Myre Big Island, Sakatah Lake, Sibley, Split Rock Creek
 
Suitable: Lac qui Parle and Lake Shetek.

Lac qui Parle is a little darker than Lake Shetek but Montevideo to the southeast maye put up a light dome. One person who has been there said he did not note any problem with the horizon. The positions of these parks are indicated on the diagram above. Both parks can be found in its lower left corner.

All state parks require reservations.

Minnesota County Parks


County parks operate on generally lower budgets and their facilities vary widely. Even so, they will likely be packed full of campers during summer. An additional factor for these parks are monthly and seasonal campers who will fill spaces semi-permanently. A brief look at County parks shows a few promising locations:

Jackson County: Sandy Point (reservation required, choose site carefully to avoid trees, needs a visit to verify horizons)  

Murray County: Sundquist, Lime, and Swenson (no reservations)

Lincoln County: Picnic Point  and Norwegian Creek (reservations required)

Lyon County: Twin Lakes (reservations required)

Yellow Medicine County: Timm Park. Needs a visit to see which if any sites are suitable. (reservations required)

Counties that have no suitable county parks are Blue Earth, Brown, Chippewa, Cottonwood, Faribault, Freeborn, Kandiyohi, Martin, McLeod, Meeker, Mower, Nicollet, Nobles, Pipestone, Redwood, Renville, Rock, Sibley, Swift, Watonwan 


Minnesota City and Town Parks

Many small cities and towns have parks that offer camping. These are generally near the population center and so will have considerable light pollution. I found none that were satisfactory for imaging. 

Private Campgrounds


I am omitting campgrounds that pack RVs tight together; giant RVs are as opaque as trees. 

All of the following locations need to be visited to assess their suitability.

Camping on Private Lake. This was found on Hipcamp. It has an LPR of only 0.3! You would need to talk to the owner about being able to set up away from the trees. If you don't need AC power siting might be easier. Reservations required.

Camp Summit in Hadley. Seven sites, accepts reservations, but also allows space-available. LPR = 0.45

Talking Waters in Gary, SD. Many sites, requires reservations. LPR = 0.51

Niemackl Lake near Herman, MN. Accepts reservations by phone. LPR = 0.26. I visited this a few years ago and found maybe 3 or four of the 10 sites were decent. Neimackl has the distinction of being the darkest campground in my survey!

There are a few places in northern Iowa that look very good, but they are generally about 3 hours distant and will be very busy.

There are probably other suitable private campgrounds. If you know of some please let me know.

Summary: The Too-Short List of Suitable Campgrounds In SW Minnesota


This omits campgrounds that need a visit to judge suitability. (Trees look bigger in person than on Google Earth!) 

Reservations required:


Lake Shetek S.P., LPR = 0.52, use only the Sunrise Campground

Lac qui Parle S.P., LPR = 0.37, use only the Upper Campground

Twin Lakes C.P., LPR = 0.43, only north portion can be reserved at this time

Picnic Point C.P., LPR = 0.42

Norwegian Creek C.P., LPR  = 0.51

Reservations not accepted:


Sundquist C.P. , LPR = 0.35

Lime C.P., LPR = 0.43

Swenson C.P., LPR = 0.41


If you have experience imaging at these or others, let me know how you liked the location!





Monday, May 25, 2015

Two "Nearby" Dark Sky Sites, Maybe--and More as I Find Them

Minneapolis and St. Paul create a substantial amount of light pollution. Even at a distance of about 50 miles their combined light dome will show up clearly in long exposures. Where can one go to find really dark skies for all-night imaging?

Existing Minnesota Astronomical Society (MAS) sites are either not very dark or are distant: Cherry Grove Observatory (about an hour away, between light green and dark yellow sky as used by Light Pollution Atlas 2006), Eagle Lake Observatory (3/4 hour, light yellow), J. J. Casby Observatory (half hour, light orange), Long Lake Conservation Center (2 3/4 hours, light blue), and Crex Meadows (not an official MAS site, 2 hours, light blue).

These are either too bright (Cherry Grove, Eagle Lake, Belwin), too far (LLCC) or lacking in any accommodations (Crex). LLCC use is limited to specific weekends, eliminating the ability to take advantage of weeknight clear sky opportunities.

I spent some time doing an initial survey of what's available in the 2 to 3 hour driving range. I've looked at Lake Shetek state park previously; it's very nice, good horizons, electricity, green zone dark, and no reservations are needed during off-peak times (i.e., Labor Day through October). This park is busy at other times, though, and reservations are needed. Given the fickle weather around here, reservations are a good way of throwing one's money away. Here's what I mean:
State Park camping reservations work like this in Minnesota in 2015: A standard drive-in rustic campsite (no electric) is $15 to $19 per night.

Let's take an example of a two-night imaging trip: Getting the reservation is at least $38.50 (this assumes a $15 nightly fee and includes the $8.50 online reservation fee (use the phone instead and it's a $10 fee). Cancelling four days in advance will get you only $20 back (The $38.50 less the reservation fee less a $10 cancellation charge. You're out $18.50. Cancel later than that--which is more likely going to be the case given the quality of cloud cover forecasts--and you only get $3.50 back because the first night's charge of $15 is forfeited. You're out $35.

Another difficulty with state parks in general is their tendency to put campgrounds in wooded areas (Lake Shetek is a wonderful exception). There are a number of parks under dark skies, but if you put your gear up next to your tent (as I do) it's going to be under trees.

The good thing about State parks is that after labor day they tend to empty out and  it's often possible to obtain camp sites without going through the reservation system. Lake Shetek would be great for this in September and October.

Parks that don't require reservations such as those administered by counties are easier to use. Generally they don't have much in the way of facilities, but if you're used to primitive camping at star parties that's perfectly fine. Are there any dark-sky parks that look like candidates within a few hours drive from the Cities?

Yes, and they're surprisingly dark.

Cottonwood county's South Dutch Charley (also spelled Charlie) County Park is little more than a wooded lot, but it sits under light blue zone sky that's 2.5 hours drive away. Google Earth images suggest that it may have some places to camp that allow a southern view. At $10 a night you don't get much beyond a shelter and pit toilet, but when one can carry one's own power that's no problem. SDC is in familiar territory sitting only 16 miles west of Jeffers Petroglyphs.

Location of South Dutch Charley Park

Renville county's Vicksburg County Park (aka County Park No. 2) is a little larger and is 2.1 hours away. $12 a night for camping, its sky is on the line between light blue and dark green. Because this park sits next to the Minnesota River it will probably have plenty of mosquitoes during summer, but spring and fall visits may be pleasant.

Skalbekken County Park (aka Renville County Park No. 1, 2.2 hours away) is farther up the river and under dark green skies. It's farther from Redwood Falls than Vicksburg is, reducing its light dome to the SE. On the other hand, the dome from Granite Falls to the NW will be substantially brighter.
Locations of Skalbekken and Vicksburg County Parks
Here's how these two areas are located relative to the Twin Cities:
Yes, one has to drive this far to find blue zone sky.
I'll visit all of these sites in June and July to see if they are suitable for imaging trips.

ADDED:

Another dark sky camping location is in Iowa, 6.5 miles WSW of Rice in Mitchell County. It has light blue zone sky and is about 2 1/4 hours from my location. $10 camping with electrical hookups available. Worth checking out, probably on the return trip from this year's Eastern Iowa Star Party (assuming I'm able to attend).

Here's a map of the proposed sites showing the Atlas 2006 sky brightness. I've include my location and some other fairly dark sites mentioned in this post.


I looked at Wisconsin and NW of the Twin Cities, but couldn't find anyplace worth mentioning. The nice dark blue area south of LLCC seems to be mostly forests, but it contains one possible site: Snake River County Park. Aerial pictures of the camping area suggest it's forested, but it is worth a look on my next trip to LLCC (probably next summer).

ADDED 5/27: Another camping area only an hour and a half from home is Clear Lake Park in Sibley county. It's in a light green zone and about 11 miles north of New Ulm so there's going to be a substantial light dome to deal with. Camping is free (you need to get permission from the county Sheriff's office) and it looks like there may be considerable open space in which to set up.

ADD 5/58: Let's add a few more possibilities. Lake Hanska County Park is a light green zone park a little under two hours away. Blue zone camping can be found at Garvin County Park 7 miles WNW of Tracy. More blue zone at Oraas Park South of Clarkfield. All of these have inexpensive tent camping.

Maybe it's time to summarize these in a table:


SITE
ZONE
DRIVE
FEE
LOC
Elec
H2O
NOTE
L Green
1:31
?
10 NNW New Ulm
N
Y
1
L Blue
2:51
$10
7 WNW Tracy
Y
Y
2
L Green
1:53
$10
9 NW Madelia



L Blue
2:38
$5
7 S Clarkfield
16 SW Granite Falls
Y
Y

L Blue
2:19
$10
6 WSW Riceville
Y
Y

Skalbekken
D Green
2:17
?
8 SE Granite Falls
N?
N?
3
L Blue
2:33
$10
4 NE Westbrook
?
Y
4
Vicksburg
L Blue
2:06
?
10 NW Redwood Falls
?
?
3

NOTES
(1) Probable substantial light dome to south; must contact Sheriff’s office to OK stay
(2) Almost all campsites have electricity (extra $5)
(3) Very forested; no direct link at present from county web site.
(4) Open through end of October (most are open only until October 15)

At this point I'm most inclined to opt for South Dutch Charley and Garvin. Garvin in particular is attractive because of it having electricity, and aerial views suggest some campsites have passable horizons.  

Sadly I couldn't find any dark blue zones within reasonable driving distance unless one goes into South Dakota or north into the forests of Minnesota. There are a few light gray zones near the SD border, but as you might expect they're devoid of campgrounds.