Author Topic: Highest SQM Reading  (Read 243 times)

Javier Gutierrez

  • Active Astronomer
  • ***
  • Posts: 100
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Highest SQM Reading
« on: December 24, 2017, 01:08:38 AM »
For the 1st time since owning my scopes, I took one to a dark website.  My backyard reads 21.1 possibly 21.2 at its most mysterious on the Sky Quality Meter.

 I drove 1 hour off and even though the moon was still out I was becoming 21.6 and occasionally high on the SQM.  It was really beautiful.  Views through my Tak FC100-DL were all amazing.

1 friend celebrating there stated in the winter he's had readings of 22 and once 22.3 on the SQM and this was with his wide version of the SQM.  I've the narrow version.

I thought 22 was going as high a reading as you could get.  Has anybody else gotten much higher reading than 22?  I wonder what it would be in the middle of the ocean.

Thanks, Kent



calfkommomu

  • Active Astronomer
  • ***
  • Posts: 130
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #1 on: December 28, 2017, 02:23:57 AM »
I think 22 is about as high as you get when its a cloudless night. With clouds you can get higher, possibly 22.3, although I suspect he had an issue with calibration.

Sean Schaefer

  • Active Astronomer
  • ***
  • Posts: 126
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #2 on: December 30, 2017, 03:19:01 PM »
My home is consistently 21.8 with no snow or ice and my highest reading was 21.9. The views support these readings.

tioteyclasbeat

  • Active Astronomer
  • ***
  • Posts: 130
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #3 on: December 31, 2017, 11:23:09 PM »
After speaking with IDA on Friday last week at Grand Canyon he said 24 was technically the limit of the SQM, however it is impossible with all the variables in place for it to ever be 24.

The 22s are around the usual norm in reality. We were reading 21.9 to 22.0 at GCSP on Friday night.

John Jefner

  • Active Astronomer
  • ***
  • Posts: 126
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #4 on: January 04, 2018, 06:17:32 AM »
Kevin, what time did you get these readings at the GC? I only got about 21.6 or so and that was around 10:30 maybe 11. Do you think there was smoke in the sky when you took your readings? Thanks.

viogreetnifi

  • Active Astronomer
  • ***
  • Posts: 134
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #5 on: January 08, 2018, 04:09:49 AM »
They were measuring throughout the evening probably starting around 10pm ending somewhere around 1am.

IDA stated it was the best measurement they've seen up there in three years of measuring. They said usually they are around 21.5 to 21.6 up there. Friday was exceptional and a surprise to many including the rangers. We had regular reading of 21.95 and one hitting 22.0. But many of the measurements were around 21.95 to 21.97.

We were up till 4am viewing with the big dobs and were really able to see things in great clarity due to the conditions of the sky.

Robert Spencer

  • Active Astronomer
  • ***
  • Posts: 127
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #6 on: January 08, 2018, 11:22:08 AM »
Oh that's great. I almost went up again that night. I wondered about the smoke though. Too bad I missed it.

ruesonecrai

  • Active Astronomer
  • ***
  • Posts: 130
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #7 on: January 10, 2018, 04:07:13 AM »
I can't speak for SQM readings but at this year's Grand Canyon Star Party I commented several times throughout Friday night that, visually, it was noticeably darker than the past few years. I couldn't help but wonder if my impression was truly accurate or not.

The Park Service has been doing a wonderful job of replacing all the park's lights with low light pollution variants and it's working extremely well. The only noticeable "light dome" was only about 3 or 4-degrees high and to the south over the nearby Market Place. I'm guessing that will probably be fixed by next year.

Thanks to everyone on this thread who made SQM readings Friday night at the GC Star Party. That cleared up any doubts I had about my visual impressions.

Demetrius Bryan

  • Active Astronomer
  • ***
  • Posts: 131
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #8 on: January 10, 2018, 08:11:09 AM »
I got a 23.0 inside a dark, light-sealed closet here at home when I tested to see what mine would read.

ciomapicsta

  • Active Astronomer
  • ***
  • Posts: 128
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #9 on: January 11, 2018, 07:21:07 AM »
My wide SQM seems to hit a wall at 22. The highest reading I have seen is 21.97, and that is from my remote dark site property, which has the darkest sky I have seen. But, we do get affected more in the Southern Hemisphere by the influence of the Milky Way which is quite bright and affects the readings in the wide SQM versions.

There is a known problem with the SQM producing higher/darker readings as the batteries go flat. They are the first thing I would change if I ever saw 22.3 on an SQM, because my experience tells me that reading is not possible.

raposttavers

  • Active Astronomer
  • ***
  • Posts: 123
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #10 on: January 11, 2018, 08:59:48 AM »
Actually, I did get over 23 one night when I checked during full overcast, it was like walking around outside in Dick's closet. So any cloud cover will also affect the reading.

naiciareamu

  • Active Astronomer
  • ***
  • Posts: 115
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #11 on: January 11, 2018, 10:44:31 AM »
@ Kent,

21.2 from you back yard?

@ Jetstream

21.8 from your home???????

Where do you guys live & are there any plots of land nearby???

inlaylale

  • Active Astronomer
  • ***
  • Posts: 116
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #12 on: January 11, 2018, 11:07:31 AM »
Hi Nick,

I live on the edge of town in Flagstaff, Arizona, USA. It is the 1st International Dark Sky City and where the Lowell Observatory is. Supposedly if I go 15 minutes north on my way to the Grand Canyon, some have measured 21.9 SQM. I am not sure how long ago that was. More homes are being built around here and I worry it will get brighter. At least I am not too far away from truly dark skies. There are homes for sale in our neighborhood. One just a couple houses from me. I'll let you look through my Tec 180FL

libulbinis

  • Active Astronomer
  • ***
  • Posts: 115
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #13 on: January 11, 2018, 03:47:01 PM »
Kent,

I live about 10,000 miles from you, but when I retire I plan to take the first plane out of Cyprus to some place else. Both me and my wife lived abroad quite a bit so we are comfortable with moving around. Flagstaff, Arizona is now on the map for me. 22 (give or take) years to retirement

I'd love to take a look through that TEC though... One can always lust after large aperture refractors...

21.9 SQM.... Sigh...

reapriavoland

  • Active Astronomer
  • ***
  • Posts: 108
  • Activity:
    0%
  • Reputation: +0/-0
    • View Profile
Re: Highest SQM Reading
« Reply #14 on: January 12, 2018, 06:45:57 AM »
Nick,

The Flagstaff area is a dream location for many. I went on a business trip out this way when I lived in Texas and liked it so much, I told my wife if a job becomes available we should move. One did and I applied and got it. I took a huge pay cut but we still think it is worth it. I have never been anywhere close to Cyprus but my 16 year old daughter is on a music tour of Europe and in a few days she will be in Athens. My wife and I are so jealous.