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

Transparency impact on NV

NV
  • Please log in to reply
40 replies to this topic

#26 GOLGO13

GOLGO13

    Fly Me to the Moon

  • *****
  • topic starter
  • Posts: 6,538
  • Joined: 05 Nov 2005
  • Loc: West Virginia

Posted 24 May 2021 - 03:10 PM

Thanks Tyson

#27 chemisted

chemisted

    Viking 1

  • -----
  • Posts: 582
  • Joined: 24 Feb 2012

Posted 24 May 2021 - 04:28 PM

Bravo, Tyson M!

In my S&T article on globular clusters I said: "Good to excellent transparency is key to resolving these targets." I made my observations from 7800 ft in the Colorado Rockies where seeing was generally pretty poor but transparency was very good. I did loose one whole summer of observations due particulates drifting in from forest fires in California. I am now in the Blue Ridge mountains of North Carolina where my seeing conditions are much improved and the threat of forest fire is much diminished. When I have had a chance to do more observing I will report back on transparency at this new location for me. I am hopeful with the little bit that I have been able to do thus far.

Edited by chemisted, 24 May 2021 - 04:42 PM.


#28 alexvh

alexvh

    Messenger

  • -----
  • Posts: 484
  • Joined: 29 Jul 2007

Posted 19 June 2021 - 01:27 PM

Can I just say how astounded at the pics of the pinwheel galaxy there. I have not seen that detail even in my 16” dob. Bravo.

#29 CARL_MU1

CARL_MU1

    Lift Off

  • -----
  • Posts: 19
  • Joined: 05 Oct 2018
  • Loc: Whitsett, North Carolina

Posted 22 June 2021 - 11:10 PM

I've seen gravity waves plenty of times with the device in otherwise clear skies.

You are joking, right?confused1.gif



#30 ButterFly

ButterFly

    Vanguard

  • *****
  • Posts: 2,388
  • Joined: 07 Sep 2018

Posted 23 June 2021 - 12:29 AM

You are joking, right?confused1.gif

Probably not the gravity waves you are thinking of, but yes.  I find them easier to see closer to the horizon - the crests appear closer to each other becuase of the viewing angle.



#31 CARL_MU1

CARL_MU1

    Lift Off

  • -----
  • Posts: 19
  • Joined: 05 Oct 2018
  • Loc: Whitsett, North Carolina

Posted 23 June 2021 - 08:34 AM

Probably not the gravity waves you are thinking of, but yes.  I find them easier to see closer to the horizon - the crests appear closer to each other becuase of the viewing  angle.

Can't visualize what you're talking about.  Wish you could illustrate or show image.



#32 Joko

Joko

    Vendor - OVNI

  • -----
  • Vendors
  • Posts: 310
  • Joined: 21 May 2008
  • Loc: FRANCE, EUROPE

Posted 23 June 2021 - 09:24 AM

Can't visualize what you're talking about.  Wish you could illustrate or show image.

These waves are atmospheric gravity waves.

NV helps a lot to see them. Not sure if someone here already took a pic of them.


Edited by Joko, 23 June 2021 - 09:25 AM.


#33 DanDK

DanDK

    Lift Off

  • -----
  • Posts: 21
  • Joined: 27 Dec 2019

Posted 23 June 2021 - 11:48 AM

My interpretation of ButterFly's post was that the wavy, thin cloud patterns caused by atmospheric gravity waves become visible at night with night vision.  I don't know if the waves themselves are visible without some sort of clouds.  

 

I've found that many types of thin clouds which can't easily be seen at night, and which reduce transparency, become bright and obvious when viewed directly through the NV monocular. Light pollution may amplify this.



#34 evan9162

evan9162

    Surveyor 1

  • *****
  • Posts: 1,726
  • Joined: 20 Sep 2013
  • Loc: ID

Posted 23 June 2021 - 06:14 PM

https://en.wikipedia...ki/Gravity_wave

 

Nothing to do with variation or modulation of gravity its self.  


  • ButterFly likes this

#35 ButterFly

ButterFly

    Vanguard

  • *****
  • Posts: 2,388
  • Joined: 07 Sep 2018

Posted 24 June 2021 - 07:56 AM

The cloud picture in the Wiki link shows the viewing angle effect well.  It's a thin veil of cloud with these waves in them.  The spacing appears to get wider as I look closer toward zenith.  The actual spacing is probably the same over the whole cloud.  The perceived contrast decreases though, simply because they appear spaced wider apart.

 

I can usually discern them up to about 20-30 degrees or so from the horizon.  The cloud needs to be fairly thin, because if it's too thick, the contrast between peak and trough would be starting off even lower, causing the perceived contrast to appear lower.



#36 Mike Lockwood

Mike Lockwood

    Vendor, Lockwood Custom Optics

  • *****
  • Vendors
  • Posts: 2,001
  • Joined: 01 Oct 2007
  • Loc: Usually in my optical shop

Posted 25 June 2021 - 12:04 PM

These waves are atmospheric gravity waves.

NV helps a lot to see them. Not sure if someone here already took a pic of them.

I saw some at Okie-Tex in 2019, photos with NV and with a DSLR are side by side at the middle of this article:

  http://www.loptics.c...kietex2019.html


  • Joko, R_Huntzberry, ButterFly and 2 others like this

#37 Joko

Joko

    Vendor - OVNI

  • -----
  • Vendors
  • Posts: 310
  • Joined: 21 May 2008
  • Loc: FRANCE, EUROPE

Posted 26 June 2021 - 12:53 AM

I saw some at Okie-Tex in 2019, photos with NV and with a DSLR are side by side at the middle of this article:

  http://www.loptics.c...kietex2019.html

Wonderful pic ! It clearly shows the waves.



#38 ButterFly

ButterFly

    Vanguard

  • *****
  • Posts: 2,388
  • Joined: 07 Sep 2018

Posted 28 June 2021 - 10:46 PM

Here is a shot of two fronts colliding last night.  This was barely a haze visually.  The disrupting blob is likely from over the mountain and thus turbulent.

 

Gravity Front Collision.png


Edited by ButterFly, 28 June 2021 - 10:49 PM.

  • blackhaz, Joko, ArsMachina and 3 others like this

#39 Clutch5150

Clutch5150

    Owner - Tactical Night Vision

  • -----
  • Vendors
  • Posts: 142
  • Joined: 10 Feb 2016
  • Loc: So Kali

Posted 20 July 2021 - 04:13 PM

I definitely notice the difference. I took these 2 phone pics of M101 on clear, moonless nights.  First one in April, on a cool night with good transparency, second in humid July.

That is a great comparison. Thank you for sharing this!


  • DanDK likes this

#40 a__l

a__l

    Gemini

  • -----
  • Posts: 3,168
  • Joined: 24 Nov 2007

Posted 20 July 2021 - 07:19 PM

It's not really clear if this is due to transparency.
The correct result should be accompanied by information about the measured background brightness (summer nights are short in the northern hemisphere) and the height of the object above the horizon.



#41 Tyson M

Tyson M

    Fly Me to the Moon

  • *****
  • Posts: 6,070
  • Joined: 22 Jan 2015
  • Loc: Canada

Posted 20 July 2021 - 07:50 PM

Probably not the gravity waves you are thinking of, but yes.  I find them easier to see closer to the horizon - the crests appear closer to each other becuase of the viewing angle.

 

You are joking, right?confused1.gif

I learned something new myself when I saw this thread earlier back.  At first I thought the same thing, must be a joke. A cool atmospheric phenomenon.


  • DanDK 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





Also tagged with one or more of these keywords: NV



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics