PDA

View Full Version here: : Light pollution panorama


LewisM
26-03-2013, 08:56 PM
Richard Muhlack kind of prompted me to make an image of the severe light pollution of my area, so tonight, I made a near-360° panorama of 2.5" exposures at f/1.4 / ISO 400.

This was taken with a near full moon, well after end of daylight. Obvious are the incandescent street lamp and the mercury vapour ones (not to mention the 3 oher Hg vapour ones behind the houses).

Tripod was placed EXACTLY on the spot I set up my astro-imaging scope rig.

With a DSLR, I was fighting HORRENDOUSLY to get any useable images out of a session, but with the CCD and the software light pollution reducing filter S-X uses, I can extract a LOT of data from VERY few exposures. I MAY try LPF's again on the CCD to see any improvement.

rmuhlack
26-03-2013, 09:18 PM
oh my! :eyepop:

i feel for you brother!

LewisM
26-03-2013, 10:32 PM
Add to the light pollution the fact that because I image from a non-gated front driveway, I CANNOT leave the rig unattended.

Had a small worry the other night - a car of teenagers came along, stopped. Reversed, flash flash from the iPhones and laughter before they disapeared. Came back and drove past. Stopped, reversed back, laughter again from the girls, but the guy driver proclaimed "Fully sick dude! Good luck!"... so not entirely bad! Still, I was on guard all night thereafter again.

Halloween last year saw 5 teenage boys FLOCK around the setup, without even asking. I had to forcefully ask hem to stand back and touch nothing, and prceeded to show them a bunch of images. Their parents turned up, and after the Hubble Telescope quips, they enjoyed it to.

If the DARK courtyard wasn't such a magnetic anomoly as well as being limited to 2 star alignment at best, and HIGH roof line obscuring easily 30° of the sky I'd go there (fully fenced, DARK, and I could literally leave it automated and go to bed) - one day I will have it surveyed for TRUE south.

For now, I make do with what I have. The CCD is an absolute god-send - it eliminates SO many issues I was having!!!

rmuhlack
26-03-2013, 10:39 PM
yep - definitely an advantage here that I image from my fully fenced and locked backyard. Means I can set up a run and then go to bed, only have to get up again if Im changing targets or doing a meridian flip. Otherwise the mount limits I have set in EQMOD will stop the mount when it reaches the zenith so i never have to worry about a physical mount crash.

This is the panorama from my imaging location - again under an almost full moon. No street lights to worry about for me though.

2.5" @ f1.8 ISO400 (ie basically the same exposure as yours)

LewisM
26-03-2013, 10:50 PM
Adopt me? :rofl:

Close enough to Temora for me to enjoy David Lowy's fine stuff too!

ourkind
27-03-2013, 12:05 AM
Like this one?


BTW can you tell me how to recognise what type of light is been used i.e. difference between incandescent street lamps and the mercury vapour ones?

LewisM
27-03-2013, 06:53 AM
Carlos,

Incandescent is white light generally.

Mercury vapour SHOULD be relatively white, but can appear yellow thanks to the plastic coverings they put over the glass bulbs and housings rapidly discolouring due to the UV emitted by them (compounded with solar UV)

Sodium vapour will look yellow to yellow orange (depending on if high or low pressure units).

I THOUGHT our street lights along the main road (right i my picture) were Sodium vapour, but an Energex guy told me they were Mercury vapour ones in need of replacement.

Sodium vapour is the best for we astronomers, as Na lights emit one line that is easy to remove/filter. Apparently most US cities/towns that have observatories use Na vapour lamps for this very reason.

ourkind
27-03-2013, 07:22 AM
Cool thanks Lewis!

LewisM
27-03-2013, 08:49 AM
Still can't get over how vivid green the grass is :) Geez we've had some rain! There's a typical Sunshine Coast night too - see all those bloody cumulus clouds???????????? GRRRRRRRRRRR

Kunama
28-03-2013, 09:38 AM
I'm curious Lewis just what exactly is light pollution??

From memory this is 15 seconds at f4 ISO6400 with some house and back terrace lights on, oh and the streetlight causing the orange glow is now been changed to a flouro downlight :thumbsup: :

ourkind
28-03-2013, 09:44 AM
Ouch! :sad::sad::sad::sad::sad:

Terry B
28-03-2013, 12:24 PM
I fee lsorry for you guys. From my observatory, the milky way casts a visible shadow. :thumbsup: