View Full Version here: : Guiding through light pollution
Gvarouha
26-06-2016, 10:18 AM
G'day all,
I'm having some trouble of late due to a host of new street lights being turned on that now make my backyard look like a stadium.
I have moved to narrowband imaging and these filters work a treat however, my issue is with guiding.
My asi120 works well near the zenith however at the start of the night the sensor is all but washed out with gradient from the lights. Has anyone used any form of LP filter for guiding.
I realise the subs may need to be longer but just looking for options to test.
Cheers
Atmos
26-06-2016, 11:59 AM
If it is stray light causing issues you may just be better off making a longer dew shield for your guide scope (assuming that is what you're using). If it is light pollution in general, you may need to increase your guiding exposure time.
janoskiss
26-06-2016, 12:50 PM
It may be well worth writing to your local council and explaining the issue with the new lights clearly and succinctly. Write a letter, don't use email. Local government can be a lot more helpful than most people believe. But if you get no reply, write a follow-up letter.
Gvarouha
26-06-2016, 05:23 PM
Colin,
I didn't think of that. I will try a ext need shield and see. This should work as I believe the main issue is stray light.
Steve
I have sent an email to council, with no response. I will try sending a letter to see if that makes a difference.
I took a sky reading before the lights were on and one after sqm reading went from 20.5 to 18.:mad2:
cfranks
27-06-2016, 10:12 AM
The ONAG from InnovationsForesight uses Infra Red light to guide with. I bought an IR filter similar to http://www.ebay.com.au/itm/25mm-25-mm-Infrared-Infra-red-IR-Filter-760nm-760-NEW-/320465795434?hash=item4a9d3ff96a:g: gSoAAMXQLw1RyrOX and, if I ever get a clear night, will give it a try. They (IF) say that IR guiding also reduces the effect of seeing which is my bug-bear.
Charles
Stonius
27-06-2016, 12:31 PM
I definitely wouldn't recommend pointing a laser at the offending streetlight's light sensor so it thinks it's daytime and turns off. It's potentially dangerous and you could get in trouble for that. :-)
Gvarouha
28-06-2016, 03:45 AM
And I definitely haven't tried that...... Didn't work
Interesting point about the IR Filter Charles. Please let us know how you go with it.
skysurfer
28-06-2016, 03:54 AM
Dangerous ? No, unless you point the laser at a car, aircraft, person or pet.
But it works for a few minutes and then it turns on again.
Better is a multi switchboard key. I got it on Amazon in the EU, but also available on ebay. Fits all square and triagonal key slots in street lamp poles.
http://www.ebay.com.au/itm/Knipex-TwinKey-Multifunctional-Cabinet-Switchboard-and-Shut-Off-Key-00-11-01-/151887140160?hash=item235d2dd540:g: Jn8AAOSw4UtWSvGw
You can switch off the street lamp temporarily and turn it on after the observing session.
But writing at the local council you should do anyway to get a structural solution.
Stonius
28-06-2016, 11:52 AM
I think I heard It's because it averages readings over time. It takes a mminute or two to switch off or even back on again. The laser needs to be mounted on a tripod and always on.
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