How much does light pollution affect viewing?

[bryanb1980]

Hey all!  First off thanks to everybody that has helped me out on this forum so far, you have been so great!

I spent my second night out with my new scope finding several new objects - Hercules cluster, M31, The Double Double, Orion Nebula among others.  It was a very rewarding night for sure.  Here's my question:

How much does light pollution affect what you're actually seeing in the scope?

I live in a small town but my street has several street lights and in my backyard it's darker but my neighbor has a large light on her garage.  Would my views be that much better if I was far away from any light pollution?  The views I'm getting are awesome but I'm wondering if they could be even better.  I'm using an Orion XT8 with a Q70 38mm lens and an orion Stratus 13mm. The orion nebula was probably the most detailed object I saw, I could easily make out the dust cloud with my lowest powered lens.  I guess I'm just wondering how much better things will look through the scope if I take the time to load my trunk up with a large scope and head for the country!

Any response is greatly appreciated and thanks again to everybody!

Bryan

[rowan46]

The short answer is it will have an effect. General lp will rob your scope of contrast but very local lp  eg from a neighbours  security light doesn't just affect the scope it also affects your eyes dark adaptation

[John]

Hi Bryan,

On deep sky objects such as nebulae and galaxies, light pollution has quite a significant effect in reducing the extent and contrast in an object. 

My back yard has some LP but I can see the milky way overhead and can pick out the Andromeda galaxy with my naked eye on a decent night. When I took a 6" scope to a star party at a dark site (not the darkest ever but pretty dark) the 6" scope showed deep sky objects at least as well, if not a bit better, than my 10" scope would from my back yard. I hope that gives you an idea of the difference 

[tdmodels]

+1   Give it a try if you can.  Get away to a darkish sky for an evening and compare the difference.  You'll be surprised as to how much extra contrast you'll get

[bryanb1980]

I haven't been able to see Andromeda galaxy with the naked eye from my backyard and when it's in the scope I can just make out the core of it.  Sounds like it would make a difference on galaxies and nebula. How much more of Andromeda would you be able to make out in a darker site?  On another post somebody said it's so large that a 70 degree eyepiece wouldn't be able to get all of it, that seems insane.  I just see a small fuzzy oval shape in the middle of the scope.

[John]

I have a 4" scope that can show nearly 4 degrees of sky with a 31mm 82 degree eyepiece. Under a really dark sky the Andromeda Galaxy is too large even for that field of view and the hazier outer regions disappear out of the field of view on either side with the oval core glowing quite brightly at the centre.

[ScottS]

Light pollution for me personally, makes the single biggest difference to my viewing. I took my scope on it's first journey just half an hour out of town and the difference was ...... well.......night and day!

[Qualia]

I live in a city and have found that LP doesn't affect planetary, lunar, double star, and solar work. In fact, curious as it may sound, I find Jupiter, for example, looking better from the city than it does under dark skies. I guess this has something to do with the contrast between significantly dark heavens and a bright Jupiter which renders it difficult to tweak detail. On the other hand, just as everyone has said, LP not only cripples what you can see when it comes to hunting out many of the Messier objects, nebulae, galaxies, and so on, but essentially robs you of their inherent beauty and detail.

[nightfisher]

I also have the misfortune to live in a town, i can see NO deep sky objects from my home, and have no choice but to travel to a dark site, lucky i am only 5 miles from the moors, and the difference is amazing

[umadog]

I haven't been able to see Andromeda galaxy with the naked eye from my backyard and when it's in the scope I can just make out the core of it.  Sounds like it would make a difference on galaxies and nebula. How much more of Andromeda would you be able to make out in a darker site?  On another post somebody said it's so large that a 70 degree eyepiece wouldn't be able to get all of it, that seems insane.  I just see a small fuzzy oval shape in the middle of the scope.

If you can't see M31 naked eye from your home site then it's not very dark. There will be a vast, vast, difference if you go somewhere truly dark. Here is what an experienced observer sees through an 8" at a dark site: http://www.deepskywatch.com/Astrosketches/Andromeda-galaxy-sketch.html Here are your dark site options: http://www.jshine.net/astronomy/dark_sky/

[jetstream]

Getting to dark skies has been the single biggest improvement for my viewing bar none.Using the light pollution maps & sat images help us pick out darker zones-I've found there are "pockets" of darkness within the different colour zones.....all unoficial observation,but this has become an interest of mine.Basically if the Milky Way is visible thats good.....seeing DSO naked eye is "gravy"....and then there are nights filled with so many stars you get lost.

I am interested in the nature of "light domes" that form the light pollution that impedes our viewing.ie.-cone angle ,height and diameter,vs intensity and size of light source,if anyone has info a post would be great.

[swamp thing]

For me, nothing effects my viewing pleasure moe than getting to dark skies. They make far more difference than anything else when observing nearly all types of DSO's

If I was to compare my LP back yard with a proper dark site, I would say the difference is nothing short of spectacular.

[Superdavo]

The simple answer is it varies. If you have or ever get a nebula filter, and use it on a Moonless night, the difference will be pretty much just the light pollution.

David

[acey]

My definition of a "dark" sky is one in which the Milky Way is capable of being seen clearly. The difference between viewing DSOs in a dark versus non-dark sky is huge, and always worth the effort. Though a dark site is only worth going to if the Moon won't be up - even a half-illuminated Moon can wash out the Milky Way almost completely.

[scarp15]

It can merely be a case of changing habits. When you have ventured out somewhere, with a true dark sky and returned having had a positive experience, then the rewards far excede the extra efforts.

[bish]

I live in an area with terrible light pollution. My garden is secluded and doesn't suffer from direct street lights but the general pollution means I can only see a fraction of DSO's I should be able to see with my scope.  Can be very frustrating but makes visits to dark sites all the more enjoyable.

[Moonshane]

I'm in the 'it depends' camp. I observe in a pretty rubbish area for light pollution being about three miles from Stockport and nine miles from Manchester  yet I still manage to see a number of NGC objects every time I observe. sure a dark site is amazing, awe inspiring and fanmtastic to view from but when you just observe from your garden you can still see lots that is of interest  if you plan your sessions properly you can get a lot out of them. everything looks better from a dark site though and often you have the company of mates which adds to the enjoyment.

[cotterless45]

Yep, it's definately worthwhile getting an achievable target list and not trying to chase the faint and obscure. Although we are perched on the edge of town, some nights have been incredibly dark and clear, especially overhead. At worst I use an lp filter.

When you experience a pristine dark site it blows your socks off, especially the sight of a wide tortuous bright glowing Milky Way, hurrah !

Nick.

[webboid]

I think light pollution is a hindrance to proper deep sky observing but is definitely not an excuse to not observe.

My back garden gives me a naked eye limit of between 4 & 4.5 magnitude stars. Despite this most of my 50 odd observing sessions this year have been done from my back garden. For me, the lack of stars actually makes me a better observer as I have to be more thorough in my star hopping. Sometimes the target is too ambitious & can't be seen. I have also developed a keener eye for the very faint. Averted vision is also becoming more successful. A proper plan for the nights session is essential for success. A few extra aids like screens to block off direct white lights, a dew shield to block stray light on the secondary, an eye patch or towel over your head when at the eye piece, can help aid dark adaption.

I would rather observe at short notice, when the sky allows, at home than not at all. Then when I do get a chance to go to a dark sky site it is a treat & so every thing is even more amazing. Those sessions confirm what I have seen from home as they are often more obvious in the eye piece & allow me to hunt the more elusive targets invisible at home.

Ideally we should all live in the middle of nowhere but alas this is not possible for many. So yes a dark sky makes a difference but 100's of things are still visible from my home & continue to fascinate & challenge me in their pursuit. 

[nicks90]

in my back garden i suffer terrible light pollution and therefore i stick to what is basically the monthly binocular viewing guide. Means they are all easily achievable in my telescope under bad skies and keeps me interested in new stuff on the rare nights its not cloudy.

but then when i get to a dark(ish) site, its tremendous!

[Steve H]

I have one of those orange street lights right next to my garden which lights it up like a Christmas tree! I recently bought a Skywatcher 200p and whilst looking east is ok, the west and south views are restricted by the light. Oh for those heady days of power cuts we had in the 70's

[foundaplanet]

I'm mostly a complete slacker when it comes to observing from my yard with exception to Moon and planets, even they have restrictions like bushes and trees and one rather big church. 

I have a nine mile drive to a good site, I am lucky in that it is easy access but even without the Bushes and the rather big church I would still do the 18 mile round trip as the difference is immense.

[AlexB67]

As already said, planning your sessions helps a lot to make best use of the skies for DSO viewing in an LP area. Of course the suburbs where I am will never be as good as a dark sky, but all the same observing near zenith or within a sort of 45 degree range, a lot can be seen where I am. There are two spots in my garden where I can cut out most light so I dark adapt better, putting the scope on the ground so I am low down( which is an option in my case having a small setup ) makes a big difference on one of those spots I use, then I put one hand over my non-observing eye, ( but keeping it open ) and then glue the eye close the eyepiece so little light comes in from the side and keep looking until you get the best out of the eye. All these little things can add up, even taking deep breaths of air can help apparently to aid with night vision, try to hyperventilate beforehand, eat lots of carrots is good for you too

[Steve H]

As an owner of an ordinary straight tube dob that must make me a member of the Non FlexDob Mob. Do you want to be Shark or Jet!