How to improve observation?

[ICR_2019]

Hi all

I am one happy newbie.

A short break in the cloud last night and I got my first hit on Andromeda.

At first it was a small grey patch but with persistence and averted vision I got glimpses of  a bright central core with grey "cloud" extending out from each side.

So my question from my LP back garden what might I be able to do to improve or at least get a more consistent visual.

I have a skywatcher 130p the best views came with the supplied 20mm. 

Would flocking and a dew shield help with contrast? A 25 or 32mm eyepiece clean up the image? Or maybe a colour filter to make it pop a little?

I understand the limitations of both the scope  and viewing site both have a major effect but there must be steps I can take to get the best from what I have.

Thanks in advance Ian 

 

[Rob Sellent]

Lovely question, Ian.

For me there are two types of light pollution: sky glow and glare. There's not much one can do about sky glow other than trying to find pockets of darkness away from urban areas. Glare is where we can gain some control and make a more positive approach to our observing.

If possible try to block all intrusive light from your sight and site. An observing hood is a great aid and probably one of the best accessories any visual observer could possess. Along with hoods, erecting light-blocks and shades etc is an extremely good idea. I'm in the process of creating a bit of a darker sanctuary in the back garden myself and if I obtain good results, I'll post them up here on SGL.

Flocking the inside of your tube may help in defeating some of the light pollution and a larger yoga-mat dew shield may help in blocking stray light from getting to the objective lens. Both are relatively cheap fixes and can't do one any harm.

Another thing I find extremely useful is a pirate's eyepatch . I observe with it on my non-observing eye and when I need to pull away from the scope, I slide it over to my observing eye. Another top tip is to use a regulated red-torch.

Needless to say planets, the Moon, brighter star clusters and double stars don't require dark skies. And with a little effort at the eyepiece even planetary nebulae and globular clusters hold up reasonably well.

Good luck with your own battle, Ian and let us know how you get along

[John]

With galaxies, the old joke is that the best accessory to spend money on is some fuel for your car to get you and your scope under darker skies. Dark skies make all the difference to the amount of detail you can see when observing galaxies. 

Rob has given some good tips above and they are really all about darkness for you and your scope.

My garden has some LP issues but I've found workarounds which include having scopes which I can move about to find the darker corners, waiting until all around me have gone to bed and switched off their lights (including my own family !), waiting for my targets to rise high enough in the sky to be less affected by the horizon skyglow and also from the effects of atmospheric extinction (dimming) and getting my eye truly dark adapted and keeping it that way by avoiding any light, even red ones. Filters work well on many nebulae but not on galaxies. I find a 21mm eyepiece is more effective for galaxies from my garden than a 32mm with my F/5.3 dobsonian because the exit pupil is more efficient and the higher magnification darkens the background sky a little.

Observing galaxies from sites that have some LP is quite challenging but success can be had if you work at it and employ some smart tactics. I've had sessions where I've racked up dozens of new-to-me galaxies from my back garden when things come together but also many where even the "easy" galaxies are far from their best so its been obvious that the best decision to move to a different target type.

 

[ICR_2019]

Thanks Rob

Last night I was thinking an eye patch would help reduce the strain on the non observing eye! sliding over to the observing is a great idea!

A hood is another great idea, one I had never considered, thank you.

The LP i have is mostly skyglow, although there are a few garden lights that add to the problem..

I'll search out a diy dew shield and have a go.

 

thanks again Ian

[vlaiv]

Already good advice given.

Here are a few more tips that can help:

- Note how LP changes over the course of the night. If you can - stay out till late in the night when most of the neighborhood goes to sleep. People tend to turn off the lights past some time in the evening / night. There will also be less traffic, so less headlights contribution to LP. Of course, try to match this with astronomical darkness - no point of staying up until morning hours if astronomical darkness lasts only until 2 or 3am. To that effect - begin observing after astronomical twilight has passed.

- Make schedule of observing and wait until selected target is in best viewing position for the night - this means as high above horizon as it will reach (near zenith is the best) and also away from main LP. If you are not situated in center of LP (like city/town center) there will be side of the sky less affected by LP - wait for target to get there if possible.

- Check forecast and mind transparency. If it is poor - don't expect too much. Poor transparency both attenuates light from target but also scatters LP more.

 

 

[ICR_2019]

I do usually wait for the street lights to go out, sometimes its a bit cat and mouse. Breaks in weather, work etc.

The "dark" side of my garden is straight up and NW which also happens to be the side facing the back of the houses and the least area for viewing. The largest viewing area is SE facing directly to town. Well we have what we have and do our best.

So flocking material, yoga mat, thick black material for hood, pirates eye patch, the shopping list keeps growing!

John you say a 21mm? maybe I should look at replacing my 20? the rubber around the eyepiece is split. 

I have seen advice on 18mm bst 25mm bst and skywatcher 32mm plossl for dso, my budget is limited.

 

 

[John]

My point is that from my back garden a 21mm eyepiece (or thereabouts) is generally better for observing fainter objects than a 32mm.

You may well find an 18mm or 25mm eyepiece (or something around those focal lengths) more effective than a 32mm or similar.

[ICR_2019]

Inspired by your responses I just did a quick experiment.

The sky is currently cloudy and street lights still on.  I pulled the scope out of the shed and put in an eyepiece.

I have some black subwoofer carpet, I rolled it up and placed it as if it were a dew shield looking through the eyepiece I removed the roll and it did indeed brighten the view.

Diy dew shield coming up.

[KingNothing13]

Instead of a hood, you can also use a bath towel. 

[Rob Sellent]

3 hours ago, loft_boarding said:

thick black material for hood, pirates eye patch, the shopping list keeps growing!

The observing hood I have is quite large, so if you're making one make sure you're generous with your measurements. Here's a handy video of how to put a hood together. 

Regarding eyepatches. The idea for me isn't so much as preserving dark adaption - although it helps - as it is to cover the other eye that you don't use without screwing or scrunching it up. You'll probably need to practice with a few, adapting according to your needs (sewing in softer material over the plastic/card, extra silky padding, enlarging area etc) until your eye fits snuggly cushioned within the patch, without any stress to the eye itself or muscles and stray light is eliminated. 

[KingNothing13]

10 hours ago, Rob Sellent said:

 

Regarding eyepatches. The idea for me isn't so much as preserving dark adaption - although it helps - as it is to cover the other eye that you don't use without screwing or scrunching it up. You'll probably need to practice with a few, adapting according to your needs (sewing in softer material over the plastic/card, extra silky padding, enlarging area etc) until your eye fits snuggly cushioned within the patch, without any stress to the eye itself or muscles and stray light is eliminated. 

This is what I do with the eyepatch - it makes for a much more relaxing observing experience for me.

[Plumb71]

Hi All

Been inspired by this thread, some really good ideas, especially the diy dew shield to eliminate stray light poolution (i have a neighbour who's bathroom light which they leave on all night is more like a lighthouse) i attempted to make one but my craft skill aint good, and thouht i would buy one, although i have been told (by Harrisons) there is not one that will fit my Skywatcher Explorer 150p? Surely there must be one, again im new to all this and have probably asked some stupid questions before, but i would have thought that being as there are dew shields available for other makes that are 150mm one must be compatible?

[darkskyastronomy]

Read up and learn how to optimise averted vision. That will get you more details even with light pollution.