Making DSO's more visable

[pel]

Morning all ,

Before having a break for the summer (I stopped in April/May) I was finding it very difficult to find DSO's (specifically M81 and M82 )in my Finderscope and viewfinder. M81 and M82 were very ver faint smudges.

I locate the general vicinity using a Telrad and Skymaps and then use a combination of Finder-scope, viewfinder (with the supplied SW 25mm eyepiece) and my DSLR with BYE.

I have medium to high light pollution as I am too near Reading.

My question is - would upgrading my finder scope or 25mm eyepiece make DSO's stand-out more. Or would a LP filter improve things?

Please see my equipment list below.

Thanks, Perry.

[DirkSteele]

First question is what kind of street lighting do you have (and the impact of lights can travel quite some distance)? The more modern high pressure lamps which emit white light and hence render standard light polution filters virtually useless. The older low pressure mecury and sodium lights emit at specific wavelengths that can be blocked. However all is not lost. If your goal is purely to enhance emission nebula, you should look at UHC filters. These filters allow specific wavelengths such as hydogen alpha and beta and oxygen III to pass and block all others. These are wavelengths that emission nebula radiate much of their light in. The effect is darken the sky background considerably and enhance the constrast of the nebula. At the end of the day, observation of DSOs is all about contrast.

As a final point though on UHC type filters, theywill do nothing for galaxies or globular clusters which radiate across the entire visible spectrum.

The reality is the best way to make DSOs more visible is to travel to a dark sky site, though most often that is not particularly practical.

[pel]

First question is what kind of street lighting do you have (and the impact of lights can travel quite some distance)? The more modern high pressure lamps which emit white light and hence render standard light polution filters virtually useless. The older low pressure mecury and sodium lights emit at specific wavelengths that can be blocked. However all is not lost. If your goal is purely to enhance emission nebula, you should look at UHC filters. These filters allow specific wavelengths such as hydogen alpha and beta and oxygen III to pass and block all others. These are wavelengths that emission nebula radiate much of their light in. The effect is darken the sky background considerably and enhance the constrast of the nebula. At the end of the day, observation of DSOs is all about contrast.

As a final point though on UHC type filters, theywill do nothing for galaxies or globular clusters which radiate across the entire visible spectrum.

The reality is the best way to make DSOs more visible is to travel to a dark sky site, though most often that is not particularly practical.

Thanks for the reply.

My ultimate goal is to photograph the Galaxies, but I am just beginning so I am leaving the DSLR mods. for now.

To begin with I just want to enhance the clarity of the DSO's in the finder scope or in the viewfinder for now so I can find the DSO's easier and then image them. I'm not that bothered by image quality or lack of HA for now.

I have the old Orangey/Yellow street lamps locally but also have the Orange sky over Reading to contend with 5-10 miles away.

I'm not that keen on travelling to a dark Sky site, too much hassle. I just want to make the best of it in the back garden,

From what you have said and as I am just trying to make locating the DSO's easier, I think an LP filter is the way to go, do you agree?

Cheers, Perry.

[michael.h.f.wilkinson]

A bigger finder scope is a good investment I have found (mine is home brew 16x70). It makes finding things from a suburban garden a great deal easier. An LP filter is OK on galaxies but not great (depending also on the type of light pollution, as noted above). A UHC filter works better emission nebulae, but not on galaxies or reflection nebulae.

[pel]

A bigger finder scope is a good investment I have found (mine is home brew 16x70). It makes finding things from a suburban garden a great deal easier. An LP filter is OK on galaxies but not great (depending also on the type of light pollution, as noted above). A UHC filter works better emission nebulae, but not on galaxies or reflection nebulae.

Hi again Michael. I'd have to buy a new/larger mount if I had a bigger/heavier finder scope. I've read that a 200p on an EQ5 is near the weight limit, especially as I have a DSLR as well.

I think I am going to buy a cheap SW LP filter and see if that enhances my view of the DSO's through the eye-piece.

Cheers, Perry.

[Moonshane]

three things affect the appearance of galaxies and other faint objects :

• dark skies
  
• getting out under dark skies
  
• more aperture under dark skies
  

Just in case I didn't mention dark skies, they are quite important too

[pel]

three things affect the appearance of galaxies and other faint objects :

• dark skies
  
• getting out under dark skies
  
• more aperture under dark skies
  

Just in case I didn't mention dark skies, they are quite important too

Will dark skies help

I'm too lazy to travel to a darksite though and my wife doesn't want to move, so I'll try and make the best of it.

Do you live somewhere very remote Moonshane?

[acey]

Apart from sky darkness the most important thing is to be looking in the right place - sweeping around in search of a galaxy is no good if the galaxy is faint. If the sky map is sufficiently detailed to show all the stars you can see in the finder, or most of the stars you can see in a low-power eyepiece, then you will be able to aim at the exact spot. Then it's a case of looking through the main telescope at the field where you know the object must be, and waiting if necessary for your eye to adjust (since you'll have been using some kind of illumination to see the map) until the object pops into view. If there is ambient glare then cover your head with a hood. For a detailed printed atlas try S&T Pocket Atlas if you don't already have it.

M81 is easily visible from my light-polluted back garden but the view from a dark site is incomparably better which is why I always make the effort to drive to a dark site.

[swamp thing]

Good points raised above. What can also help when star hopping is to know the size of each hop! aka FOV. Most finders have around a 5degree field. Knowing this can really help you estimate your position a lot more accurately than just hopping about from star to star with no idea how far you've moved.

Once you know your finder FOV you can hop very accurately indeed accross pretty sparse areas of sky

[pel]

I think my main issue is the LP because M81 and M82 are very difficult to make out in the finder or 25mm when I have found them. I think I do a pretty good job getting in the right sort of location. I find them by drawing a line between 2 stars in Ursa Major starting at M109. The length of the line will be approx double the distance between the 2 stars and then I'm only the width of the largest Telrad Ring away (4 degrees).

I use the following map -

http://www.atmob.org/library/member/skymaps/MAP5.PDF

Perry.

[Tinker1947]

A good quality EP with a decent FOV will make a big diffrence, i find a 36mm Hyperion works for me and the little grey smudges just pop into view with a aid of a Telrad.......I keep think about a Pentax XW 30mm or 40mm.....

[acey]

I think my main issue is the LP because M81 and M82 are very difficult to make out in the finder or 25mm when I have found them. I think I do a pretty good job getting in the right sort of location. I find them by drawing a line between 2 stars in Ursa Major starting at M109. The length of the line will be approx double the distance between the 2 stars and then I'm only the width of the largest Telrad Ring away (4 degrees).

I use the following map -

http://www.atmob.org/library/member/skymaps/MAP5.PDF

Perry.

If you can see M109 you should have no trouble at all seeing M81/82. I think you need a better map. If you don't want to pay for one then use the free JR TriAtlas.

http://www.uv.es/jrtorres/triatlas.html

[John]

A question was asked on another forum: "what is the best thing I can buy for $100 to get better views of deep sky objects ?". One reply was "a tank full of gas (petrol) to get you and your scope to dark skies". It was a great answer !.

While filters can help with some objects, the impact that dark skies have on the views of deep sky objects cannot be overstated. At the SGL star party last year my 6" scope was showing deep sky objects better than my 10" does from my back garden which is moderately, but not terribly, light polluted. I'm not able to get under really dark skies that often but no accessory can match the improvements that they bring.

[Moonshane]

Will dark skies help

I'm too lazy to travel to a darksite though and my wife doesn't want to move, so I'll try and make the best of it.

Do you live somewhere very remote Moonshane?

Hi Perry, I wish. I live about 9 miles from Manchester.

I am pretty lazy too if honest - although in fairness it's the thought of putting my gear in the car and the clouds rolling in as I roll up at a dark site that puts me off. it's bad enough at home.

[pel]

A good quality EP with a decent FOV will make a big diffrence, i find a 36mm Hyperion works for me and the little grey smudges just pop into view with a aid of a Telrad.......I keep think about a Pentax XW 30mm or 40mm.....

Thanks Tinker, I was going to buy a better EP too. I'm on a budget though as I have very young children, so maybe a BST Explorer.

[pel]

If you can see M109 you should have no trouble at all seeing M81/82. I think you need a better map. If you don't want to pay for one then use the free JR TriAtlas.

http://www.uv.es/jrt...s/triatlas.html

Thanks for the Link Acey, I'll give them a go.

I haven't seen M109, I meant where M109 is on the Skymap

[pel]

Hi Perry, I wish. I live about 9 miles from Manchester.

I am pretty lazy too if honest - although in fairness it's the thought of putting my gear in the car and the clouds rolling in as I roll up at a dark site that puts me off. it's bad enough at home.

Yes, it's too much like hard work. If I was sociable I'd go out with my local group, unfortunately I'm not though

[pel]

A question was asked on another forum: "what is the best thing I can buy for $100 to get better views of deep sky objects ?". One reply was "a tank full of gas (petrol) to get you and your scope to dark skies". It was a great answer !.

While filters can help with some objects, the impact that dark skies have on the views of deep sky objects cannot be overstated. At the SGL star party last year my 6" scope was showing deep sky objects better than my 10" does from my back garden which is moderately, but not terribly, light polluted. I'm not able to get under really dark skies that often but no accessory can match the improvements that they bring.

Maybe when I have reached the limit of what I can do with the scope in the back garden I will go to a dark site, for now I can't bring myself to transport all the gear, especially as I am mainly into imaging.

[michael.h.f.wilkinson]

This is one reason I got myself an 8" SCT: some much more compact to transport. My back garden is OK, but a colleague lives some distance out of town, as do my parents. I do go there from time to time to observe.

[pel]

A smaller scope would be better, I guess maybe an ED80. I'd still need an EQ mount, DSLR, laptop ,leisure battery etc. etc.

I think I'll make do for now :-)

[astroeddie]

When I first started out in astronomy 20 years ago, first thing I got my hands on was Wil Tirions Sky Atlas 2000.0, field edition. Huge charts, very detailed. I gauged my finder FOV using stars, then cut a hole in black card to emulate this.

I then placed this onto the chart being used, and hopped to the desired object. VERY effective. Infact going to make a new one at the weekend.

[Moonshane]

top tip Eddie - I may do this myself!

[astroeddie]

Only too glad to add what I can, and thats not very much I can tell you.

[swamp thing]

I use the laminated version of the sky atlas 2000 and then use a circular stencil the same size as my finder FOV, then with a chinagraph pencil draw my star hops directly onto the map. At the of end of the session I wipe the maps over with a wet cloth, job done

Sent from my iPad using Tapatalk

[astroeddie]

I went to a shop here and asked how much for these to be laminated, ermm.... £17.50 EACH !!!!!

Going to Staples for a students Art pouch.