Star adventurer and light pollution

[bish]

Hello all,

I might get a star adventurer for star parties, but will need to practice at home under  a  bottle 8 sky. I assume I could use my AZ4 tripod legs. I've a canon camera body and a few lenses. I would need clip in filters,  light pollution/narrow band. Should I also get a camera astro moded? Does anybody manage to get anything under really bad pollution? When I go to a dark site I don't want to have some clue what I'm doing.

Thanks

[Elp]

Have you tried using your camera as it is? This will give you a good idea of what you're working with.

Some filters are good some not so much, it depends on the surrounding environment, what targets you will be shooting, your ability to guide for long enough to get good signal.

General light pollution filters like CLS, CLS CCD, Optolong L-pro do block a little light pollution glow but I've found the gradients can still swamp the image. If your local light pollution is LED based you're out of luck here as LED is broadband through almost the whole visual light spectrum so this type of filter will not work very well. They work well at blocking the older sodium vapor based orange/yellow lamp light.

Optolong l-enhance and l-pro work better at concentrating on allowing only the narrowband type signal through so are only really good for certain type of nebulae. For this reason you have to expose for longer to get decent signal (but not too excessively), decent tracking comes into play here also depending on your focal length and exposure lengths. These generally work well with colour cameras.

It's generally not a good idea to use any filter while imaging galaxies as they are broadband and a filter will block/reduce the signal from them.

To give you an idea here is an image of the Orion Nebula using a CLS CCD filter, you can see a lot of the nebula detail is missing despite the high ISO used and relatively large amount of images (though it's a short exposure time per image which is the main reason it's dim), but with this target it appears like this in around 3-4 seconds of exposure without a filter so you can see how aggressive it is in blocking light:

 

Here is an unedited 3 minute autoguided exposure with my modded dslr (via my 60mm refractor) of the horsehead and flame nebula from a bortle 7 backyard with no light pollution filter (so it is possible):

 

I'd try with what you have at the moment with a few targets, for DSO you will need some kind of tracker. I had a Star Adventurer but got frustrated trying to find targets as they will be invisible to the eye, so now I use an azgti which has goto so it's much more rewarding (with plate solving which you have to add with additional equipment).

Edited March 17, 2022 by Elp

[bish]

12 hours ago, Elp said:

Have you tried using your camera as it is? This will give you a good idea of what you're working with.

Some filters are good some not so much, it depends on the surrounding environment, what targets you will be shooting, your ability to guide for long enough to get good signal.

General light pollution filters like CLS, CLS CCD, Optolong L-pro do block a little light pollution glow but I've found the gradients can still swamp the image. If your local light pollution is LED based you're out of luck here as LED is broadband through almost the whole visual light spectrum so this type of filter will not work very well. They work well at blocking the older sodium vapor based orange/yellow lamp light.

Optolong l-enhance and l-pro work better at concentrating on allowing only the narrowband type signal through so are only really good for certain type of nebulae. For this reason you have to expose for longer to get decent signal (but not too excessively), decent tracking comes into play here also depending on your focal length and exposure lengths. These generally work well with colour cameras.

It's generally not a good idea to use any filter while imaging galaxies as they are broadband and a filter will block/reduce the signal from them.

To give you an idea here is an image of the Orion Nebula using a CLS CCD filter, you can see a lot of the nebula detail is missing despite the high ISO used and relatively large amount of images (though it's a short exposure time per image which is the main reason it's dim), but with this target it appears like this in around 3-4 seconds of exposure without a filter so you can see how aggressive it is in blocking light:

 

Here is an unedited 3 minute autoguided exposure with my modded dslr (via my 60mm refractor) of the horsehead and flame nebula from a bortle 7 backyard with no light pollution filter (so it is possible):

 

I'd try with what you have at the moment with a few targets, for DSO you will need some kind of tracker. I had a Star Adventurer but got frustrated trying to find targets as they will be invisible to the eye, so now I use an azgti which has goto so it's much more rewarding (with plate solving which you have to add with additional equipment).

Thanks for your reply. I will try an untracked exposure and see what that is like. I think all of the old sodium street lights have been replaced now, which doesn't look good for light pollution reduction.

[Elp]

Its still possible, moon glow is more of an issue for RGB. If you're shooting untracked you may only be able to do less than 10s depending on the focal length.

Using an Omegon LX I was able to do 2 minutes with a 14mm lens. Using the lens however wasn't ideal due to the wide angle and collecting light from nearby lampposts.

If you've got the funds a mono camera with narrowband ha sii and oiii filters works wonders in light polluted environments. Narrowband though requires 2-5 min exposures at least per image which leads to requiring autoguiding.

Edited March 18, 2022 by Elp

[wongataa]

15 hours ago, bish said:

Hello all,

I might get a star adventurer for star parties, but will need to practice at home under  a  bottle 8 sky. I assume I could use my AZ4 tripod legs. I've a canon camera body and a few lenses. I would need clip in filters,  light pollution/narrow band. Should I also get a camera astro moded? Does anybody manage to get anything under really bad pollution? When I go to a dark site I don't want to have some clue what I'm doing.

Thanks

I took the photo here: https://stargazerslounge.com/topic/391273-orion-nebulae/ with a completely stock Canon camera and lens.  No filters were used.  It was taken in suburban Birmingham so quite a lot of light pollution.  The camera was mounted on a Star Adventurer.

I think it always best to try the kit you already have to see how it performs before contemplating extras like filters or astro modding.  You may decide you don't need that.  You may decide you need different stuff to what you originally thought of.

[bish]

2 hours ago, wongataa said:

I took the photo here: https://stargazerslounge.com/topic/391273-orion-nebulae/ with a completely stock Canon camera and lens.  No filters were used.  It was taken in suburban Birmingham so quite a lot of light pollution.  The camera was mounted on a Star Adventurer.

I think it always best to try the kit you already have to see how it performs before contemplating extras like filters or astro modding.  You may decide you don't need that.  You may decide you need different stuff to what you originally thought of.

Thanks. I live in Dudley, so can't  be too far from you.

[Rustang]

Its really going to depend on what you would like to achieve and what your expectations are. I live in Bortle 6 skies and I've been playing with the Star Adventurer for a short while now with a few different cameras and lens under these skies and at some much darker sites.

My thoughts and experiences are that under light polluted skies, a filter such as the L-enhance which I used, definitely helped filter out some light pollution and bring out the Ha much better and allow for longer exposures, the downside is that you lose some natural colours in the stars etc. Without any filters, even with a modified camera, its been a struggle and most of the time your washing out after 30 sec exposures, I've never achieved anything that great. 

-Example 1 below with a modified Canon 600D and the L enhance filter  in ok Bortle 4 skies with light pollution still visible. 

Ive played around with my Fuji XT-2 which is not modified and I got an ok image of Andromeda from the Bortle 6 skies.

 

Now onto dark skies (good Bortle 4), these are SOOOOOO much better and worth the drive to as the difference is crazy, from 30 sec exposures nearly washing out at home and not bringing out much detail to 90 sec exposures with lots of details coming through and you can actually shoot at f2.8 with out any issues of washing out!.

-Example 2 below taken using an Astro Modified Canon 6D no filters in good bortle 4 skies approximately 1hr's worth of data.

 

Even with an un modified Camera such as my Fuji XT2, on the East coast in Norfolk where there's lovely dark skies you can bring out the Nebulosity with no camera modification or filters.

-Example 3 below a non Modified Fuji Xt2 in lovely dark skies no filter again about an 1hr's worth of data.

 

You could spend a few hours in light polluted skies at home gathering lots of 30 sec exposures to try to get a good image but personally I would keep the Camera, lens and Star Adventurer set up for darker skies and spend your 3 to 4 hrs getting somewhere dark to gather data. You will 100% need good processing skills though unless you can get useable calibrations frame's, I couldn't so its been a struggle!!

 

 

 

Edited March 18, 2022 by Rustang