What is possible from London?

[BrendanC]

Hi all,

I started out in astrophotography about three years ago, taking advantage of the Bortle 4 skies where I currently live . I shoot deep sky objects - nebulae, galaxies and clusters. However, I may be moving back to London some time soon, and am considering my options if I want to continue with the hobby, given that it's one of the most light polluted areas in the world!

I understand that solar system photography is possible, but would probably require a whole new rig (I have a Sky-Watcher 130PDS, NEQ6 and ASI533MC). I might be able to continue with deep sky work if I use narrowband filters for emission nebulae, but would broadband be possible? For reflection nebulae, galaxies, clusters etc?

Any takers?

Thanks
Brendan

[DaveS]

When I was living in London it was pretty much NB only and 3nm at that.

[vlaiv]

It is always possible - but takes progressively more time to get the same results, so it gets painfully slow and question becomes - if it's feasible for you.

If I recall correctly - every two SQMs equals about 6 more time imaging to hit the same SNR.

Being in Bortle 4 skies - you SQM is likely somewhere around 20.5 while in London you will be around 17.5 SQM. - that is 3 mags of difference, or you'll need about x16 more time to get same result.

What you've accomplished in one hour will take several nights.

Investing in good LP filter, being mindful of sky transparency and imaging only objects directly overhead at the time of the night there is the least LP (majority of people is asleep but morning services have not yet kicked in fully) and being willing to spend multiple evenings per target - and you will be fine

 

[vlaiv]

If I'm not mistaken @Lee_P images from heavy LP so he might be able to share some thoughts on this?

[saac]

I think you will be surprised at what is possible from London. There are a number of SGL members from London and they produce the most amazing astrophotography in deep sky, planetary and solar. I'm always amazed at what can still be achieved in some of the more heavily light polluted areas. 

Jim 

[BrendanC]

Just now, saac said:

I think you will be surprised at what is possible from London. There are a number of SGL members from London and they produce the most amazing astrophotography in deep sky, planetary and solar. I'm always amazed at what can still be achieved in some of the more heavily light polluted areas. 

Jim 

Sure, and I know someone who does great solar system stuff from London, but I'm just doubtful that if I were to want to continue with deep sky, I'd be able to do broadband. It seems narrowband is the only game in town (or city for that matter), and as @vlaiv says, extreme conditions are probably going to warrant an extreme approach ie very narrow filters with very long exposure times.

[DaveS]

@carastro images from SE London but I think she does NB only and travels to a Bortle 4 campsite for BB imaging.

[saac]

7 minutes ago, BrendanC said:

Sure, and I know someone who does great solar system stuff from London, but I'm just doubtful that if I were to want to continue with deep sky, I'd be able to do broadband. It seems narrowband is the only game in town (or city for that matter), and as @vlaiv says, extreme conditions are probably going to warrant an extreme approach ie very narrow filters with very long exposure times.

Check out Lee's work at Urban Astrophotography. Lee images from Bristol and has produced some amazing results in both NB and BB. He is active on SGL just cant recall his username at  the moment but his web site is well worth a visit from useful guidance. 

https://urbanastrophotography.com/index.php/2021/06/14/overview/

Jim 

[BrendanC]

I've come across his site before, and in fact it was after reading it that I decided to opt for an OSC with dualband filters as a next step, after trying mono and not really enjoying it. But, even Bristol, at Bortle 7, isn't London. I'm specifically referencing London, specifically DSO.

[Lee_P]

1 hour ago, vlaiv said:

If I'm not mistaken @Lee_P images from heavy LP so he might be able to share some thoughts on this?

57 minutes ago, saac said:

Check out Lee's work at Urban Astrophotography. Lee images from Bristol and has produced some amazing results in both NB and BB. He is active on SGL just cant recall his username at  the moment but his web site is well worth a visit from useful guidance. 

https://urbanastrophotography.com/index.php/2021/06/14/overview/

Jim 

Thanks for the mentions. Yes, I image from the centre of Bortle 8 Bristol -- not quite as bad as London, but in the same ballpark! I use an OSC camera. For narrowband I use an Optolong L-Ultimate and Askar D2 filters. For broadband targets I don't use any filters at all.

Lots of example photos here: https://urbanastrophotography.com/index.php/gallery/

There are plenty of tips if you browse that website. The "secret" is to aim for long integration times to combat light pollution -- think 20+ hours. This is very achievable if you have an imaging rig that's easy to set-up and pack down. I typically produce an image every 2 - 8 weeks. (But not right now as my camera is broken and with ZWO in China for repairs!) 

I'm happy to answer any specific questions you may have.

 

[Lee_P]

2 minutes ago, BrendanC said:

But, even Bristol, at Bortle 7, isn't London. I'm specifically referencing London, specifically DSO.

You'd need to put a bit more time into each target compared to my skies, but DSO from London is achievable.

[BrendanC]

Thanks Lee. I guess that you don't even bother with broadband then?

[Lee_P]

1 minute ago, BrendanC said:

Thanks Lee. I guess that you don't even bother with broadband then?

Broadband is not a problem. I don't even use a filter. Loads of examples in my gallery. Here are three:

[BrendanC]

Outstanding. I'm particularly impressed you got the Angler Fish. Thanks, this is very encouraging.

[saac]

As a broadband target from Bortle 7 skies that image of Andromeda is absolutely outstanding. 

Jim 

[Elp]

I think milage will vary depending on your immediate light pollution, Im bortle 7, my east has an immediate LED lamppost right on the other side of my garden wall with another two going down the street northward and another two going south. This means anything rising in the east say below 60 degrees is out of bounds for me and any background extractions struggle to process out. Even targets nigh on vertical suffer from yellow or washed out colours when doing OSC with just a luminence filter, the lextreme suffers from odd green/red patterrns because of all the light sources around hitting it at angles. My vicinity is also surrounded by industrial lights, on a cloudy night it looks like something is on fire in the near distance or illuminated near white by the LEDs. Imaging mono narrowband however I do not have so much of an issue, contrast separation does suffer a little but not too bad, I can even image targets at 15 degrees altitude hovering just above said lights.

[carastro]

6 hours ago, DaveS said:

@carastro images from SE London but I think she does NB only and travels to a Bortle 4 campsite for BB imaging.

I do indeed.  I rarely attempt broadband from home as l get swirling gradients.  

Bright narrowband nebulae work well in narrowband in Bortle 8. 
 

Carole

[DaveS]

When I was living in Ruislip I did try imaging a couple of galaxy targets but the results were very poor so I limited myself to bright NB targets. "Galaxy Season" was pretty much dead time.

[Mal22]

1 hour ago, carastro said:

I do indeed.  I rarely attempt broadband from home as l get swirling gradients.  

Bright narrowband nebulae work well in narrowband in Bortle 8. 
 

Carole

@carastro Where is the Bortle 4 site that you visit outside of London? I’m in Essex in Bortle 6 so good to know what better options might be within reach! Thanks 

[carastro]

It is in East Sussex just South of Bewl Water.  PM me if you want to join us.  Not going again until May 2024.  

[mal30]

I image from Bortle 9 skies in SW London. Solar System objects are fine from here. Narrowband targets, when weather allows, are also good. I’ve also had some tolerably decent results with broadband, with appropriate LP filters attached. There is a "Science" section on my website with some of the results.

www.malcolmpark.com