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Examples of extreme processing with extreme light pollution

PortableAstronomer

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PortableAstronomer

PortableAstronomer

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Hi everyone,

I thought I'd just post some examples of my attempts to image some DSOs from one of the most unfavourable enviroments.

Location: Medemblik, Netherlands, 2m below sea level

Various greenhouses around spluttering orange light into the sky.

Urban location.

All photos are using an IDAS LPR filter.

I show the basic stack+histogram stretch (saturated with orange background), and the result of using PixInsight's Dynamic Background Extraction tool (with some further tweaks, e.g. Screen/Mask/Invert).

The results are quite 'grainy' but quick, all are 5x5 min stacks.

Equipment: Equinox 80, QHY8, EQ6+EQMOD, QHY5 guiding

I'd love to see what other members on here have done, regarding extreme transformations of a bad urban environment, from an extrememly LP'd stack into a respectable processed result. Feel free to post any of yours, I'd be most interested to see how you are doing it.

Have a great Christmas break.

Regards

Chris

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PortableAstronomer

PortableAstronomer

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Cygnus through a 28mm Pentax lens.

QHY8, 5x5 mins

LP removed using DBE tool in PixInsight, then re-stretched.

Certainly not up to the standards of many other members on here :

This is very grainy and needs a proper flat field, severe vignetting at the sides, but OK for a quick urban attempt in a backyard under an orange sky...

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PortableAstronomer

PortableAstronomer

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Thanks for the responses so far. Well my examples are really quite modest as I haven't put the time into it and there are pics on here of the same objects that would put mine to shame. The Netherlands may be the most LP'd in Europe but I used to live near Guildford and that was pretty much the same. Remember the UK is only 2nd most LP'd country because of all that 'relatively' sparse area away from Central & SE England. If 'SE England' were a 'country' then it would probably be equal or possibly worse than NL.

However my motivation here was to show to the many urban-bound folks not to give up or feel disillusioned by the entries by the fantastic photos that came from our more dark-sky-based friends. You can do a lot from your appartment balcony, especially with narrowband. I've been using only an IDAS filter so far. If someone can show me something to rival the power of PixInsight's DBE tool (for the urban imager) I'd be fascinated. I certainly have a lot to learn.

Unfortunately in the Netherlands the greenhouses nearby produce vertical LP at wideband wavelengths; i.e. they're not just low-pressure sodium laps, they're a mix of tungsten bulbs and various other devlish emissions that infect a broad spectrum. So visual deep-sky astronomy is a no-go really. That's what put me into CCD imaging; the ability to use tools such as narrowband imaging and image processing. I think many of us in Western Europe would see some relevance in that we do CCD imaging (as opposed to visual deep-sky observing) out of *necessity*, rather than choice.

It's great to see amazing photos on here from people who've worked really hard and spent so much time on them, but it would be even better to see how they did it. Not a wordy report, but a video replay of them actually doing the processing (like my exampe), or showing the "before and after" images. Some of the desktop-recording software is free and creates a valuable 'audit trail' of exactly how you arrived at the amazing results that I know many of you are producing. Then can we really see and appreciate the work that's gone into it. I've given a link to some of my modest processing recordings, but that's only to give some ideas on what I beleive could be an amazing resource if we could all contribute our ideas & techniques.

Anyway, keep up the great work that you guys & girls are doing out there.

Best wishes for 2010.

Groetjes

Chris

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PortableAstronomer

PortableAstronomer

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arrrghhh.

Oh go on then, one more....

NGC7000 ( North America Nebula ) from earlier in 2008.

This is just TWO subframes stacked in DeepSkyStacker, then stretched in PixInsight.

The right frame shows the effect of Dynamic Background Extraction again.

The edges are quite poor in this image, I didn't use a good flat-frame, and the focus wasn't spot-on. Anyway, it's another good example of the transformation between an awful environment and an 'ok' picture.

Regards

Chris

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PortableAstronomer

PortableAstronomer

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Thanks for your kind comments, for quite modest results!

They were 5 min subs, with just bias & flats, no dark frames.

It would be great of some of the others could post something about what environment they're up against, and how they're processing things around it. As I know I'm not the only one!

When I was living back in the UK, members of my (then) local club tended to regard such enthusiasts as myself as crankish inhabitants of an unimportant amateur-astronomy backwater. I want to prove them wrong. As our environments become more densely populated, urbanised and brightly lit, city observers are the vanguard exploring trails to our future. A paradox is growing as equipment improves while dark skies retreat.i.e. Better technology in a poorer environment.

By the way, does anyone here use CCDStack to do their processing. Is it worth $199 over the freeware stuff I use (e.g. DeepSkyStacker, PixInisight LE)?

Anyway, have a great 2010 all..

Clear skies

Chris

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PortableAstronomer

PortableAstronomer

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This one shows how good H-Alpha imaging can cut through the orange skies. This was a stack of only two 10-min subs through a Pentax 28mm lens with a 'cheap-ish' HA 7nm filter. Stacked in DeepSkyStacker.

There are many excellent H-Alpha images of the same region of sky which would put this to shame, but they don't show the environment that they're in.

Anyway, I must stop nattering on...

Cheers

Chris

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PortableAstronomer

PortableAstronomer

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I just threw this composite together, based on an M42 attempt I made last year with my old Nikon D70s camera. I removed the filter myself as that particular camera happens to be particularly easy, and of course it has a proper Sony ICX CCD sensor, the same as found in the QHY8 (although the Nikon D70s is not a QHY8)

The bottom shows some frames from a modified webcam that I used to record the imaging session in Guiildford UK with my mate Andy, you can see that on the video (links above).

The top shows the processing sequence, then in the middle the finished result by blending layers together using Gimp. I was using a technique that they used in SkyAtNight magazine in Dec2008 (using GIMP), but just using my own captures. It was quite a good transformation, but nothing compared to some of those photo winners on SGL.

Keep up the good work everyone.

Chris

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Wiltshiresaint

Wiltshiresaint

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Inspirational thread Chris, and not only for those unfortunate enough to be badly affected by light pollution. Thanks for letting us see some great images.

Having finally sorted my Mac out and partitioned it so that I can run Windows on it, I really do need to get around to learning about GIMP, layers, etc and posts like yours are a great incentive.

Simon

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PortableAstronomer

PortableAstronomer

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Any other members out there who might like to post a wide angle pic of their observing environment, e.g. the view from their back yard, say a 30 sec wide angle exposure from a DSLR on a tripod ? I'm keen to see what you're up against; I'm sure I'm not the only one.

Actually I thought about doing a quick poll to see if SGL should do an imaging contest specifically for urban imagers. The current 'picture of the week' system shows some amazing work that's being done out there, but I thought how about a contest like 'most amazing transformation of the week' so the rest of us in LP'd environments can *connect* to it and try it out ourselves, rather than just dream of darker skies. We would learn a lot about choosing the best tools for the job. I'm sure it will make a much more powerful connection to the majority of us who have a non-favourable environments. Just a thought...

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PortableAstronomer

PortableAstronomer

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One example I forgot to post earlier was one that made it into the Astronomy Now mag (July 2009 I think) ; which I did with my friend Andy Lee (who submitted it to AN). Of course it's M81/M82.

We put together his 190MN scope with my Equinox 80 and QHY5 to create a guided system in a car park at the Royal Surrey County Hospital just outside Guildford.

It came out quite good in-print in AN, but I found the original stack before I removed the light pollution.

Since then I've purchased my own 190MN scope and moved to the Netherlands!

These were taken Andy's Sony A300 DSLR , stack of 7 x 4min exposures. 3 dark frames were averaged, could have done with lots more exposures but it was getting late , we had to pack up, put all the kit back into the car, and drive home to go to work the following morning!

Since then, Andy did some further processing to remove the grainy appearance that you see on this one (again, using PixInsight).

I think this is a good example of people getting together to put their equipment together to form an imaging system, so spreading the cost. Sadly I've met too many people who are trying to buy everything to use on their own, with the intention to do everything on their own. I don't think that's the way of the future, as dark skies retreat from the reach of most of us, both the land, environment and the tools are becoming more and more 'private'.

I think meeting up with others and joining forces is much more fun, and much more cost-effective!

Clear skies

Chris

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