Rosette Nebula in Narrow Band - Now with RGB data

[Paul Haese]

This project has taken 11 nights so far with RGB stars yet to be collected. I have tried to keep the magenta stars toned down and the RGB stars will remove those.

This image is an integration of 24 hours, with SII 240, Ha 450 and OIII 750. There is still some noise present in the data which I am overlooking at present. Although it does not show up on my iPad retinal display.

Click here (http://paulhaese.net/RosetteNebula.html) for large resolution

Edit RGB data now makes the image 29.7 hours of total integration. I have included a smaller version of the new image which can be compared a little the previous version. Detail levels have not changed much but the colour data has had an impact to the overall colouring of the image.

[Slawomir]

Awesome image...:eyepop:

As for iPad, I have also noticed that the retina display does not show faint detail as well as computer screen, adjusting brightness does not help much.

[multiweb]

Turned up great! Love the color palette. :thumbsup:

[clive milne]

That is very good as it is Paul, it should be a belter of an image when you're done with it.

It's good to see you getting good results with your gear.

c

[RickS]

Great detail, Paul. Colour a little muted for my increasingly outrageous tastes :lol:

Cheers,
Rick.

[DJT]

Great stuff. Like the palette and the detail is marvellous. Well done.
Looking at the overall exposure per filter it's heavily weighted on Oiii. What's the driver for deciding what the exposure time is going to be for each filter?

Great stuff

[Paul Haese]

I usually process out the channel and see what level of noise is present in each channel and decide whether I am going to accept that level of noise. If not I continue onwards with collecting data. Some objects require a lot more data in one channel over another to lower the noise. The SII really needs a lot more data but the noise in the channel is at a point where it is hard to see even in the full res. I also only use data that has good seeing and tight focus. I monitor what data I discard and what I use purely to produce sharp images. One bad sub leads to a blurry look in images and no amount of sharpening will resolve that look.

There is still noise in the image but I am ok with how it looks overall at the moment. I am still collecting data and may collect a bit more yet in SII and OIII, but that is for my obsessive taste in being noise free. Since I don't use noise control anymore I prefer to control the noise with mega data. It is just a personal preference, but I think it leads to better results.

[Paul Haese]

Thanks for the comments. I am not certain about faint detail not showing up but the noise levels are harder to see with an iPad.




Thanks Marc, I am particularly fond of this palette these days. I think it gives a real 3D feel to many objects.



Thanks Clive, I think there is a bit more data to get yet. This rig is relatively trouble free these days. It is the other rig that is playing up. The beauty of having two working remote observatories is if one goes down the other is usually working and that eases the frustration.



Yes I have noted your tastes in fluro have increased. :)

[John K]

Beautiful Paul - amazing structure and not too noisy on my monitor.

Merry Xmas,

John K.

[stevous67]

The nebulosity at 12 o'clock and the inner dark clouds [notably the Cheater] are very clearly defined. Very nice.


Steve

[Rigel003]

Beautiful image Paul. Lots of detail and colour, and it's kind of dark and moody. Makes for a great composition.

[gregbradley]

Wow, that's impressive Paul. Really nice work.

Greg.

[Phil Hart]

wow.. some serious potential brewing there. look forward to the end result!

Phil

[alpal]

Hi Paul,
that's a magnificent result - so much detail.
I like the colors too.

cheers
Allan

[SimmoW]

Amazing effort Paul with deep results. I really like your explanation to David that talks thru your approach to noise and sub review. Makes the result even more significant.

Posting my own meager version soon.

[Paul Haese]

Thanks John. Nice to know the noise level is low.





Actually my favourite area is down near the five o'clock position and around there near where the Ha, SII and OIII sort of merge together. It gives the impression of looking through the gas and seeing wisps of detail. I think there is something for everyone in the this object though.



Thanks Graeme, I reckon it depends on the time of day you view this image. During the day the light levels seem to influence how your eyes see things, but yes it is a little darker than I would normally present. I guess I am looking for that dividing line between clipped and mood setting. At least you got to see some of it being gathered last weekend.




Thanks Greg, I hope this sort of result helps to convince you of going long on the subs and getting lots of integration time. Perhaps even automation. ;)



Thanks Phil, with some careful processing I am hoping to present this as a standout from previous Rosette images presented around the traps. Some more work to do yet though.




Thanks Allan, the detail level on these big objects always presents great opportunities to give a great result. It might interest you to know that I sort advice from several people as to saturation on the colour and was told to check the luminance by several. That really impacted on the colours which I think work well. One of my previous images I used a very similar colour palette and I quite like the look myself.





Everyone starts from the same position really, so don't discount your results. Equipment certainly makes a big difference but I can afford to be more choosy with automation in place. I will be looking out for your image now.

[IanP]

Noise :question:
Just awsome ...
:hi:

[meade expert]

Very impressive Paul !:)

[Bassnut]

wow, that link is bravely large, and you got away with it Paul. Huge detail and razor sharp. It looks on fire, excellent colour.

[Placidus]

Joyously beautiful, Paul. And thanks for the excellent tutorial. Much appreciated. Can explore this image for a long time. Best, Mike.

[Stevec35]

A seriously good Rosette there Paul - well done.

Steve

[PRejto]

That is a really fantastic image! It does indeed look 3D. I envy you the time that you can devote to collecting so much data. I feel like a beggar; begging for the clouds to part and then begging that they stay open for even part of a night! (oh, I forgot to beg that all the equipment plays nice too.)

Peter

[astronobob]

Mighty Spectacular & top Class imaging Paul ,,, :cool3:

[Paul Haese]

Thanks everyone for taking the time to respond.



Yes Ian even in my images I see noise. Like I said I try to limit that noise by gathering as much data as I can to limit the noise. Screens that show very high resolution can see the noise. So it is there, but certainly lower than most would be worried about.



Thanks Fred. You might have noticed that I have been increasing the resolution of my images in the last year or so. This one was at 2600 pixels wide. Images with slightly more noise I set to 2200 pixels wide. I thought you might like the colour too. Slightly more saturated than normal for me.



Thanks Mike. Like you I think there is lots to see and explore in this object. There are some really interesting gas and dust sections.



While our levels of cloud are less than you guys over there on the east coast, our levels of cloud this year have been a little higher than in the last few years, though not producing as much rain; so I understand where you are coming from.

The return of the cloud after the drought is what prompted me to work towards automation and it has worked for me. You have the equipment and I would encourage you to work along the path of automation, in particular a roof that opens and closes without you undertaking the task. It will mean you are more productive on nights where even a sub or two means you are building on an image.

A stable system is a starting point and something you need to get right first. Hangs and equipment failures need to be eradicated so the automation does not hang on you as that can lead to gear being exposed to rain. Once you have all that sorted you won't be begging for data anymore, it will start to flood in for you.

[timcz]

Wow -incredible!

[lazjen]

Great image even without the RGB data!

[Paul Haese]

Thanks Tim for the compliment.



The preliminary RGB data has made a large impact to the overall finish again of this image. While the NB data looks good, adding the RGB data in really going to hit the spot I think. Another session or two might yet be required to eliminate any noise in the colour data before I release the image to the web, so stay tuned. :)

[alpal]

Hi Peter,
Your pic is already one of the best I've ever seen.

To halve the noise - which is so small now -
you'll need too much more data:

SII = 8 frames now = 1/√8 = 1/2.82 of noise follows half noise again = (2 * 2.82)² = 31 follows that
31 - 8 = 23 extra frames = 690 minutes = 11.5 hours extra hours.


Ha = 15 frames now = 1/√15 = 3.87 (2 * 3.87)² = 60 frames
60 - 15 = 45 extra frames = 45 * 30 minutes = 1350 = 22.5 extra hours.


OIII =25 frames now 1/√25 = 5 ( 2* 5)² = 100
100 - 25 = 75 extra frames = 75 * 30 minutes = 2250 = 37.5 extra hours.


That equals a total of a further 71.5 hours to halve the noise in each channel!
Isn't 24 hours of data enough?

These are the days of mega data.

cheers
Allan

[Paul Haese]

Yes the point of diminishing returns is quite relevant here Allan. It is not worth doing that much data for this image. Although I was only going to do data collection on the RGB data not on the NB data. I am content with the NB data. When I was saying I would collect a few more nights worth I actually meant on the RGB data set.

The image I have in process has virtually no visible noise in it now after adding the RGB data. I was concerned that the noise of the RGB data would affect the NB image in a negative way but it has not. I will wait until tonight to post that for people to see.

[alpal]

Hi Paul,
Ok - I would have thought that just an hour of data for the RGB stars would be more than enough
& keep the narrow band as it is - it's so nice.

cheers
Allan

[SkyViking]

A fantastic view of this fine nebula Paul, the level of detail and colouring is impressive and the 3D look is very obvious. Great work :thumbsup:.
With RGB stars it'll be an amazing image, looking forward to see that!

[Paul Haese]

Thanks Rolf, the detail and colour is what I was aiming for from my previous effort. I am quite happy with the look of this image now and will be moving onto the next target.

The image now has RGB data included and is finalised. It is 29.7 hours of integration.

[alpal]

Hi Paul,
that's fantastic.
Please submit it for an APOD.

cheers
Allan

[Paul Haese]

Thanks Allan. I submitted a couple of days ago but given the amount of images that are submitted I doubt that it will get up. Time will tell but at least I am in the pool.

[alpal]

That's good Paul,
I see it submitted here:

http://asterisk.apod.com/viewtopic.php?f=29&t=34161&hilit=APOD+submissions&start=125

Good luck.


cheers
Allan

[atalas]

Looks awesome Paul!well done.

[Star Catcher]

Absolutely wonderful Paul! Love the detail and colours.
Ted

[niko]

best thing to come out of Adelaide in a long time :-)

[Paul Haese]

Thanks Loui and Ted for taking the time to comment.



Hey, watch it Niko. ;) I will take it as high praise though. :)

[cazza132]

Wow! that is outstanding!!! One of the best I have ever seen of Rosette. Nice differentiation with narrowband - something that cannot be done with a DSLR. An inspiration for me to finally pull the trigger on a genuine imaging scope some day :)

[Paul Haese]

Thanks Troy. I wanted to produce an outstanding image of this object myself. There are still some niggling things to me but overall I am pretty happy with the image.

[marc4darkskies]

You should be happy Paul! Excellent detail and very pleasing colours. :thumbsup:

Cheers, Marcus

[Paul Haese]

Thanks Marcus. Yes quite happy with the image now.

[Leonardo70]

Excellent result Paul. Congrats.

All the best,
Leo

[Paul Haese]

Thanks Leo. :)

[clive milne]

it might be the monitor on my tired old imac, but I'm with Rolf on this point... the stars would look better if they were rendered with more intensity and a stronger blue channel.

In saying that, the number of images I have seen employing the hubble pallet (or some variation of it) that look aesthetically pleasing to my eye, I could count on one hand with two fingers spare. This is one of them.

[Paul Haese]

Thanks Clive. I am going to take another look at the RGB star saturation at some point soon. It is a little pale as pointed out. The rest I am happy with. :)

[Geoff45]

Too right. Software correction of acquisition or hardware deficiencies can never compete with good data.
Stunning image. The level of detail is amazing.
Geoff

[Paul Haese]

Yes exactly, if you can afford the time get the data; it makes processing enjoyable and gives anyone the potential to produce a lovely image.

[Bassnut]

Whoa, id disagree with that absolutely. Data and processing are equally important at least. Ive seen (and done) great data and standard processing for an ordinary result, and conversely, subs that were so bad the object was almost invisible, buried in noise, and with vast time and carefull processing produced a better result. . Astrophotography is all about noise reduction. This can be done in many ways. Yes, good data is always a better start, but not always possible which makes processing more than competitive.

[multiweb]

+1 Crappy data will make you better at processing. A good astro photo is 80% processing. :thumbsup:

[RickS]

+1 from me as well. With the right tools and experience you can polish a turd. Or you can just roll it in sparkles :)

[Paul Haese]

Aah yes but still a turd none the less. ;)

[Geoff45]

Yes you can polish a turd. I've done it many times. But if you start with something better than a turd you'll end up with something better than a polished turd.
Come on guys (Fred, Marc and Rick) are you really suggesting it doesn't matter how crappy your data is because you can hide all the crap with processing?
Geoff

[RickS]

Speaking for myself, that's not what I'm saying. Given the option I'll take good data any time and I'm prepared to work hard to get it. However, I think that weak data with good processing will usually produce a better result than good data with weak processing.

To produce a great result you need both, of course, and that's what we're all aiming for. A really good image is the result of good data and every small aspect of your processing being just right. A few percent better here and a few more there and eventually you're talking a big difference.

Cheers,
Rick.

[Geoff45]

No problems with that Rick. In my original post I was assuming a single competent processor and my original statement was simply stating that he/she would produce a better image with better data, reinforcing what Paul posted concerning noise. Sure if someone has eggy stars they can resort to star rounding in Photoshop but the final result they produce is never going to be as good as getting round stars in the first place.
Geoff

[RickS]

I didn't think we were really disagreeing, Geoff :thumbsup:

Noise is an interesting topic, though. It's always there no matter how much data you collect (damn Physics!) We just do our best to hide it in the background by not stretching our data too hard.

Cheers,
Rick.

[strongmanmike]

I think the word Turd is a rather exaggerated and perhaps more of a self justifying term really, there are plenty of amazing images out there that weren't compiled from mega data (check some of Leo and Marco Lorenzi's work for example) and may have had some noise reduction or other processing applied, there is a point of diminishing returns here too. To me mega data's real benefit is in surfacing very faint features, so really comes to the for when imaging galaxies or faint nebulae that have otherwise invisible features and perhaps the finest example of this type of work is that by Rolf Olsen, the king of mega data, he has revealed some hither too unseen features with the greatest exposure times of anyone yet he still has some noise in his images.

Mike

[Rod771]

Excellent image Paul! :thumbsup:

Great detail and colour. Very inspiring!

[Paul Haese]

Yes noise can never be totally eliminated but it can be reduced effectively as you know. Your point here about stretching is certainly why I do long subs and then lots of them to reduce the appearance of noise in each filter set.





You have a few basic misunderstandings here Mike. Rolf images still contain noise despite 75 hours simply due to sub length and stacking methods. Faint objects need extended subs to collect enough photons to build the signal. You cannot effectively manage noise given a certain size aperture by doing lots of short subs. It is a complicated equation to managing noise for any given system and any given object. Aperture plays a big part as does calibration. However general a 30 minute exposure will have greater signal by large margins over 5 minute or 10 minute subs despite the aperture size. The signal will beat down the noise level and when combined in a mega data set that noise will be nearly unapparent after a certain amount of subs for each filter set. It will be different for every object and every filter set. You cannot simply point to one persons results and suggest it is the same over the entire board.

With regard to noise reduction ideas: if you don't have the time to collect the data then you will most likely need to employ noise reduction to varying levels of success. I don't use noise reduction at all anymore as I can and do collect vast amounts of data simply because I can. I have expended the money and time to allow me to collect mega data. This is my personal choice and I understand that not all people have the time to stay up all night after night to collect the data needed to reduce the noise.

Everything in the end boils down to your individual ambitions and budget, but ultimately this is not a job but an adventure in producing art and showing the night sky as I see it.

[strongmanmike]

Ooooh, o-k :question: thanks for that Paul :)



Of course and there are many ways to skin a cat too I guess, but to call all images that are not composed of days of exposure, a turd, is still a little...absurd :)

Mike

[Paul Haese]

Actually I never said that. Those are your words Mike. I simply said a Turd that is rolled up in glitter is still a turd. That is not the same at all.

[Geoff45]

Wow! I really started something here with what I thought was an obvious and uncontroversial statement.

Let me rephrase what i was getting at:
If you have instrumental defects (bad tracking, miscollimation, poor focusing etc) you are better off fixing the hardware problem rather than trying to fix it with software. If you have vignetting or dust motes you are better off correcting them with proper flats rather than resorting to software (DBE and/or cloning). If your images are noisy you are better off collecting more data rather than using noise reduction etc, etc. I was essentially talking about what I think is the optimum way to correct problems, not about how a skilful Processor A can produce a better image with bad data compared to what a newbie Processor B can produce with good data.
Geoff

[strongmanmike]

Oh and I got that Geoff, all good :thumbsup:

I was just suggesting that a lovely image can indeed be created from less than so called optimal data and especially without mega data :)

Lets not get too serious and misinterpret posts, no malice, ill will or otherwise here, regardless of how it may seem :love:

Mike

[nebulosity.]

Wow, what a stunning image! beautiful :thumbsup:

Cheers
Jo

[Bassnut]

Well, I disagree again Geoff. Im not getting cranky, its just an interesting subject.

I think "competing" and "optimum" ways of producing a result (sometimes "any" result) is always a balance of hardware and software, and that balance always depends critically on circumstances.

Unless you already have gear perfectly set up and unlimited imaging time, there is always some sort of compromise on a given project that may absolutely give software the edge.

A/ Say you have 2 nights imaging at Wiruna or other dark site, some things arnt quite right with hardware, as you mention, so you sort them out the 1st night rather than take a risk taking bad data. The second night is cloudy, no result.

B/ Instead you image the 1st night with dodgy guiding, need to focus manually, pointing is bad so you hunt down the object manually. Take 6 hrs of dodgy subs and spend 10 hrs with software repair monday and post a pretty good effort on IIS and feel satisfied.

I saw exactly this at my last visit to Wiruna. The astrophotgrapher in question had rediculous hardware problems and just powered on (to my amazement) to produce, with software correction, a very pleasing result.

If you like, software out "competed" hardware perfection in this situation, easily. Software was the "optimum" solution by far.

Ive seen many hardware perfectionists on IIS spend months iron out hardware issues before producing an image. Is that an optimum situation?, lost opportunity can be a dire cost of perfection.

Many times I have sacrificed hardware setup perfection by compensating with software correction just to get a friggen result when circumstances demanded a result or tedious endless tuning and no image at all. If i and probably the majority of us always considered hardware perfection always the "optimum" path, then you would see a lot less images posted on these hallowed pages :thumbsup:.

[multiweb]

Crap data with good processing always looks better than good data with crap processing. ;) Honing one's processing skills on average data will yield excellent results with good data.

Of course good data with excellent seeing always win. Quality of the gear used also makes a big difference. Although sometime I look at the pics and gear specs and cringe a little... and that's primarily due to lack of processing skills.

TBH a few of the best shots I've seen were done with modest gear. Ray's stuff (Shiraz) for instance produces pictures that are right up there because he has a good understanding of both processing techniques and tuning his equipment.

[Geoff45]

:driving:
Hi Fred. I think a simple summary of what both of us are saying is "Do whatever you can to get the best data but if your data is not so good then just bring on your processing skills to deal with it"

The trouble is that "optimum" means different things to different people. There are those that are happy producing one "perfect" image rather than 10 they see faults with but others prefer to get 10 images with a few warts. Without naming names, there is one prominent astrophotographer who suggested spending a year perfecting your hardware before starting to image (PEC, polar alignment, feeler gauges to check squaring of the image train and the like.) He gets lots of APODS.

So I guess we won't get consensus on what is the "optimum" strategy.

I think we've now done this to death--I'm outa here.

Geoff

[strongmanmike]

No, no, don't...I think you should all continue to discuss the bleeding obvious :whistle:

:lol:

[alpal]

Hi Mike & others,
People are taking this all too seriously.
Just take one night - get as much data as you can of LRGB & maybe Ha.
Do your best with that data.

( except for those who want to use mega data )

cheers
Allan

[Paul Haese]

Yes those that want to do both should be able to do that and not get criticised for it or poked at. Like I said do what you can achieve. I prefer mega data myself.

[strongmanmike]

Need to imagine we are sitting around the eski at a star party and discussing this sort of stuff, which I am sure we all have, then the spirit of the discussion is clearer and things are less likely to be taken too seriously or personally :drink:

[Paul Haese]

No I don't think you did Geoff. There are certainly differences of opinion amongst imagers out there as to how to combat and beat noise. Not everyone agrees with each other. However, discussion is always interesting to see what people think about the subject so long as it remains civil and not personal. For me mega data with long subs allows me to have the data to work with and I can choose which data to reject and I always reject data. My processing skills these days (that is not to suggest there is not more to learn; as there always is) allow me to extract what I can from the data whilst producing my own artistic bent. Part of that bent is to produce an image without the obvious presence of noise. Our eyes in normal life don't see noise and I am trying to produce what our eyes might see. To me an image with noise is an incomplete view of what is out there. At one point or another one has to compromise about the level of noise one is going to accept. That is the part of the argument that is interesting and everyone has their limit.

[alpal]

Hi Paul,
noise is a natural phenomena.
If you have a dark area of space with no appreciable signal then the
noise will be above any signal.
In that case you cannot get rid of it no matter how many sub
frames you take.

e.g This Hubble picture of galaxy NGC 1300:

http://upload.wikimedia.org/wikipedia/commons/5/52/Hubble2005-01-barred-spiral-galaxy-NGC1300.jpg


There is plenty of noise in the background but does it take anything away from the picture?
I would say no & it's far better to leave that noise there than to try
& cover it up with processing or spend more time taking sub frames.

Actually knowing where the noise level is in the image is also more valuable in scientific terms i.e. - it answers the question -
where is the natural noise floor in the picture?
I think we should all leave a bit of natural noise in our pictures.

cheers
Allan

[Paul Haese]

Yes noise is in the shadows. This is why I don't like stretching a lot and hence why I do long subs. Though the use of median stacking does eliminate a lot of noise that is visible in an image.

I don't like noise in my pretty pictures. I am not doing science so I try to eliminate it where ever possible from visible view. I am looking for artistry in my images, I also look for that in others images too. Images that I consider stunning incorporate colour control, detail and noise elimination.

For the most part given enough frames the noise floor is not visible in all images. Only a few of my images this last year show visible noise in the shadows. I am not suggesting it is not there in any of my images, I am saying it is not visible to the eye. It does not require a processing technique to remove it from view other than stacking. My point of view of course and no doubt many will disagree.

I respectfully disagree that there is always signal every where we look in space. I guess appreciable is a matter of degrees though. I am yet to image to point when I cannot see an improvement in the reduction of noise. I know it is there, I have just not encountered it yet. Mind you I have only done the occasional image of 40 odd hours. And; it is a method that works for me and a few others too. :)

[gregbradley]

Rob Gendler started the mega data images back 15 years ago and his images were always the best. I noticed though in his later images they tended to be shorter but then he was hiring a remote 14.5 inch RC in WA for a lot of them. So cost comes into it. So yeah mega data is a good thing. Martin worked with Rob when Martin was starting out and no doubt Rob instilled some good imaging approaches in him. Martin would collect some Tak FS128 data and Rob would process it (they both would).

I have noticed getting good data always makes processing a piece of cake. More is almost always better. Its more productive to work on having the basics done well than spending endless hours on Photoshopping bad data but you can always improve a so so data image but its never going to be top class. But I agree spending time getting your setup humming is the best time invested. I am not in the software is 50% of the image camp. Its definitely a big part but perhaps overstated in importance. Overprocessed images always look substandard to my eye. Because PI is so powerful in its processing tools it has tended to create a series of highly processed images that create a look which some like which is fine but its a bit like HDR photography - not generally a popular look to an image.

My problem is not so much automation, as my observatory is at home so I can image every night/all night on a target, its more clear sky time. Hence a site with good weather and seeing is ideal.

The modern way of dealing with the losses in time from weather, work, hardware glitches and so on is to use larger aperture and faster F ratios to get the all important SNR up. That certainly seems to have been the trend in the last 5 years. Faster wider aperture scopes are becoming more common. The ASA was one of the first. Fast F ratios have their own set of problems of flex, smaller critical focus zone.

So mega data would be different for different setups as different read noises of CCDs, different cooling power, different scopes of different apertures, different locations with better/worse seeing and clear weather times, permanent observatory versus setting up and breaking down. So I don't think you can put a number of hours on it but rather a SNR achieved or level of noise that is acceptable (that obviously varies between astrophotgrapher and the audiences). But lower noise is better than higher noise obviously. More detail is better than a lack of detail. Round pinpoint stars are better than eggy blobs. Sharp detail is better than blurry fuzz. As total hours target its more often than not limited by the weather.

I have done images over 30 hours that were not as good as images that were 10 hours. Seeing comes into it big time when doing longer focal length (not so much for widefield).

Sometimes weather interrupts an imaging sequence and puts it on hold until next year.

One advantage of using a similar setup over many years is being able to add to the data from earlier years and build it up that way.

But mega data of 20 hours plus I think assumes good weather that will often allow that. Sometimes Sydney gets many clear nights in a dry spell other times they are rare. My dark site tends to be clear because even if there is cloud about it tends to go around the large hill/geography of the site. I am sure Paul's site is more often clear than the major cities.

On the other hand this hobby is different things to different people and getting out under the stars is part of the fun to me. Some travel and setup, some live in light polluted cities, some live in rural dark sky areas and some have remote scopes in ideal sites. Different levels of commitment to the hobby and each has its own reward and its fun at the end of the day. There is also the major factor of cost and budget as its an expensive hobby.

Sorry for the long post.

Greg.

[alpal]

Paul,
Hi Paul,
Isn't there such a thing as sky noise? - the atmosphere glows.
There is thermal noise & shot noise etc

If the signal is below that noise you won't see any signal.

What is the signal from a dark area of open space?
The Hubble Deep field would tell us that at our resolution
it is a the sum of light from all those 1000's of galaxys.
In which case we can't resolve them & they just turn into a smudge of background noise.

I believe the correct term is signal to noise ratio.

cheers
Allan

[Paul Haese]

Some interesting point Greg.

I have had the benefit from Martin's advice on a number of occasions. So I guess Martin is passing on the knowledge just as Rob did.

Equipment can differ quite a lot in the end and that can determine outcomes and I quite agree with your comments here. There is no one set formula. Each system will require differing levels of data to achieve a desired result.

Automation has meant I can sleep while the system is collecting the data. I don't have to stay up all night. Nor is that helpful to me anymore. I have been a council member of the Astronomical Society of South Australia for 4 years now and more recently am now the instruments officer for the society as well as managing the cladding of the new 8 metre turret we are building. Not to mention other duties like wife time and for that matter work which seems to take a back seat a lot. All that as you know takes up time so in the end I just want the data. Though I still spend time under the stars with mates around new moon if the skies are clear and I enjoy that. Staying up night after night and being sleep deprived isn't much fun anymore.

I do get quite a few clear nights a year, though most of that seems to coincide with the moon in visibility. Hence more NB images I am producing.

Certainly the hobby means different things to different people and each to their own.

[Paul Haese]

Point taken. Though noise being a random thing stacking methods will hide the noise pretty well.