The First Rule about Imaging is...

[JamesF]

...you don't talk about all the data you throw away...

I'm as guilty as anyone else of saying "oh, yes, I took a few thousand frames, stacked half and here's this lovely picture of Jupiter". Or something along those lines. And with that we neatly gloss over the times when it doesn't work out and give people considering trying imaging the impression that if you can just point the scope in the right direction and capture enough data you'll have NASA hammering on your door wanting your images to assist with their landings on Europa...

Well, very much in the spirit of trying to encourage people to keep trying when it goes wrong and really not wishing to put anyone off (because I think it's just as much fun as visual astronomy and would therefore encourage anyone interested to give it a go) I'd just like to formally point out that sometimes it's just not like that.

I didn't get much time outside last night, but ended up with a reasonable number of captures of Jupiter. I'm coming to the end of processing them now and, frankly, the entire night's imaging is going to get stuffed in the bit bucket because, to be brutally honest, it's pants. For whatever reason, perhaps that the seeing wasn't actually as good as I thought it was, every single image I've processed so far is rubbish. Once I'm done I'll probably delete the lot, free up the space on the hard disk and move on. And sometimes, often when you've spent hours sitting outside freezing your brass monkeys off and there's ice from the condensation from your breath collecting in your scarf, that is just the way it goes. You dust off the camera, check sat24.com, get your kit outside on the next clear night and try all over again. That's just the way it goes.

Or, at least, it does for me. I assume it happens to everyone, but I don't actually know because the first rule about imaging is...

James

[BuzzBomb]

I thought the first rule was never to talk about imaging?

I'm guilty of deleting data which I could have re-processed to better effect.

Sent from my GT-I9001 using Tapatalk 2

[swag72]

I started a thread some time back about things not to underestimate in imaging. While not necessarily a rule per se, if you use those two words infront almost everything you actually learn and understand quite a bit!!

Never understimate ....

.... the effect of seeing

.... the amount of exposure time

.... the expense of AP (!!!)

.... the amount of processing time to get a passable image

.... the importance of bang on focus

.... the amount of time and frustration that decent kit can save you

.... the number of subs you will throw away

And so it goes on!!!

[VigdisVZ]

I thought the first rule was "remove the lens cap".

Seriously though thats the way it goes. On the other hand, if we had a 100% efficiency in each step of the process, it wouldn't be the same when we got that stunning result we didn't expect at the beginning of the day. My impression is also that as hobbies go, astronomers aren't afraid to talk about when it goes pear shaped. It makes for a good story usually.

And speaking about throwing away data. I have saved so many rubbish raw files in photography (and other stuff) that my 2.5TB of harddrives are getting full, and my laptop is choking with dog pictures. Deleting stuff is healthy, because the alternative becomes unmanagable after a while.

[ArmyAirForce]

I would have thought the first rule is to 'enjoy it', even when it doesn't work as you had hoped. Once it becomes a chore, you're in a downward spiral towards another hobby!

If you have a failure, the forum is a great way to find out why, and how to fix it. If you don't understand what's causing the poor results, you can't fix it, and it will result in more disappointment. The English weather has a great way of messing things up in most outdoor hobbies, but especially in astronomy, it can do it in very subtle ways leading you to think you're doing something else wrong!

[Gina]

I certainly agree that I collect far more data than goes into images posted here. Maybe we should post about all the nights that go wrong and why (if possible).

Since the spring we have had very few clear nights here when I've been able to do any imaging. But when the sky has been clear there are various things that go wrong. For a start there's "the nut behind the wheel" as they say in motor maintenance. Sometimes I just can't seem to do things right, I forget things, and it often takes time to get back into things after weeks of no imaging. Then there are times when the computer plays up, for no apparent reason. A complete power-off and restart can often fix things. USB connections can somethime become intermittent etc. But how often have we got everything set up and apparently working well only to find the clouds gathering again!!

Often when everything seems fine and we go ahead and capture dozens of apparently reasonable subs, when we process them they're rubbish. This can be due to very high wispy cloud that doesn't show in single frames viewed on a small screen at the time. Also, the atmosphere can be turbulent - this is referred to as the "seeing" - the better the seeing the more stable the atmosphere. Then there's the clarity, visibility in terrestrial terms. Sometimes the atmosphere can be really clear, for instnce after rain. Other times there's a very slight mistiness which impacts on image quality and can reflect light pollution or moonlight. I think this is the cause of a brightness gradient in the background.

The sky can be very variable both in time and space. A good example of time was a couple of nights ago. It looked like excellent viewing and I got set up quite early and collected about 70 lights of M33 hoping for an improvement on what I'd collected before. I stopped when the guiding started to get poor and the stars started elongating. I though that at least the earlier frames should be good but they weren't. Even with a careful examination of individual frames and selecting only ones that seemed fine, the result of stacking and then processing in Photoshop was dire. The image was much worse than my previous effort. As a result I didn't post anything about that effort - I just put it down to "one of those things".

After M33 seemed "done" I saw that Orion has risen well in the east so I pointed my scope at that area. I had a new lens I wanted to try out for a wide field view and chose the Sword of Orion area. That is M42 up to the Flame nebula. At the same time the scope covered the M42 locality only. Having both wide-field camera - 1100D DSLR with 200mm telephoto lens - and scope with Peltier cooled 1100D, both on the same mount and solidly coupled to a guiding system and available at the same time I am able to collect two different views of any region of the sky. But I digress... The result of imaging this area of sky proved very fruitful and I was able to get some good images which I posted in the "Imaging - Deep Sky" forum.

SO... This goes to show that the same night can produce both rubbish and a good imaging environment.

I'll try to post more about my failures as well as my successes in future in the hope that I can encourage others not to be too distressed at the inevitable failures.

[reddoss]

I take the approach that every imaging session is like a fishing expedition, you never know what you are going to get!

I often have to throw away many subs as I sometimes get a 'stagger' effect when the guiding is not working well.

I also used to discard subs that had satellite trails. Now that I use Nebulosity 3 to stack the DSO images, it has a function which gets rid of them automatically! Just getting these few extra previously discarded subs can make a big difference to the final image.

On the first night at SGL7 last year, nearly every imager I talked to had equipment problems of one sort or another. Then again on other nights, it can all go very well.

[Baz Pearce]

I was gonna throw out some data. But after reading this thread i couldn't just chuck the 2 captures i got of Jupiter after my Saturday night broadcast. I had been pretty much clouded out, so after saying my goodbyes to the fans i was ready to put my feet up. But then a clear patch came over so i grabbed 3000 frames properly exposed and a 1000 over exposed for the moons. Had to boot out last 300 of the 3k because of a dust bunny. Used 2199 frames to stack the planet and 200 or so for the moons. Lost quite a bit of colour with the sky hazing up, but the moons came out well. Cutting the over exposed planet, then pasting in the detailed shot in GIMP. I bucket filled the whole image, then went round and tidied up the moons and got out this shot.

From left to right Europa, Io, Ganymede, then Callisto.

I guess my 1st rule of imaging would be - Try and get something from every session. Even if it's only a lesson learned.

Baz.

[Gina]

Nice motto and far from bad image

[Radar2312]

I'm with Baz.

Still very new to all this, got loads of rubbish subs on my hard drive (need to tidy up) but try to take every failure as a lesson learned (hopefully) and more fool me if I don't learn from it!!

Really looking forward to SGL8 and getting some 'eyes on' what you more experienced imagers do and hopefully pick some brains.

Rick