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Dare I bore you with even more Saturn pics...


ruiyyanko
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...especially with one as rubbish as mine?

ruiyyanko-albums-things-sky-picture10079-foggy-saturn-another-first-attempt.jpg

That's actually just a screenshot as it was so bad there was no point trying to stack it...there is also a (very short) video of it here.

In my defence, it was my first time imaging Saturn. The night started out so well - sky was clear, neighbour next door was out (so lights were off...though cannot do much about streetlamps), and I'd just had a lovely dinner (very important variable)...so hubby and I decided we would set it all up in the back garden.

We'd seen Saturn a few weeks before when it looked really sharp through our scope, and although it didn't look as brilliant this time, it still wasn't bad. We could both spot Titan, and David (pook on here) claimed he could see the shadow of Saturn's rings. Anyway, we decided to go ahead with the imaging.

That's when it all started to go wrong...we just couldn't get a clear image of Saturn at all, and we couldn't work out why. After awhile, we noticed there was actually a thin layer of cloud slowly covering Saturn (no idea where it came from), and could also see dew on the mirror. Could this be why my Saturn looks like this?

Also, is it meant to look so...orange? Has it got something to do with my eyes, my screen settings, something I did when setting up the webcam, or all of the above? There was a streetlight happily casting its glow in our general direction. In other circumstances, I would consider it benign, but in this instance, I have decided to blame it for scuppering my efforts last night! :D

Oh well, better luck next time...

Edited by ruiyyanko
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Its not the streetlights i have one glowing on my scope all the time. not sure what scope this was, but you need more power and by virtue good focusing, to see what small scopes can do theres a few posted on here. a barlow is whats needed i think to up the scale. then things like focusing become easier as you can see the planet better. the problems are too small a magnification and likely focusing was off. make sure collimation is good, and saturn is as high as it will get, before trying the things mentioned. hope that helps

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Thanks for the advice...Scope's a Skywatcher Explorer 150P (which I understand is better for viewing DSO than planets), and has been properly collimated (according to David, since he was the one who did it!). We did also try with a barlow, but that did not greatly improve matters.

Btw, the streetlamp comment was a joke...We have previously had decent viewings through our scope in spite of its presence. It is still an annoyance, however.

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I'd agree on using a barlow. If you are having trouble seeing when you are in focus, get the focus as close as you can, and then de-focus a little bit by turning the focus knob away from you, then take several avi's and adjust the focus a tiny bit towards you between each avi - this way you may just catch it in focus on one or more of them.

Out of interest, what settings are you using in sharpcap?

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We tried many different settings, but no matter what we did, that was as good as it got. There was some light mist around, but despite this, it was a lot clearer in the eyepiece when viewing saturn.

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Hikej-albums-saturn-march-27th-picture10080-sat02tiff.jpg

I am the same, pretty new to all this(as in weeks) this morning tried the old Philips webcam and pretty much got the same at about 04:30 this morning.

This was also after stacking, although I found it hard to focus, so would a barlow help?

Cheers

Keith

kej-albums-saturn-march-27th-picture10081-sat03.jpg

Edited by KEJ
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Oh.. if anyone can shed some more light, Ruiyyanko and my saturn AVI was shot with the following SharpCap settings:

Philips SPC 900NC PC Camera]

Resolution=640x480

Frame Rate (fps)=20.00

Colour Space / Compression=I420

Exposure=-5

Brightness=74

Contrast=32

Saturation=0

Gamma=24

ColorEnable=255

BacklightCompensation=255

Gain=3

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That's actually just a screenshot as it was so bad there was no point trying to stack it

Charmain

Hope you don't mind me saying this, but it is always worth trying to stack it. The stacked image will always be better than any single frame from the avi. Then with a bit of tweaking on the 'wavelets' tab, you can bring out a lot of detail at that point (if all else fails, playing with the brightness/contrast sliders on this page can make a tremendous difference). Please give it a go, I think you will be pleasantly surprised.

HTH

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Charmain good morning

Out of interest would a Barlow help?

And does anyone have information on the wavelet sliders?

It all seems a bit hit and miss, I am not sure which does what and the various numeric settings etc?

Thanks

Keith

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I notice the frame rate setting you have is 20fps. Could it be that you're losing image quality due to compression at that speed? Might be worth dropping the frame rate to 10fps or 5fps to see if that helps.

I started off trying to get images with the the webcam alone, then the webcam and a barlow and finally a webcam and barlow with an extension tube (actually the Skywatcher barlow with the lens removed) and it was harder to find focus each time (it was quite hard to even find the planet at all with the extension tube in as well) so be aware of that if you do try with a barlow. It may be worth turning the gain right up until you find the planet and then switch it back afterwards if you're trying the same.

It also seems to be true that even though the sky can look clear to the eye it can be nowhere near good enough for imaging. I captured my images of Saturn (see this thread http://stargazerslounge.com/imaging-planetary/136271-my-first-images-saturn-again.html) on Friday night and found that whilst I couldn't see any cloud the image of Saturn was jumping about in the frame a fair bit which can't be a good thing. I think if the stars are twinkling a lot then it's going to be more of a struggle to get good images.

The other thing I'm going to do for next time is to make a focus mask to help getting the focus spot on. Apparently it doesn't have to be any more complex than a Y-shaped piece of card of the appropriate dimensions. See this thread for some more information: http://stargazerslounge.com/beginners-help-advice/134838-bhatinov-focus-mask.html

James

Edited by JamesF
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kej-albums-saturn-march-27th-picture10102-28032011672.jpgJames Hi

I must admit I did that initially, I had some white card and made three tabs at 3, 12 and 9 oclock and then cut two square holes at 3 and 9 oclock. Then cut about about 4 thick elastic bands to wrap around the scope, then pushed the tabs under to hold it in place, in all honesty worked a treat to focus on a star.

Someone else gave me advice as well stating that at 90 degrees straight up we have approx 10 miles of atmosphere to look through, at 30 degrees its 20 miles and on the horizon its 100 miles, so that is a lot of potentially dodgy air to look through.

Edited by KEJ
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Out of interest would a Barlow help?

We did try it with a Barlow, but that did not seem to greatly improve quality. :D

It also seems to be true that even though the sky can look clear to the eye it can be nowhere near good enough for imaging.

Yeah, this is my suspicion as Saturn looked clear enough through the eyepiece.

Anyway, just to recap...Scope properly collimated, tried with Barlow, also tested with our Bahtinov mask (sorry forgot to mention this before), sky clear to begin with but once imaging started noticed thin layer of cloud, and also dew on mirror. I'm just going through all the possibilities here to see if I have left anything out. We did also remove webcam later and checked again through eyepiece and again Saturn did look alright...this makes me think either it's webcam settings or like what James said above about it being clear enough to view but not clear enough to image.

Although we did try many different settings, I can't quite remember what they all were, so I'm not going to say we tried every possible combination. Hopefully, on the next clear night we'll be able to have another go and try out James' suggestion...and maybe do it at a different time too, when Saturn's higher.

Thanks for all the advice guys...Fingers crossed!

Edited by ruiyyanko
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Might be worth putting a towel or something similar over the scope when it's cooling down to try to help with the dew problem. It seems to me sometimes that there's a period around twilight when the atmosphere is presumably cooling quite rapidly and dew forms very fast, after which it seems to slow down. If the scope is covered during that period perhaps it would help.

James

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Meant to say, I think using a barlow is likely to reduce quality in the short term as you're creating a larger image from the same amount of light and making life more difficult for yourself. It's a big temptation (and one I've given into myself :D though because of the larger image.

Assuming we get some decent seeing in the near future I think I shall write myself a plan of things to try out whilst imaging Saturn and just work my though it. I find it easier to plan everything beforehand rather than get set up and then decide what to do, and that way I have to write fewer notes...

James

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Thats not always so James. sometimes without a barlow the image can be so small, its next to impossible to focus accuratly. Adding more scale and dimension, makes focussing actually easier, if the seeing isnt terrible, and if your not seriousely over powering your telescope. At the image size here, im positive under even just reasonable conditions, and good collimation, twice that size, ( x2 barlow) is no big deal. ot shouldnt be ( im at a loss as to why it is )

x2 should infact be a starting point. prime focus if you want detail, to all intents and purposes on fast scopes, is pretty much a waste of time. you just will not reveal much, the resolution and seperation will be too small, to show anying other than a tiny globe with wings

really there can be only 3 possible reasons seeing was really very bad ( even then often something should be possible ) collimation isnt as good as what you think it is, ( though would have to be fairly off to kill a image) focusing is being missed either side of focus. thats not as unlikely as it sounds, the images i posted recently, at one point i kept struggling to get accurate focussing. eventually i did. if seeing is variable and worse at times you hit precise focus. you will think its not focused and so move forward out of focus again. i know ive done this often. when seeing is variable sometimes you have to focus in small steps, and wait for the seeing to calm for a few seconds, before judging if focus is actually any better or improving. Jumping in for a few seconds either side of focus, during rubbish seeing, and then saying i cant get it. is poor technique. i know all this because ive played these cat and mouse games too, for many years. the worse the seeing. the longer it takes, and harder it is to get precise focus. Infact everything im mentioning could in theory all be adding its own little problems. its always a case of working through, and being sure that certain problems are cured. Oh yes and cooldown takes at least 3 hours before the optics will start to give there best. an hour is not enough.

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Interesting points. Neil, particularly regarding the barlow. Thank you. I'm beginning to realise that a) it's actually far harder than some people make it look and :D there's an awful lot to learn.

James

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As Neil say's focusing is a tricky business as times, I spent last year learning about collimation and how much of an improvement it makes to image detail when it's spot on.

Lost a fair bit of hair over that but it was worth the effort, I also use the capture softwares zoom to enlarge the object to help on focus.

With Registax I usually capture 3000 subs and then limit to 800 to stack. Once you are on the wavelet page, do an RGB auto align first. Then I apply an increase in slider 2 and 3 only. As my images have improved in detail I have started to pay more attention to the selection quality before stacking.

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Good first attempt.

A barlow would definately help but they are a pain if the image isn't dead centre.

I usually work my way up from say a 32mm to a 10, then try the webcam which is about the equivalent of a 6mm EP. Last but not least is the barlow. Adjusting focus and position all the time.

Don't worry about it dancing around when capturing Registax will take care of that.

Try and go for 1000 frames +

cheers

Spike

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Thanks for all the feedback...really learning a lot here! :D

Meant to say, I think using a barlow is likely to reduce quality in the short term as you're creating a larger image from the same amount of light and making life more difficult for yourself.

It did look like that was the case (using x2)...a bit similar to taking a lo-res pic and stretching it, I guess...but as the seeing possibly wasn't as good as it could have been, it's a little difficult to tell. We'll try it again with the barlow next time and see if the result's the same.

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