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Hi and request for help for a newbie

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#1 harbinjer

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Posted 18 January 2013 - 01:18 AM

Amazing stuff you guys do here! I have done some deep sky imaging, but sadly haven't done much in over a year. I did get a new scope and try it once or twice last year, but that was very short. Anyway, here is my attempt at Jupiter with a Vixen R200SS, with a cheap 3X barlow, and a Canon T2i in crop mode. I don't know where the bridge between my efforts and some of these amazing ones with more details are. Is my focal length too short? Bad seeing? Or is my focus off? Or is the problem with my processing. For that I did a mostly default Registax6, tutorial-type. I understand that there's a learning curve, and I don't expect instant or amazing results, but I'd love to focus my efforts in the most productive way.

Here is a link to my raw data: raw data. If anyone wants to get more out of it, I'd love to see.

Here are my results so far(from 1-16-2012)

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#2 GreatGigInTheSky

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Posted 18 January 2013 - 06:11 AM

Hi and welcome.
Watching the .mov file, I'd say your seeing was not very good, and it's possible your focus isn't quite spot on. Since your scope is native f/4, you're working at about f/12, which is a reasonable place to start, but if you get into this, you will probably want to be able to get to f/20 or so for more image scale. Your camera is not idea for this purpose, but there have been reasonably good results with it posted by others.

I would suggest next time out really trying to dial in focus as best you can, and hope for some good seeing. You might try stacking in AS!2 -- most of us here are using it these days, then do wavelet sharpening/denoising in R6 as you've done.

Your effort is by no means a bad first attempt -- it's pretty similar to many first tries I've seen, including my own. This is a pursuit that rewards patience, and a lot of trial and error.

#3 harbinjer

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Posted 18 January 2013 - 11:49 AM

Thanks Jeff! To improve my focus, I'm thinking of making a bahtinov mask. In that calculation, would I get one for just my scope's focal length, or scope+barlow?

Also, this was kinda tacked onto the end of a DSO imaging session, but I also have a 150mm Maksutov, that I don't normally use for imaging. Despite it smaller aperture, do you think it would achieve better results?

#4 bunyon

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Posted 18 January 2013 - 12:05 PM

Bahtinov masks don't really work for planetary photography. You need a point source and neither the planet nor the moons are. You'd need to get lucky and have a bright star very close to the planet.

Best bet is just to play with it carefully. If you have poor seeing, it's very, veyr hard to achieve good focus. In good seeing, move slowly and just go for best looking focus.

You don't mention acquisition details. At that focal length you can go for 2-3 minutes. Do. Get as many frames as you can. I concur with AS!2, which most people use. Your processing doesn't look bad, though. As Jeff said, this is not a bad first go at all.

Good seeing this time of year can be hard to come by. You'll know it when you see it and you'll be amazed what a difference it makes.


OH! One other thing. Collimation is very critical as well. Make sure you're bang on with that as well as focus.

Good luck.

#5 harbinjer

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Posted 18 January 2013 - 02:38 PM

If I can, could I focus on,say Aldebaran, with the mask and then lock the focuser and then mosey over to Jupiter? Is there a problem with moving the scope far? The camera is pretty light and the focuser is a low profile(moonlight maybe?) aftermarket one. I did try to get collimation right on. I think I'll try to collimate my collimator too. I only have a laser, do I need something else?

I did take several movies between 1.5 and 2.5 minutes. I grabbed between 300-700 frames in the limiting step, which was 10-40%. Would it be better to try with more or less?

Are there guidelines for shot length if I switch to my Mak, or change barlows?

Would someone be willing to share some "good" unprocessed planetary data, or is there some out there for instructional purposes? I'd love to see what it is I'm looking for ideally, and to practice processing.

Also is there a good very quick way to determine the seeing?

Thanks for you kind words and patience with newbie questions.

#6 bunyon

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Posted 18 January 2013 - 02:56 PM

The quickest way to determine seeing is to look at the stars. If, by naked eye, you see a lot of twinkling, try something else. That isn't to say that if you don't see twinkling that the seeing will be good. But twinkling generally equals bad. Other tips: don't set up on concrete or asphalt, don't image over buildings (if you can avoid it of course, etc).

EDIT: and, of course, you can look at the stars in your scope. If you put an eyepiece in and look at Jupiter, or a stellar Airy disk and it's waving all over the place (and you're satisfied that your scope is close to thermal equilibrium), then it's unlikely to be a great imaging night. It's usually worth imaging anyway by that point - you've set up after all - and the seeing can be fickle. It'll be good for a few moments on even bad nights. Of course, you're usually taking a brake, or straighteing cables or something when that happens. But a bad night is also good for practice on your routine.

As to focusing on a star and moving, in principle, it could work. I've found - and I think others agree - that if you have to move very far, the focus will shift slightly. But given Jupiter and Aldebaran's proximity, sure, maybe it would work. It would certainly get you close enough so that you know you don't have to change focus too much. But the image itself really is the key. Watch the image from about a meter away - if it looks sharp, then you're focused. If not, then you're not. So, give the mask a try but be sure to look carefully at the image. If it looks soft, it probably isn't a trick.

As to collimation, in a f/4 reflector, a simple laser collimation is unlikely to be bang on. It should be close, of course, but I found when I went to a barlowed laser and then to an autocollimator that my images improved dramatically (I image with an f/4.5 Newt). That will be especially true if your laser isn't already well collimated. Moving from relatively wide field imaging and observing to high focal length imaging really exposes mis-collimation.

#7 bunyon

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Posted 18 January 2013 - 03:02 PM

As to "good" data - I have no way to upload avis and I don't use a color cam but I will attach an unsharpened stacked image. I don't know if that helps you much, but you can work with it to see about sharpening and bringing out detail.

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#8 bunyon

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Posted 18 January 2013 - 03:03 PM

Here is the same image sharpened using wavelets in Regi 6. It might not work as well for you since I was using a raw image and you'll have a jpg.

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#9 zAmbonii

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Posted 18 January 2013 - 04:03 PM

Below is what I ended up when processing your video. There is really not much else you could do with such bad seeing. The MW has been under the jet stream really bad for the past couple of weeks.

I think that your focus was good, but the seeing was particularly bad. For planetary stuff, I have ditched the Bahtinov mask and just tried to get the best focus I can. The last time out I threw on my mask and focused on a star, and with minute movements of my dual speed crayford, I really couldn't tell much difference with the pattern on screen live. If I would have used something like Bahtinov Grabber, I could notice a difference. Not sure.

I feel more confident in trying to focus on some detail on Jupiter itself, rather then using a mask on a star and then slewing. I also tend to question during a run whether or not focus has shifted, and I'm not going to slew to a star and focus with the mask and then slew back....takes too much time. Rather just use detail on Jupiter for the focus.

Paul has some good advice listed there, but you have to remember one thing. For the most part, if you don't have good seeing, not too many things you can do will improve your images :). When I first started imaging, I was out with my scope on any clear night, and was disappointed with the results, when I finally had a night of good seeing, I knew that there was nothing I was doing wrong, but it was all up to the conditions.

My general rule is try try and get as many frames as I can. For your image scale you were imaging at, 3 minutes should be fine. If you want to see how things are at shorter videos. Take that 3 minute video and split it in half, then process and compare between the two. There really are not hard set rules, but going out on different nights will get you a feel for how good the seeing is and how many frames to stack and how hard to push the processing.

As for judging how seeing might be. I now have three tools that I look at 1) clear sky chart - find your location and it gives an estimate on how things are forecast. 2) this map plot - magenta to dark blue good....anything else, not so good :). 3) meteoblue - I saw someone post something about meteoblue a week or so ago and I'm going to see just how well they predict things.

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#10 bunyon

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Posted 18 January 2013 - 04:33 PM

Yeah, just in case I wasn't clear, if you don't have good seeing, it doesn't really matter what else you do. My thinking was, especially as you're learning, is to use bad seeing nice to play with things and then use the settings that give you the best of a bad bunch.

But, once you image in good seeing, you'll be amazed at how crucial that is.

#11 harbinjer

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Posted 18 January 2013 - 05:19 PM

Thanks zAmbonii, and also thank you for the data Paul! I wasn't able to get what you did, but it was much better than the fuzzy beginning.

It is a bit disappointing to know that the seeing is my biggest problem, because I definitely can't fix that, but I will wait for it to improve. As they say, "garbage in, garbage out".

Thanks for the links. I know about the clear sky clock. The unisys link is interesting. Is there more to meteoblue than meets the eye? It looks like a (detailed) forecast, but nothing about astronomical seeing.

How many 1-3 minute videos are worth shooting? 5? 10? Seeing can, of course change for the better or worse, but what do you find worthwhile?

I definitely understand what you mean Paul. Given my time constraints, I will practice a bit, but not so much until the seeing improves, at least a little.

#12 zAmbonii

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Posted 18 January 2013 - 07:35 PM

I personally like to take a series of videos and then process each of them and put them together into an animation. It all depends on how much time you want to spend outside capturing and inside processing :). If the seeing isn't that good, you could wait a bit and see if it may improve or if the forecast isn't good, decide to try another day.

Because Jupiter rotates pretty rapidly, you get a different view all the time. Mars doesn't rotate as rapidly so it isn't as important to get that many videos. Saturn because the clouds are kinda boring, one good capture and I might pack it in for the night, because it doesn't change much :).

I think on the the meteoblue site, the most important value is the "Seeing arcSeconds" value. With the lower the better. I haven't been out imaging since I discovered the site so I can't really compare imaging results to what they forecast.

For someone who is just getting into imaging, I'm not sure if it is even worth it to go out when CSC is only forcasting 1 or 2 out of 5 seeing. But I wouldn't want to rely on just CSC because up here in the MW, if the jet stream strays one way or another, it can lead to a big change in the actual seeing. I'll see what CSC says, and if I go to the Unisys site and see we're at the edge of bad seeing...it could be a good night.

#13 Chris_H

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Posted 18 January 2013 - 08:40 PM

Never rely on forecast sites. Meteoblue says its clear at the moment but its actually snowing outside! :lol: I've actually had some of my best seeing when Meteoblue and similar sites have said it was going to be horrible and not worth imaging. So if it's clear, always go out and look in the telescope ;)

#14 harbinjer

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Posted 18 January 2013 - 08:56 PM

Interesting seeing that Seeing arcseconds forecast. What is good seeing? It says 0.8 for my location tonight. CSC labels it "poor seeing".

I have seen the csc say clear when it's actually overcast, and vice versa. Accuweather also has an astronomy option, that is about as good as CSC I think i.e. gets it very wrong sometimes.

#15 zAmbonii

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Posted 19 January 2013 - 12:40 PM

I went out last night mainly because it was clear. I really didn't expect much because we had a lot of wind whipping around. CSC said 1/5, and that is what I got. I captured a couple of videos and there really wasn't anything much worth posting. At the bottom of the page was one of the "best" I got last night.

The bad seeing wasn't surprising because surface winds were coming from the SW, and the higher level winds were coming maybe from the WNW (and clouds moving with them). Where those two levels of winds meet there is going to be some turbulence leading to bad seeing.

Although meteoblue said 1.8 arsec of seeing, so I guess 1.8 really isn't good :). Their seeing indexes 1 & 2 were only showing 1/5, so i guess they were right on that :). On a good night of imaging, I am going to have to compare what they said to what the results I got to try and figure out their forecast better. Conditions up here have been so crummy, I have been itching to get out and do *something*, but tonight wasn't a good night for it.

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#16 AlanL

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Posted 19 January 2013 - 02:08 PM

Just a quick comment on focusing masks. I am able to use my Bahnitov with Jupiter's moons, esp. Io, with reasonable success. It's not perfect and in good seeing or with a larger scope one could probably do better visually. The Bahnitov is fairly immune to seeing.

#17 harbinjer

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Posted 19 January 2013 - 06:03 PM

I went out last night too. Meteo said .8 arcsec seeing. I'm not sure that it was, but it was definitely better than a few days ago. Here is my next result. This time I tried AS!2 with registax.

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