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CKemu

Photographing the Planets

12 posts in this topic

Whilst I am only a year in to this wonderful hobby, I've managed to learn enough to feel confident with my equipment and have some reasonable success with the Moon, M51, 42, 27 and 13.

Planets on the other hand...pah!

I can get pin sharp focus on stars and DSO's, yet a shot of Jupiter would merely reveal an orange blob, Saturn would be a glorious blob with a blob around it...yet my focusing mask suggests that I have good focus.

Now it seems that most people would at this point interrupt me and go "webcam" - but currently with bills, a lack of hours at work and other commitments, means buying additional gear for my projects is somewhat out of the question.

So I ask the following:

  • Why does the target look so out of focus, my mask and star photographs suggest that I am in perfect focus?
  • A webcam takes thousands of frames, surely an SLR that can handle 8 fps would produce enough frames to get a good shot and at higher resolution?
  • Is there a technique that will let me take good photos (after a stacking process) of our local sol neighborhood?

Basic equipment list is in my signature.

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I will be interested in ideas on correct focusing for planets.

It's a huge problem I have.

DSO's / Stars - used my bathinov mask, but planets, I just can't get .......

Cost of a web cam is really low (compaired to some of the other bits, we need). There are recent threads on a cam in Asda for under £3 !!

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To get a good focus I use my mask to focus on a very near by star and then move across to the planet. I find that I am in perfect focus with my scope/barlow/cam setup. Others say that they do not get the correct focus on the planet this way. That's not what I find though. Would be interested to hear the science on why focus on a distant star is not the same as on a distant planet.

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problem lays with how you focus.

most of us are fairly poor so we own cameras without a live view. with live view you can instantly zoom in and check focus.

without live view we have to strain our eyes to see into the viewfinder, thats a little tiny view we have to see. some will buy a viewfinder extender cup, this adds a couple of mags higher.

i run a 350D canon, no live view. so to get around having no live view i run some test shots, i pick a planet, then snap a shot, zoom into the picture and check focus. i keep doing this until i get best i can. then i take 3 more shots each one has a slight adjustment in shutter speed. this allows me to check exposure.

once i have the camera focused thats it. i do not touch it in any way. i fire the shutter via a wired trigger. this keeps wobble to a minimum. if possible i also lock the mirror up, this to stops wobble and a blurred picture.

the hard part is knowing if a shot was affected by telescope/camera wobble or optical focus issues.

so for advice, keep plugging at it You WILL nail the focus get a perfect exposure and a good set of subs. just takes a little time to nail things down

your problem sounds to me as an exposure bug. could you let us know what ISO and shutter speed you are running ? planets are bright and tend to need a little faster shutter speed than DSO and star fields.

try an iso around 200/400 and speed up that shutter a little, see how that plays out. for the moon i would tend to shoot at around 1/500-2000 a planet maybe around 1/100-1000

Edited by Mr TamiyaCowboy

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My confusion lays in the fact that the focus is spot on because any adjustment to the focuser will take the planet utterly out of focus - yet the planet still appears fuzzy.

I have attached a photo of my Saturn attempt from awhile back, surely something like registax, even with thousands upon thousands of frames couldn't fix this?

attachment.php?attachmentid=85790&stc=1&d=1335344827

Now I have had some nights where detail on the surface was present, but the Cassini division, and the cloud structures never really show up.

post-22545-13387776753_thumb.jpg

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Your really have to focus on a star if you are not doing so already. Focusing masks simply will not work on planets.

My cameras does have live view but this is not good enough. To get perfect focus, I always take test exposures and run them through bahtinovgrabber.

PS:Note that the atmospheric seeing will make planets look a bit out of focus, but not as fuzzy as you are seeing there CKEmu with an 8" scope I wouldn't have thought.

Edited by Shibby

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Focus is probably off, but I have a few other comments...

In your sample photo it appears that the Red and Blue are not aligned. Registax can fix Red/Blue alignment but it appears you have a bad case. I'm not an expert on astrophotography but in my experience the Red/Blue problem is *much* worse when the planet is low in the sky. The problem is greatly diminished if you shoot planets straight up. With the inner planets you just have to deal with poor conditions.

If you're trying to capture images when a planet is low then results will be poor due to the atmosphere/seeing. Too much air in the way.

You might want to check the Seeing conditions too before wasting a night's effort. I use cleardarksky.com as my reference and I try to image planets when Seeing is average or better.

To help with focusing I use a motorized attachment: AccuFocus from Orion. With the motor there is much less shake of the OTA. I use liveview to watch the image and I move the focus back and forth until I find the best focus. On a good night I can clearly see the Cassini division in liveview with a 8" newt.

Doug

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Hi

I started taking images this year (what we've had of it) and as already said I think the trick is to use a Bahtinov mask on a nearby star first in stills mode (using the x12 manual focus feature) - I'm using a panny GH2 so not strictly a dslr as it is mirrorless

Then I move to the planet e.g. Saturn and shoot in manual video mode, this was at 640x480. I usually shoot in 3 min segments

Then just stack in your favourite stacking program

This is one I did in mid April, not perfect but shows you can do something with a 'dslr'. This was a C11 with no barlow just camera attached at prime focus

I tried 2 different modes for video - mpeg and avchd, I think avchd gives the best quality but I haven't had a chance to try again for about 3 weeks

PS - no idea why attached image of saturn isn't showing up?

post-22594-133877771593_thumb.jpg

saturnBest2p.tif

Edited by billhinge

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Hi

PS - no idea why attached image of saturn isn't showing up?

It's because it's a .tif Bill - try posting a jpeg and it should be displayed.

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Thanks Simon

Here they are, don't claim they are anything special but they show you can use a micro four thirds camera

post-22594-133877771937_thumb.jpg

post-22594-133877771938_thumb.jpg

Edited by billhinge

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Nice pictures.

I have read on here that the Cassini division is father out than you realise and I can see from your pictures why I am missing it when I look through my scope. With the mag of my 102mm scope it will only be obvious on the outer extremes of the rings, and only with perfect seeing.

Bryan

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That's a good shot. I managed to get Saturn last night for the first time - just on my DSLR, Strangley the iso that was 500 worked far better than going higher. I tried a few.

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