First Planet Shot

[Freff]

I mounted my Canon 5D2 and 1.4x converter to the back of my Mak 127 and took a photo of Jupiter a few nights ago. It was a rush shot, I really had no time to set things up properly or to experiment. It's a single image blown up and cropped. Any hints, tips or comments would be appreciated, thanks.

Tony

[msinclairinork]

Hi Tony, Well done their! looks like you've got the beginings of a great shot.

I'm no expert. But i think your problem lies in the fact that it is just a single shot, menaing theirs not that much data their to play with when you crop it etc. So next time try taking as many shots as you can and stack them togeather using registaxs (free app) or somthing, and i think you should have a much sharper image.

You do have to consider the rapid rotation of Jupiter though.

so...more images= more data and i believe this is the main reason most people will prefer to use a webcam or similer as they can then break down the...say 10 minuite video into hundreds if not thousands of individual images and then go on to stacking and processing.

But like i said im no expert i just read alot on this forum! lol

So im sure somone will corect me if im wrong.

Good luck and keep at it!

Michael

[Freff]

Thanks for the info Michael. The skies are clear tonight so I may go out and try taking more shots and try stacking.

Tony

[msinclairinork]

Good luck! keep us posted!

[mark7331]

Hi Tony, looks like you've got the start of a good shot there.

I agree with Michael that you need more data and I've played with the levels a bit just to show what data is already in there (though I'm not great at this). The more images you stack up the more detail will appear.

Nice first shot.

Mark

[Freff]

Thanks Mark. I never did get to do any processing on the image, it came straight from the camera. I thought it to poor an image to do anything with it.

I have just played with it briefly and this is the best I can do.

Tried again last night and didn't get a single image. All were over exposed or out of focus. Don't know what went wrong, the sky was clear all night. Perhaps I did something different. I'll try and figure it tonight.

Tony

[mark7331]

Tony how are you getting to focus? Is it purely visual or do you use a mask / camera feature etc?

I struggle for a whille by way over exposing - Jupiter appeared as a white blob or looked like a star if I got it really wrong. I ended up having exposures of around 1/30-1/60 of a second so it's worth while playing. When you save an image record the exposure time in the file name - it'll help when you're working out what happened later on.

It's also sensible to try and tackle one problem at a time even if it means you don't make any useful images you've at least mastered focus then exposure then tracking etc.

Hope this helps & keep posting on your progress.

Mark

[Freff]

Hi Mark

Focus is through live view on my 5D2, adjusted on the scope. So at present visual. I have nearly finished making a mask which I'll try next.

All the Exif data is intact so I have a record to analyse later.

I'm trying to find the best combination to attach my camera. I tried initially with the 1.4x converter, (reduces vignetting) next I'll try it without it. There is also a webcam option I can try. So yes I'll try to resolve the camera focus issues first.

This is why I haven't made any efforts yet with post processing.

Tony

[mark7331]

Hi Tony,

Just a suggestion (if you haven't considered this already): I made a Hartmann mask. It's less complex than a Bathinov (is that how you spell it?) mask but I've found it really easy to use and gives very clear results. The first one I made was out of a bit of card and it worked really well.

Anyway - it's easy to make and if you want I'll post a diagram of the mask I made. All you need is card, a compass and a sharp knife.

As far as how to attach your camera to the scope I'm not the guy (CCD's for me) but if you post a question in equipment help you'll get some of the big guns to help! And they do know what they're talking about. They're the friendliest bunch too.

Very poor skies here tonight so I will be staying indoors and going to bed early as I've been moving my son's stuff into his university digs today and I'm done in!

Clear skies my friend

Mark

[Freff]

Thanks Mark a diagram would be helpful.

I don't have a problem mounting my camera, i'm just experimenting with different adapters, converters etc to get the best focusing system. My images haven't been very encouraging so far.

Tony

[mark7331]

Hi Tony,

Here's the Hartmann mask that I use. You'll have to scale to your scopes dimensions. Just in case you'd like some guidance on making the mask this is what I do:-

1. Measure the diameter of the telescope tube and on the card draw circle A keeping the centre point marked clearly.
   
2. Draw another circle, this time the diameter of the aperture of your scope. This is circle B.
   
3. With the compass still set to the radius of the aperture make a mark right at the top of circle B then put the compass point on it and with the pencil end make a mark on circle B, move the point to the new mark and repeat making a third mark. I've labelled these as C.
   
4. Draw lines from the centre point to these C marks.
   
5. Now you need to measure the secondary mirror obstruction as Circles E must fit in the clear part of the aperture.
   
6. Once you know the size of the obstruction, you'll know the size of the unobstructed part. My SCT is 150mm – so it's radius is 75mm, with an obstruction radius of 28mm and clear aperture of 47mm. This means Circle D for me would be (47 / 2 + 28 = ) roughly 51mm. Circles E need to fit into 47mm so their radius would be 22mm because it's easier to measure with my ruler and compass.
   
7. Draw circles D then E where D meets the lines going out to points C.
   
8. The draw lines F and you have two sides of each triangle. Complete the triangle by joining the lines up and all you have to do now is cut out the triangles.
   

Try it with card and if you like it make one out of wood. When out of focus you'll see multiple images and as you focus they move together until you have one sharp point with diffraction spikes (six of them) point outward.

Reply or PM me if you need any help. Best of luck

Mark

[Freff]

Many thanks Mark, I'll give it a go on the weekend. I have a CNC machine so if sucessfull I can make one in acrylic etc.

Tony