Astronomy and Astrophotography

[steve]

This is all very interesting stuff. The bad news from this part of the world is that Mrs L's EOS 300D broke a few days ago. The better news is that I've bought her a 600D to replace it . Once she gets the hang of it we'll see if we can have a go with attaching it to the telescope.

[Gina]

I was out late morning today with telescope and camera. Rather windy but using a high ISO and short exposure the results weren't as bad as I expected. Some adjustment of brightness and contrast for this example. Several sunspots and flares are visible.

sun-sml.JPG

I should point out that the flares are not outside the disc but slightly lighter patches, mostly near the sunspots.

Celestron Astromaster 130 EQ HD with x2 Barlow plus Baader AstroSafety Film solar filter on front of scope
Sony A200 DSLR at prime focus with T-ring and T-adapter in Barlow.
Date Taken: 2011:04:09 11:38:39 - Exposure Time: 1/640 sec. - ISO Speed Rating: 800

[mcrossley]

That's a great first image Gina. I have tweaked it a little to make the colour a little more 'eye friendly' and applied a very mild sharpen. I see the dust bunnies are making their appearance as little doughnuts. Some nice little sun spots and faculae you have captured there.

[Gina]

Thank you Mark Yes, that looks better. I gave the CCD a good blow off with my dust puffer before I started but still the dust bunnies appear At least you can tell then from sunspots due to their doughnut shape. I guess if I were to take several images (not precisely lined up) and used Registax on them, the dust bunnies should fade away.

So much to do - so little time!!

[Gina]

Took 200+ shots of the moon last night. The high level cloud we had earlier had gone And this morning I've taken 200+ shots of the sun in an area where there are several sunspots. The image is too big to get the whole disc in the frame. The idea is to feed them into Registax later.

After I've finished this mug of coffee I'm going to set up my MS Lifecam HD image sensor and see if I can get the sunspots with that. I think I might have difficulty keeping the image lined up. Really need my new motor drive. The supplied one if just hopeless, as I said. I keep trying, but when the knurled screw is in behind the coupling it's virtually impossible. You absolutely need the slowmo manual drive to align the image initially.

[Gina]

No joy with the webcam sensor Two or three things to sort out. For a start, even with the sun's image covering the sensor, the auto sensitivity control can't cope - the image is vastly overexposed. So I'll want a neutral density filter in addition to the mirror film at the scope front. A working motor drive is essential to keep the image on the sensor. The sun's disc moves right across the sensor in a few seconds. I took single frame sequences as the image moved past and also movie but examining with GIMP showed that the detail in the middle was totally non-existent because the image sensor was overloaded. The only thing showing was dust bunnies. And that's the third thing that needs sorting out. I think I need a clean room, extract the dust and then seal the sensor behind a UV filter.

If I want to capture the full disc (of either sun or moon) I'll need a shorter focal length. May try a telephoto lens with the webcam sensor. I've got enough astrosolar safety film to make a filter.

[Gina]

Captured 200+ images of the sun this morning ready to feed through Registax. Here is a section of one exposure with brightness/contrast altered to bring out the sunspots. I'll post the stacked image when I have it. Taken with Sony A200 DSLR at prime focus with x2 Barlow.

sunspots.JPG

[Gina]

Moon images taken with Sony A200 DSLR - cropped slightly and scaled down by 4x :-







I'll sort out some sun pics to upload and link to later.

[Gina]

More sunspots today :-

[mcrossley]

Blimey, Gina did you see one chap on SGL had done a 98 pane web cam mosaic of the Moon - that is dedication!
http://img857.imageshack.us/f/104201198panes.jpg/
Click on the image to zoom it

[Gina]

Quite incredible Mark, I agree!!

I've got Registax installed on my XP machine but not tried it yet - had to allocate more HD space to XP. Might remove Linux from it altogether and let XP have the lot - might need plenty of space for image files and working space.

I read in a spec for a different 2x Barlow that if you unscrewed the lens cell and screwed it direct onto the T-adapter it gave 1.5x. So I tried it with the Celestron Barlow and reduced the magnification enough to get last night's moon all in the frame. It wouldn't fit with the normal x2 Barlow. Then I thought I'd try the camera body hand held in front of the focusser. A shorter T-adapter - without the shoulder of the Celestron - would work without Barlow. I found such an item on eBay and have ordered it. I'm hoping I can get the whole sun or moon disc in the frame.

I have also been trying to capture Saturn on CCD. I have some tiny fuzzy images showing globe plus rings. Focussing is very difficult and the image wriggles across the frame in a couple of seconds. Any thoughts of imaging Saturn need to wait until I have a decent motor drive and the EQ mount accurately aligned onto Polaris. So I've been working on that today.

I'm also thinking I need to build myself a little hut to protect myself and telescope from the wind.

[Gina]

Took some images of Saturn with my DSLR. Needless to say, it's very small. I can't use any more magnification because the image moves too fast. This is at 1:1 raw image to post image. Full frame is 10Mpx. No image processing - this is exactly as taken.

Saturn.JPG

[mcrossley]

For high magnification planetary imaging the web cam (or equivalent) is king, take 100's or 1000's of images, only pick the best ones least affected by seeing and mount drive errors and then combine these to reduce the noise. This is where Registax is almost mandatory.

[Gina]

Some more but I can't see a lot of difference. I took several dozen and will feed them into Registax later.

Saturn2.JPG

Saturn3.JPG

Saturn4.JPG

Saturn5.JPG

[Gina]

For high magnification planetary imaging the web cam (or equivalent) is king, take 100's or 1000's of images, only pick the best ones least affected by seeing and mount drive errors and then combine these to reduce the noise. This is where Registax is almost mandatory.

Yes I will be using my MS LifeCam HD Cinema image sensor next time. I tried the other night after taking the shots with my camera but in spite of carefully lining up the image just off centre to allow for the earth's rotation it was nowhere to be seen. I had the USB cable fed outside through an open window and the monitor indoors facing the window so I could see the image from the scope position. I was using Yawcam preview.

Once I get my motor drive working and we get a clear night I shall have another go. I may also try my 0.001 lux monochrome CCTV image sensor. That's a bit bigger sensor (1/3") but of much lower resolution being a CCTV device.