Saturn May 22

[lcd1080]

I imaged Saturn with a Canon T2i DSLR camera and 2x barlow on an 8 inch SCT at 12:39 AM (Eastern USA time zone) on May 22. The camera has a sensor that includes 5184 columns and 3456 rows of pixels. By choosing the camera's zoom function one can select any 640 x 480 block of those pixels which is what I did to capture the video file for this image. The 2x barlow has special threads that mate with the T-ring of the camera.



(http://i983.photobucket.com/albums/ae312/Peter177/SaturnwithCassiniDivisionimagedwith DSLRand2xbarlow.jpg)

[renormalised]

Nice shot, Peter:)

What was the seeing like the night you took the piccie??

[Clayton]

Not a bad shot Peter. :thumbsup:
I hope you don't mind me taking the liberty of running your pic through RGB align in Registax to reduce the colour fringing.

[lcd1080]

Thank you! The seeing was good; this was the first clear night over the past 10 nights during which time the clouds were thick and persistent. The last time I had an opportunity to image Saturn was May 12 when the jet stream was moving directly over head at 120 miles per hour (192 km/hr). That was not a pretty picture! Not knowing when another opportunity would come along I did the best job I could on this shot from May 22.

[lcd1080]

Thanks Clayton! Sure that's fine I'd be interested to see how you're able to further process the image, I've only been doing astrophotography for less than a year now so I'm still learning the finer points of Registax.

[Clayton]

Happy to help where I can Peter, though there are others here with much more experience than me. How do you find focusing with the DSLR, and do you have manual or motorfocus. I only ask because I thought the image a little soft for a night of good seeing? And I have difficulty focusing DSLR's. But it could be any one of many things.
The misalignment of RGB suggests a low elevation ? Ah! I see that from Baltimore Saturn had only about 20 degrees elevation, is that right?? If so that would explain a lot, and in that case a pretty good job.
Collimation and Tube currents can also affect your image.

[lcd1080]

I thought that I could have done a better job of focusing. I just started using a JMI EV3CM Event Horizon electric Crayford focuser and thought that would be the answer to my focusing problem but I'm not sure that I'm using it correctly. When I pushed the button on the hand control switch to advance the Crayford tube the image of Saturn split in two. I ended up rotating the focuser knob on my SCT which is a very imprecise way of focusing plus it introduces problems related to mirror flop of the primary mirror. I'm thinking of buying the JMI's "Smart Focus" but I'm not sure if it's worth doing: http://www.jimsmobile.com/buy_motor_controls.htm#Smart Focus
Another mistake I made is that I should have focused on a star or one of Saturn's moons rather than Saturn itself. I'll try that next time. Finally I'm thinking of buying a program called ImagesPlus DSLR Camera Controlf to automatically control focus but I have to play with the program demo to see if it would help. http://www.mlunsold.com/ILCameraControl.html

I do my imaging from my condo balcony which means that I can only see celestial objects when they fall below 40 degrees altitude. Above that the ceiling of my balcony blocks my telescope from seeing anything but the balcony ceiling.

I do have a question; do you think that it would be worth upgrading from my 8 inch SCT to an 11 inch SCT? I was thinking that if I could capture more light with a larger aperture that I could reduce the DSLR exposure time and "freeze" the atmosphere to better reduce the distortion. Do you think it would make a significant difference?

Thanks Clayton I've been to a lot of AP forums but this is by far the most helpful one and your input here goes a long way to explaining why that is true.

Peter

[renormalised]

Peter, want to take great happy snaps of the planets?? Grab yourself one of these....

http://www.flea3.com/

Far superior to anything you get out of DSLR and a hell of a lot lighter on your scope:)

[lcd1080]

I am familiar with the Flea3 however I want to see how the recently announced Imaging Source (TIS) webcam competes against it. The TIS camera will have the Sony TIS ICX618 chip; the question is will the TIS webcam's image quality surpass that of the Flea3 in terms of lower noise and higher gain? Also will it eliminate ghosting at 60 fps?

http://www.astronomycamerasblog.com/2010/12/01/the-imaging-source-astronomy-camera-with-sony-icx618/

Saturn hunting season is almost gone and Jupiter won't be here until the end of the summer so in the meantime I'd like to do more experimentation with the T2i that I have. A DSLR does have one advantage over astronomy webcams like the Flea3, namely that the sensor is physically larger which means that if a planet like Saturn ever moves off the chip due to imprecise tracking or other factors it's a simple matter to de-select the camera's zoom function thereby widening the field of view by 700%. Saturn then becomes viewable on the laptop screen outside the normal webcam field of view and can easily be re-centered without having to use a flip mirror or (heaven forbid) having to re-insert the eyepiece.

Peter

[Troy]

good picture :thumbsup: