Barlow making the difference?

I was looking at Michael Scully's photo of Jupiter ( www.irishastronomy.org/boards/viewtopic.php?t=1874 ) and his scope is only 1 inch bigger than mine yet I can't see anything close to the detail of that pic. I've a 200mm NR and looking at it through a 10mm eyepiece I can make out the two brown lines but nowhere near enough detail to see the GRS. Would using a Barlow make the difference or is there something else that'll improve definition?[/url]

Steve,

Remember the images by Michael et-al are taken from webcams and stacked using registax to bring out the finest detail. You cannot expect to visually see the kind of detail that is evident in these images. Only by using webcams and software in this way are these images possible. Even in Michaels scope while he was taking the images, he would have been very lucky to see the GRS.

You will see the GRS in an 8inch NR, I know I have, but the 'seeing' conditions must be just right. ONly when the seeing conditions are good will extra magnification, (such as a barlow) bring out extra detail. On poor nights a barlow will make things worse.

The GRS can be seen in scopes much smaller than an 8" but as Dave says, the atmospheric conditions must be reasonably good. I know I could see it really clear in a 4.5" scope early one morning, but the conditioons were superb at the time. In an 8" though, it's a bit easier.
What I use my 8" LX90, I find that If I keep the magnification reasonably low it's easier to see. About 100x should be plenty to see the GRS clearly. Also, make sure your scope is collimated. Make sure you are looking at the coreect time to see the GRS, It's only visible on certain nights due to the fast rotation of Jupiter.

Steve,
Keep in mind that you need to let the scope cool down for an hour or so outside before you use it.
If you dont let it cool down, the image will be terrible due to turbulance in the tube.

I think that everyone above have answered your question Marcos. That night, when looking visually at Jupiter I could just make out that the Great red spot was there.

To the eye that night it was only seen as a dent in one of the cloud bands. Other nights, when the conditions were better, more detail was visible. see a previous topic on sketching www.irishastronomy.org/boards/viewtopic.php?t=703 but again be warned that to see all the detail takes alot of time at the eyepiece.

Also to agree with Dave Lillis, the cooling down of the telescope is critical. The moons of Jupiter should be steady points of light. Some nights they never change from a dancing, irregular spread of light

Finally, I was amazed at the detail that Registax can get from images taken on a night of poor seeing. Below is one frame from the AVI. It reflects the amount of detail that was to be seen visually fairly well although the image in the eyepiece was much brighter.


Michael Scully. KAC/SAC