Skywatcher P130mm 650 focal and cassini division of saturn....anyone been able to observe it?

Question

Just curious if anyone out there owning the above scope has been able to resolve the cassini division to any success. I have been trying it but no success.

I have tried to use a 2X barlow with my 10mm and 25mm eye pieces but as theory dictates correctly with increasing manification through a barlow the image gets darkened and blurry.

I know apeture increase it the only practical way to increase possible seeing resolution but cannot fail to wonder if anyone out there has been able to see the division with skywatchers 130mm 650 focal. Perhaps due to atmospheric seeing or other factors I might be missin the ablity to resolve it.....

thanks

Answer 1

You should have enough aperture and magnification to see the Cassini division, but there are other factors to consider.

You are already aware that atmospheric seeing can have s big effect. One way to judge seeing is to look at a star at high power. If the star image and the diffraction pattern around it are steady, seeing is excellent. If the star is constantly breaking up and jumping around, seeing is poor. Use a star in the same part of the sky as Saturn, as seeing will be better higher in the sky and worse lower.

If you observe carefully, you can sometimes catch moments of good seeing when everything suddenly gets sharp. To take advantage of these moments, you need to be well-focussed. Focus is another potential problem, You must be precisely focussed to see the Cassini division, and in a short focal ratio scope like yours, this takes a very light touch.

Two other equipment issues could affect your results. One is cooldown. When you take a warm telescope into a cold night, heat coming off the mirror will ruin your view, sometimes for hours. If possible, put the scope outside to cool a couple of hours before observing, or store it in an unheated (but dry) area. There is also collimation. A reflector telescope needs to be aligned to function properly. Be sure to check your collimation. If you don't know how, learn.

You will also find that your ability to see details will improve with experience. The Cassini division is fairly subtle in a small scope, so learn to look carefully, and to recognize proper focus.

Answer 2

Yep, the problem is most likely poor seeing.
With a 130mm scope and decent eyepieces, it's resolvable...but you'll need good seing to be able to nail it.

You'll have much better luck with a shorter focal length eyepiece (preferably a wide-field one, at 4mm or 5mm the eyelenses on plossls are awfully tiny and hard to see through), than you will with your 10mm and a 2X barlow.
Be sure you get away from houses (which warm up during the day and give up their heat at night, ruining the seeing), parking lots, etc. Light pollution won't matter too much with Saturn, but the darker it is the better contrast you'll have and that *can* make low-constrast features pop out more. And finally, you may want to try a light orange or green filter if you have one -- these will increase constrast in certain color ranges as well.

I've seen it in my 90mm scope (Takahashi Sky90) with a 4mm eyepiece, you should be able to nail it with your scope. Of course, in the 8", 10", and 12.5" reflectors it's easy...:)

Good luck.

Answer 3

Try waiting until Saturn is higher in the sky. Your 10mm with barlow is 130x, that should be enough magnification. It will be dim with only 130mm of aperature, but in good seeing it should be possible.

Answer 4

The inclination of the rings (the angle we see them at) is pretty low. That makes it difficult. It will keep getting worse until 2009, then it will get better. Maximum inclination will be in 2015.

Of course by then you'll have a better telescope. :-)