check out saturn as of 6/4/2010, 9 30 pm

[tungkian]

the sky is very clear and air is very stable. can use 500x on saturn b4 the image starts to break down. btw, the 4 most easily visible moons are all on one side of saturn now. do check it out.

[timatworksg]

yep! just did bro! it is clear with stars shining at pasir ris! Saturn is clear and it's moons too! Took the chance to fool wit the Meade DSI as well after finally getting it to run on Windows7 via VMPlayer. Also did some PHD guiding with the IOptron Goto! All in all an eventful nite. Darn.,...I have work tomorrow!! sigh!

[Bergkamp_]

ya.. saw the starry night.. but the clouds kicked in...

[tungkian]

nahh...jus whip out the scope n leave it there...when the cloud moves over then quickly peek!

[Bergkamp_]

=P try again today.. its pretty clear blue skies... tungkian.. the mini mount tracking is pretty gd..

[Canopus Lim]

Yes the seeing was good. I could actually see 6 moons with my scope. 400x was very sharp. However, I think last Thursday was better than last night.

[Canopus Lim]

the sky is very clear and air is very stable. can use 500x on saturn b4 the image starts to break down. btw, the 4 most easily visible moons are all on one side of saturn now. do check it out.

Just curious though, what do you mean by the image 'break down'? I just wonder why a lot of people use such a term when there is no such optical term that exists. As you go higher magnification, the sharpness will reduce as the planet is magnified more. It is like 'zooming' onto a digital photo and seeing it more 'pixelated'. Each pixel being the seeing 'cell'.

Furthermore, the contrast reduces because as you go higher magnification the brightness reduces and the eye is not able to discern low contrast details as well. For example it becomes harder to see the banding on the globe. If you go too high the magnification, you will notice that the subtle shadings on the globe will disappear and the globe of Saturn will look 'uniform'.

[tungkian]

it's like it becomes more blur..haha...lingo i picked up reading the astro websites..but yes, it's what you say, brightness is reduced and contrast becomes crap

[Canopus Lim]

Ha, the thing is when is it considered 'more blur'. Probably this connotation may come from people who think that going higher in magnification is like car performance. 1000x magnification as if like the car has 'max speed of 300km/h' or something like that.

For me, in Singapore context when my eyes cannot get fully dark adapted, the ideal exit pupil (eyepiece focal length/ F number) is between 0.7 to 1mm. I find that in this range, it give the best balance of magnification and contrast. Going below 0.7mm, IMO does not translate to better viewing and usually or if not most of the time, very low contrast subtle shadings on the planets will disappear. In fact 1mm exit pupil (25x/inch) already provides >95% of the details visible on the planet. The only time I ever saw more details going below 1mm exit pupil was when I was seeing the Keeler's Gap (some say Enckle division) on Saturn at 400+ magnification.