Saturn

It's the pest here again folks. Just come in after seeing Saturn for the first time. I must say, every time I observe something, it just gob-smacks me. However, being a real glutton, I want more! I'm viewing through a 26mm Super Plossel, now I believe the smaller the number, the greater the magnification, so can I put another eyepiece on and make Saturn bigger and therefore see more details? Not that I have another, not sure what they cost, I spent every penny I had on the LX90. If so, what would be the biggest mag to use? Also, I'm not terribly sure, but would I be seeing three moons? just tiny, tiny specks nearby, or would I be seeing very distant/faint stars?
Regards,
Bill H.

Hi Bill,
So you have seen Saturn for the first time. That is something they say one never forgets. It is just such an amazing sight, no matter what observing equipment you have. It's rings are angled almost at maximum to us at the moment, making it a wonderful sight. As to magnification: yes, the higher the number the greater the magnification, with a 4mm being about the highest usualy available, and 50mm at the other end. Now high magnification isn't always a good thing. No telescope will give a really useful magnification of more than about 50x per inch of aperture, and even then only on a good night. It is advisable to keep magnification as low as possible, as soon as the image begins to get a bit 'fuzzy' drop back to the previous magnification. You will actually see more detail of a planet at a good, clear, sharp low magnification than by using a slightly blurred high one. At high power most planets turn into fuzzy blobs of light, unless the night is perfect, and that doesn't happen very often. If you are going to get higher powers, get good quality ones. They are worth it. As to Moons, you will see Saturn's largest moon, Titan, quite clearly as a star-like object of about mag. 8.5. It is quite obvious, even in a small telescope.

All the best,

Denton P. Walter

Astronomy & Space Magazine

[Beaten to the draw by milliseconds]

Those in the know (Patrick Moore et al) say that the maximum useful power is X50 per inch of aperture of mirror or lens (depending on if you have a reflector or refractor).

I have a 10" reflector so the maximum magnification I could use without deterioration of image would be 10"X50 or 500X magnification.

To determine what the magnification is you divide the focal length of the scope by the focal length of the lens.

I have an LXD75 10" SNT with a focal length of 1016mm.

I currently have (until my New Year's resolution wears off) lenses in the following focal lengths.

26mm giving a magnification of 1016/26 = 39X
8mm giving a magnification of 1016/8 = 127X
3.6mm giving a magnification of 1016/3.6 = 282X

A 2X Barlow will bring the 3.6mm up to 564X which should still be ok-ish though I can't think of anything I would want to see through it.

I have used the 3.6mm lens on Saturn and saw the Casini division in the rings but these days I am quite lazy and prefer photography. I just use a lens to find objects and then let the camera take over.

Your scope or manual will have the focal length of the tube.

Many thanks folks. Is there a particularly good brand of eyepiece I should look out for and save up for?
And yes Denton, I don't think I will ever forget that first view! I just pressed goto and I couldn't believe my eyes when it came into the lens, funny thing was, when aligning the scope - with thoughts of viewing Orions nebula again - my scope used a nearby star to saturn for algning, and I didn't even realise that that was Saturn nearby, with the naked eye I just thought I was seeing another star.
I never had so much fun staying out of bed
Bill H.

Hi,

I find that things start to loose detail once I go over 300x with my 10"SN. To go beyond that with these scopes you really need to have the collimation spot on.

With the LXD55 mount, perhaps the LXD75 is stonger, I have to use the electric focuser over 300x as touching the focuser shakes the scope too much.

As for saturns moons, they are visible but faint (mag 9-10) apart from Titan (mag 8 ish). I've caught them in a webcam images before in a 4" Mak fairlyeasily. Starry night et. al. will show you the positions, though you may find it more interesting to sketch the positions of the 'stars' near Saturn, then a couple of hours later sketch them again and see if any have moved. Sketch 5' or 10' area around Saturn though as Titan can be quite far away.

My first view of the rings came from a 3" reflector scope that I had borrowed from my scout troop, with a primary mirror that someone had 'washed clean'. It was mounted on a thin metal garden table. The view wasnt great, but the patience paid off, and I'll never forget the first glimpse of the ring.

Cheers,
~Al

Many thanks folks. Is there a particularly good brand of eyepiece I should look out for and save up for?

Hi Bill.

There are eyepieces out there that can often cost more than your main scope. For example the Televue 'Nagler' range give a super wide angle field of view but some of these eyepieces can be very expensive. For the modest amateur a range of decent quality plossl eyepieces is invaluable. For most scopes I would suggest something like;

25 or 26mm Plossl
15mm Plossl
6mm Plossl

Have a look around you can find some sets which contain all the most useful focal lenghts and perhaps a barlow lens to effecively double each eyepieces magnification. I own a celesctron set which contains about 6 eyepieces all of the common colour filters (for increasing planetary contrast) a moon filter and a 2x Barlow lens.

If you want to save up I suggest to strongly look at the Tele-Vue range. Their panoptic range is extraordinary as are the naglers.

Regards,

Dave.