Jump to content

SATURN! I'VE FINALLY SEEN SATURN!

WiKi_KiKi

Recommended Posts

WiKi_KiKi

WiKi_KiKi

Posted
Posted

Okay so I've just took out my 10" dob to the garden as I can see Saturn at this time of the morning... Finding it was easy, but I was a little disappointed it was so small even in my 10mm eyepiece.

I can't see any detail of the planet or color really, and I was thinking that maybe something is wrong. How can I see Saturn bigger?

Cheers,

Scott

(BTW The view, even small, is absolutely breathtaking! Well worth the cold temperature and heavy lifting!)

Link to comment
Share on other sites
umadog

umadog

Posted
Posted

Good you found Saturn!

Your max power will be limited by the seeing (the turbulence in the atmosphere). The 10 mm gave you 120x. A night where you can push to 250x or 300x would be unusual. A 5mm on its own will get you to 240x. There's no way you'll get seeing good enough to support barlowing the 5 mm.

You want to shoot for an eyepiece that gets you around 200x (+/- about 15x) and perhaps another one or two to cover 250x and 300x. You'll be using the higher power rarely, though.

There are two paths you could take. One is to go for a 6mm as that will get you get you to 200x and you're likely to use that on more nights than a 5 mm. See how it goes with the 6 mm. If you still feel you can push more power out of the scope then get a 5mm and/or a 4mm. The other path is to buy a barlow, which off the bat gets you 300 x with your 10 mm, and a 12 mm or 13 mm, which will cover the ~200x range when barlowed. That path seems more appealing, actually, since it gives you a ~90x eyepiece also, which is nice to have.

The other advantage of barlowing is that it preserves the eye relief offered by the eyepiece. In short focal length eyepieces with more simple designs, such as Plossls, the eye relief is proportional to the focal length. So the high powers can have uncomfortably tight eye relief. In fact, this is the trick Televue use to get their Radians to have good eye relief at short focal lengths: the higher power Radians are effectively barlowed versions of their longer focal lengths cousins. Paradoxically, that makes the higher powered eyepieces larger and heavier.

Link to comment
Share on other sites
brantuk

brantuk

Posted
Posted

Congrats Scott - Saturn first time is a jaw dropper - I had a newbie round last night who was amazed to see it too :)

I find saturn and jupiter make very nice viewing at 150x to 180x magnification on a clear night. With your 1200mm scope and a 25mm eyepiece you are looking at 48x mag and the 10mm yields 120x mag. Just divide the focal length by eyepiece size to get magnification (e.g. 1200/25=48). A 2x barlow will double these mags.

But two things to bear in mind - being f5 focal ratio, your scope will be less tollerant of standard eyepieces like the supplied ones that come free with a scope. Plus the seeing and elevation of the object affect the view (higher mags will reveal distortions in the atmosphere as well as magnifing the object).

So you'll likely want to get some better eyepieces for clearer views. And saturn is quite low so you're looking through a lot of atmosphere - so don't go too high. It's a good idea to start trying a few loaner eyepieces at local observing meetings to find out what suits you and your scope best before you buy :confused:

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.