View Full Version here: : Best setup for a sw 10" dob
26-03-2012, 06:31 PM
I got my 10" SW dob on the weekend. Bairly used it yet. Just wanted to know what would be the best combination of barlow / eye peices for viewing the planets like saturn / jupiter.
Managed to find the planets but looking at them I can bairly see anything except for just a small bright dot almost the same size as in the finderscope
Venus looked ok like a small 1/2 moon. Just using the 25mm eye piece that came with it..
Not collimated yet only just orderd a laser collimator waiting for the moon to appear so I can have a look.
These people seem to know a bit about eyepieces - definitely worth a good read when you're considering how to assemble a collection (not just televues either).
26-03-2012, 09:05 PM
With your eyepieces the low power ones are the best to start off with. If you use these they will give the clearest views. Lowest power eyepieces are the ones with the longer focal length. Power is determined by dividing the focal length of the scope by the EP focal length. Your scopes FL is 1200mm so a 25mm EP gives 1200/25 = 48x and a 10mm one gives 1200/10 = 120x.
You will read that you can get up to 50x per inch of aperture but that is a "theoretical" limit based upon perfect "once in a year" conditions, the usuable power is usually no more than 10 or 15 per inch.
Jupiter is very low in the sky so seeing is usually poor. Mars is well placed but needs a bit of power and good seeing to tease out details. Saturn is rising late but will improve over the next month or so unless you are able to wait until early mornings.
With collimation ascope that size can be quite easily collimated without a laser, in fact it is best to only use the laser as a final tweak. There is a good guide to collimation here http://www.astro-baby.com/collimation/astro%20babys%20collimation%20guide .htm that I have found helpful.
Good luck with the scope
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