Old Dobsonian help

[ianjns]

Hi everyone, I am a newbie and have been interested in astronomy for some time but never had a scope to use. A friend has just given me an 8 ¾ Dobsonian that has been stored for about15 years and was filthy, I read up on cleaning the mirror and have managed to get it working. To my delight I saw Jupiter for the fist time last night. I managed to make out the cloud rings and moons. However my question is can I get any more magnification and clarity out of my scope? I have two eye pieces a Celestron 12mm and a 40mm unknown with an adapter reducing it to 1.25 barrel size. Should I get a Barlow x2 or say a 4mm eyepiece. I have limited funds so want to make the right decision. Any sound advice would be appreciated.

So much to learn!

Many thanks.

[dtr42]

the working magnification in the uk is based on150- 200x [you can go higher but tbh the nights you can with a dob are rarer than hen's teeth ], so magnification is length of scope divided by eyepiece size , so your 40mm gives you 30x mag if its a 1200mm long scope your 12 mm ep gives you 100 x mag based on a 1200mm scope length , a barlow basically doubles your mag [it actually doubles the focal length of your scope ] so with a 2x barlow and your 12mm you will get 200x mag but your fov may make it harder to see the object with clarity . i had the 200mm dob and found a set of revelation ep's was pretty good and they come up pretty regular on astro buy and sell , the bst ep's are good value you can get them on ebay for about £47 each also a revelation 2.5 barlow is about £37.good luck

[Astro Imp]

I see you come from Essex, it might be useful to contact http://stargazerslou...-cloud-dodgers/ and arrange a meet. I am sure one of the members will let you try a variety of eye pieces to help your selection.

HTH and good luck.

[NGC 1502]

Welcome to SGL. On most nights, 150 - 200x magnification is as high as the turbulent atmosphere will usefully allow, smaller and sharper beats larger and fuzzier every time.

If you are in SE Essex, maybe you would like to come along here http://www.cpac.org.uk/ or to our public open night on Nov 24, details on the link, but please check the weather before travelling to save a wasted journey.

Regards, Ed.

[bingevader]

Is this just a question about EPs or are you asking about the 'scope itself?

Your best bet, seeing as how they've offered, is to get along to the Essex get-to-togethers and ask they to check things out.

I'm sure they'll help with collimation and give the mirror the once over to see if it needs re-coating.

Cheers

[ianjns]

Thanks everyone for the clarification I now know what to look for. I recently had an operation on my spine but when I am up and about I will explore the possibilities of meeting alike minds.

Many thanks to all.

Ian