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astrolunartick

20inch Dobsonian Construction

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Lovely write up Pete and really lovely looking scope

I'm really pleased that you have had some clear skies to test it out with.

Job well done and you should be very proud of the achievement.

Enjoyed the read too

Thanks

Damian

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It looks awesome. I'm sure will be looking back in this thread for some ideas for my 20" f3.8 I'm making now. I've only just started on the mirror.

Question. If your scope was 8" shorter would you get to the eyepiece with only a small step? I want to make mine as low as possible but I don't want to use a secondary any larger than 4" so I'm stuck with f3.8. F3.3 would be good but it puts the price up with needing a pricy secondary.

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It looks awesome. I'm sure will be looking back in this thread for some ideas for my 20" f3.8 I'm making now. I've only just started on the mirror.

Question. If your scope was 8" shorter would you get to the eyepiece with only a small step? I want to make mine as low as possible but I don't want to use a secondary any larger than 4" so I'm stuck with f3.8. F3.3 would be good but it puts the price up with needing a pricy secondary.

Hi there. I think your right. I found at the zenith I some time went up to the third step. Just for comfort. I suppose it depends on how tall you are as well. I'm 5.8 so if your taller then you might be hovering between the 1st and 2nd step. Thanks for your comment. And don't hesitate to ask any questions should you need too.

Pete

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stunning build and a fantastic result....john does make superb mirrors..clear skies!

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Great effort Pete, excellent viewing log and an amazing looking scope. Never mind going to dark skies yet just wait till the end of summer for longer nights, that should give the cloud gods time to be appeased and give you some well earned cloud free evenings with this beauty.

Great thread with loads of ideas for all who are of a mind to build their own! :)

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Hello Scopers 

Another update. Ive had a few sessions with this 20 inch now. Despite it being midsummer and the weather being rather poor for Observing. Last night i got a couple of hours in and saw some nice things.

I spent most of my time looking a globular clusters.  M13 was fantastic with a 11mm 82 degree Explore scientific. The cluster filled the field of view. so many stars.   M15 and m2 were also amazing to look at. 

I sometimes use Stellarium for quick finding objects. and last night i noticed Neptune was up. so that was my next target. Neptune appeared as a sky blue dot in my 24mm 82degree Explore Scientific.

i gave my 11mm ES  a go. Neptune was now a small round sky blue disk and to my surprise there was Triton. Ive never seen Triton before ;-)

I aslo gave NGC 6543 the cats eye nebula a go. WOW this was bright green and so bright with a central star clearly visible. 

All in all a nice short session. left me smiling as i packed up. 

I made a video slide show of the construction of my 20 inch and included is set up clip from last night. Enjoy!!

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Excellent update Pete and really enjoyable video. 

May the dark clear nights cometh!  :grin:

Damian

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Lovely scope. I only wish that I had the skill and patience to embark on such a project.

Thanks for sharing.

Paul

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Hello Scopers 

Another update. Ive had a few sessions with this 20 inch now. Despite it being midsummer and the weather being rather poor for Observing. Last night i got a couple of hours in and saw some nice things.

I spent most of my time looking a globular clusters.  M13 was fantastic with a 11mm 82 degree Explore scientific. The cluster filled the field of view. so many stars.   M15 and m2 were also amazing to look at. 

I sometimes use Stellarium for quick finding objects. and last night i noticed Neptune was up. so that was my next target. Neptune appeared as a sky blue dot in my 24mm 82degree Explore Scientific.

i gave my 11mm ES  a go. Neptune was now a small round sky blue disk and to my surprise there was Triton. Ive never seen Triton before ;-)

I aslo gave NGC 6543 the cats eye nebula a go. WOW this was bright green and so bright with a central star clearly visible. 

All in all a nice short session. left me smiling as i packed up. 

I made a video slide show of the construction of my 20 inch and included is set up clip from last night. Enjoy!!

lovely vid, just noticed you set it up as a left hooker. lovely scope and well done.

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lovely vid, just noticed you set it up as a left hooker. lovely scope and well done.

Cheers Faulksy 

Was a goof up hehe. some times one forgets which way round. I view and sight with my Left eye all the time. so find it most comfortable this way.  

Im still yet to find a ladder. Im using an old wobbly aluminium decorators ladder. Not ideal.   ive seen these ones below, but im not sure yet.  I met a guy when i was hiking last month who has a ladder company. Henchman Ladders.  These look really well made.  But rather expensive. I like the idea of having 2 ladders one with a shallow angle and a hand rail with a large platform for people that are unsteady on there feet and one these below. 

post-5432-0-55744100-1437305119.jpgpost-5432-0-25937900-1437305124.jpg

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Hi Pete,

Enjoyed the video of the build and reading your thread. You have put a lot of work into it. I didn't see a mirror cover, are you intending to fit one. Or have I just missed it somewhere.

Derek

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Try Midland Ladder Co Ltd, Droitwhich, very competitive prices.   :smiley:

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Does anybody use a tripod ladder as these are better on uneven surfaces.

I'm sure I've seen them used with several large scopes although I've never used one myself.

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Hi All,just had tree surgeons in and they had a superb 3 leg aluminium ladder,just waiting for a call from them as to suppliers,not cheap but very steady!!!!   :grin:

Regards

Mike

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We have recently been bequeathed a 20" Dobsonian but at F3.5 it doesn't need a ladder, just a Paracorr. From the illustrations I think they have only two legs.  :smiley:

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just read all this again. brilliant thanks for sharing pete :grin:

Good to read a few build threads if your planning your own?

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Good to read a few build threads if your planning your own?

sure is damian.

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