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First Light: 10" F11 Report

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#1 StarryHost

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Posted 08 December 2012 - 02:00 AM

Thank you for all of you who have helped bring this scope to first light (Peter, Dave, Mike, Kevin and many others).

I got first light tonight with my 10" F11. I am positively tickled! Even with what turned out to be poor collimation (one of the tube sections was not snug), this was the finest view of Jupiter I have ever had. Io's shadow was crisp. I was so excited I forgot to look for Io! :-)

Mechanically, this is a Dob mount using 3/4" Baltic. The base is 24" diameter using Teflon/Ebony Star (or Ebony look-a-like...I'm not sure). I used 12" diameter alt bearings, again with Teflon/Ebony Star.

The motions in alt/az were smooth with a perfect amount of stiction. Even with a 14mm 100 Explore Scientific eyepiece barlowed, objects were easy to get into the field of view and keep there.

Wobble and vibration were not much of an issue to my surprise. At top mag vibrations dampened in less than a second and wobble continued for only up to 4 seconds depending on the altitude, but closer to zenith wobbles were again very short-lived.

I nervously attached the 21 lbs Explore Sci refractor on my custom mount attached to an alt bearing and the 10" scope barely even noticed it. The mount is exhibiting great balance.

The OTA is not painted (blonde wood on the inside) so contrast was down quite a bit on the Orion Nebula, but the seeing/transparency tonight is very difficult anyway.

I am about half-way done with a custom EQ platform which will add another 5.5". Currently the eyepiece is 104" off the ground.

I've got a list of about 10 must-do enhancements to keep the scope safe and more usable as a result of my trial tonight, but I am very pleased with it's performance.

More to come,
Jack Swaton
www.StarryHost.com

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#2 Jeff Morgan

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Posted 08 December 2012 - 09:36 AM

Congratulations on first light! At f/11, just getting the mirror in the tube is "collimated"! :lol:

While long focus Newtonians get pigeon-holed as "planetary" scopes I think you will find it does exceptionally well on DSO's too. With the right eyepiece, you should be able to manage about 3/4 degree maximum true field.

#3 StarryHost

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Posted 08 December 2012 - 09:52 AM

Jeff,
First of all, I love your tag line..."Wile E. Coyote School of Telescope Making". I belong to the "Professor Grampy" School (http://en.wikipedia....But_Once_a_Year). I'm not that old but the concept is true...but mine usually blow up and fall down like Mr. Coyotes. :-)

I only use (only have) two eyepieces any more and I love them: Explore Scientific 100 degree 20mm and 14mm. I have an OPT 2x Barlow I also enjoy.

Thanks for your encouragement.

Jack

#4 Sean Cunneen

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Posted 08 December 2012 - 11:54 AM

Great job, don't forget your parachute!

#5 ccaissie

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Posted 08 December 2012 - 11:55 AM

Telescope size is limited by ladder technology.

Congrats on a real performer. I may have missed earlier posts on this, but tell me about the mirror. Spherical or parabolized? How close do you think you are to a paraboloid?

We had a 10" f/10 that had a marginal mirror (spherical with a turned down edge), but even then, it was a super scope. I like the square wooden tube. I find them to be excellent at conveying tube currents out.

#6 StarryHost

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Posted 08 December 2012 - 12:49 PM

Parachute? I don't need no stinkin' parachute! ;-)

The mirror is a 10" f/11 ground by me and Peter but finish polished and coated by OWL: 1/10th wave. Good stuff!

:-)

Jack

#7 Dave O

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Posted 08 December 2012 - 01:16 PM

Wonderful Jack! It really looks like a dandy! I can feel your excitement half way around the world! Congrats! :)

#8 starman345

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Posted 08 December 2012 - 01:17 PM

Great project Jack, thanks for sharing

#9 glennnnnnn

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Posted 08 December 2012 - 01:28 PM

Maybe you should just get one of those cherry-pickers. In fact, you could attach the whole assembly to it and make it the first telescope you can actually drive !
-Glenn

#10 StarryHost

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Posted 08 December 2012 - 02:02 PM

Glenn,
Do I need a special license to drive that at freeway speeds?

Jack

#11 tim53

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Posted 08 December 2012 - 02:05 PM

I'd be tempted to put a large-format CCD camera on the focuser, another camera on the finder, add drives to the mount, and never have to look through an eyepiece or climb a ladder again! :grin:

-Tim.

#12 StarryHost

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Posted 08 December 2012 - 02:24 PM

I'm taking donations for Tim's CCD camera...I'm sure he'd appreciate it! ;-)

Seriously though Tim, I agree it'd be great. I'm half-way done with an EQ platform (EzCBP (http://home.netcom.c...tem/cablet4.htm) but even that has it's special needs for a scope this large. I'm optimistic that I chose a good solution. I've got the wood all cut and just have to assemble it then.

Once on the platform, I would LOVE to see about adding video or live image of some kind.

I don't have the time for processing images, so I'm mostly looking for an outreach CCD solution.

Thoughts are welcome.

Jack

#13 tim53

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Posted 08 December 2012 - 02:31 PM

You might want to consider something like a Mallincam, then.

I've already done something like this for my roof-mounted C 9.25. I have a 2x barlow and Pt Grey flea2 camera on the main scope for planetary video imaging, a Flea with an 11mm c-mount lens for a finder, a robofocus on the 9.25". I operate the scope from a desk in our attic space using software like Sky Safari. There's a hatch cover over the scope and door under it, so it's isolated from the attic room environment. Once I set things up for observing and turn everything on, I can't even see my telescope! :grin: But the 11mm lens on the finder camera gives a wide enough field of view that I can monitor sky conditions and watch clouds rolling in.

-Tim.

#14 Jeff Morgan

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Posted 08 December 2012 - 03:10 PM

Telescope size is limited by ladder technology.


Indeed. A rolling platform ladder is my solution to the problem. It has a nice platform on top, handrails, and is very stable. You can get these from McMaster-Carr. The ladder in this photograph has the platform at 4'2". The largest they offer has a platform height of 13'4".

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#15 StarryHost

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Posted 08 December 2012 - 04:43 PM

Jeff,
That's a beautiful scope and a very nice ladder. Lots of options there...

Jack

#16 magic612

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Posted 09 December 2012 - 12:14 PM

Freaking AWESOME! Nice job - fantastic! :waytogo:

#17 tim53

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Posted 09 December 2012 - 01:23 PM

I'm considering one of these guys' 3-steppers for my 12.5" f/7 Cave:

X-deck platforms

-Tim

#18 StarryHost

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Posted 09 December 2012 - 07:00 PM

Tim,
That's a very interesting ladder site. I have a thought to share...last night I setup my foldable ladder to look just like the scaffold ladder you suggest in your link. It was very easy on my feet rather than the straight rungs, but I noticed that I felt much more comfortable leaning against the A-frame of the ladder. Now your choice has rails and I think that's great. But then I noticed that as the eyepiece changed height, I had to bend and stoop rather than just climb down one ladder rung.

Now then, my handyman brother has introduced me to the Little Giant platform. It's only $40 bucks and it slips onto your ladder (if your ladder is supported). It will support 300 lbs and gives you an adjustable height platform: http://www.littlegia...-platform.html.

There is a YouTube on this I can't find right now and it shows how easy it is to use this.

I've not purchased it yet but I'm leaning towards this solution because I still have to get that dang ladder into the car.

As far as I've seen, your link is the next best thing I've seen!

Jack

#19 bremms

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Posted 09 December 2012 - 07:51 PM

That's a BEAST!!! Love it!! Makes the Vintage 12.5 F8 in the closet not so daunting...

#20 David Castillo

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Posted 09 December 2012 - 07:59 PM

That focuser is way up there :bigshock:. The views must be worth the climb. Are you going to use a Sherpa to assist you in getting your eps up that ladder ;)
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#21 StarryHost

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Posted 09 December 2012 - 08:40 PM

The last Sherpa I used would not work without a parachute. Now I use oompa looompas.

#22 StarryHost

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Posted 09 December 2012 - 08:45 PM

Several of you have mentioned your long focus news which sound like real gems... With the success of this project maybe I need to start a conversion business! There must be dozens and dozens of dollars in a business like that!
;-)

#23 Jeff Morgan

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Posted 10 December 2012 - 12:19 PM

I've not purchased it yet but I'm leaning towards this solution because I still have to get that dang ladder into the car.


The standard car interior is a pretty limiting factor for large gear. Years ago I used a kayak roof rack for my old 10" f/9 scope. No reason you could not put a ladder up there.

Currently I already have a kayak micro-trailer, so it is a natural to press it into service for hauling astronomy items. During kayak season it takes about 10 minutes to add/remove fittings to switch uses for the trailer. It really opens up the possibilities for astro equipment, and in my case was a bit more practical than buying a pick-up truck.

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#24 tim53

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Posted 10 December 2012 - 12:57 PM

My dad conditioned me to prefer vans over cars when he traded our 1953 Hudson Hornet in on a 1960 Ford Econoline. I drove that and his 1966 dodge van until buying my first VW van in 1975. I've had vans in the corral ever since.

It's nice to easily accommodate scopes 8 ft long as a rule!

Tim

#25 kfrederick

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Posted 10 December 2012 - 01:00 PM

Jack how high was the eyepiece when you used this mirror as a chief?






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