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Posts Made By: Jeff Young

June 20, 2005 08:00 PM Forum: Eyepieces

Where is your Televue made?

Posted By Jeff Young
8mm Plossl (newer style): Japan
11mm T6: Japan
19 & 27mm Pans: Taiwan

June 23, 2005 06:24 PM Forum: Eyepieces

Eyeball fogging

Posted By Jeff Young
Thanks everyone for the replies. Now all I have to do is wait for the movers (now 3 weeks late) to turn up with my scope.

-- Jeff.

July 31, 2005 10:56 AM Forum: Eyepieces

TV rec for 8 inch SCT

Posted By Jeff Young
Dmitri --

I have an 8" SCT with 27mm & 19mm Pans, an 11mm Nagler T6, and a couple of Tak LEs (7.5mm and 5mm) for high power.

The 11 gets used most of the time. The 19 goes in and out when I can't find something in the 11, but it doesn't tend to stay in long. The 7.5 goes in and out to see if the seeing will support 266x, but it generally won't. The 27 gets used second-most often behind the 11.

So at the low/medium end, I think the 24 & 13 (or even 11) are good fits. I'm not a fan of the 9 recommendation. On the odd night when the seeing will support 250 or 300x, you're going to want to make use of it. But it's only the odd night. So I think you ought to have several high-power eyepieces, but not spend Nagler-type money on them since they won't get so much use. If you want to stick with TV, their 8mm Plossl and a barlow might make more sense -- less money together than the 9mm Nagler T6, and it'd give you 8m and 6.5mm (with the 13mm barlowed).

August 4, 2005 02:23 PM Forum: Eyepieces

New eyepieces or richfield viewer?

Posted By Jeff Young
I got some feedback on the LX200GPS list that I'd probably be disappointed in the color correction of the Lumicon focal reducer (it's evidently a "simple" doublet -- which I assume means an achromat).

I also got a suggestion that a commercial SCT's image starts to fall apart more than 12 to 15mm off-axis anyway, so even a more highly-corrected reducer wouldn't necessarily help.

Anyone want to provide counter-opinions, or do these sound right?

Thanks,
-- Jeff.

August 5, 2005 04:46 PM Forum: Home Observatories

Another pier design to critique

Posted By Jeff Young
Here's a picture of the site (the red circle marks the approximate location where the digging etc. will take place).

August 6, 2005 10:19 AM Forum: Home Observatories

Another pier design to critique

Posted By Jeff Young
Went looking for J-bolts yesterday, and the biggest I could find were 8mm. That clearly wasn't going to work....

So, I ended up with 3 (1m) lengths of 20mm stainless threaded rod. I borrowed the use of a mate's Oxy/Accetylene rig (actually, I think it was Oxy/Propane -- it certainly took longer than expected) and put a bent leg on each.

August 7, 2005 04:44 PM Forum: Home Observatories

Another pier design to critique

Posted By Jeff Young
I've got about a 100m cable run from the house; the first 40m is under gravel and grass, so that was fairly easy (I burried the armored cable a couple of inches deep). The next 60m is under the field, which needs to go down at least 24". So I'm getting a back-hoe in.

And as long as I've got a back-hoe, a 5' deep pier footing is called for. But I've got serious misgivings about being able to squeeze into a 5' deep, 3' square hole with a 22" concrete pipe and a bunch of rebar in order to tie the rebar together. (I can't tie the rebar first, because I don't have anything to lift the concrete pipe 15' in the air to lower it down over the rebar.) So it seems like the easiest thing to do is dig the pit 4' square to give me a bit more working room.

4x4x5 is 2½ cubic meters of concrete, which is 5 times the mass of the post, which seems like overkill. Granted, I think concrete here is less than than €100/m³ delivered, but I'm still thinking that I might leave the larger outer dimensions, but go back to 4' depth. A 4' cube gives me roughly 1.8 cubic meters, which is still better than 3x the mass of the post, and leaves the CG a healthy 18" below ground surface. Seem sufficient?

August 8, 2005 12:55 PM Forum: Home Observatories

Another pier design to critique

Posted By Jeff Young
Here's a pic of the cable trench w/ cable.

August 9, 2005 03:09 PM Forum: Home Observatories

Another pier design to critique

Posted By Jeff Young
Like John (see previous post), I was also coming around to a concrete block skinned pier. But I wasn't so happy about it. You see, I had gotten quite attached to the idea of a smooth, circular, pier in the middle of my observatory.

But my local builder's merchant had called back to explain that they got their pipes from Redimix NI, where they don't stock the 2.5m lengths. I was welcome to drive down to Naas, where they do stock them, and pick up a pipe myself, but they couldn't get one to me. Now, Naas is a good 2 hours away during the day, in heavy stop-and-go traffic. Keep in mind that we're talking about towing a 2000lb trailer with a 1800lb pipe in it with a 1.6l Ford Mondeo. Not a pretty sight.

A mate suggested calling a local civil engineer, which I did, and duly explained my predicament. While he didn't have one in his yard, he did offer to call up to the building site he was at. He called back a few hours later and said if I showed up in Dundalk with a trailer, he'd load one up for €80. Now, Dundalk is only 15min away, and there's no traffic in that direction. Plus, my mate had just shown up with his Volvo diesel....

Looks like I'm in business again 8)

August 10, 2005 03:01 PM Forum: Home Observatories

Another pier design to critique

Posted By Jeff Young
"The Pipe" goes halfway down into the footing block. But it weighs 1800lbs, so I need more than a bit of timber framing to keep it there for the pour. (There will be timber framing as well, but just to keep it vertical.)

I laid some blockwork at either side of the 4'x4'x4' pit, with a pair of 6" pre-stressed concrete lintels to carry the pipe. This will leave the center of the pipe un-cluttered, allowing the rebar cage to extend through the pipe and down into the footing.

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