ARCHIVE May2008
RE: Need to find a source for Birch ply
Hi Jimbo – How the heck are you? I was just thinking about you last week and was wondering what you were up to. Sorry for the delay in getting back to […]
Trixie design sessions – weight calculations, cont.
On mounting “big” scopes I always thought that 12 or 12.5 would be what would finally end me buying things. Getting above that size starts to put a serious strain on any […]
Trixie design sessions – weight calculations, cont.
The new 13” mirror is only 1” thick. By my estimate, this means the mirror weighs something like 11, maybe 12 pounds. That’s only twice the weight of Veronica’s mirror. That means […]
Trixie design – an early victory!
I just got an update from the original owner of Trixie’s mirror. Mdearingjaxfl wrote: I had the wrong measurements wrong about the primary thickness……….it is 1” thick, not 1.7” This should really […]
amateur telescope making – an ultralight 13.1" telescope
Hi Paul, Here’s a page with some photos of the kind of thing that I’m thinking about building around my new 13.1” f/4.5 mirror. The major design dilemma will be to keep […]
Trixie design sessions
I’ll have to see whether the concept has any legs at all when the mirror arrives. If it’s obviously too heavy, I will enjoy having a big Dob around. My main plan […]
Fear my mathematical prowess
It took me awhile, but I finally figured out that the name of the figure that you get if you put a compass at each point of an equilateral triangle, and sweep […]
Re: ASTROMART – Response to ad #562793
I asked the original owner of the 13” mirror for some information so I could start working up a .. er.. “balance” sheet for the scope. I’m not doing cost analysis — […]
Camera at the Newtonian focus
My D70 is 5.5”x4.4”. That’s a coverage of 24.2in^2. A 13.1” mirror has an area of 134.78in^2. That’s a 17% obstruction. Even if I mounted the thing on a 5.5” disc, basically […]
Blue CR-1
Art asked if he could buy the blue CR-1 focuser that’s been sitting in my parts box. Until a day or two ago, I didn’t have a use for it. But now, […]
RECENT UPDATE
Polar Alignment Calculations
Here’s a page that derives Polar Alignment Calculations. (update 5/2020: the original site is gone, so I found the text on Wayback and am inserting it below. This is by the original […]
Gear / Observatory / Telescope
Special Guest Star takes the mount at Hilltop O
The Astro Jedi needed somewhere to store his light sab—- I mean, bucket, and I was only too happy to accommodate him. I have decided that I need to come to a […]
General / Maintenance / Observatory
Dome shutter is motorized again!
I finally decided to bite the bullet and fix the shutter motor. Things went sideways last winter, and I’ve been opening the shutter manually (and tying it shut with rope, so we […]
Trixie 2017 – tube mods
I finally got around to cutting the MTA-UTA tubes to length; the only eyepiece that would come to focus with the focuser spacer in place is the Televue 55mm Plossl. If I […]
MOST COMMENTED
Observatory
Observatory 2.0 – Time has come today!
General / Maintenance
First Light, a deeper look
Mount / Observatory / Telescope
Observatory 2.0 – Result!
Observatory
Observatory 2.0 – The Pier goes in
Gear / General / Maintenance
Martin Farmer Wormblock installation notes
Deep Sky / Long Exposure Photography
NGC2244, The Rosette Nebula
Deep Sky / Long Exposure Photography
Another beautiful night.