Thursday, February 20, 2014


140218 Telescope Workshop notes 730-9p Tuesday evening
Attendees:  DmitriiZ, TomT, JerryW, TimC, EdK, ChrisU, DavidH (+M)

TomT asking JerryW how to set up Registax6 for stacking his 99 frame video of Jupiter.  Used only a few frames to get a better view of Jupiter with a shadow or two on its face.

JerryW brought in Oculus All Sky Camera, a gift from his wife, which records the night sky at various shutter exposure times to catch meteors.  He usually will set it to record 1 minute exposures, then there is a 5 second delay between shots.

TimC, after showing Madeline how to grind mirror and setting her up with coloring pens, is continuing aluminum oxide 12 micron grit grinding (polishing compound) on the 8” donated mirror.  JerryW checked the surface with the loupe and called for another hour to be sure.  But Jerry says you cannot really see the pits on the surface at this point, just put 3hrs in at each fine grit.

 EdK has finished setting up his Celestron on the Losmandy tripod with the adapter at home.

DavidH brought in his older Celestron mount to start putting the motors in place.

ChrisU brought in 10” polished mirror and pitch tool that was made by ChuckMcP, but more figuring is needed per Jerry.  Need to keep mirror and polishing equipment perfectly clean, away from old grit materials.

More photos posted at Flickr eventually:

Tuesday, February 11, 2014


140211 SBAU Telescope Workshop, Tuesday, 730-9p

EdK brought in 14h? x 17w? framed astrophotography of M31, the (Princess) Andromeda Galaxy, created by Paul Winn...very beautiful.  Ed is working on his Losmandy tripod adapter to the Celestron CGEM mount.  He will be looking to pour pitch on his Perfect Pitch silicone form soon.  TimC says he will want to pour pitch in about 4 weeks for his mirrors, hoping he can do it at the same time with TomW's perfected pitch pouring procedure.

TimC was working on the start of his From The Workshop Note #3.  Also carrying on grinding the donated 8" mirror with 500 grit, while talking about the Giant Magellan Telescope mirrors being made at the University of Arizona.  Seven 8m mirrors will be placed together to form the GMT.  Mirrors are heated to about 1200C to melt the borosilicate, then cooled to about 1000C to resolidify, all the while the 27 foot diameter mirror is spun at about 1RPM to help form a parabolic surface.

The 8" grinding was going well until TimC noticed a scratch on the surface.  Possibly some older larger grit bit that was caught behind the tool tiles had come out to leave the scratch?  The tool and its tiles were examined from the backside and thoroughly cleaned.  A bit more 500grit grinding and the scratch was disappearing.  Examining the surface with the 8X loupe only a few internal bubbles (with shadows away from the LCD light source) could seen below the smoothing surface.

Wednesday, February 5, 2014


140204 Telescope Workshop notes 730-9p Tuesday evening
Attendees:  TomT, JerryW, TimC, EdK, JoeD, ChuckM, ChrisU

JoeD brought in the 6” AstroTech f/4 that he is modifying for portability:  He has stiffened the tripod further and made a spotting tube with fishing wire for crosshairs.  Tim consulting on further solutions for stiffening.

TomT discussed summer meetings with JerryW, need sign up sheet for member presenters.  Jerry says he can always do a talk if not enough people volunteer.

TimC did a little more 500 Al2O3 grit grinding on the 8” donated mirror.  JerryW checked the surface with the loupe and called for another hour to be sure. 

TimC asking for suggestions for his next article, perhaps reviewing some telescope/mirror defintions; Jerry thinks covering one term might be enough.  Joe suggested to focus on “choose your own” theme, e.g. how to design a telescope that meets an individual’s needs.

EdK will be making a smaller tool, using the Perfect Pitch silicone form, but waiting for it to arrive.  He will be using chordal strokes with a 6.5” Tool.  Ed consulting w/ Jerry on some other telescope factors.
JerryW working at home on the 6” secondary mirror for his Corrected Dahl Kirkham (CDK) 14.5” system.  One test will be by laying desired convex mirror on ground concave glass and shining monochromatic light through them, looking for a light pattern.

ChuckM asking Jerry about need for multiple dark frames for stacking photos with Photoshop CS4.  Jerry converts to Fits files, using Nebulosity program?  Jerry warns that hot pixels may depend on temperature of the camera chip as well. is being used by Chuck to determine star field if unknown.