They can be made to track though. There was an article about it awhile back in S&T or Astronomy mag. If it can be made to do that, there might be a way to make...
19842
Peter
peterpekurar
Jul 28, 2010 9:55 pm
Mike, Fabulous work! I love to read about new and innovative approaches to telescope making. We need more innovators around here! As a point of reference I...
19843
startestisbest
Jul 28, 2010 11:31 pm
Thanks for the reply Peter! My mirror mount is very simple. It consists of a flat-ground plate of 1/4" Aluminum cut to fit at the correct depth inside the...
19844
startestisbest
Jul 29, 2010 2:47 am
Here is the trackball mount http://www.sff.net/people/j.oltion/trackball_mount.htm which was described in the S&T article. This provides sidereal motion only,...
19845
geodandrew@...
geodandrew
Aug 4, 2010 8:49 am
I live very close to where NEAF is held, about :20min away. So I saw the scope in person. It looked great. The construction was very nice. George 20" Obsession...
19846
alwittstein
Aug 4, 2010 8:50 am
Hello, I'm not sure if this is the place to post this question, but I cannot find a Lumicon Yahoo Group. I just recently completed construction of my first Dob...
19847
Patrick Moore
prmo...
Aug 4, 2010 11:42 am
Arnie,  Here is a list from the JMI site. The Sky Vector is a Tangent box, same as the JMI.  http://www.jimsmobile.com/html_docs/ngcmax_db_stars.htm  Pat...
19848
peschman2001
Aug 4, 2010 3:16 pm
Catalogs are not identical across all the Tangent based units, but the ST catalog may be. Once you have selected an object, say ST001, hit the enter button to...
19849
Roger Greenwood
astrocrumb
Aug 4, 2010 4:40 pm
Heading out for Stellafane tomorrow. I hope to see some of you there. One of the few star events I get to go to. Weeee... -Roger 18" Obsession SC/AN/FSA ...
19850
starryskyn
Aug 4, 2010 5:57 pm
About 43 to 38 years ago Norman James of San Diego showed a sphere telescope at RTMC. It was a 12.5 inch reflector with a 28 inch fiberglas sphere merged with...
19851
Len Philpot
lphilpot01
Aug 4, 2010 10:39 pm
[ From bigdob@yahoogroups.com (peschman2001) on Wednesday, August 04, 2010 ] ... FWIW, the alignment stars in my old NGC Sky-Vector are listed by name: Achenar...
19852
startestisbest
Aug 6, 2010 8:35 am
In Texereau's 2nd Ed. Pages 403-406 are some of his detailed fiberglassing methods and diagrams. Certainly Mr. James design was unique and revolutionary for...
19853
Randallo
rogauntt
Aug 8, 2010 4:50 pm
Hi Folks, I am new to the group. Joined as I am putting together a big dob from a nicce 17.5' F4 mirror. Getting ready to build a base for a 17.5" F4 mirror...
19854
atmpob
Aug 8, 2010 5:46 pm
You need to get the book "The Dobsonian Telescope" by Kriege and Berry. It will answer all of those questions and more. http://www.willbell.com/tm/index.htm ...
19855
xrpb11a
Aug 8, 2010 7:24 pm
Hi all,just put together a 15" obsession i bought on the cheap? ( 2700 about 3 years ago ). been a LITTLE BUSY, so just getting around to using it. had it...
19856
startestisbest
Aug 8, 2010 7:31 pm
Welcome to the group Randy! Since you are starting from scratch, maybe consider a sphere-mount scope...
19857
xrpb11a
Aug 8, 2010 7:38 pm
Update: Checked Lasermax TLC-202 laser colllimator in focuser. rotated it 180, then back again. found the spot on the center of the primary rotates by about...
19858
startestisbest
Aug 8, 2010 7:54 pm
The simplest way to check for collimation is look at a star at high power. If it is perfectly circular and symmetric in the center of the field, then you are...
19859
atmpob
Aug 8, 2010 11:09 pm
Even more sensitive is to defocus the high power (300x) view of the star both inside and outside of focus. Look to see if the shadow of the diagonal is in the...
19860
xrpb11a
Aug 9, 2010 5:51 am
ok, used the barlowed laser method with a hotech laser.... cut the paper circles, all that... centered er up....big noticable difference in stars tonite. very...
19861
John Mahony
jmmahony
Aug 9, 2010 5:26 pm
The circular surface doesn't have to be precise since the tube actually rides on the teflon pads, but it gives you the option of adjusting the position of the ...
19862
John Mahony
jmmahony
Aug 9, 2010 5:30 pm
This could be just bad seeing, or an error in the laser. -John...
19863
John Mahony
jmmahony
Aug 9, 2010 5:35 pm
... That's a very interesting concept. It certainly saves on complexity. By "the mirror mount is fixed" do you mean the primary? Is _all_ collimation (both ...
19864
startestisbest
Aug 10, 2010 2:51 am
Yes, The primary mirror mount is fixed into position. That approximate position is determined by measuring that the distance from the edge of the mount(plate)...
19866
gnowellsct
Aug 12, 2010 4:37 am
The comet-flare is a good technique for collimating the primary without a laser, and certainly a way to double check the laser's accuracy. I wrote an article...
19867
startestisbest
Aug 18, 2010 9:19 pm
The important star test for quality of the primary is to carefully look at the slightly defocussed star with a very high power under good seeing, and compare...
19868
ctastronomer
Aug 20, 2010 4:46 pm
The morning of 8/19 I got up around 2 am to some amazing views of Jupiter through my 20". I had a box fan on the mirror all night until observing, and images...
19869
WILLIAM BYRD
web0178213
Sep 5, 2010 4:50 am
http://cantinygamboa.es/en.php...
19870
Roger Greenwood
astrocrumb
Sep 8, 2010 3:33 pm
Hello group, Heading out for Black Forest Star Party and hope to see some of my fellow Big Dob cohorts. One of the two star parties I get to do a year. Hope...
