Mel asked: ". . . .was the entire defect covered by the secondary?" Yes. It's a six inch F-4 mirror, Mel. The "hill" was completely covered by the 1.5" MA...
18766
jacot
suppjos
May 8, 2011 9:44 pm
ADDITION do you thing it is possible to make a slit whit welding glass cut at 45 ' and polish like a mirror this kind of glass we used for seeing the sun...
18765
Ed Majden
bolideca
May 8, 2011 6:00 pm
I have never heard of a restriction on the size of the scope you can bring in crossing the border into Canada. Just stop at Customs and declare it, saying you...
18764
Mel Bartels
Mel_Bartels
May 8, 2011 5:28 pm
Art, it depends on the details - was the entire defect covered by the secondary? I have a psychological take on this issue: I don't like to see mirrors with ...
18763
Mel Bartels
Mel_Bartels
May 8, 2011 5:28 pm
There used to be a restriction on size of scope crossing the border. Dobson once was held in custody for a day(?) because his 24 inch was bigger than the 20...
18762
suppjos
May 8, 2011 3:14 pm
ok spectroscopy speaking what is the best polishing slit OR what the best material to do a slit for a spectroscope the chrome or metal look good but...
18761
Mark Whitaker
tnut55
May 8, 2011 2:56 pm
I don't often use Ronchi and as not as familiar as I should be with the patterns. I acknowledge my mistake there. To get rid of the oblate, the center needs...
18760
UMESH B
umeshthetrader
May 8, 2011 1:54 pm
@Jerry - It's amazing how you can explain things in such detail, it is very very educating. I appreciate your patience and efforts, thank you so much. @Mark -...
18759
art.bianconi
May 8, 2011 11:56 am
I thought I had a good mirror but for the fact that it was slightly oblate. Others said to ignore it as it was in the center and in the shadow of the secondary...
18758
art.bianconi
May 8, 2011 4:22 am
I suspect that the cause of the additional security has been identified. Laying on it's side, a metal telescope tube or eyepiece barrel won't pass light x-rays...
18757
Mark Whitaker
tnut55
May 8, 2011 3:30 am
Umesh, After reading Jerry's explanation and dwelling on the subject, I admit I was wrong. There does appear to be a slight depression at the mirror's...
18756
art.bianconi
May 8, 2011 12:16 am
I've just ordered a four gun hand gun case from Cabela's which will be used to carry a 6" F4 Grab-N-Go open truss scope. It fits within the airline carry-on...
18755
art.bianconi
May 7, 2011 11:53 pm
Thanks Mel. A felt a little stupid asking so basic a question but sometimes assuming some things are simple and rudimentary has gotten me into trouble. Art ......
18754
Jerry
atc322asd
May 7, 2011 9:12 pm
Hello Umesh, Whether the center is a depression or a hill depends on whether you compare the center to outer parts of the mirror or you look at only the center...
18753
Mark Whitaker
tnut55
May 7, 2011 12:52 pm
Consult a second source: http://www.atm-workshop.com/ronchi-test.html I have no reason to dispute the Stellafane page except that the example foucault...
18752
UMESH B
umeshthetrader
May 7, 2011 9:16 am
Thank you Mel for clarification. I will update after doing couple of sessions as you have suggested. Umesh ... -- Best Regards, Umesh Thank you Mel for...
18751
Mel Bartels
Mel_Bartels
May 7, 2011 6:09 am
Umesh, the 90% zone is high. I never said that the center was high. In fact, it’s not low either. If you smooth out the 90% zone, you’ll see that the ...
18750
Mel Bartels
Mel_Bartels
May 7, 2011 6:09 am
Yes, a shim will be fine. The Earth not being flat or the mount not being perpendicular to the ground mean nothing (if too extreme, however, the tipped mount...
18749
art.bianconi
May 7, 2011 5:39 am
The head on my friends GEM is set at 40 degrees in anticipation of being used at a summer home on Georgian bay in the Quebec province of Canada. My intention...
18748
UMESH B
umeshthetrader
May 7, 2011 5:11 am
Hi Mark/Mel, The Ronchi Pic is shot inside ROC, are u guys sure it's a hill because i was referring to stellafane and it says it's a depression (please correct...
18747
Mel Bartels
Mel_Bartels
May 7, 2011 1:20 am
Yesterday i tried normal 1/4 TOT COC strokes for 1 hr and did see a difference in over all form of the mirror surface. I have also trimmed the pitch lap edges,...
18746
Mark Whitaker
tnut55
May 6, 2011 6:21 pm
Actually it is a bulge or high area. Mark ________________________________ From: UMESH B <umesh.b69@...> To: atm_free@yahoogroups.com Sent: Friday, May...
18745
UMESH B
umeshthetrader
May 6, 2011 12:01 pm
Hello Friends, I hope all you guys have been keeping well. I am back after a long absence, had been travelling a lot these days and hardly had time to work on...
18744
Mark Christensen
mjcw500@att.net
May 5, 2011 8:33 pm
Art, Since your eyeball's iris will be only a 2-4 mm wide in daylight, you should have an eyepiece that gives 50X or more (Exit Pupil = Entrance Pupil/Power, ...
18743
art.bianconi
May 4, 2011 10:49 am
I'm bringing my refigured grab-n-go on vacation. It's an open truss design that is airline carry-on-legal. I've never attempted to use such a scope for...
18742
art.bianconi
May 4, 2011 4:37 am
I ordered this unit today. At $17 delivered, it's not that expensive. I'll play with it and see what happens. I'll keep you all posted. Thanks Art ... Rate. ...
18741
art.bianconi
May 1, 2011 10:28 pm
Gene wrotw: "For applications where vibration is not wanted synchronous motors can be used." Yes indeed! My 12.5" F-8 is on a GEM that weighs less than the...
18740
art.bianconi
May 1, 2011 10:09 pm
Marciel wrote: "It's possible (and easy) to synthesize it "by hand. . . . ." Marciel, I have neither the time, the talent nor the patience to do software...
18739
art.bianconi
May 1, 2011 10:04 pm
Steve wrote: "Don't know why you dislike Verizon. . . . . " Everything! I never thought that one company could master so much ineptness. I suspect it's hired...
18738
art.bianconi
May 1, 2011 9:56 pm
Greg Wrote: "AT&T is my cell company (best coverage in this rural area)" Hi Greg! Got a nice deal with AT&T at Best Buy. They gave me the Samsung Captivate...
