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Posts Made By: itz marcus

September 15, 2008 05:23 PM Forum: Refractors

artificial star test

Posted By itz marcus
Hi,
Ok here goes. I hope I did it right. I took an L.E.D. flashlight and covered it with an ep cover. I took a thumb tack and made the hole. I moved my scope about 150ft away.
At 225x it was very hard to make out the diffraction ring but it was there. It did seem to go all around, but as it was so faint my eyes were playing tricks and I kept thinking that the diff ring did not go quite around. I bumped it to 450x (2x barlow Knight owl) and boy was it evident that the diffraction ring DID go around the "Airy"
disc (although at that power there was some tubulance evident).
Anyway, does it sound like I did anything wrong in the artificial star set up? I only tested at focus (although the few seconds that I did an out of focus test the in and out images looked good but I didn't concentrate on them)


October 10, 2008 10:42 AM Forum: Refractors

Eon 120 interferometer results

Posted By itz marcus
Hi Guys,
OK many of you know that I obsess about my optics. I'm surprised that it took me so long to cave in but I did.
I sent my scope to the folks at OMI and here are the results.
Output Units: Waves
RMS 0.031
Peak-Valley 0.24
Strehl Ratio 0.96
Astigmatism 0.05 22.4 deg
Spherical 0.20
Scale -0.50
Wavelength 550.0 nm
Description Orion Eon, Itz Marcus
Date Tested Oct 10, 2008
Operator JCM
Comments Tested on the wavefront at 550
It is well into diffraction limited territory as I understand that .80 would still fit the bill.
Its PTV is a little better than 1/4 but it has a nice strehl which I understand is more important that the PTV.
The folks at OMI said that the scope should be a solid performer (which I have found it to be so)
Any comments appreciated (just don't make to much fun of my obsessing).
Clear Skies

November 1, 2008 07:11 PM Forum: Refractors

Jupiter in Eon 120 daylight shadow transit

Posted By itz marcus
Hi,
I can only get planets and a few dso's from my light poisoned city but I did get what I think was a shadow transit during daylight today (6:10 P.M.) just after sunset but still plenty bright outside. Using a Meade 5.5 series 5000 for 163x ( I didn't try for lower mags) I caught what I think was a shadow transit. The moon had already passed the planet and was just separated but the shadow was there. At first I thought it was a swirl in the band but as it got darker it sure as heck looked to me like a little black circle. The darker it got the clearer it was but as I didn't look at a moon transit calculator I don't want to sound like an idiot and say that I saw it and it turns out that the moon was occulted by the planet so no shadow could've been seen.
Anyhow I love this Eon and hope to get to darker skies one day soon.


November 11, 2008 11:38 AM Forum: Refractors

Saturn in the EON

Posted By itz marcus
Hi,
It's sooooooooo sad. The majesty of the most beautiful planet is diminished. When the rings are on display I could sit and stare for hours at a time. Even with the promised added detail that is supposed to be visible (which I haven't yet seen), it just ain't the same seeing a sphere with two "sticks" coming out of both sides, Oh well next year will be here soon.


November 16, 2008 03:04 PM Forum: Refractors

PTV results and dust

Posted By itz marcus
Hi,
Just out of curiosity, if a scope is tested intferometrically for a PTV result, wouldn't dust on the lens have an impact? Since the deviations are so small anyway would'nt dust throw off the PTV?
Probably a stupid question but curious anyway.

November 22, 2008 05:04 PM Forum: Refractors

bang for the buck and what does it means

Posted By itz marcus
Hi,
I constantly read "for the money it's a great scope". That always bothered me. At what point does a scope become good period end of subject. I mean a department store scope for a penny might be called "good for the money"
Anyway, since I had my EON 120 tested I asked the folks at OMI if it is safe to assune that a scope like mine which tested at .96 strehl and .031 rms would match a TAK DOUBLET in the same aperture range. I know that a TAK triplet will have a wider range of optimal correction and such and that is why I specifically asked about comparing the EON 120 to a TAK fs 128 or some of the older premium doublets (most "premium" makers make triplets these days) The answer I received was that YES!! one could expect and EON with those nimbers to perform similarly to a tak fs128. Of course not counting the extra 8mm of aperture.
So the mass produced scopes may be the "best bang for the buck" but they are also just plain good because they are good.
Now I'll let the bricks fly!!!!!!

December 2, 2008 04:13 PM Forum: Refractors

cleaning lenses

Posted By itz marcus
Hi,
First things first! I am not cleaning my lens (When needed I'll send it to Dr. Sherrod) Well here goes.
Can lens tissue really do any scratching (after one blew off whatever could be blown off)?
Also, it seems from many posts, that people are afraid they [COLOR="Navy"]MAY[/COLOR] have caused damage, then whatever scratches were caused would only be visible at certain angles and in bright light otherwise it would not be a [COLOR="Maroon"]"may have caused damage"[/COLOR] but there would be no doubt about having done damage. Being the case can micro scratches that are so tiny as to not be visible readily be any worse than some dust on the lens?
I hope I make sense. I still am scared stiff of cleaning my lens but maybe I shouldn't be!


December 4, 2008 08:28 PM Forum: Refractors

Eon focuser

Posted By itz marcus
Hi,
My Eon focuser has always been very smoothe until tonight. It has started making loud squeeking and rubbing noises.
The focuser has not been banged nor has the scope been exposed to moisture. The noise only happens at some parts of the drawing of the drawtube.
Any ideas as to what went worg and if there are any fixes?
Thanx


December 25, 2008 06:59 AM Forum: Refractors

1.25 diag for eon 120 ed

Posted By itz marcus
Hi,
I would like to buy a high quality diag. for my Eon 120. It will be a 1.25 diag. My oices are the TV enhanced for $140 or the TV Everbright for $190. Is the Everbright worth the extra 50 dollars. Also, I am looking into the Tak 1.25 prism diag. for $115. I know that prisms sometimes work better with ed scopes and I have found that to be the case but I'm not sure if its the prism or the fact that my mirror diag is a cheaper make. I have been satified with it but collimation seems to be slightly off. Anyway, your input really counts.
Thanx
clear skies

January 19, 2009 06:50 PM Forum: Refractors

compression ring accessories in refractors

Posted By itz marcus
Hi,
I was just wondering, since a compressionring diag or other accessory shifts the ep over a bit why doesn't that push off the collimation of the scope to the ep. Or when one is using a cheshire how can one rely on results achieved if the cheshire was shifted to one side due to the comprression ring?


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