Astromart

I have the 15mm version of the celestron widefield series.A 16 mm version did not exist. The widefield versions were apparently the predecessors of the Axiom series of celestron eyepieces. I find the 15 mm widefield ultima to yield a bright and contrasty image but with coma at the edges.

March 17, 2003 09:54 PM Forum: Equipment Talk

Need advice on Coma Corrector

Posted By Rod Kaufman

I have a Televue 1.25" coma corrector and it is probably one of the few remaining 1.25" units as they are now made only in the two inch size. The unit functions somewhat similiar to a barlow lens and seems to work well with meade widefield eyepieces. Premium eyepieces, such as the pentax units and the speers-waler 10mm as well as those from televue can handle a short-focus scope to f-4 so if you upgrade to one of these eyepieces a coma-corrector may not be necessary. I have a Discovery 12.5" f-5 truss dob and an Astrosystems 16" f-4.5 dob and neither require a coma corrector with premium eyepieces.

March 26, 2003 08:14 PM Forum: Equipment Talk

To Plossl or to XL?

Posted By Rod Kaufman

Rob,
I have tried televue plossls in both of my dobs and I find them to be of high quality without significant ghosting issues. I am not sure of the reason for poor quality images in your scope unless seeing conditions in your area are poor or your optics are not collimated properly. I would recommend a laser collimator made by Howie Glatter. His laser costs about 100.00 for the 1.25" model but it is highly accurate and it will withstand being dropped on the ground without being de-collimated. I have found the lasers provided by Discovery to be un-collimated as have other amateurs. I returned one to Discovery and their replacement laser was even worse.

March 25, 2003 08:53 PM Forum: Equipment Talk

To Plossl or to XL?

Posted By Rod Kaufman

Rob,
I have a Discovery 12.5 truss dob and an Astrosystems truss 16" dob.I believe the pentax units work quite well and my pentax 10.5 does not ghost on Jupiter in either scope. You may also wish to try the university optics orthos or the ultima plossls which have good contrast and little or no ghosting. I read posts from other amateurs claiming their Radians do ghost on bright planets.

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Posts Made By: Rod Kaufman

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Comet Garrard Aug 20

Little Dumbell

A faint Andromeda

Andromeda mosaic

Celestron Ultimas

Celestron Ultimas

Need advice on Coma Corrector

To Plossl or to XL?

To Plossl or to XL?

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