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Posts Made By: Larry Seguin

May 22, 2004 03:33 PM Forum: Equipment Talk

Helical vs. Linear focusers

Posted By Larry Seguin
I've been looking at Ed Taychert's 14" T-scope and noticed that it comes standard with a helical crayford focuser. I've always used the linear crayford's in the past. Anybody got any input on the use of helical crayford's? Thanks for any and all feedback!
Larry

October 18, 2004 10:50 PM Forum: Equipment Talk

"ENOUGH" EYEPIECES?

Posted By Larry Seguin
I apologize in advance if I'm beating a horse that's long dead, but I'm curious--How many eyepieces is "enough"? That is to say, how many does the "average" astronomer own/use to cover the neccasary magnifications/fields of views? A simple numerical answer would be interesting, but any other information (such as preferred eyepieces, aperture of scope, f/ratio of scope) would be just as interesting. Just for the record, I'm using a 14" f/4.7, and a 8" f/6. The eyepieces I'm currently using include:
40 mm MK-70
25mm TV plossl
22mm Panoptic
14mm XL
10.5 XL
9mm UO HD ortho
8mm TV plossl
7mm XW
7mm Pentax ortho 6mm UO HD ortho 5mm UO HD ortho
4mm UO ortho
for a total of 12 eyepieces. Anyone who has time to respond, I'd love to hear what does it for you. Thanks,
Larry Seguin
Taos, New Mexico


October 23, 2004 03:49 PM Forum: Equipment Talk

Formula for astigmatism?

Posted By Larry Seguin
'Morning everyone!
Does anyone happen to recall the formula for figuring out at what focal length eyepiece observers with astigmatism no longer need to wear eyeglasses? Thanks in advance for any help on this one.
Larry Seguin
Taos, New Mexico

February 19, 2005 06:42 PM Forum: After Dark

Blue Level Support

Posted By Larry Seguin
Hello Herb and all,
Can any one explain to me what blue level support is? I see it with some of the ads, but can't find it on the Support page. thanks for any help on this.
Larry Seguin
Taos, New Mexico

February 19, 2005 08:40 PM Forum: Eyepieces

Nagler/Pentax-barlow comparo

Posted By Larry Seguin
Hi all,
Wonder if any one has experience with what I'm considering? For higher powers on my scopes I've been using a 10.5 Pentax XL riding on a 2.8X Klee barlow, for a 3.75MM focal length. I've gotten to wondering lately whether I might now be better off with a simple, short focal length eyepiece, say a 3.5MM Nagler. Anyone tried both set ups? Barring that, anybody tried the 3.5 Nagler, and care to comment?
thanks for any feedback!
Larry Seguin
Taos, New Mexico

March 9, 2005 05:33 PM Forum: Equipment Talk

The discontinued 17

Posted By Larry Seguin
Hey guys,
Does any know the first and last production years for Televue's 17mm Plossl?
Trying to figure out: if I see one for sale, what is the newest (or oldest) it could possibly be.
Thanks for any help,
Larry Seguin
Taos, New Mexico

March 11, 2005 03:59 PM Forum: Eyepieces

Re: advice needed on 40mm UO mk-70 and/or Axiom

Posted By Larry Seguin
Hi Nils,
I don't have experience with the Nagler, but I have had the MK-70 for a couple of years now. If you do the math, the MK-70 does have a slightly wider field of view than the Nagler (1.5* compared to 1.3* in my 12.5" f/6). I bought it for the same reaon you mentioned--not willing to spend that much for an eyepiece that sees limited use., Here's some good news though. I'm moving up to a 14" f/4.7 scope, and wanted to know how the eyepiece would look at that f/ratio. Tried it in my friends 17.5" f4.5 and the edge of field was NOT mush, nor was a secondary shadow visible. Cheap, comparitively, and it works great, too!
Larry Seguin
Taos, New MExico

June 24, 2005 03:31 AM Forum: Equipment Talk

Binoviewers and barlows

Posted By Larry Seguin
Two problems: I've got a lot of money already invested in my eyepiece case, and I'm cheap. So binoviewing wasn't in the cards--that is until Burgess Optical came out with a TWO HUNDRED DOLLAR BINOVIEWER! The problem is that their 1.5 relay is still in production, and dealer websites say just to use a shorty 2x barlow. I've heard it said (I think it was Todd Gross) that a 2x barlow on these set ups will often give substantially MORE than 2x. Does anybody out there have any real world experience with a barlowed binoviewer? Thanks in advance,
Larry Seguin
Taos, New Mexico

June 25, 2005 04:29 PM Forum: Equipment Talk

Wavefront error question

Posted By Larry Seguin
So how do you measure wavefront error at the EYEPIECE, anyway? Example: If your primary AND your secondary both have the same measurement (say, 1/15 wavefront leaving the surface of the mirror) then do you have a 1/15th wavefront optical system at the eyepiece? Or do you add the measurements together for (1/15th+1/15th=1/7.5th wave) at the eyepiece? A lot of talk is heard about "diffraction limited" optics, but is that at the primary or at the eyepiece? And what is considered an "acceptable" minimum for wavefront error AT THE EYEPIECE? Any help with these questions would be very greatly appreciated, thanks in advance!
Larry Seguin
Taos, New Mexico

July 6, 2005 02:13 AM Forum: Equipment Talk

Astronomik filters

Posted By Larry Seguin
These have been out for a couple of years now, I understand, but there's relatively little that's been said about them. Have any of the guys out there A/B'd them against Lumicon, and you're willing to render a judgement?
I'm wondering if they're worth pursuing, or is one premium brand pretty much as good as another? Thanks in advance for any input!
Larry Seguin
Taos, New Mexico

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