RE: [APML] Re: Bisque IFocus eyepiece

["John Lanoue" <johnlanoue@hotmail.com>]

Hi Emmanuele,

I fumbled around in the dark for about a year trying to find cheap 
alternatives to the SoftwareBisque IFocus before finally biting the bullet 
and shelling out the $140.  I'm glad I did, it works every time and now find 
and focus with the st-4 is just one more simple step.  I use it in 
conjunction with different scopes, so that makes it very worthwhile for me.  
If your st-4 is used only with one guidescope or pick-off prism, then you 
might consider just finding perfect focus once and noting that with a 
lockring on one of the other suggested eyepieces.

One down side of the ifocus eyepiece is that the human eye has, I think, a 
3% 'correcting' factor where it will automatically focus an image (star) 
inside of a certain range on both sides of the focal cone.  So the ifocus 
gets you very close, but you still need to muck with focus by a hair and 
reading the st-4's brightness value to get the best focus.

john

John Lanoue
Principal Software Engineer
Bedford, NH
http://www.geocities.com/johnlanoue/





>From: Emmanuele Sordini <vega@bloomingstars.com>
>Reply-To: Discussion of Film Astrophotography <astro-photo@seds.org>
>To: Discussion of Film Astrophotography <astro-photo@seds.org>
>Subject: [APML] Re: Bisque IFocus eyepiece
>Date: Thu, 11 Dec 2003 10:01:59 +0100
>
>apml@andreasroerig.de Scrive:
>
>>
>>Hi Emmanuele,
>>
>>I don't have any experience with the eyepiece from Bisque but I found
>>that the Vixen LV 9mm eyepiece is parfocal with the ST4. I use it to
>>focus my ST4 for several years now and it works great.
>
>Did you have to add some setting ring, or did it work just fine right out 
>of the box? This could be a better option than an IFocus eyepiece, because 
>the Vixen unit could make a fine accessory for visual use too.
>
>>I never was able to get a better focus than I got with this eyepiece.
>
>Do you focus visually? I ask you this because I wear glasses, that might be 
>a hindrance to using any kind of eyepiece.
>
>>However you can use
>>almost every eyepiece in combination with one or two 1.25" setting
>>rings.
>
>I don't have any setting rings at hand... but I'll try looking from them.
>
>>That means you once focus the ST4 by using a computer and
>>Hartmann mask or whatever, lock the focuser of your guidescope and then
>>slide in the eyepiece as far as needed to reach focus. Then you lock
>>this position on the eyepiece with the setting ring. It may happen you
>>need a setting ring on the ST4 as well to reach the focus with the
>>eyepiece.
>
>That's a good idea: have you ever tried it? If that's the case, what 
>software do you use to focus the ST-4? Since I don't have any old DOS PC, I 
>guess I'll have to try searching for some a program running under Windows 
>(ME/2000/XP).
>
>Thanks anyway,
>Emmanuele _______________________________________________
>Astro-Photo mailing list
>Astro-Photo@seds.org
>http://seds.org/mailman/listinfo/astro-photo

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