Building a solar filter for an SPC-8

Hi folks,

I'm currently cutting up a circular cardboard box in order to build a
solar filter for the upcoming Venus transit.

The question is: should I go for an off-center design (which
apparently improves image quality) or should I go for maximum
aperture, i.e. cut a complete ring around the center SCT mirror
obstruction?

If I decide to go for the off-center design, does the hole need to be
exactly circular or can it be elliptical in order to gather some more
light?

I've measured the "business end" of the SPC-8 and it looks like 7,5cm
would be the perfect radius for an off-axis design.

Thanks much in advance for your thoughts and comments,

uwe



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mail replies to Uwe at schuerkamp dot de ( yahoo address is spambox)
Uwe Schuerkamp //////////////////////////// http://www.schuerkamp.de/
Herford, Germany \\\\\\\\\\\\\\\\\\\\\\\\\\ (52.0N/8.5E)
GPG Fingerprint: 2E 13 20 22 9A 3F 63 7F 67 6F E9 B1 A8 36 A4 61

Uwe Schürkamp wrote:
Hi folks,

I'm currently cutting up a circular cardboard box in order to build a
solar filter for the upcoming Venus transit.

The question is: should I go for an off-center design (which
apparently improves image quality) or should I go for maximum
aperture, i.e. cut a complete ring around the center SCT mirror
obstruction?

If I decide to go for the off-center design, does the hole need to be
exactly circular or can it be elliptical in order to gather some more
light?

I've measured the "business end" of the SPC-8 and it looks like 7,5cm
would be the perfect radius for an off-axis design.

Thanks much in advance for your thoughts and comments,

uwe


I don't see why an off center design would improve image quality? I.e. since
when did smaller telescope produce superior images over bigger telescopes?

I have a full aperture solar filter for my C8.

Clear skies
Carsten A. Arnholm
http://arnholm.org/
N59.776 E10.457

Uwe Schürkamp wrote:
Hi folks,

I'm currently cutting up a circular cardboard box in order to build a
solar filter for the upcoming Venus transit.

The question is: should I go for an off-center design (which
apparently improves image quality) or should I go for maximum
aperture, i.e. cut a complete ring around the center SCT mirror
obstruction?

If I decide to go for the off-center design, does the hole need to be
exactly circular or can it be elliptical in order to gather some more
light?

I've measured the "business end" of the SPC-8 and it looks like 7,5cm
would be the perfect radius for an off-axis design.

Thanks much in advance for your thoughts and comments,

uwe


I don't see why an off center design would improve image quality? I.e. since
when did smaller telescope produce superior images over bigger telescopes?

I have a full aperture solar filter for my C8.

Clear skies
Carsten A. Arnholm
http://arnholm.org/
N59.776 E10.457

On Sat, 29 May 2004 00:35:01 +0200, Carsten A. Arnholm wrote:
I don't see why an off center design would improve image quality? I.e. since
when did smaller telescope produce superior images over bigger telescopes?

I have a full aperture solar filter for my C8.

Hi Carsten,

thanks for your reply.

I don't understand either, but it was mentioned in the brochure that
came with the SkySolar filter I bought from the german company Baader
Planetarium, so I thought I'd make sure and ask here first before I
start cutting up that precious item ;-)

Cheers & thanks again,

uwe



--
mail replies to Uwe at schuerkamp dot de ( yahoo address is spambox)
Uwe Schuerkamp //////////////////////////// http://www.schuerkamp.de/
Herford, Germany \\\\\\\\\\\\\\\\\\\\\\\\\\ (52.0N/8.5E)
GPG Fingerprint: 2E 13 20 22 9A 3F 63 7F 67 6F E9 B1 A8 36 A4 61

On Sat, 29 May 2004 00:35:01 +0200, Carsten A. Arnholm wrote:
I don't see why an off center design would improve image quality? I.e. since
when did smaller telescope produce superior images over bigger telescopes?

I have a full aperture solar filter for my C8.

Hi Carsten,

thanks for your reply.

I don't understand either, but it was mentioned in the brochure that
came with the SkySolar filter I bought from the german company Baader
Planetarium, so I thought I'd make sure and ask here first before I
start cutting up that precious item ;-)

Cheers & thanks again,

uwe



--
mail replies to Uwe at schuerkamp dot de ( yahoo address is spambox)
Uwe Schuerkamp //////////////////////////// http://www.schuerkamp.de/
Herford, Germany \\\\\\\\\\\\\\\\\\\\\\\\\\ (52.0N/8.5E)
GPG Fingerprint: 2E 13 20 22 9A 3F 63 7F 67 6F E9 B1 A8 36 A4 61