My advise: don't worry about the details. Make one from cheap material and try it out.
I second that!
Posted 04 September 2008 - 08:09 PM
My advise: don't worry about the details. Make one from cheap material and try it out.
Posted 04 September 2008 - 09:51 PM
Posted 04 September 2008 - 09:58 PM
Posted 04 September 2008 - 09:59 PM
Posted 04 September 2008 - 10:03 PM
O.K. Just so I understand the formula correctly, FL*3 / 175(mean)= the total width. Then the width is divided into a slot & a bar? My scopes FL is 2024. So that would be 2024*3=6072 /175=34.6mm. The slot would be 17mm & the bar would be 17mm, correct?
Does the first 20° slot intersect the circle center, cause from what I can tell, it looks like the two angeled slots intersect short of center, Or is this not critical?
Does the number of slots matter?
Posted 04 September 2008 - 10:06 PM
Did you put the center strap off-center on purpose? I put mine in the middle. I suspect it doesn't matter but I'm curious if you had a reason.
Posted 04 September 2008 - 10:23 PM
Naw, not really. I just quickly reworked my existing drawing to lessen the overall light blocking. The off center bar does not affect anything. It just makes a center brace for the overall structure and 'covers' where all the cutouts would otherwise meet.
Posted 04 September 2008 - 10:25 PM
I'll have to look at optimizing this a bit more to see if I can make the pattern 'sharper'.
Posted 05 September 2008 - 08:23 AM
Good idea. I was thinking about my struggles with my cardboard Hartman mask, and when you mentioned this I remembered I had a big piece of leftover foam board from a different project. I'll probably still have trouble cutting it out, but not like dealing with corrugation.I glued the paper mask on a piece of foam board
Posted 05 September 2008 - 08:30 AM
Good idea. I was thinking about my struggles with my cardboard Hartman mask, and when you mentioned this I remembered I had a big piece of leftover foam board from a different project. I'll probably still have trouble cutting it out, but not like dealing with corrugation.
- Gus
Posted 05 September 2008 - 08:53 AM
Posted 05 September 2008 - 08:56 AM
I'm thinking I'm going to make a square mask, with tabs for the edges of the OTA. I don't want it to ride on the mirror / spider vanes anyway, so if it's on the outside, why does it have to be circular?
- Gus
Posted 05 September 2008 - 10:06 AM
I'm thinking I'm going to make a square mask, with tabs for the edges of the OTA. I don't want it to ride on the mirror / spider vanes anyway, so if it's on the outside, why does it have to be circular?
- Gus
Posted 05 September 2008 - 10:19 AM
Posted 05 September 2008 - 11:20 AM
Posted 05 September 2008 - 11:25 AM
Posted 05 September 2008 - 11:34 AM
Here is the front.
Posted 05 September 2008 - 12:24 PM
Posted 05 September 2008 - 12:29 PM
Posted 05 September 2008 - 01:39 PM
Nice work folks! Looking good!
Chris - Have you tried removing the Popsicle stick that is blocking the middle slit to see if there is a difference in the clarity of the center diffraction spike? I am curious if there will be a difference.
Cheers!
Posted 05 September 2008 - 01:49 PM
Posted 05 September 2008 - 02:00 PM
Posted 05 September 2008 - 02:03 PM
I tried one too, will give it a test run tonight. Scaled the drawing (Thanks Snowdragon!), printed, glued it to a piece of cardboard from the back of a pad of notebook paper, cut a plastic container lid that is a close fit, done. Cost $0. If I like it, I plan to buy John's...
Jim
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