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Advice for "right side up image" device Cassegrain

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6 replies to this topic

#1 KewlToy

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Posted 30 June 2013 - 07:42 PM

I'm hoping for advice for the device I need to correct the upside-down image in my Orion StarMax 127mm Cassegrain.
web page

I understand that it is possible with one device to get things swapped right side up, but then right/left will be swapped?, and that may be fine.

Is there a decent device that corrects both? up/down and right/left?

Should I avoid swapping right/left? (quality loss?)

Advice on decent namebrands? names of devices?

#2 SeattleScott

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Posted 30 June 2013 - 09:13 PM

There are erect image diagonals for daytime use. But not recommended for nighttime use.

#3 Kraus

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Posted 01 July 2013 - 03:08 AM


Get used to it. It takes more glass to get it the way you want it; more glass=more light loss.

#4 Jon Isaacs

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Posted 01 July 2013 - 05:02 AM

I'm hoping for advice for the device I need to correct the upside-down image in my Orion StarMax 127mm Cassegrain.
web page

I understand that it is possible with one device to get things swapped right side up, but then right/left will be swapped?, and that may be fine.

Is there a decent device that corrects both? up/down and right/left?

Should I avoid swapping right/left? (quality loss?)

Advice on decent namebrands? names of devices?


Hi:

Any star diagonal, that is a single reflection prism or mirror will erect the image if the diagonal is oriented vertically, the image will be reversed left and right. The 127mm Starmax comes with a mirror star diagonal so you should be set.

There are diagonals to correct for both top to bottom and left to right but they have a rather complicated light path that typically results in reduced sharpness at higher magnifications.

Jon

#5 KewlToy

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Posted 03 July 2013 - 05:15 AM

Thanks for the information and advice!

#6 Tony Flanders

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Posted 03 July 2013 - 08:45 AM

I'm hoping for advice for the device I need to correct the upside-down image in my Orion StarMax 127mm Cassegrain.


OK, I'm baffled. Are you sure that the image in your Mak-Cas is upside down? That shouldn't be true unless you're viewing straight-through, with an extension tube instead of a diagonal -- something that few people do.

Have you viewed terrestrial objects to verify the orientation? It's kinda hard on celestial objects, which don't usually have an obvious "up."

If you're using a normal diagonal, your view should be right-side up and mirror-reversed left to right.

#7 KewlToy

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Posted 04 July 2013 - 02:04 AM

I'm hoping for advice for the device I need to correct the upside-down image in my Orion StarMax 127mm Cassegrain.

OK, I'm baffled. Are you sure that the image in your Mak-Cas is upside down? That shouldn't be true unless you're viewing straight-through, with an extension tube instead of a diagonal -- something that few people do.
Have you viewed terrestrial objects to verify the orientation? It's kinda hard on celestial objects, which don't usually have an obvious "up."
If you're using a normal diagonal, your view should be right-side up and mirror-reversed left to right.


Hmmm, I got this unit used from a co-worker. He mentioned the upside down image issue. I am assuming it still has the stock diagonal. web page
I did view terrestrial images at the beach... (guilty as charged) (and yes they are still pretty upside down)

I just noticed that this Orion Apex unit comes with a correcting diagonal.
web page

Anyway, it sounds like I simply need to get an image correcting diagonal?

Removing the diagonal and eyepiece, and just looking throught the barrel showed right-side up images, but with the expected hole in the middle mirror issue.


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