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Trying to Figure Out Flip Mirror

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#1 js10

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Posted 21 November 2020 - 06:26 PM

First of all, I'm not sure if this is the correct category for this question, but since this piece of equipment is, I believe, used primarily for planetary imaging, I thought it seemed appropriate. If not, feel free to move. 

 

Anyway, my newest acquisition in terms of equipment is a flip mirror, but am having a hard time figuring it out (and good luck contacting the manufacturer in China on this). First of all, so I put the eyepiece in the hole on top of the device, and then I guess the way it works is that I push the little levers on the side down, and then I should no longer see the object through the eyepiece but should then be able to see it on my laptop screen through the camera attached at the end? If so, it's not working. I can see the object basically perfectly centered in my eyepiece, but then once I push down the levers, it doesn't appear on my laptop screen at all. Any idea what can be wrong?

 

Also, the one I have has something called a "microfocuser." I assume that's the dial with numbers at the end of the device. If so, do you just turn it to adjust the focus? How is that any different from the focus dial that already comes with the telescope?

 

I hope this all makes sense. Again, I really should be able to ask the manufacturer these questions, but apparently that's not really an option, so I'm hoping someone here actually has experience with this type of equipment. Thank you. 



#2 junomike

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Posted 21 November 2020 - 06:34 PM

Sounds like the CCD may not be in focus.  Try setting it up in the day, focusing on a far away target (pole, tree, etc).  You may need to space the eyepiece or CCD to get both parfocal.



#3 js10

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Posted 21 November 2020 - 07:06 PM

Sounds like the CCD may not be in focus.  Try setting it up in the day, focusing on a far away target (pole, tree, etc).  You may need to space the eyepiece or CCD to get both parfocal.

Uh oh. You say the CCD. As stated in my signature, what I have is the ZWO ASI385. As I understand it, that's a CMOS camera, not a CCD camera. That having been said, the description for this product states that it is an "advantage with all cameras" and refers to "popular webcams," which I believe is what my camera kind of is. Please tell me it's compatible! 



#4 Lacaille

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Posted 22 November 2020 - 12:57 AM

The camera is perfectly compatible with it but you may have issues with:

1. the focus - you may be in focus in the eyepiece but not in respect of the camera;
2. The alignment- as I recall there are adjustment screws in flip mirrors so that you can get the eyepiece and the camera well aligned;
3. The camera settings - you may have the gain and exposure too low so the target does not show.

As stated above, start to get these issues sorted using a distant terrestrial target. Then work up to the moon, using high gain to help. You can use your scope’s focuser to adjust focus for the camera, then adjust the eyepiece focus so the two are in tune. Finally you should be ready for a planet!

Regards

Mark
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#5 RedLionNJ

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Posted 22 November 2020 - 01:27 PM

You may well have one or more of a few issues going on.

 

Mark's list is nearly complete, but there's also the point worth remembering your FOV with the 385 is likely significantly smaller than it is with the eyepiece.  This is where a cross-hair eyepiece and a ton of patience for the initial alignment of the flip mirror are invaluable.

 

Now, if you have a variety of flip mirror with no fine adjustments (tip, tilt, etc.) on it, you maybe be simply out of luck. With flip mirrors more than most other astrophotography gadgets, you get what you pay for. A really good one can cost a small fortune.

 

Now, I realize you already bought the flip mirror, so you want to get your money's worth out of it - but a well-aligned 9x60 RACI finder is a MUCH better solution for putting planets on the sensor.


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#6 js10

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Posted 22 November 2020 - 07:28 PM

Okay, two quick points here. First, in order to give it as fair a test as possible, before removing my regular diagonol and attaching the flip mirror with the eyepiece and camera, I was already filming Saturn and therefore had it fairly well-focused on my laptop screen attached the my 385. Now, of course, it's possible that during the act of making this switch, I threw off the focus a bit, but I doubt enough to the point at which it would be totally invisible. So, on that basis, I don't THINK that lack of focus was the issue, unless it could be perfectly focused without the flip mirror but then completely out of focus with it -- I don't know.

 

Second, for whatever it's worth, I paid about $180 for this flip mirror. No, that's not what most people would consider to be a "small fortune," but I've seen others for a lot less. So, even with getting what you paid for, it seems like this should be good enough that I should at least get some image of the object on my screen.



#7 astrovienna

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Posted 22 November 2020 - 09:19 PM

. . .  unless it could be perfectly focused without the flip mirror but then completely out of focus with it -- I don't know.

It definitely can, and almost certainly was.  Whether the image is in focus or not is a function of the distance between the attachment point to the scope and the detector in your camera (CMOS or CCD or DSLR doesn't matter for these purposes).  Unless the diagonal and the flip mirror insert EXACTLY the same distance here, the distance of the detector from the scope will change.  A single millimeter makes a huge difference in focus.  (BTW, ditch the diagonal.  Your flip mirror should be able to take its place.)

 

You need to calibrate your flip mirror.  That means focusing the camera (attached to the flip mirror) first, then focusing the eyepiece part of the flip mirror separately.  It's usually easiest to do this on a distant object in daytime, since it can be very difficult to find a target on a tiny camera chip at night.  If the moon is available, that's a good second choice.  Then you need to use the position adjustment screws/levers on your flip mirror to make the eyepiece part of the flip mirror point at exactly the same position as your camera.

 

After that, life should be a lot easier for you.  Insert your eyepiece, find the target, focus it, and you should find that it's also centered and nearly focused in your camera as well.  Chances are that you'll need to adjust focus, since focus for your eyepiece and your camera will be slightly different.  Your eye can adjust for varying focal positions, but your camera can't.

 

Let us know how it works out.

 

Kevin


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#8 js10

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Posted 22 November 2020 - 11:59 PM

Thank you astrovienna! Okay, I guess where I went wrong is thinking that flip mirrors are "plug and play," so to speak. Just attach the lens and camera and whatever's in my eyepiece will just perfectly appear on my screen and I can just start recording -- no work required. But hopefully once I get the initial work done, as you say, my life will be a lot easier. 

 

Oh, and I probably will ditch the diagonal now. The only reason I was using it last time is that it's what I'm used to. Again, my plan was to then swap it out for the flip mirror once I had the object on my screen and just go with that instead, but that was made more difficult by the fact that then I lost the image! 




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