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question about "finding" objects on my CCD

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#1 prefetch

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Posted 15 June 2013 - 08:01 PM

i've started playing around with several different cameras, and what i have found is that the hardest thing is actually *finding* the object!

i mean, i can find it without any problem with an eyepiece and my eye, it's just when i switch to my camera, i can't find the object again, or it takes a really long time to figure out where it is again. it's really frustrating.

how do you solve this problem? a really good finder scope? a wide field autoguider of some sort?

#2 ccs_hello

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Posted 15 June 2013 - 10:15 PM

Goto Mount perhaps??

#3 prefetch

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Posted 15 June 2013 - 10:44 PM

goto mounts will get you close, but when you switch to your CCD camera, the goto computer won't help at all.

how do you do it?

#4 jchaller

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Posted 15 June 2013 - 11:55 PM

I don't switch between eyepieces and camera. I make sure my stock finder scope is properly aligned and perform goto alignment using the camera. I use the Samsung camera and created crosshairs using the privacy mask to aid alignment, but now use crosshairs inside the capture software to do the same.

#5 bhuvfe

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Posted 16 June 2013 - 02:43 AM

What is the FOV of your setup?


I have a CG-5 and generally after two star alignment and 1 calibration star the object is in the center of the field of view (0.4-0.5 degree). I use also a e-finder that is more or less aligned with the main scope and I never switch to eyepieces.

#6 Dragon Man

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Posted 16 June 2013 - 06:59 AM

Your statement tells me that your GoTo's aren't very accurate.

Make sure you are Polar Aligned properly first, then do a good Star Alignment.

The only way you'll have trouble finding an object after that is if you are at too high a magnification (eg: f10) and the object is just slightly off centre, putting it out of the FOV.

Widen your FOV with a faster scope or use a Focal Reducer (or both is even better). :waytogo:

#7 nytecam

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Posted 16 June 2013 - 07:45 AM

i've started playing around with several different cameras......

Why don't you allocate one cam as an e-finder with wideangle lens and forget the regular [optical] finder. Under my severe LP only the brighter alignment stars are easily visible in the latter - certainly none of the faint fuzzies but an e-finder makes short work of them with 1s-2s exp in display loop! Checkout my e-finder :grin:

#8 S.Boerner

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Posted 16 June 2013 - 07:53 AM

I use a flip mirror with a long focal length eyepiece and my camera. I first center the object with the eyepiece then switch to the camera.

As an example when I did the AL's Double Star program I used a C14. A goto would get me close but still a bit away from the actual object. I'd find it in the finderscope and center. A 40mm eyepiece on the C14 gave me a fov of about 30 arcminutes and I'd center the double in the eyepiece (no cross hair on the ep so it was a judgement guess on centering). Switching to my SDC-435 camera gave a fov of 2x4 arcminutes and the double was almost always in the fov of the camera. Without the flip mirror finding the double with that small fov would have driven me crazy. It usually took less than a minute from the end of the goto to centered on the SDC-435.

Good luck

#9 Atl

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Posted 16 June 2013 - 11:05 AM

Don't use an eyepiece and switch to camera...this doesn't work well. Use a cross hair with the camera...like in wxAstrocapture. Then align the telescope using the screen and the camera instead of an eyepiece. I rarely put an eyepiece in anymore while doing video.

#10 jgraham

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Posted 16 June 2013 - 11:32 AM

Ahhh yes, I remember that problem. As others have mentioned it is a good idea to leave the camera installed. My initial fix was to set up a second wide field eFinder using the lens from an old pair of binoculars and a spare camera. That worked very well. The ultimate fix was getting a mount with more accurate GoTos. I still use the eFinder approach when I am doing very narrow field planetary imaging.

My original eFinder...

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#11 core

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Posted 18 June 2013 - 01:01 AM

You can parfocal your camera and framing eyepiece, eg on a 6/8SE setup, I have a f/6.3 FR on the rear port followed by the visual back (standard 1.25"). Since a 90° diagonal is needed so that the camera can clear the base close to zenith, parfocal of the eyepiece/camera is achieved after the diagonal. There is a 0.5x FR threaded to the nosepiece of the camera, you can see the amount of extension tubes required for the eyepiece to come into approximate focus (it bottoms out to the prism, which acts as a 'stop').

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#12 core

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Posted 18 June 2013 - 01:12 AM

For a setup without the need of a diagonal (but still using the f/6.3 and 0.5x FR), this would be the approximate parfocal setup. The prism helps to take up most of the lightpath.

It's easiest to do the parfocal on daytime targets; later at night focus should be done with a bright star on the camera, and then swap out to the eyepiece and fine-tune by moving the ep up and down a little.

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#13 gmussman

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Posted 25 June 2013 - 10:14 AM

I'm following this with interest. I have an 8 inch f4.9 reflector on an Atlas EQ-g, and I have the same problem no matter how picky I try to be with alignment. Throw in frame integration, and it gets super frustrating waiting after every single adjustment -- very hard to hunt around for an object.

Next step for me is a focal reducer to increase FOV. I didn't think of doing the alignment with the video -- going to try that, too.

#14 Busgosu

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Posted 26 June 2013 - 04:47 PM

Seeking in Ebay i saw these interesting lcd monitor with video input, few with autonomous batteries, light and cheap,possibly very useful for astro camera



http://pages.ebay.co...&globalID=EB...


http://pages.ebay.co...&globalID=EB...

http://pages.ebay.co...&globalID=EB...

#15 Dragon Man

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Posted 27 June 2013 - 10:06 AM

Seeking in Ebay i saw these interesting lcd monitor with video input, few with autonomous batteries, light and cheap,possibly very useful for astro camera



http://pages.ebay.co...&globalID=EB...


http://pages.ebay.co...&globalID=EB...

http://pages.ebay.co...&globalID=EB...


I can speak highly for the first link.
Those little monitors work great with our AstroVideo cameras.
A friend of mine uses one with a Video camera as his finderscope.

As for the other 2 links, I've never seen them before.

#16 Dwight J

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Posted 27 June 2013 - 11:16 AM

One way to improve pointing is to goto a bright star near the object, center it, sync on it, and then goto the object.






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