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Where Oh Where Has the Cel. NexImage Camera Gone?

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#76 WarmWeatherGuy

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Posted 21 May 2012 - 12:03 PM

What you're talking about is called afocal photography.

http://en.wikipedia....cal_photography

From my experience I get better pictures with fewer optical elements. The eyepiece projection often gives too much power and not enough light.

The Barlow and Registax will give you the greatest improvement. You can get a used Barlow on eBay for well under $40.

To learn how to use Registax you can go to YouTube and search for Registax and watch some of the videos there. Here is one by AstronomyShed:

Registax 6.Primer
http://www.youtube.c...h?v=ALqQfExMRBA

#77 Tel

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Posted 21 May 2012 - 12:36 PM

Hi HH,

Personally, I would not recommend a-focal imaging before you have good experience of prime focal astrophotography. To be honest, I can't say that I've ever seen it done with a Neximage or webcam but then perhaps, I haven't lived (?) :idea:

I would suggest, (perhaps as before), that you get yourself a Bahtinov mask, (if you don't have one already). Then, with your new Barlow attached to your Neximage, first focus accurately on one of the brighter stars in our skies at the moment.

Once the Bahtinov mask indicates "best focus", slew to your target planet and look for its appearance on your Craterlet screen. The chances are though it won't be there for various reasons; normally attributable to the lesser accuracy of the slew and to the very small FOV presented to the Barlowed Neximage.

As I think I've already mentioned somewhere earlier, no matter: just remove the camera assembly and substitute it with a 25mm EP WITHOUT touching the focuser. You should then see the planetary image you seek, albeit probably blurred, but visible enough to allow its centralisation in the EP. Once centralised, remove the EP and replace it with the Barlowed Neximage which should have remained in focus.(If not make some minor "tweaks" to it but bear in mind that by and large, you will see the image on screen as somewhat of a blur as it "boils" in the Earth's atmosphere) !

Now, with "something" on screen, make your adjustments to Craterlet, (i.e. reducing the Gain so as not to give too bright an image and setting your shutter speed to something less than say, 25 frames/second. Keep the Gamma setting at Zero and make minor adjustments, if you think necessary, to the brightness and contrast. I can't overemphasise though the need to keep the image more on the dim rather than the bright side. Brightness and contrast etc. will come to the image during post capture processing.

Try to capture at least ca. 2000 frames when you're good to go. When you have them, I or for sure others, will certainly help you align and stack them in Registax and indeed take you through the entire process.

Hoping this helps you a little further,

Best regards,
Tel

#78 harioharima

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Posted 21 May 2012 - 01:36 PM

Tel and WWT,

I read the wikipedia article that WWT linked- I am not sure that what I described is afocal photography. In afocal, the camera WITH a lens seems somehow attached to the OTA. I've also seen some pics where a camera (no lens) is attached to the OTA (with no telescope eyepiece).

What I posted seems a bit different (?)-- I want to attach an interchangeable lens camera WITHOUT lens (i.e. sensor only) to the telescope-eye-piece. This 8-24 eyepiece seems have a T-threading on the outside (haven't seen this on other eyepieces).

The great views seen by the naked eye seem bright enough for a MFT camera to capture but I could be wrong.

I do intend persevering along the lines you suggest with the neximage also...the clicking camera would be a side diversion. It will be a bit before i go for the mask approach, but if i manage to record a nice long avi, this is where i will come.

PS: Also thanks for the youtube link, that would probably be the way to learn for someone like me. :-)

#79 Arctic_Eddie

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Posted 21 May 2012 - 02:32 PM

I've used that setup with marginal results. By marginal I mean only narrow FOV and difficulty focusing due to scope vibration. I have the setup in place on an AT80EDTA and ready for the Venus transit. Also present is an improvised mounting plate and my newly built stepper focuser. A photograph is forthcoming. You will need an adapter to go on the EP to accept the camera. Agena has one just for that purpose. The adapter screws directly onto the back of a Celestron 8-24mm zoom eyepiece T threads then accepts any webcam with a 1.25" snout.

http://agenaastro.co...-back-e-10.html

#80 Arctic_Eddie

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Posted 21 May 2012 - 02:44 PM

Here's the photo of a Philips SPC900 webcam mounted on a Celestron 8-24mm zoom eyepiece. It uses the Agena/Blue Fireball adapter. Also present is the stepper focuser. A solar filter will be attached for the Venus transit event.

Attached Files



#81 WarmWeatherGuy

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Posted 21 May 2012 - 03:01 PM

Hario, you're right. I confused afocal with eyepiece projection. Afocal is where you hold your camera up to the eyepiece. Eyepiece projection is where you take the lens off of your camera and hold it up to the eyepiece.

I tried eyepiece projection and it was too dark. I gave up and went the Barlow route. If you can adjust the camera to eyepiece distance you might get something to work.

Look at the pictures on AstroBin and see what other people use. Here is one where someone used both a 2x AND a 3x Barlow.

http://astrobin.com/1698/

#82 Stmag

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Posted 09 March 2013 - 01:46 PM

This may not be the correct location to post this question, but I'll through it out there. First of all my wife and I just bought our first telescope..it's a orion xt8i which is awesome, I also purchased the Neximage 5 to use with my hp laptop which is running windows 7. The software iCap v2.2 that came with it will not install correctly, so I tried Sharpcap and Handyavi. Both programs shut down as soon as I select the Neximage 5. Any ideas what I'm doing wrong?






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