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Old 20-09-2013, 09:43 PM
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Spookyer (Brett)
Brett P

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how to connect ccd to flattener

Hi all

I just got my WO adjustable flattener type 4 out and attached it to my WO FLT132 scope for the first time. The end of the flattener has a thread that I can attach a t-ring to and therefore my DSLR.

Call me silly but I take it one adjusts the flattener to help obtain focus? How does this work in conjunction with the focuser?

I am looking at getting a ccd camera like the sbig STT8300M, they seem to have a connection that you shove into the tube type thing. How would one attach a CCD camera to the flattener?

If I am missing something happy for someone to set me straight
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Old 20-09-2013, 09:59 PM
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acropolite (Phil)
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There's a specific distance requirement from the flattener to the CCD sensor, I don't know what it is for your combination but I'm sure someone else will be able to answer that. For connection there are usually adapters available to suit the camera/reducer combination.
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Old 20-09-2013, 10:12 PM
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RobF (Rob)
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Wow, sounds like things are coming along Brett! Must be one nice scope now you have it in your hands?
You've pretty well got 2 choices for joining things up usually - adaptors with 2" fittings with thumbscrews (like you'd use for eyepieces) - easy, fast to rotate, potentially more movement (bad).

OR screw in fittings - firm hold, but more time to fit and usually you have to work to get the right spacings. For DSLRs and T-rings usually not too bad, for often for CCDs you might have to resort to specialty adaptor makers (e.g. Precise Parts)

This also often helps ensure your new hobby remains financially extravagent
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Old 21-09-2013, 12:01 AM
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2stroke (Jay)
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55mm from corrector to ccd, with my ossp v2 aka qhy8l i just got sorted the other week being in the same boat lol. My ccd sensor was 10.7mm inwards used a 5mm t2 spacer between the nose ans camera then the nose goes into the corrector/reducer i'am using making it 55.7mm. From what i understand most correctors ect use a 55mm distance and the badder one has a tolerance of +/-1mm. My T2 thread is at the base of the camera which is great as theres no vignetting as this then goes to the nose piece to a 48mm thread, my sensor is a APS-C size. Anyhow thats how i'am running mine though still haven't had time to crack off some real shots.
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Old 21-09-2013, 11:48 AM
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Spookyer (Brett)
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So I guess the fact my flattener has 66 to 86 marked on it means I have 20mm of play?

Just thinking aloud here, so to adjust the flattener I would set it to some given amount and then rack the main focuser in and out and see if I can focus, if not adjust the flattener slightly and repeat?

Is there a quicker way of doing this?

Brett
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Old 21-09-2013, 01:07 PM
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Spookyer (Brett)
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I had a play last night the WO page says the recommended distance is 71.5mm for my scope with no other explanation other than a technical looking diagram that only someone who already understood the issue completely would be able to make sense of.

I set the flattener to an estimate of 71.5mm (there is no gradation on the scale, just min of 66 middle of 76 and max of 86) took a shot and it looked pretty good. I tried some other settings but gravitated back to around 71mm so tightened it down there. I noticed the effect is not even across the entire frame, some corners had more rounded stars than others depending on small adjustments to the settings so I just went for what looked best overall. I guess that is all there is to it.

Last edited by Spookyer; 22-09-2013 at 07:15 AM.
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Old 24-09-2013, 11:23 AM
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White Rabbit
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I have the same Reducer/Flattner.
Download the trial version of CCD inspector from CCD Ware. It will analyse the image and tell you how flat your image is. It takes the guess work out of it. It gives you a 3D curvature map so you can make the correct adjustments. Otherwise is a frustrating trial and error approach. Remember that you have to refocus after every adjustment.
You may still need to have spacers in between the camera and the flattner to achieve the flattest field possible.
With my STF-8300m, I'm using an Orion flattner an I have a filter wheel and about a 2cm spacer between the corrector and the wheel. I haven't used the flat 4 on this camera but the principle will be the same. You may or may not need the spacer.

Link to CCD Inspector http://www.ccdware.com/products/ccdinspector/
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