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2" Filter Wheel with visual back / for visual use

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#26 tonyt

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Posted 20 June 2011 - 07:20 PM

put together:

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#27 junomike

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Posted 24 June 2011 - 10:17 AM

Tony, Thanks for the updated pics and parts info. I have one question though. Are you using the Filter wheel in a Diagonal or just as is in a Newt? (Your first pic shows It in a Diagonal and your last pic shows It without). Reason I ask is I currently use an EarthWin PFS-DBSE which has the two filter sliders. I noticed that when using my UO 40mm MK70 or 42mm LVW there was severe Vignetting. Turns out that the EarthWin eyepiece collar has a threaded Dovetail (so It can easily be swapped out for direct attachment of Binoviewers) and is roughly 1.75" in diameter, not a true 2"! Once I swapped the EarthWin set up for my StellarVue Diagonal (which has almost 2"), the Vignetting went away. Have you experienced any Vignetting with large F/L EP's (40mm) with the new larger aperture parts?
I know the WO Diagonal (as well as others) are not quite 2" either due to tapering in the eyepiece collar.

Mike

#28 tonyt

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Posted 24 June 2011 - 07:45 PM

Hi Mike, the pics above were just to show a possible combination that was requested by Lane. I'll be using the filter wheel with a diagonal.

I've got the wheel connected to a GSO diagonal. The smallest thread is the inside of the M48 thread used to connect parts to the wheel, giving a clear aperture of 44mm. Due to poor weather I haven't had the chance to use it with the C11 and 41mm Pan, but it's sunny today so maybe tonight.

Unfortunately the Baader sct threaded ring is made to very poor tolerances and I had a hell of a time getting it threaded into the GSO diagonal, so I didn't post a pic of the setup. The diagonal takes the place of the clicklock adapter in the pics above.

The WO diagonal is 40mm CA while the GSO diagonal is 46mm CA.

Tony

#29 tonyt

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Posted 24 June 2011 - 07:57 PM

Mike, regarding the Earthwin vignetting, did you have any of the power changing optics in the light path and is their aperture even smaller than the 1.75" dovetail?

#30 junomike

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Posted 24 June 2011 - 10:01 PM

Tony, Thanks for the explaination. I look forward to your results!
In regards to the EarthWin, I didn't have any optics in the light path. The Dovetail which is threaded into the bottom of the eyepiece collar (to allow for easy changing to Binoviewers via a thumbscrew) is approx. 40mm. The optics themselves are almost the same so, whether you use the lenses or not, the CA is approx. 1.574". I've only had Vignetting issues with the 40mm 70 Deg eyepieces. For those I have a StellarVue Diagonal.

Mike

#31 tonyt

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Posted 25 June 2011 - 08:18 AM

I checked for vignetting tonight Mike using the C11 and 41mm Panoptic. Comparing the filter wheel/GSO diagonal to a Televue Everbrite it was hard to see a difference in the width of the field or the appearance of the field stop (slightly fuzzy in both).

Vignetting could be seen with the slightest turn of the wheel while using an empty filter hole, the holder immediately intruding at the edge of field, so I'm thinking 44mm CA must be right on the border line for interfering with the view through an eyepiece with a 46mm field stop.

In any case, the wheel/diagonal combo works well. On NGC 3372 an OIII gave the best contrast between nebulosity and dark lanes, while an NPB(UHC) filter gave the best detail within the nebulosity.

The filters themselves have about 43mm CA and I thought I could see a bit more edge darkening in comparison to the empty slot.

Tony

#32 junomike

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Posted 25 June 2011 - 11:10 AM

Tony, Glad to hear It all worked out as planned. Your results will help others for sure. I never even considered Filters as a Vignetting source. I have the same as you (Lumicon OIII measures 41mm and a DGM NPB which measure 43mm). Even when threaded directly to the eyepiece there would still be Vignetting so I guess that's one trade off to using Filters. A worthy one though IMHO.

Mike

#33 Mariner@sg

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Posted 13 January 2013 - 12:46 AM

While searching for info on the filter wheel for visual use I didn't find much but I did find this thread, so I'll add another option to the list. The wheel can be joined to a WO diagonal using Baader part # T2-29.


Sorry for resurrecting an old thread. I recently got the same FW and am having trouble joining it to the WO 2" diagonal as suggested by tonyt (Using the Baader T2/M48).

The diagonal uses the same T2 threads as the FW so I should be getting a T2/T2?

I was told there are 2 versions of the diagonal,older which uses the M48 thread while the new one uses T2. Heres a pict of my diagonal (nose piece end)

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