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Old 26-01-2015, 04:11 AM
dp297 (Dimitris)
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CCD+Starlight Xpress FW+Nikon

I would like to build a setup consisting of my CCD+Starlight Xpress FW+Nikon 180ED lens. The problem is that since Nikon lenses have a 46.5mm backfocus it is impossible to make this system work without an extremely thin adaptor to connect the lens to the FW.
So far I have been using a TS drawer solution which means using each filter one at the time....(horrible).
Anyone has any ideas whether there might be a vendor or machineshop that can fashion such an adaptor (preferable <2.5mm)? (Nikon lens to M42 mount)
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Old 26-01-2015, 07:17 AM
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gregbradley
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I got a FLI adapter for Nikon lenses for my FLI filter wheel. It recesses into the filter wheel. The only problem with it is it goes in too far and tends to impede the filter wheel. So I leave it slightly unscrewed (1/2 turn). I used a bit of masking tape to stiffen it up as it had very slight wobble which meant some images on one side of the mount were angled slightly differently to the other side meaning it was hard to align the images.

Precise Parts is also the usual place for adapters. Starlight express have quite a few adapters so I would check them first.

I use a Nikon 180 ED at times. Its quite good but it has chromatic aberrations. A better lens would be the Pentax 67 165mm F2.8. Its perfect wide open and you can get cheap adapters off ebay and the lens is further away from the filter wheel giving more freedom for an adapter.

I got an adapter from Precise Parts where he got a t thread adapter and screw fixed it to a machined part to fit my filter wheel.

Pentax 67 75 F3.5 and 165mm F2.8 are fabulous and cheap lenses. Better than the Nikon 180ED. The Pentax 67 300mm EDIF is expensive but is as good as many scopes.

These are the lenses I have used or have seen used and give good results:

1. Pentax 67 - 75mm F3.5, 165mm F2.8, 300mm F4 (some chromatic aberration unless you get the EDIF but the regular 300mm (about $400 2nd hand or less) is good for narrowband. The 75 is worth about $85 the 165 around $100 or so.

2. Nikon 105 F2.5 AIS - very nice, not much chromatic aberration but a bit.
3. Nikon 50mm F1.8D (the g is also good but the D has an aperture ring).
4. Pentax SMC 200mm (not 67) (Marc on this site uses this one and the images are great) also the 150mm.
5. Zeiss 300mm (that'd be expensive).
6. Nikon 85mm F1.8G (good from about F2 on).
7. I don't have many Canon lenses but the 50mm of any brand is usually good. Canon/Nikon 50mm lenses are pretty close in performance.

I would stick to the Pentax 67 lenses as they are cheap, they have more backfocus are very tolerant and have metal construction and manual aperture rings. Most modern lenses need the camera to move the aperture so you need an adapter that will change the aperture (sometimes they hide whether or not it has this ability, if they don't specifically state they do then assume they don't and you'd be right 99% of the time).

Ebay lists millions of adapters that are very cheap.

Greg.
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Old 26-01-2015, 06:18 PM
dp297 (Dimitris)
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Dear Greg,

I appreciate your analytical response very much.
I am surprised that u think that Pentax is a better lens than Nikon 180ED.
I will most certainly look into that.
To tell u the truth I have only used Nikon with narrowband and it was perfect but not with LRGB..so I dont have direct experience other than what I have read on the web.
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Old 26-01-2015, 07:06 PM
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Quote:
Originally Posted by dp297 View Post
Dear Greg,

I appreciate your analytical response very much.
I am surprised that u think that Pentax is a better lens than Nikon 180ED.
I will most certainly look into that.
To tell u the truth I have only used Nikon with narrowband and it was perfect but not with LRGB..so I dont have direct experience other than what I have read on the web.
I use Lightroom to defringe the stars that have blue halos from the chromatic aberration of the 180mm. It works well. That was at F4. Perhaps F5.6 it may clean up more. But the Pentax 67 165 F2.8 is sharp to the corners of a 16803 chip wide open and nice and sharp. The 75m is a very sharp lens and very little aberrations (a few more than the 165 but a wider field of view).

Greg.
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Old 27-01-2015, 07:04 AM
gbeal
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I'll echo Greg's comments on the Pentax lenses. I have the 75mm also. Years ago I used the 200/4, but now only have the 75mm. I know of the 200/4 and the 300/4 here in NZ that are available if you want to try them though, PM me. They are great lenses for astro.

The beauty of the medium format lenses is their generous back-focus, as well as their relative cheapness.

If it helps, I checked, and I have a new Nikon to M42 adaptor (I knew I had one from years back). It fits Nikon lenses onto Pentax M42 cameras I believe, although I have never used it, don't even think it's been out of the packet. Try e bay for these. The one I have is about 8mm "thick".

If you are still wanting to use the Nikkors, get a Nikon mount adaptor fitted directly to your CFW. It will need some slight machining skills, but nothing too hard.
Gary
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