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Old 09-07-2008, 08:20 PM
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multiweb (Marc)
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Pentax 18-35 lens to QHY8

I have a Pentax *istD with a 18-35mm Lens. Recently purchased a QHY8. If I wanted to piggy back the QHY8 and fit somehow the Pentax Lens onto it what would I require? The 2" nose piece of the QHY8 as a T-thread. The Pentax Lens on the other side has a bayonette kind of attachement.
[I have the piece that does the exact opposite when I used the Pentax body to prime focus on my Newtonian.]

Any pointers would be much appreciated.
Thanks.
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Old 10-07-2008, 12:21 AM
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There are converters around, but cant remember who sells them. They are similar to the ones that SBIG brought out recently, so maybe check what threads they use.
I use the old M42 thread lens's and a spacer. You can pick up some really nice and cheap len's from second hand shops all around.
Maybe cheaper this way, and that way you dont use the main Pentax camera anymore.

Theo.
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Old 10-07-2008, 12:29 AM
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Tandum (Robin)
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Hong Kong Pete might have what you need -> http://www.tan14.com/gears.htm Sh .. it loads cheaper than here.
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Old 10-07-2008, 12:31 AM
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Also this guy on ebay, this is for the Nikon len's to M42. http://cgi.ebay.com.au/Nikon-Lens-to...ayphotohosting Im not sure if Pentax use the same bayonete.

Theo
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Old 10-07-2008, 01:13 AM
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Theo,
I could do with a new guide camera. How much do the 5's cost in Oz now?

The 5's are B&W aren't they?
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Old 10-07-2008, 06:53 AM
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Thanks for the links guys - I'll check it out.
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Old 10-07-2008, 07:01 AM
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Quote:
Originally Posted by Gama View Post
There are converters around, but cant remember who sells them. They are similar to the ones that SBIG brought out recently, so maybe check what threads they use.
I use the old M42 thread lens's and a spacer. You can pick up some really nice and cheap len's from second hand shops all around.
Maybe cheaper this way, and that way you dont use the main Pentax camera anymore.

Theo.
Does the adapter replace the nosepiece/filter all together (i.e. you open the box and expose the sensor) or do you fit it on top of the existing filter? Sorry if this sound like a stupid question, I'm totally new to filters, adapters and what not.
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Old 11-07-2008, 12:13 AM
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Quote:
Originally Posted by multiweb View Post
Does the adapter replace the nosepiece/filter all together (i.e. you open the box and expose the sensor) or do you fit it on top of the existing filter? Sorry if this sound like a stupid question, I'm totally new to filters, adapters and what not.
Marc, always assume the filter is permanetly mounted.
The only time you will ever remove the filter is to clean the sensor or replave the filter with another filter, eg. UVIR Block to clear filter.

The filter has a T thread on the front so you can mount accesories to it.

I too use a MPCC and use a spacer from the Meade f3.3 reducer kit.

Although you can get spacer kits of many different lengths, their may be someone there that is not using one of theirs from their own kit that may sell one.

Theo.
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Old 11-07-2008, 12:14 AM
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Quote:
Originally Posted by Tandum View Post
Theo,
I could do with a new guide camera. How much do the 5's cost in Oz now?

The 5's are B&W aren't they?


PM sent.

Theo
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Old 11-07-2008, 12:51 PM
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Thanks Theo - If I was to use a WO 2" APO field flattener, 0.8x on the Orion ED80 [F7/5] am I likely to get any vignetting on the QHY8 sensor or It's all good?

Quote:
Originally Posted by Gama View Post
Marc, always assume the filter is permanetly mounted.
The only time you will ever remove the filter is to clean the sensor or replave the filter with another filter, eg. UVIR Block to clear filter.

The filter has a T thread on the front so you can mount accesories to it.

I too use a MPCC and use a spacer from the Meade f3.3 reducer kit.

Although you can get spacer kits of many different lengths, their may be someone there that is not using one of theirs from their own kit that may sell one.

Theo.
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Old 11-07-2008, 10:55 PM
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Vignetting is dependant on the light path to the sensor. The QHY-8 has a clear window of 40mm, and the sensor is 28.4mm diagonally, so the camera doesnt have an issue, check to see that you have nothing to prevent all the light from reaching the sensor.

BUT, the sensor has microlensing, and you may need a flat field to remove the gradient it may cause due to this effect. Any CCD with micro lensing will have possible issues with wide angle len's or mirrors.

Theo
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