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04-13-2019, 09:13 AM - 2 Likes   #61
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Pentax Q & Q10 : IR-cut Filter Removal !

QuoteOriginally posted by kayakfari Quote
It's a 1.2mm fisheye 220 degrees. I just wanted a REALLY wide circular FE lens on the Q!
It looks the same as this one:
https://www.aico-lens.com/product/1-2mm-16mp-4k-fisheye-lens-ac1612mm/
.
220° Lens for the Pentax Q ?
4.2 mm Image Circle, more suitable for 1/3"-1/4" ?
At 2.1 mm from the center =~ about 37° Oblique Rays on the Pixels ?!
in the imx144 Specs, Sony measures Oblique Rays = 0-20°
and =~45° on the Protective Glass !?
.
Thus you'll have to Cut its IR-Filter-Box at less than 2 mm from the Sensor's Protective Glass !
... If you suppose the Sensor's Protective Glass to be 0.6 mm Thick :
http://mecastronics.free.fr/PentaxQ10AstroIR.html
( = the thickness of the IR cut Filter )
.
QuoteOriginally posted by kayakfari Quote
... BUT I was thinking that it may be even easier to just swap it out with an Action Cam lens (also M12 mount).
.
In the Kayak World, that wouldn't be too hard to get some friend lend you his Action Cam ?
One with 12 MP 1/2.3" sensor and the capability to record a Raw File...
... so you could evaluate the Aberrations ?
Especially the - Red Side - Chromatic Aberrations...
.
Can't wait to see the results...



Last edited by geo444; 04-13-2019 at 10:54 PM.
07-22-2019, 11:52 PM - 1 Like   #62
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@geo444 I now have an spare old working Q that I will start my IR filter removal surgery following your process. 1st to have a Q body with which I can do daytime IR photos and then can consider attempting deep space Astro.
08-02-2019, 06:49 PM   #63
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QuoteOriginally posted by kayakfari Quote
It's a 1.2mm fisheye 220 degrees. I just wanted a REALLY wide circular FE lens on the Q!
It looks the same as this one:
https://www.aico-lens.com/product/1-2mm-16mp-4k-fisheye-lens-ac1612mm/

So I will probably cut out the IR filter in a spare Q "sensor guts" that I have laying around and then try to connect that to the "rest" of my Q.
This way I can always switch back the original if I want to .. BUT I was thinking that it may be even easier to just swap it out with an action cam lens (also M12 mount).

@kayakfari, For that fisheye
You can probably do some work on the back of the lens itself to shorten it. There is an extra ir cut filter right on the end which we don’t need on a Q. Take off a couple mm maybe enough if you try. 16MP lens is very high resolving power and I would love to use it on a Q myself !

Last edited by 2old4toys; 08-02-2019 at 07:01 PM.
08-16-2019, 08:26 AM   #64
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Thanks! I thought about that but it looked like the IR glass was just a very thin cap at the end. So I didn't think it would help much. Now that you've cut out the Q IR cut filter no need to mess with the lens!

02-25-2020, 08:00 PM - 1 Like   #65
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Back onto Astro on a Q (now I have my Q body with the IR cut removed)
Looking to do prime focus on an old 1000mm reflecting telescope that is waiting for me.
To connect the Q body to the telescope without any eyepiece optics, I’m thinking to use a typical PQ - C mount adaptor. Then screw in a C to 1.24” adaptor. Hope it just drops into the telescope and can infinity focus without any extenders or need to further shorten anything else.

Also how about putting a filter on the end of the 1.25” tube to stop dust falling onto the q sensor?

Like this...

With one of these


Waiting for an EM-1 motor to make the rig track stars across the sky. Excited to put it all together. At the moment, don’t even know if the telescope works on its own.

Last edited by 2old4toys; 02-25-2020 at 11:58 PM.
02-27-2020, 12:26 AM - 2 Likes   #66
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I already replied to 2old4toys via PM, but anyway. In the past I made this post about removing the eyepiece adapter on the focuser, that's one way to achieve infinity focus on my Newtonian scope (but it might not be enough depending on the scope).
https://www.pentaxforums.com/forums/136-pentax-q/292702-astro-nature-telesco...ml#post3217010

Since that post, I thought that unscrewing focuser adapter ring each time I want to take a picture is annoying, so I modified Q-C adapter to remove about 5mm or so.

In the attached, to the right is the original Q-C adapter, to the left is a modified Q-C adapter with C-1.25" adapter. If I make the second one, I'll just throw away the inner ring of the Q-C adapter, make the C-1.25" adapter sit flush on the surface where the ring used to sit, and epoxy the two together, taking time to make sure that the two parts are concentric. That's basically what I did except that I machined the Q-C adapter, that was unnecessary. Originally I planned to make this a three-part system that are screwed together, but before making the third part I thought that epoxy might work as well, tested it (JB Weld) and was satisfied with the strength.

Anyway, on my scope, with this modified adapter I don't have to remove the eyepiece adapter.
Attached Images
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PENTAX Q7  Photo 
View Picture EXIF
PENTAX Q7  Photo 
02-27-2020, 01:31 PM - 1 Like   #67
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Hmm, I wasn't thinking it through, machining was necessary after all for my purpose.

If I didn't machine it, the outer part of Q-C adapter would have interfered with the focuser adapter ring, and I'd have only gained ~1mm (basically the thickness of the lip of C-1.25" adapter) instead of ~5mm.
02-27-2020, 07:19 PM   #68
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QuoteOriginally posted by kwb Quote
If I didn't machine it, the outer part of Q-C adapter would have interfered with the focuser adapter ring, and I'd have only gained ~1mm (basically the thickness of the lip of C-1.25" adapter) instead of ~5mm.
Thanks for sharing the images, it gives me a very good idea of what I need to do for the perfect setup. I’d love just to be able to pull out the optic and drop in the Q like you do. How much wiggle room do you have now to focus the Q with the side knob on the eyepiece holder. Is it nothing at all or still have a few millimetres buffer before hitting the limits of downwards travel.

Also how about adding some kind of glass filter on the end of the C - 1.25” tube to help minimise dust and debris that can get attracted to the exposed Q sensor.


Last edited by 2old4toys; 02-27-2020 at 07:38 PM.
02-28-2020, 03:34 AM - 1 Like   #69
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I have no problem at all to focus using standard C/PQ adapter plus C-1,25 in my Newtonian. It is not true for all my other cameras, but for Q it works. I'm just putting the eyepiece cap on the eyepiece adapter when not used.
02-28-2020, 07:28 AM - 1 Like   #70
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2old4toys, there's a couple mm of headroom left.

Piotrek K, good to know that your Newtonian doesn't need anything special! I tried my Q7 with the machined adapter on my friend's 10" Dobsonian, it didn't reach the infinity but I didn't have audacity to ask if I can remove eyepiece adapter as it looks so nice and expensive.
I'm not that worried about dust as the sensor is facing down, not up, when in use. Like Piotrek K, I put my 1.25" eyepiece cap when not in use.
03-08-2020, 10:33 PM   #71
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@kwb, cheers, do I spy some nice interior black flocking you added as an additional mod to your c->1.25” adaptor? Is it something sticky-backed to buy from amazon?
03-09-2020, 10:44 AM - 1 Like   #72
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QuoteOriginally posted by 2old4toys Quote
@kwb, cheers, do I spy some nice interior black flocking you added as an additional mod to your c->1.25” adaptor? Is it something sticky-backed to buy from amazon?
Sharp eyes!
Yes it's sticky-backed flocking I bought it from scopestuff.
ScopeStuff

I don't know if that's better than something available on Amazon, but this thing works. It's much better than any matte black paint I've tested including but not limited to chalkboard paint.
07-19-2020, 07:57 AM - 7 Likes   #73
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Given how Hong Kong has less than ideal conditions, as a novice 1st timer, I am pretty chuffed with this early result. Can make out the Milky Way from the raw file, shot with my Pentax Q-S1 and 02 standard zoom at its widest. ISO400, 30 second exposure aided by the Sightron nano.tracker.
07-20-2020, 05:45 PM - 1 Like   #74
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QuoteOriginally posted by 2old4toys Quote
Given how Hong Kong has less than ideal conditions, as a novice 1st timer, I am pretty chuffed with this early result. Can make out the Milky Way from the raw file, shot with my Pentax Q-S1 and 02 standard zoom at its widest. ISO400, 30 second exposure aided by the Sightron nano.tracker.
Great shot! That's Hong Kong? Looks kinda like the high desert ..
08-18-2020, 09:21 PM   #75
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QuoteOriginally posted by kayakfari Quote
That's Hong Kong?
Yup, was amazed to find Hong Kong has such scenery.

Finally back in the UK now and have access to my bargain yard sale 1000mm reflector scope for the 1st time. Took my 1st Q images today of the Sun and then Mars. Very excited.

Have a newb question, I took apart scope for cleaning and with the focuser was surprised to find a glass element at the bottom of it, could be a lens or a filter of some kind. I left it and without further stack shortening, found I could already rack focus to infinity to the Sun/ stars with my IR modified original Q.

Question for anyone who would know: Should I remove that glass in the focuser for sharper “prime” focus?

Can’t wait to shoot my 1st nebula on my Q.

Mars tonight, Pentax Q no cropping 1/100s ISO 1250
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