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Icodome now converting DSLRs to true monochrome

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#51 bilgebay

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Posted 30 January 2013 - 07:27 AM

Hi Alfredo,

I am planning to use this camera with Hyperstar. So exposures will be much less than 10 minutes for narrow band and maximum 2 minutes for LRGB exposures, depending on the target. I don't think I will have a problem with the thermal signal.

The Nikons, I just learned from another thread, has 46,5mm back focus from bayonet to sensor. Filter wheel is not an option with camera lenses and Hyperstar. For Hyperstar, I will buy the relevant adapter from Starizona and for camera lenses I will develop a solution to fit a 2" filter inside the camera of an off the shelf solution is not available.

For shooting with a refractor or SCT, I will be using a filter wheel without an issue I believe.

#52 Jim Chung

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Posted 30 January 2013 - 07:34 AM

Hi Alfredo,


Although it's always nice to get a full well of photons, it's not necessary to have 15 minute subexposures for narrowband imaging. I've gotten good data with my QSI532 using the extremely narrow Astrodon 3nm Ha filter with just 5 minute subs. What's important is the SNR and the Nikon D5100 appears to have good noise control so you can get by with much shorter subs. You can see in my earlier posting with the much older D90, I only used 2 minute subexposures with a 2" Baader Ha filter (7nm window) and got very good results, especially for a DSLR!


Jim

#53 Alfredo Beltran

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Posted 30 January 2013 - 08:55 AM

Jim: By all means that is an impressive shot. I think the plus of a mono DSLR is the FOV compared to CCD cameras and the cost.

Sedat: I agree. Hyperstar exposure times are a lot lower, so that will take care of it. At prime focus with a low thermal signal camera and cold ambient temperatures thermal noise shouldn't be a huge issue

Best regards

Alfredo

#54 zerro1

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Posted 30 January 2013 - 09:50 PM

I was wondering about this. Given the size of the APS-C sensor, what filter wheel could be suitable to keep the right focal distance? I also think filters should be 2" to avoid serious vignetting. Do Nikon DSLRs have the same focal distance as Canons (55 mm with T-ring)?


I'm using a Quantix KAF6303E mono camera 33mm diagonal sensor. The snout of the CCD is designed with a nikon lens connection and distance from sensor to lens connection is 46mm. Filter wheel is connected to a Nikon T-ring so I suppose that adds about 10mm. I'm using 2" mounted baader filters in an Orion manual filter wheel and see next to nothing for vignetting at 35 second Luminance and even 10 minute narrow band subs through my AT65EDQ or my AT66ED.

A similar config on one of these DSLR's should work well... at least well enough that flats could clean it up "IMHO".

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#55 MikeCMP

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Posted 06 February 2013 - 06:06 PM

Can someone clear up a little bit of info for me? I have read the 5100 offers "Visually Lossless" compression, whereas the 7000 has a RAW NEF mode with no compression. From what I can gather, the only difference is that the highlights in the 5100 are affected by this, but most reviews of these camera do not use them for super long exposures of star fields :) Since a few folks have both cameras it might be interesting to see if there is a difference, thought how a difference would be measured is beyond my meager abilities however :)

Mike

#56 orlyandico

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Posted 13 February 2013 - 02:30 AM

Jim, so how goes the QHY8 conversion?

I assume after removing the Bayer filter and micro-lenses, the cover plate is still replaced so the sensor is not bare?

Isn't there going to be a measurable reduction in QE with the micro-lenses gone?

#57 fetoma

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Posted 17 February 2013 - 01:22 PM

I believe Jim ran into a snag on the QHY8 and put that project on hold for now.

#58 orlyandico

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Posted 17 February 2013 - 01:37 PM

He told me he has so many Nikons to convert that he's postponed the 8.

In answer to my prior question.. in the KAF-3200 product sheet it shows about 20% reduction in QE if there are no micro-lenses (E vs ME model).

#59 ccs_hello

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Posted 17 February 2013 - 02:44 PM

Please note teh referred KAF3200 mono is a
(1) large pixel 6.8x6.8um,
(2) monochrome (not Bayer array),
(3) full-frame readout (i.e., not interline type) thus much less circuit,
(4) CCD

The story on CMOS RGBG primary-color Bayer 4.78x4.78um active-pixel (typically 4T structure) image sensor is quite different.

Clear Skies!

ccs_hello

#60 fetoma

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Posted 17 February 2013 - 04:14 PM

This is a quote from Jim in another post:

"With regret I have to announce a halt to my QHY8 monochrome conversion development. QHY does utilize a Nikon sensor platform from the D40/D50 family but while very similar and definitely a Nikon product, it is neither a D40 or D50 sensor board but some strange hybrid. Releasing the board was difficult because QHY decided to cover the PCB surface with a silicone sealant which effectively becomes a glue. I must have been tired as well because I damaged the sensor wires while removing the Bayer layer and now have to contact QHY to see if they have any extras. The idea of just swapping Nikon D40 sensor boards is definitely not feasible."

#61 Jim Chung

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Posted 18 February 2013 - 12:41 AM

Had some nice clear skies tonight so I tested a newly converted D7000 for a client in Rome. This is the very large Rosette Nebula. You can see a full sized center cropped version here:

http://dl.dropbox.co...NikonD7000b.jpg

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#62 Jim Chung

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Posted 18 February 2013 - 12:42 AM

Here's a center crop at 100%, no dark subtraction was used since I couldn't really see any thermal noise, a very quiet SONY CMOS sensor.

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#63 Brad

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Posted 18 February 2013 - 10:15 AM

Looks great!

#64 jb300

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Posted 03 March 2013 - 04:28 PM

Hi Jim, I have sort of figured out how to use the monofied Nikon d90 I purchased on my Hyperstar lens equipped N11GPS. I am taking 30 second subs with an Ha Astronomik EOS clip-filter inserted sideways in the Nikon body. Now, 30 seconds is not very long for an Ha image, but I have gotten some decent results. I am not real proficient at processing images, I am just learning, but I am proud of my results and very happy with my monofied camera. I am amazed at the sensitivity the d90 is showing. Just thought you would like to know. I have attached one of my latest images. It is of ngc2359, Thors Helmet, and is a stack of 30 second Ha subs taken with my Hyperstar lens. Thanks for the great camera.
Jim

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#65 Campos

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Posted 04 March 2013 - 06:26 AM

Hi guys,

This is historical....to all that said that it could NEVER be done, remember that when the Wrigth brothers said that man would fly everyone said that they were nuts! Never understimate human ingenuity, remember this.
I cant wait to see more results, please keep us updated of your work.

Best wishes,

Luís

#66 Ricky

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Posted 04 March 2013 - 09:58 AM

Jim,
Great work! What available cams do you have in inventory?

#67 Jim Chung

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Posted 04 March 2013 - 03:09 PM

Hey Ricky,

Since I've moved my conversion to current Nikon DSLR models I've discovered with increasing pixel density comes increasing complexity and danger! I've had success (and failure) on the D90, D5100 and D7000. The D90 is the easiest but the sensor on D5100/D7000 exhibits incredible low noise performance. I'm basically converting cameras on a per order basis but have to stress that you have to be prepared to risk your investment in case of failure (at which I will not charge for my services). This is not meant to be a cheap alternative to dedicated monochrome astrocameras but to give you a DSLR that can shoot in monochrome and all the advantages a DSLR gives (like real IR photography).

#68 guyroch

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Posted 05 March 2013 - 10:02 AM

I've been at the receiving end of a success D5100 mono conversion from Jim... but with every new gear comes the cloud spell. My monofied D5100 has yet to see first light :(

Guylain

#69 Ricky

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Posted 05 March 2013 - 04:28 PM

Thanks Jim!

#70 Ricky

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Posted 05 March 2013 - 04:40 PM

Jim,
Keep us up to date on your camera inventory...im leaning towards picking one up from you!

#71 fetoma

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Posted 14 March 2013 - 08:27 PM

And your QHY8 adventure Jim!

#72 starhunter50

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Posted 24 March 2013 - 08:58 PM

Q? what are you guys using for capture software being a Nikon DSLR? or are you just using the Cards?
Mitch.

#73 guyroch

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Posted 24 March 2013 - 09:07 PM

Q? what are you guys using for capture software being a Nikon DSLR? or are you just using the Cards?
Mitch.


I'm using an intervalometer for now but I'm working on BackyardNIK for Nikon cameras; I'm aiming towards end of calendar year 2013 for a beta release.

I'm really loving my D5100 monosensor camera.

Guylain

#74 *skyguy*

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Posted 25 March 2013 - 11:02 PM

The M42 and Rosette images seem to show significant background brightness variations that mimic nebulosity, but are not actual nebulous parts of these objects and appear to be imaging artifacts. Could this be a byproduct of the process used to remove the color filter layer or possibly frost forming on the imaging sensor?

#75 Cyclop_si

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Posted 27 March 2013 - 12:32 AM

Hi Skyguy,
Can you be more exact which background brightness variations you consider as imaging artefacts?
I have visually compared above image with this one, which I randomly find on internet and looked deep to me:
http://www.aznightsk...s/M42 900-5.jpg
but I can not detect it.






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