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3-Camera Wide Field Astrograph

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#1 hbastro

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Posted 13 July 2014 - 11:07 PM

Here is a CAD rendering of a 3-camera astrograph assembly and off axis guidescope. The parts are with a local machinist being made. I hope to have it operational next month.

Posted Image
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#2 Christopher Erickson

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Posted 13 July 2014 - 11:46 PM

Impressive!

#3 GJJim

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Posted 14 July 2014 - 12:52 AM

Dave,
I see there are focus motors for each lens. Are you using the new Starizona driver to control them, or something different?

#4 David Pavlich

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Posted 14 July 2014 - 07:56 AM

Just too cool! What would be terrific is if you can get the machine shop to take pictures of the progress of the project. That would make for a great write up and will certainly be great entertainment for we equipment junkies! :ubetcha:

David

#5 hbastro

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Posted 14 July 2014 - 09:13 AM

Thanks for the comments. I'll post progress for the like minded equipment junkies...

Here is a CAD rendering of it in the RoboDome, it was tough getting it to fit in that little dome... Posted Image

#6 hbastro

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Posted 14 July 2014 - 09:18 AM

I have a bunch of Robofocus controllers and motors leftover from a project years back. I had planned on using them. I wasn't aware of the Starzona equipment, thanks for the lead, I'll check it out.

#7 GJJim

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Posted 14 July 2014 - 11:13 AM

I have a bunch of Robofocus controllers and motors leftover from a project years back. I had planned on using them. I wasn't aware of the Starzona equipment, thanks for the lead, I'll check it out.


The latest MicroTouch USB driver supports up to four focusers. Getting one app to run all of them is another story :grin:. Bisque says that *some day* their camera add on will handle simultaneous multiple imaging sessions. And AFAIK, Sequence Generator Pro is the only app available now that recognizes the four available focusers when connected to the MicroTouch box. It would be interesting to see how multiple instances of SGP (or Maxim) would work in a system like this.

#8 hbastro

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Posted 14 July 2014 - 11:34 AM

Hi Jim,
Agreed, it would be nice to run multiple sessions on a single computer. Seems a misuse of resources but each camera has its own computer. The guide scope will share one of the STIL11000m cameras and that computer will have two imagers and two focusers to control. Only one focuser at a time as the guide scope only needs refocus occasionally.

I am currently running two cameras in the larger dome and synchronization of images is an issue. I just make sure that the integration times are the same and take a minimum of 3 imgages to assure the slave camera gets at least 2 prior to slewing to another object. It will be a lot more complicated with 3 cameras running. Do you know of a solution?

Regards,
Dave

#9 GJJim

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Posted 14 July 2014 - 05:50 PM

Hi Jim,
Agreed, it would be nice to run multiple sessions on a single computer. Seems a misuse of resources but each camera has its own computer. The guide scope will share one of the STIL11000m cameras and that computer will have two imagers and two focusers to control. Only one focuser at a time as the guide scope only needs refocus occasionally.

I am currently running two cameras in the larger dome and synchronization of images is an issue. I just make sure that the integration times are the same and take a minimum of 3 imgages to assure the slave camera gets at least 2 prior to slewing to another object. It will be a lot more complicated with 3 cameras running. Do you know of a solution?

Regards,
Dave


With the small form factor PCs available now (fanless, NUC, etc.) it might make sense to have each camera on its own controller with separate USB busses and data storage. Synchronization is a question -- does an offset of a few seconds matter for 5-minute subs? The newer cameras from QSI, QHY, and Atik all have external trigger inputs to sync exposures for multiple cameras. It's a feature used for machine vision setups but it would work for your three-channel imager.

#10 hbastro

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Posted 14 July 2014 - 07:57 PM

Hi Jim,
With this setup I'll have a total of (6) small computers on the mountain. One running 24-7 for network, weather, allsky camera. The other (5) each control a single astrograph camera. The master has mount control and scripting for imaging sessions. Because the facility is "off the grid" and completely solar powered these are low power units from Stealth Computers running on 12 volts and only consuming 36 watts each. As you know this is much less than the cameras they control. I write data directly to a NAS RAID-mirror using SSD's. I had planned on a watchdog program that would commumicate the file write status of the two slave cameras to the master and delay slewing until file writes had started. I'll look into the trigger but I don't think its a feature with the SBIG cameras...

Thanks again for the input any additional thoughts would be appreciated.

Best regards,
Dave

#11 hbastro

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Posted 15 July 2014 - 09:25 PM

Well I got the machined parts and as promised here is another image. Ok, Ok… I am a bit excited and this is not the best image, but I think it gets the point across. The two 180mm lenses are missing Posted Image


Here is another picture of the computer interface I’ll be adding a couple of more computers to.
Posted Image

#12 coinboy1

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Posted 16 July 2014 - 10:00 PM

Very cool!

#13 hbastro

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Posted 17 July 2014 - 08:39 PM

Here are a couple of images of the 3-camera wide field astrograph fit check assembly, "prior to paint"...
Posted Image

Regards,
Dave

Posted Image

#14 GJJim

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Posted 17 July 2014 - 09:34 PM

Looks good Dave. I see a filter wheel on the central camera, LRGB? Are the other two dedicated to narrow bands? IIRC, you mentioned the lenses are 85 mm which gives a FOV big enough to frame Orion (16x24) degrees.

#15 hbastro

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Posted 17 July 2014 - 10:01 PM

Thanks jim,
That camera is a place holder for a one shot color camera 8300C that will attach to the 85mm lens and have roughly 9X12 degrees coverage. The other (2) are 180mm's on the STIL11000M's are for narrow band at roughly 7.5X11 degrees. The objective as you point out is to collect both narrow band and color data at the same time, and cover a lot af area quickly at reasonable depth.
Regards,
Dave

#16 hbastro

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Posted 22 July 2014 - 08:05 PM

Ok, I made the trip to the site and fit checked the astrograph in the dome. This is a wise move as the entire design is based on Solidworks Models. Fortunately the models had enough fidelity to show where the issues were and they have been successfully resolved. The astrograph fits in the dome! Attached is an image. Its back in the home office for finishing touches. These include painting the aluminum structure, installing the two additional computers, and writing control software mods.
Thanks for the continued interest.

Best regards,
Dave

Posted Image

#17 Raginar

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Posted 22 July 2014 - 10:10 PM

How do you deal with the artifacts from your lenses compared to your telescope? Those lenses aren't flattened the same. Do you find you have trouble matching up the stars?

#18 hbastro

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Posted 22 July 2014 - 10:33 PM

Great question...Not sure yet. 2- of the lenses are identical design 180mm F/2.8 and have similar wave fronts. There are measured wavefront differences in these lenses so I expect some slight differences in distortion but don't expect registration issues. I have the capability available to map the image planes but haven’t taken the time, I've just done interferometry on axis and off axis.

The third astrograph center lens is completely different design; an 85mm F/1.4 on a 8300 chip camera I expect some issues here but think they will be within the alignment capabilities of the software I use for registration. I've done some registration with different image scales and distortion in the past with good results...

I'll post some images from first light in a month or so...

#19 Raginar

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Posted 23 July 2014 - 08:35 AM

That'll be really cool. Can't wait to see them!

#20 hbastro

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Posted 25 July 2014 - 10:22 PM

Bench top glamour shot. Posted Image :tonofbricks:
On the Left: The astrograph focus motors getting DB-9 connectors,

on the right: Remote interface rack surgery,

in the middle: The monitor and keboard standing by for software upgrades. :p

It will look better when its done I promise :o

#21 iwannabswiss

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Posted 14 August 2014 - 10:47 PM

That's a beautiful mess.  I can only imagine how excited you'll be once it's all cleaned up and running smoothly.  Nice concept and design build, look forward to seeing more.



#22 Midnight Dan

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Posted 16 August 2014 - 08:43 AM

 It will look better when its done I promise :o

 

:lol:  If it didn't look like it does now, you wouldn't get any work done!

 

-Dan



#23 hbastro

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Posted 21 August 2014 - 10:11 PM

Thanks for the comments and words of support...

 

OK, its in the dome and here is an image. I have accessed it remote but want to be on site for the first full imaging session . I am looking forward to first light when I get back from a business trip to Asia. These trips always seem to come at new moon...

Attached Files


Edited by hbastro, 21 August 2014 - 10:14 PM.


#24 hbastro

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Posted 02 September 2014 - 07:58 PM

It has been a busy month for things not astronomy. Just got back from Korea after finishing work on an 18" interferometer. After a long flight and a restful night I made the 3.5hour drive to Serria Chaparral Observatory and finished the installation of the new 3-camera astrograph over the last two nights.

At least 100 trips up the 16' tower ladder in the dark over two nights working and checking things... A switch on a Robofocus controller broke needed to be removed and rewired. Lots of new driver conflicts with the old software. Installed Maxum DL6 and I cannot get the off axis guider to guide while the main STL11000M camera is imaging, both work fine independent but won't play together. So reinstalled CCDsoft will use the internal guider and work the OAG issues later. All the networking addressing, protocols and the C++ software for remote control are fine tuned, up and running. The astrograph is a bit large for the Robodome so I spent several hours tuning its posiiton so the dome slit will accomodate all four apertures in all sky posiitons.. It is now operational on site and by remote control, so I'll be posting some wide field images soon...Here is the astrograph in the dome.  The photo was taken toward the west at sunrise this AM Sept 2, 2014... Dave

 

Attached File  3CamAstOperat_1200.jpg   190.05KB   0 downloads



#25 iwannabswiss

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Posted 02 September 2014 - 10:54 PM

Beautiful skies you have out there.  Look forward to see some pictures.








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