2 Camera imaging?

[gazza]

Hi,

I posted earlier asking about mono cameras (I currently have an Sbig ST8300C), it had been my intention to perhaps sell the camera and replace it with a mono. However, after checking out the cost of good filters it seems that buying a mono camera and keeping my Sbig might make financial sense (that plus the fact that I really like the Sbig 

How feasible is it to say put a mono on my Tak TSA120, use that for luminance, whilst using a smaller scope (ED80 or similar) with the ST8300C simultaneously taking the color? Then later combining the data. This would maximize imaging time - particularly whe visiting dark sky sites?

Is this a worthwhile idea?

cheers
Gary

___________

[swag72]

It is an excellent idea - There's a growing number of people using such dual rigs with a whole host of different combinations. Have a look at the fov calculators out there as I'd say you'd want to get a close field of view with both combo's otherwise you are going to be wasting space! 

While I don't have a dual rig, I understand that it can be a little tricky to get them pointing to the exact same place in the sky, but once you do.... should be doable and there's many folks on here that have experience so can offer help if required.

[sloz1664]

One issue that doesn't seem to be raised when dual or triple imaging, well I haven't come across it,  is you cannot use the dither method for reducing background noise.

Steve  

[steppenwolf]

It's a great idea and one that I have used myself -  the biggest problem is camera synchronisation (see 'dithering' above) and having (in my case at least) to use two different capture programs, one for each camera. This is my dual imaging rig, mono on the left and one shot colour on the right:-

[Earl]

It is doable however there are a few things to take into account.

1) the scopes need to be well aligned and the cameras angled  together so the frames are as even as possible this can be tweaked in processing but getting it as close as you can originally its saves problems.

2) Flats that work well with both setups to stop gradient from one creating issues on the other.

3) software capturing both cameras at the same time, this can be a headache, its doable on a single PC but can cause issues for some, a pc for the second camera is a good idea. (although not essential it all depends on trial and error)

4) no software that i know of currently supports dithering and a dual scope setup.

I do believe that SGP is looking at dual camera control in greater detail in the next version 2.5 onwards.

[perfrej]

Software is the issue here. Alignment and stability can always be solved by using more and heavier metal. Drivers that come with cameras usually do not lend themselves to distinguishing between two identical cameras connected to the same computer (there are exceptions). None of the standard imaging packages support more than one camera, but FocusMax v4 has support for two focusers at the same time, which is an improvement.

I have a couple of A3 pages with sketches of a structure for a multiple (arbitrary number) camera control, but I find the driver situation to be somewhat hopeless. I may, in the end, succumb to writing an alternate driver for my "package" so that more cameras can be handled, but hopefully there will be drivers eventually...

So, in conclusion, this is troublesome...

/per

[perfrej]

Earl, the dithering problem is indeed a problem with packages like SGP, THey all need guider logic to do the dithering, while ACP and CCD Autopilot can do it without guider. My imaging is always done unguided so I cannot use SGP at all... I have ACP in Provence and CCD Autopilot on the balcony...

/per

[Earl]

I seem to recal nebulosity was reliable with two atik 383's

However I abandoned the whole idea and just focused all those funds into a single fast OTA which although might not be quiet as fast as two scopes working in tandem is far less of a head scratcher.

[Sp@ce_d]

Having run a triple shooter for a while (before I saw the light & went over to ACP) I know the Atik drivers support this. They identify each CCD by its serial No. I found it more stable to use different apps for each one.specially when controlling all the filter wheels. I used Atiks own capture proggy.. Forgot its name now.. Doh! Maxim & Nebulosity. Also timed it so each CCD had its own download window so that they didn't saturate the USB. Otherwise I noticed issues with the guide cam & the EQDir locking up.

Sent from my iPhone using Tapatalk

[perfrej]

Thanks for the pointer on the Atik drivers! Didn't know that...

/per

[gazza]

Hi all,

thanks for the replies .... I've not thanked you earlier as I have been ill with a bad case of Influenza (the REAL TYPE, not "man flu" or a cold) and been quite ill. Getting better now, so starting to review how I'll be going with imaging / cameras

cheers

Gary

[ampleamp]

A little late to this but you can easily run capture on two, or more, ccds using Maxim and a programme written by Tom How from Curdridge Observatory - Maxim DL Multiple Camera synchronisation. 

http://astro.neutral.org/software/astronomy-software.html

As has been stated above, using two computers is a lot easier, and is one of the requirements of this  programme. Guiding and dithering are controlled by one pc, and this one also runs a sequence of images (master) - ie just using Maxim as normal. The secondary pc just runs one sub of the same length as the master (slave). The two pcs communicate through a network. When the master starts a sub, Tom's software sends a signal to the slave telling it to run a sub at the same time. They both stop together and whilst the master dithers, re-acquires guiding etc, the slave sits doing nothing until the next master sub is ready to go, the software sends a signal and the slave starts up again. All the above caveats re alignment etc still hold

The video explains it all a lot better than I can 

As the saying goes, if I can use it, anyone can use it.

OK, its not the cheapest option, but it is very simple and just works.

[perfrej]

I wrote a Maxim "Spy" application that fires off Nebulosity when Maxim fires off. It works fine, but there is still the problem of using multiple cameras of the same type (driver problems).

/per

[ollypenrice]

The need to dither is reduced considerably when you use two cameras, which Tom and I have been doing for some time. They don't share the same hot pixels, of course. For the OSC you could run an aggressive hot pixel filter and this won't do any damage under a luminance layer. An occasional manual movement should be enough during a shoot to keep the lum clean. We don't find this business to be much of an issue and one of our cameras is pretty tired in the chip department!

If one scope has a significantly shorter FL then alignment might well be easy since the FOV will be larger. We use a Cassady TGAD to align our dual rig which uses identical scopes.

Olly

[sloz1664]

The need to dither is reduced considerably when you use two cameras, which Tom and I have been doing for some time. They don't share the same hot pixels, of course. For the OSC you could run an aggressive hot pixel filter and this won't do any damage under a luminance layer. An occasional manual movement should be enough during a shoot to keep the lum clean. We don't find this business to be much of an issue and one of our cameras is pretty tired in the chip department!

If one scope has a significantly shorter FL then alignment might well be easy since the FOV will be larger. We use a Cassady TGAD to align our dual rig which uses identical scopes.

Olly

Thanks Olly on your experience with dual imaging. I'm setting up for this when I get alignment and focusing issues sorted.

Steve