AstroPhotography Tool 2.7 multi-camera one mount experiences

[The Thing]

I thought some might be interested in this...

APT now offers the opportunity to have multiple cameras (DSLR and CCD) synchronise the start of an exposure. The idea is to have more than one imaging system per mount.

APT comes with three configured startup links. One is general and just finds a camera, the other two relate to a notional Camera_1 and Camera_2 identification. You can set up more links and each one will have a folder under APT (or wherever you put it) with its identifier for its subs.

To initialise it's best to turn on one DSLR, start the APT for Camera_1 and then repeat for each other DLSR/CCD.

What you then do is set an instance of APT to be server i.e. in control and the other to be clients.
In each Client you then  frame, focus, select exposure plans as normal and then press start. Nothing happens. Good.
You set up the Server APT as usual then when you press Start, all exposures start. If they are of differing length the clients will all wait for the Server to Sync, initiate Dithering and start the next exposure. Thus all the shutters fire at the same time preventing a shutter firing mid some other exposure and ruining the sub with vibration. APT seems to stop mirrors dropping until the last exposure stops, I think it uses a LiveView function to do this as it does to replace the standard type of Mirror Lockup in capable Canons.

What I would like to do is have two DSLRs with the same lens/FL running on the same target so that I get twice as many subs between clouds.  This is what I have been trying on my StarAdventurer but I really need two lenses of the same quality. The 50mm Pentax SMC produces very different stars to the Nikon zoom I've got. Or image two targets at once by having the second DSLR on a ball joint. Or I could have a DSLR on top of my main scope doing a wide angle view of the same object etc.

It works very well as long as:
1) ...you have enough USB bandwidth to get all the subs back if all the exposures e.g. 300s stop at the same time. If not it will crash. I have now got each DSLR on its own laptop port with passive extension cables and no hub.
2) ...you turn off image preview as all APT instances will try to render the returned RAWs at once and my experience is the second instance will then be delayed and its exposure will be behind the first. You could have RAW + JPG set in your plan and probably avoid this as APT will display the JPG which is much faster.

Have fun!

[MarkS]

Sounds interesting.

You definitely seem to like being on the leading edge of new developments!

Mark

[Carole]

That VERY interesting, am I right in assuming it will do 2 cameras in any combination of 2 DSLRs, 2CCD cameras, or one of each?

I tried to set up a dual imaging rig once before, but for various reasons I gave it up, but was thinking of trying a different way of doing it.  (Still in the thinking stage).  Ivo does come up with some great upgrades in APT. 

So if you don't have enough bandwidth, but if the subs of are different lengths, would that be a solution i.e. they don't download at the same time?  I know non server camera has to wait for server camera before starting a new sub if I've understood you correctly. 

I will investigate this when I have thought further about a dual rig.

Carole

[RobertM]

It's the first iteration but a very useful one, especially when the 'features' are ironed out.  Personally I would prefer if the APT server acted like an intervalometer for each client.  That method has much more control but I can also understand would be more difficult to code (if only because APT has become much more complex).

Hope you're feeding those useful experiences back to Ivor.

Robert

[MarkS]

Hope you're feeding those useful experiences back to Ivor.

Is Ivor planning to use APT?

[RobertM]

Hope you're feeding those useful experiences back to Ivor.

Is Ivor planning to use APT?

Oops, that was meant to be Ivo the author.