Hi there, thought I'd post this incase anyone else was thinking of purchasing a used Nikon D90 or wants to use an existing D90 with Ekos/INDI.
First off - INDI via the gphoto2lib does an excellent job of running this camera and in my opinion, it is a great camera considering the price of a used one ($125 CAD) at the local pawn shop.
Only problem I've come across in Ekos is that liveview (aka streaming) does not work if you do not trigger a photograph first. Once a single image (even 1sec exposure) is taken - preview or streaming works great.
Unfortunately - the Camera itself (or better said, it's firmware) has, what I consider, a major flaw for astrophotography. The shutter cannot be triggered via software if the camera is set to bulb mode. I have confirmed this exhaustively - even going to the point of borrowing a windows computer and downloading and running the Nikon Camera Control Pro 2 software. Even Nikon's own software cannot trigger the shutter of the D90 in bulb mode (and the camera firmware is up to date). Nikon's own software pops up a message telling you the camera is in bulb mode and you'll have to trigger the shutter manually via shutter button on the camera or using the Nikon optional remote shutter release.
So - if you want to use the Nikon D90 with Ekos/INDI, (or any other software), you will be limited to exposures of 30sec unless you trigger the shutter manually via the button on the camera - or via a remote shutter release.
It <strong>MAY</strong> be possible to use a programmable shutter release device to get longer exposures (I have NOT tried this) - but this kind of defeats the purpose of using Ekos/INDI for running your observation sessions. Amazon has some listed as compatible with the D90 that I may still look into, as I do like the camera and I'm not sure I'll send it back to the pawn shop.
Just thought I'd share this as I spent many hours trying to figure out why bulb mode wasn't working. I went so far as to sending PTP opcodes to the camera based on output from gphoto2 debug sessions and gphoto2 shell. Today I finally borrowed a windows computer and - well Nikon's own software output was the nail in the proverbial coffin for bulb mode on this camera...
Cheers - I'm off to try to find a new camera for DSO that won't break the bank.
Note that the Bulb mode over USB triggering not being supported is an issue up to the D5300 (Some people said D5200 works, I know the D5100 doesn't work) and D7200 (D7100?) and impossible (Nikon left it out) on D3xxx series. I'm not sure on the more expensive cameras.
A trick I got introduced to if you have an IR port is NikonRemote ( github.com/outofjungle/NikonRemote ) Which you can feed into INDI's serial port and it works. Which uses just a Uno, resistor and IR LED. (It may not work with clones as is because it relies on the reset behavior of the Uno, but if you are relying on an external thing (or gpio like from a Pi), you can trigger it by the arduino's reset pin.)
So I built a small IR transmitter (using an IR LED salvaged from an old remote - so can't say what model IR LED it is) and hooked it to the GPIO pins of my Rpi 4.
Using info from several different web sites - I was able trigger the Nikon D90 shutter using this cobbled together IR remote.
In addition - I can confirm, that if you setup the D90 so the shutter is triggered by the IR remote and shutterspeed is set to "- -" (it doesn't say "bulb" in IR remote mode) you can open the shutter with the 1st press of the IR remote and close it using a second IR remote signal. I was able to take a 67sec exposure using this trick. Next I'll see if I can get the GPIO pin controlling the IR to trigger using the GPIO Serial input on the RPi. If I it get it all working - I'll post the whole setup here. But that's gonna have to wait. Cost so far - nothing but time and and old unused remote control.
I use a D90 in my telescope. I use a kmtronics usb relay to shot long expositions. You only need a D90 camera conector cable. the relay is connected to the pi via usb and indi controls it perfectly. I let you know in case you did not know about this possibility
Thanks. Was not aware of these devices. The ones from Kmtronics - with shipping to my location are nearly $100 CAD - and at that price - I'd just get one of the DSUSB devices from the US. I'll see if there's something else similar available locally. Again - thanks for this suggestion. Can you let me know the wiring connection from the camera remote shutter release cable to the USB relay controller - and did you need any protection circuitry like in this home made cable solution...www.cloudynights.com/topic/457536-usb-co...r-control-for-nikon/
I'm also kinda having fun playing with the IR circuitry and programming. It's been a long time since I dabbled in this stuff. The only unfortunate part - is I'm 4hr round trip to the nearest electronics store.
yes, the cable goes to the lower connector in the D90. It is an open/close switch. You can see three cables because the nikon cable uses 3, but two of them go to the same pole in the relay. I just checked Amazon and the relay is 35 euros here in Spain. Kmtronics also sells the relay with no cover and this is cheaper.
You only need a remote Nikon cable/plug, nothing more.
It's only 30 euro for the device in Canada as well. But estimated shipping charge to my location was another 29 euro and probably more for brokerage fees and duties. There are other similar devices available locally much cheaper. But thanks again for the info and especailly for the idea.
The IR solution works - but has limitations - the IR remote setting for the camera has a time limit for how long it will wait for a signal to trigger the shutter. You can set it to 15 min. But if no IR signal is received after this - it will change back to normal shutter behavior. And capturing the RTS signal from INDI driver to trigger the IR is not so easy. Not a deal breaker - but just more things that might go wrong...
I'll likely order a USB relay and shutter cable - and a USB hub since I'm out of USB ports on my RPi. But I'll keep playing with the IR until the parts arrive. My delivery time even with Amazon Prime is usually 2 weeks due to my remote location and unfortunately, paying for expedited shipping doesn't improve the delivery speed - it just costs more. Guess I have to pay for not having light polution some how
I'm supposed to get a clear night on Saturday (only the 2nd one in the last 6 weeks), which is why I'm trying to cobble together a solution with available parts.