Imaging Jupiter in LRGB

[MattJenko]

Hi Imagers,

I am reliably hopeful I will be getting a planetary camera for Christmas, so I will be attempting some planet images in the coming winter months. I would like a mono version as I will also want to use this camera for guiding which I already do with a borrowed DSI Pro.

My question is that for doing LRGB imaging on planets, how long can you shoot individual image sets for?

This is my train of thought:

- Jupiter rotates in less than 10 hours.

- Using the society C11, with an ASI120MM, this gives a resolution of 0.28"/pixel, which I understand to be a nice ratio. With my 2.25 Barlow, this would be 0.12"/pixel if the seeing allows.

- If my maths and internet searching is correct, this means that a feature which is 0.25" wide will move its own width in 60 seconds

If I have to capture 3 or 4 videos, is the maximum video length for each video going to have to be < 20 seconds each - assuming I have an instantaneous filter wheel!?

Or am I being too hopeful of individual pixel precision ?

Cheers

Matt

[red dwalf]

Jupiter is certainly a tricky target with a mono camera, i used a C8, flip mirror, filter wheel, and a asi 120mm camera, as i understand it i`m limited to not much more than 30 seconds a filter until rotation of Jupiter becomes evident, so 2 minutes or there abouts max. some software can help with de rotation but i haven`t got that far yet.

now i found the real trouble is that the filters and not 100% parfocal even though they state that they are you still need a tiny bit of re focus in different channels which adds to the excersize, my filters are not the cheap ones either. the good thing is that the asi 120 camera can take a lot of frames in 30 seconds, if i remember i was getting 170 fps, i also enlisted the help of my mate to change the filters while i operated the software as at that time i used a manual filter wheel, now replaced to usb one, so it was a real hands on rush, we laughed as hands where flying and shouts of go where issued.

luckily the other planets are a little easier to image, but i can certainly understand why people get a colour planetary camera.

must say that i am impressed with the asi 120 camera even though it has caused me some head aches as it does not like my usb hub or 5 meter active usb cable, but i bought a normal 5 meter usb cable from flea bay for less that £2 and a 1.6 meter printer cable plugged into that as i need the distance from my desktop pc to camera and i now have no problems, full resolution i`m getting 17-20 frames per second which i`m happy with. 

[Space Cowboy]

The stacking software can compensate for a small amount of rotation so you can get about 45 secs per channel or if you want to read up on winjupos you can take longer captures and de-rotate each avi.

[MattJenko]

Much as the idea of a F1-style wheel change team approach to filter changing appeals to my comedy side, it may be worth my while going for the colour version, as long as this will work well enough for guiding as well which leads me to another question:

Doesn't the bayer matrix in the MC version effectively lose resolution compared to the mono, in quite a significant way? I just have in my head that each colour channel is only 1 pixel from 4, with spaces around it compared to a mono, so the mono with a filter is a significantly better proposition to a colour camera, all other things being equal? For guiding the mono is a much, much better proposition is it not?

Cheers

Matt

[red dwalf]

that's the reason i bought the mono version, better resolution although i seen some fantastice images with the colour version, plus i wanted to use it as a guide camera also.

they also make great all sky cameras which is an interesting thing to do when there's a meteor show forecast or you want to watch the clouds passing by, which i do a lot of.

[Zakalwe]

Hi matt,

I use a DMK21 with a PowerMate 2.5 and Baader filters.  My Jupiter images are 50 seconds per RGB filter. If you use FireCapture then you can automate the filter swaps between runs. That means you can just hit Record and it will run an avi, swap the filter, run the next avi, swap to the next filter and so on.

[MattJenko]

Thanks all. Swinging strongly back to a mono then. Guiding is the main use of the camera anyway, so I will play to that strength, and I will be able to get better resolution lunar images and some greyscale planets until I get myself a nice auto filtter-wheel, although I believe my society has one anyway I could use, seeing as I will be using the C11 they have when it comes to trying out imaging the planets.

Cheers

[MattJenko]

Santa has ordered the mono version for me although I obviously know nothing about it.