A question for you planetary imagers

[DaveS]

I am considering the purchase of a Lunar/Planetary camera, to provide with some imaging activity when the Moon restricts DSO work.

At the moment the prime contender is the DMK21, albeit at 640x480 it is quite low res, but as Lunar/Planetary imaging would be a secondary interest for me, then a significant expenditure is not really an option.

However, my question is, Mono or Colour.

As all my DSO imaging is done with mono cameras and filters, I am well aware of the increased sensitivity of the mono camera, so perhaps this should be the preferred option.

My concern is, that given the rotation of the planets, there is a time restriction on the length of an imaging sequence, before the rotation starts to impact on the image. I believe this is something like 90 seconds for Jupiter.

So, while a 90 second sequence would be fine for mono, to do the same for R,G and B would require 270 seconds, which would not be possible without issues arising from the planet's rotation.

Therefore, I'm guessing that you guys producing coloured planetary images with a mono camere and filters are, in the case of Jupiter for example, having to limit the R,G and B sequences to 30 seconds each.

Of course being able to image at a high frame rate, would allow for the capture of an adequate number of frames I guess.

How do you approach your planetary imaging in colour, with a mono camera, or do you use colour camera.

Your input would be much appreciated, and to know what camera you use, and your opinion of it.

Dave

[Kieron]

Hi Dave,

If, like me, you hope one day to produce planetary images that have scientific value, then shooting through filters is the only way to go. I am thinking, for example, of the way that various atmospheric and dust phenomena on Mars are revealed by different wavelengths.

I would say that changing filters manually (in a filter wheel, of course) can be a pain, especially with the faster rotating planets like Jupiter. This is made worse by the fact that you have to adjust gain settings after each filter change. But I expect a man of your calibre has a motorized filter wheel :)

For what its worth, I use the DMK 21AF04.AS with the supplied IC Capture software and I am happy with the results, although I have never been able to capture at the maximum available 60 fps.

Hope this is of some help.


Regards, Kieron

[DaveS]

Hi Kieron

Thanks for that feedback

I do have a motorised filter wheel, so filter changing is a fairly slick procedure, but of course, as you say the gain would still have to be reset between filters.

My filters are very parfocal, so that's one less thing to worry about.

In the case of the Moon, I much prefer mono images, so a mono camera 'fits the bill' very nicely

From what I see on the forums, the DMK21 does seem to be a popular choice.

The subject of manufacturers stated frame rates, does seem to be a controversial subject.

Dave

[prokyon]

Hi Dave,

I have a mono and I am very happy with it. I know someone, who has a mono and bought a colour now too. He is disappointed, because the colour cam is less sensitive and the resolution of the mono is better.
I have a manual filter wheel and it is no problem to change filters.

Regards

Werner

[DaveS]

Thanks for that Werner.

When you image Jupiter for example, how long do capture your R,G and B sequences for, and what sort of frame rate do you achieve?

Dave

[Rob_Jn]

Hi Dave,
I use a DMK21AU04 mono camera and typically image at up to 30fps for Jupiter, from memory I take 40s each filter which is probably pushing it a bit but I'm pleased with the results I've had. I would definitely go for a mono camera. My filter wheel is a homemade one, initially manual but upgraded to motorised which does help a great deal - my scope is about 8ft away through the shed door so it was a bit time consuming to change the filters manually

Rob

[DaveS]

Thanks Rob, all feedback is useful

Dave

[Frodriguezv]

Hi
I have used the DMK21AU04 as well. Very nice Camera. I am currently using the DMK21AU618 which has a much better sensor in the DMK family lineup. Both are MONO and the difference is huge compared to COLOR. 640x480 is actually high resolution imaging. Remember planets are really tiny compared to DSOs. Large sensors will render a smaller image and Planetary is all about focal length and scale. The big names in Planetary Imaging like Damian Peach, Don Parker, Chris Go and Anthony Wesley use a Flea3 camera from Point Grey considered to be the best camera around. You would need to check though if they already sell the USB model. Last I checked the camera was a Firewire. If the investment is based on a priority meaning you don't justify paying a FLEA3 since your main activity is DSOs, you might be very happy with the DMKs. If you want the best of the best maybe the Flea3 is the way to go and computing requirements might become more demanding. Now always keep in mind, Seeing is king. The best camera will not make any difference with bad seeing.

[DaveS]

Useful feedback Fernando, thank you.

Lunar/Planetary imaging is secondary to me, as my main interest in with DSO imaging, and I'm really looking for something to do when the Moon restricts the DSO work.

So, an expensive camera was not 'on the card' for Lunar/Planetary work.

Things have moved on a step now, as Roger is buying the DMK21AU618, and I am going the have his DMK21AU04, which will suit my needs just fine.

Dave

[Frodriguezv]

you are very welcome and that is a wise choice. Fine camera. I have an extra DMK21AU04 not being used so if anyone is interested please let me know.
FR

[jcm]

Hi
I have used the DMK21AU04 as well. Very nice Camera. I am currently using the DMK21AU618 which has a much better sensor in the DMK family lineup. Both are MONO and the difference is huge compared to COLOR. 640x480 is actually high resolution imaging. Remember planets are really tiny compared to DSOs. Large sensors will render a smaller image and Planetary is all about focal length and scale. The big names in Planetary Imaging like Damian Peach, Don Parker, Chris Go and Anthony Wesley use a Flea3 camera from Point Grey considered to be the best camera around. You would need to check though if they already sell the USB model. Last I checked the camera was a Firewire. If the investment is based on a priority meaning you don't justify paying a FLEA3 since your main activity is DSOs, you might be very happy with the DMKs. If you want the best of the best maybe the Flea3 is the way to go and computing requirements might become more demanding. Now always keep in mind, Seeing is king. The best camera will not make any difference with bad seeing.

Thanks for the useful info.
There are (3) Flea3 USB3 Cameras - sounds a bit silly but you know what I mean - non of them has the 618 chip.

John

[Dave Smith]

Dave, with my DMK21 I find that SharpCap (free) is more reliable than the supplied software (which frequently crashed in the middle of a run).

Dave

[DaveS]

Duly noted Dave, thanks

Dave

[prokyon]

A good choice Dave! And maybe you can do DS too? I made the core of M42 with the DMK for example. And you can make planetary nebulas with it or double stars.

Cheers

Werner

[michaelmorris]

On the subject of changing camera settings between filters, FireCapture software (http://firecapture.wonderplanets.de/) will allow you to semi-automate image capture, with different exposure settings for each filter and, from memory, I think it also has ASCOM filter wheel control. Hopefully it will eventaully also have ASCOM focuser control so that it can perform completely automated RGB filter webcam imaging runs.