Lunar/Planetary Camera Frame Rates

[DaveS]

For those of us that have imaged with a web-cam, and the generally accepted limit of around 10fps, what we would like to have is the ability to capture AVI sequences at a much higher frame rate, to help combat the 'seeing', and capture as many frames as we can before planetary rotation becomes an issue. About 90 seconds with Jupiter I believe.

The main "high frame rate" camera contenders seem to be the DMK, Luminera, FLEA, and QHY.

Each manufacturer publishes the maximum achievable frame rate for their camera, at a given resolution.

However, it would seem that in the case of two of the above brands, the cameras are not achieving anywhere near the published frame rate.

If this is generally the case, then the manufacturers figures, in turn published by the dealers, are very misleading.

Do you have one of the above brands, and if so, do you find that it 'falls short' of the manufcatuers claims, in terms of achievacble frame rate?

Dave

[Dennis]

There is a new DMK reviewed in the current S&T that goes up to 60fps. No indication from the reviewer that it failed but he did mention that you probably need a 7200rpm hard disc to avoid writing errors at that frame rate.

Dennis

[Roger]

Well it does seem Dave that all is not true. i know alot depends on your set up, plenty of hard drive space , lots of ram , everything working smoothly.
Ok for me i have 3 Planetary cameras, albeit one is now knackered, the Toucam produced what it should do at 5 FPS sometime 10.
My DMK21 Mono seems to deliver what it should ,being able to set the frame rates first , never seem to have aproblem with that rate, although the IC software like to crash at the most inconvenient times.
My new QHY IMG132E has the advantage of two cameras in one being able to use a Hi Res and a low Res.
Frame rates achieved are at low rate 29/41 FPS ,86 expected,and at Hi Res a mere 8/9 FPS.25 expected
True i have to experiment a bit more yet with the camera , if poss i will try it on a my larger computer with mega ram and the 8 inch Edge. this i feel would give a more realistic report on it.

[Roger]

Thats right Dave , so hold fire till i have tested mine on the Celestron Edge and computer which has 3.2 gb of Ram , no excuses then ,

[Dennis]

Is the frame rate in any way affected by the buffer it is downloading into? I fancy having a go at this planetary lark, why should I buy the DMK at the higher price? Is it just the chip size, which is enough anyway to get much better moon pics without resorting to a fifty pane mosaic.

Dennis

[DaveS]

The download must have some impact on the frame rate, as especially with the larger image size of the higher res images, the file size will be correspondingly large.

If the 'buffer' can't store enough of these, the usb connection is slow, or there is inadequate RAM or a slow HHD in the PC, then this must impact on the frame rate.

I would say that a usb 1.1 connection is a non starter, but usb 2.0 should be plenty adequate.

I know that the Flea camera, as used by the likes of Damian Peach, runs at something like 120fps, but I don't know at what resolution.

I'm leaning towards the new QHY IMG132 at the moment, as it does offer both Hi and Low Res options at reasonable cost. However, it is very new and as such doesn't have much of a 'track record' as yet.

There is a link to a video review on the camera, located on the Modern Astronomy website, but the review is quite 'low tech', and without much real imaged material.

At the moment, I'm letting Rog do the assessment, as he has just bought one

Dave

[Roger]

It seems i have been doing things wrong with regards the white balance , so hopefully tomorrow night if clear ,and Dave says it will be , i,m dragging the Edge out ,and using my updated Desk top with 3,2 GB ram ,so that should be well enough. this will give me time to do as Dion who runs Astroshed and is testing and reviewing QHY ccd at the moment,thanks to his help i may be on the way to resolving my issue , but we will see .
WATCH THIS SPACE

[mightymonoped]

This is quite a controversial subject. There are lots of factors involved, the PC hardware, the limitations of USB2 (circa 480mbps), the codec used for capture and download (they are not always the same). As always in astronomy, there are various (very vocal) schools of thought on all of these factors . I have been following a similar thread on Astronomyshed.

There have been a couple of recorded instances of people capturing at 30fps in 1280 x 720 using a MS Lifecam Cinema, but I have not been able to achieve it, though I have captured at 30fps at 640 x 480 YUY2 (which is not bad for a £30 camera).

The capture software and camera will certainly have an impact as well (make sure you don't have "auto-exposure" on, as this may override any fps settings you're expecting.

I'm going to go have a play, I think, to see if I can get 15fps uncompressed at 1280x720. It was dropping frames quite alarmingly when run through a 32 bit virtual XP session, but I have configured the Macbook to boot as 64bit W7 using 8Gb of DDR3, so it may well deliver the goods.

Time to play.
Tony

[Roger]

I dont have aproblem with the DMK Tony , only this new QHY, but as stated i have been doing it wrong, so lets see what the next imaging session brings .

[mightymonoped]

Just looked out of the window....maybe not this evening after all

[Dennis]

what shutter speed were you using Rog? I just read that if you are using a slow speed then it will not run at the faster frame rates. Makes sense.

Dennis

[Roger]

The capture software has these functions
Gain
Exposure .. done in MS...1 second = 1000 milliseconds
White Balance Button
1 red slider
1 blue slider
1 green slider
This of course is what you have to do once you select the camera, then where you save it, and also what res you want to use, and how many frames you want to do .
i am told this is what you do , get focus on the object , take the gain back so no artifacts colour wise are shown. move the MS slider to get the correct exposure , this is easy as you need to keep the object to the darker side rather than to bright , then once happy hit the wb Button white balance and then this puts the red /green and blue channels to the correct position also it tweaks the gain. then hit REC.
Simple Peeps!!

[DaveS]

Found this comment on the QHY forum:

Also note that this sensor has rolling shutter - if you put it into a big scope and the seeing won't be nice - you may get some artifacts from the rolling shutter (like some users had with DMK72) - that needs to be tested[i]

It will be interesting to see how the camera performs on the 9.25, as you have only tried it on the 120. The guy reviewing it, was using an ED80.

Dave

[Steve 1962]

I have a DMK21AU618 and it happily ticks along at 60fps. I use it for lunar imaging in the near IR (my next purchase is a filter wheel and RGB filters) and as a guide camera when I'm using my DSLR and FLT98. It does exactly what it says on the tin!

[Roger]

Thats good news Steve ,can you tell us your operating system for example computer stats etc