I have a Coronado PST arriving this coming week and I'm considering getting a Meade DSI for imaging the Sun.
I am considering the DSI II or DSI pro (not II).
Trying to decide which will give better resolution - I am astounded by the images that Paul (1ponders) produces using a DMK and would like something approaching the sharpness he is able to achieve.
The II (colour ccd) has a 1/2" chip
- pixel count 437,600
- pixel size 8.3 x 8.6 microns.
The pro (mono ccd) has a 1/3" chip
- pixel count 250,00
- pixel size 9.6 x 7.5 micron.
I see the II has better software and cooling but is more complicated due to the filters (supplied in the price).
I read that you need an IR filter to go over the RGB filters and need to refocus as they aren't parfocal - perhaps just need refocussing when using the L filter as it blocks IR so no extra filter needed.
So, would they give similar resolutions, actually would the images be just as sharp taken with either camera?
Is it a lot of bother taking multiple shots with LRGB?
I haven't done any imaging before but I am really looking forward to using Registax or similar to enhance images. I think it would be fun & interesting.
Yes, I see the DSI II for sale here and I am considering it - a good price.
Forget the colour one Craig. It will be less than useless. You need to image in mono and the DSI is not necessarily your best bet. You want something that will snap a lot of frames in a short time frame. 60/sec sounds about right but you could get away with 15.
The only place I see the DSI beating the DMK is that it is a true 16bit camera and you would also be able to use it for Deep Sky stuff (though the DMK is no slouch there either by a long shot. I snapped a ripper eta carina a couple of months ago).
And you can forget about using Registax with the DSI. Yes you can do it but the DSI saves as Fits (in 3 different formats ), Tiffs, bmps or jpegs. While Registax will handle them it much prefers avi or lots and lots and lots of bmps.
You don't need filters for PST imaging. I only have the filters for Jupiter, Saturn and deepsky stuff with my ATiK 16IC. If you are imaging in Ha then you can forget about any other colour. In fact colour cameras can create more problems than they solve. You are only imaging in a very narrow red band, but unfortunately some cameras (SAC 4.2 for example) end up with better exposure in the green channel than the red. (See pdf link below for explanation). You can successfully solar image using colour cameras like the 300D or a DSI or a ToUcam, but you will not get the same quality of image as using a Mono camera and then creating a false colour image. Infact you will have to create a false colour image anyway using a colour.
The best thing you could do is have a look at this site http://www.astro-nut.com/ in the Solar images section and also at the bottom of the page for the Solar Imaging Primer. This Primer sorted out a lot of issues I had and made life very much easier for me.
BTW if the sun ever shines here during the day again and the Jetstream isn't blowing it's head off, I want to try my ATiK 16IC for solar imaging. Theoretically it should walk all over the 8 bit webcams for tonal range (65535 compared to 256) but I may be limited in the number of images I can capture before movement on the solar surface starts to smear the stacked images. This is where the mono "webcam" have it all over the larger format and dedicated CCD cameras. Their rapid frame rate that allows to capture those ellusive moments of good seeing. Oh for a camera with 1280x1024 pixels that is 16 bit and can capture and download at 30 fps
Oh, I don't need a filter for solar imaging. Thanks, I understan and I save quite a bit.
At The Image Source website it says that the DMK gets its power through the pcmcia but also seems to say that with a laptop then a psu will need to be connected to the pcmcia. Is this correct?
What program do you use to colour?
Thanks for the links, I'll read them later.
I've been trying to find a small monitor type of device that can be hooked up to DMK or similar, so the realtime image from the camera can be viewed through it and then on to desktop pc (so I don't have to get a laptop). I visited 2 pc stores but the staff didn't think there was anything. Have you heard of anything?
I don't know how you will go finding a monitor as the DMK is firewire. I run mine direct from my laptop through a powered PCMCIA firewire card, though you can also run it through a powered hub to the PCMCIA rather than direct from the card.
I use Images Plus to colour, but you can also use Astra Image or even Photoshop if you know how to work with the colour channels. If you have a good read of the Primer, he goes into detail on the process of colourizing.
Paul, I am looking for the same camera. They are coming! The next two years will see huge developments in the planetary imaging cameras.
Craig, I agree with Paul neither of the Meade products are suitable for this type of imaging. Colour is useless when imaging in monochrome (PST Ha light is considered monochrome).
Using the DMK is the way to go. In terms of filters, the astronomiks ones are the best for the business of planetary imaging and any future DSO imaging you may have in mind. Baader filters are good, but not of any use in you plan on planetary pursuits. However, for now just the DMK on its own would work the best for you.
Allright, it's the DMK, it's really not expensive and the resolution is great.
I am trying to avoid getting a laptop until later, so I will get the camera and use it with a pc for now, however.......
I have been thinking of how to view the realtime DMK images using my bluetooth phone. There are some small programs, on the Net, but I haven't located any that I am sure do what I want.
I'm going to start a new thread on this issue in Tips, Techniques,.... section.
Craig I'm about to try a 1/2" chip in the form of the SAC 4.2 mono (maybe end of next week at the latest). I should by rights be able to get a full solar image on the chip and have room to spare. If this is the case then I may be able to select a Region of Interest (ROI) and get up to 10 - 15 fps with the USB 2. I'll let you know how I go. If successful it will be about half the price of the DMK. It will also save in Raw format.
The amount of object to be imaged that you can fit on the chip depends on the size of the chip, the size of you pixels and the focal length of your telescope.
Based on a 400mm FL, a 1280x1024 chip with 5.2 micron^2 pixels the sun through the pst with the SAC 4.2 mono should look like this picture below.
From memory it is a bit tighter fit than that, but I'll experiment and let you know.
edit: While SAC don't let you easily find out on their site, the SAC 4.2 is a CMOS chip not a CCD. But it is an 10 bit chip, the DMK is only 8bit so you get a doubling of tonal range (theoretically )
Last edited by [1ponders]; 27-06-2007 at 09:40 AM.
I viewed some pics of the sun taken with PST an Mintron (apparently the Gstar is a Mintron).
The detail and sharpness isn't to the same standard as Paul's. Is this due to the camera or Paul's skill?
I had a quick go with a compact digital camera to image the sun but the glare was too strong to see much on the screen. So would I need to build a hutch to shade a laptop?
It's the frame rate that is important in this case. Being able to capture at 60 or 30 or even 15 fps is going to leave 2.5 fps sitting in the dust unless the seeing is really really good. Imaging at high frame rates gives you the opportunity to select many more quality frames for the final composition.
With the DMK and similar can you do streaming video?
Is the video then smooth as silk or is it a bit stuttery?
Can the images be colourized? Easy as editing a still?
One thing I don't understand is that the images taken through the PST are larger than what is seen in the scope. This is probably the same for night views also, I assume.
I have a 6mm and even with 2x barlow I can't see the big detailed images. Is this perhaps just the way that cameras work or is something done when editing the images?
I have been thinking about the costs that I am considering for imaging equipment - I need to justify spending up to $1000 on gear. Also just imaging the sun may not be totally satisfying. So it looks like later on I'll be starting up the night time viewing but with imaging as the focus. Seems like a real challenge to track down the prey and capture it in all its glory.
I am really looking forward to editing images. How long does it take to edit an image of high quality?
Paul, I'm still eager to see your report on the SAC 4-2. Where did you get it, please.
And why are your images so much better than others I have seen taken with the PST + DMK?
![[1ponders]'s Avatar](../vbiis/customavatars/avatar45_9.gif){kind=avatar}
but you could get away with 15.
), Tiffs, bmps or jpegs. While Registax will handle them it much prefers avi or lots and lots and lots of bmps.
Thanks, I understan and I save quite a bit.
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