MEADE CCD's

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MEADE CCD's

Postby anthony566 » Fri Jan 06, 2006 2:10 am

Hi I have just purchased my first scope a Meade LX200 GPS 8" and would like to buy a CCD, Meade make 2 ccd's ( [b][font=arial][size=2]Deep sky imager & Pro ) [/size][/font][/b]and i was woundering if anyone has eather one of these and what do you think of it ? im thinking of taking photo's of planets to start with and then move on to multi images for stacking of lower light objects. Thanks in advance of any advice you all may have.

Also is a ccd better than an LPI ?
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RE: MEADE CCD's

Postby gammalog » Fri Jan 06, 2006 3:13 pm

Hi Anthony

I have both the LPI and the DSI and make good use of both of them.

The LPI is basically a web-cam, but has the ability (via it's software) to take longer exposures. It makes an excellent job of imaging the Moon and brighter Planets. However, it is far too insensitive for 'deep sky' imaging, but then it wasn't designed to do this. The Autostar Suite software that comes with it, is very 'newcomer' friendly and has the ability to control your LX200GPS, allowing it to 'track' the object being imaged. It will also retain only the images that meet or exceed the chosen quality setting, before aligning and combining them.

The DSI is much more sensitive than the LPI, and as such is capable of imaging 'deep sky' objects and producing reasonable results. The Software, which will also drive' the LPI, is very similar to that supplied with the LPI. As you have an LX200GPS, you will be able to use the 'guide' function as opposed to just 'track'. The software also enables you to undertake some elementry image processing. I don't image with the DSI, but employ it only as a 'guide camera' attached to an 80mm 'guide scope' which is 'piggy-backed' on my 10" LX200GPS. For 'deep sky' imaging, I use an SX MX7C camera.

Don't expect to get the same quality of image that is achieved with cameras costing many times that of the DSI, but as someone just about to get into CCD astro imaging, I don't think you would be disappointed. Also keep in mind, that many of the images you see in the magazines, are produced by people that are quite skilled in image processing. This is something that has to be learned, and improves with experience. To 'sum-up' the DSI, I would say that it's a good way for someone to start out in astro imaging at a reasonably low lost, and supported by some elementry, but easy to use software.

The DSI Pro is a 'step-up' from the basic DSI, in that it has a higher grade CDD and is, I believe, something like four times more sensitive. It is of course a Mono camera and as such, it is necessary to use RG & B filters in order to create a colour image. The separate RG & B frames are then combined with a Luminance frame, to create the final colour image.

I would suggest that you take a look at the Yahoo DSI and LPI groups, where you will find lots of information and be able to see the sort of images people have produced using these cameras.

You asked about the LPI as opposed to a CDD. The LPI, like most web-cams uses a CMOS device, as opposed to a CCD, for capturing the image. The CMOS sensor is very adequate for terrestrial use but starts to struggle in very low light conditions. The Moon and the brighter Planets are well within the capability of the CMOS sensor, hence to LPI achieving good results with these objects.

The CCD is much more sensitive (and expensive) and has the capability of working with much lower light levels. As such it is well suited to 'deep sky' imaging.

Hope this helps.

Dave
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RE: MEADE CCD's

Postby anthony566 » Sat Jan 07, 2006 4:16 am

Dave Thank you I could not of asked for a more complete bit of advice I think im going to go for the DSI Pro as I can get it for £320 from the USA ( posted ), I do like the idea of the lpi as a finder i was thinking of doing this with a webcam The Philips Toucam Pro could you give me details of the finder scope that you have and how it is attched as the one that came with the scope is a bit on the weak side, would you say that the lpi is better than the The Philips Toucam Pro as a finder imager ?

Thanks again Anthony.
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RE: MEADE CCD's

Postby gammalog » Sat Jan 07, 2006 1:26 pm

Hi Anthony,
I think that you are confusing the 'Finder Scope' with a 'Guide scope'. The 'Finder Scope' that comes with the 10" LX200GPS (I'm think its the same one on the 8") is a 50mm. This is quite adequate for initially aligning on a star.

My 'Guide Scope' (as used for Autguiding) is a Skywatcher Startravel 80mm F5 Short Tube Refractor. This was bought as the Optical Tube Assembly (OTA) only, that is without the tripod, for £119. It is to this that I attach my DSI as a 'Guide Camera'.

The 80mm 'Guide Scope' is mounted in a pair of 'Scope Rings'. Although the scope is supplied with a pair of 'rings' these are a close fit and as such leave no room for adjustment. I purchased (from Rother Valley Optics) a pair of Skywatcher Scope Rings for one of the larger refractors in the Skywatcher range. I think, from memory, they were for the Skywatcher 120mm. Whatever, they gave 15mm clearance around my 80mm Startravel. I then dilled a 'tapped' the rings at 120 degree spacing, to take M6 Stainless Steel Studding. Some M6 theaded plastic knobs from RS Components were screwed onto the outside ends of the studding. Some small plastic 'caps' were fitted over the inner ends of the studding, to protect the scope. I now had a fully adjustable guide scope. If you look at the way the 50mm 'Finder Scope' is mounted, then imagine that my guide scope is pretty much the same, but on a much bigger scale.

The 'Guide Scope' rings are mounted on a steel bar that runs along along the length of the LX200GPS's OTA. This in turn is supported at each end with a bracket, which is secured using two of the screws that hold the front and rear cells in place.

The first of the two bracktes, I bought from Astro Engineering where it is sold as a 'Piggy Back' camera adapter (PH026 for the 8" & PH024 for the 10") at a cost of £45. Having received this, I took it along to a local engineering company, who made an identical copy for £10. The Astro Emgineering one is, unforunately, only supplied with a multi-angle camera adapter, which I didn't need and haven't used.

I use a DSI as a guide camera as I found that the LPI, being a lot less sensitive, meant that very often there wasn't a bright enough star in the main Field of View (FOV), to guide on. This meant swinging the guide scope around in it's mounting rings to find a suitable star on which to guide. However, a friend of mine uses an LPI and a 70mm F10 guide scope, and seems to manage quite well. I guess its me being a bit lazy and preferring to have a guide star appear in my main FOV, and not having to hunt around for one.

I believe that the Philps Tou-Cam is CCD based and therefore a bit more sensitive than the LPI. However, I've no experience of this particular camera so I can't really comment.

I'm sure that the DSI Pro will be a better 'bet' than the basic DSI, although you'll need a 'filter wheel' if you want' to image in colour. As I said, I only use my DSI as a 'Guide Camera' and not for imaging. It would not be a fair to compare the results achieved with my SX MX7C USB, with those that could be achieved with the DSI. The DSI costs only £269 (or less if you shop-around), whereas the MX7C was almost £1,100. That said, people are producing some very good images with the DSI.

You are not limited to using Meade's software for guiding or processing, as there are other more capable alternatives. Some 'freeware', some at a reasonable cost and others far too expensive.

I'm sure that whatever way you go, you will get a lot of enjoyment from it.

Regards

Dave
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RE: MEADE CCD's

Postby anthony566 » Sun Jan 08, 2006 4:10 am

Dave do you have some photo's of your setup ? and if so could i have some please ? as im one of those people who understands things better when i see them ( as i do have the odd thick streek ). I have also just found out today that my LX200 GPS 8" is not in stock as i was told when i ordered it on Tuesday and that it could be 2 to 4 weeks before it is. im also now thinking that I should be going for the 10" version as this seems to be what most Meade LX200 users seem to be useing. what do you think ? I hope you dont mind the question after question Dave.

Regards Anthony.
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RE: MEADE CCD's

Postby gammalog » Sun Jan 08, 2006 2:43 pm

Anthony, I can certainly send you some pictures of my 'set-up', however, I would need to know what particular aspects you are interested in, as there are a great many pictures, ranging from the 'hole in the ground' dug the Pier Base, to close-ups of equipment.

With regard to choosing the 10" as opposed to the 8", there are a number of factors that you need to consider, not least being the increased cost. As always, its light gathering power that we strive to achieve, and the 10" does offer a useful advantage in this respect. Prior to buying the 10" LX200GPS, I had an 8" Celestron SCT, and there was a noticable visual advantage when I got the 10". With CCD imaging, this is not quite so critical, as we can increase the exposure time to compensate. I believe that Meade sell more 10" LX200GPS's than any other model in the LX200GPS range.

You also need to consider how you are going to use the scope. I if you intend to set it up in the garden each time you use it, you should know that the 10" is quite heavy. So if this is the case the 8" would be easier to handle. If however, like me, you intend to have it permanently mounted in an observatory, the size and weight are not an issue, and I think that the 10" would serve you better.

Incidentally, you might not be aware, but if you join the Society for Popular Astronomy (SPA), which I consider very worth while, you can obtain a 10% discount from some well known dealers. This represents a signifcant saving on the cost of a 10" LX200GPS, when compared to the £15 for SPA membership.

As far as asking questions is concerned, its not a problem. That's what this forum is all about. I only wish that something like it had been around when I started out in astronomy.

Regards

Dave
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