Crazy Question No2

OK all, here's my next possible crazy question, just don't gazump me!
I found this item on eBay, also a 60mm version. Could I, instead of investing in a smaller scope, put my DSI or LPI into this finder scope to image, using the main sope for tracking? My reasoning being, that through the LX90 I can only get small portions of objects such as Orion nebula, lunar and pleides images. When funds were available my intention was to get a reducer or smaller scope for these lager objects. I know I'm better just buying a reducer and using this as a finder. I'm not sure, just thought it would kill two birds with the one stone, ie a decent finder and smaller imager at the same time until I could afford a reducer later. Hope this makes sense!
cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem...&item=6172089893
Bill H.

Bill - there's always a trade off, isn't there...

Your 8" (is it 8 or 10?) with the DSI will give a certain field of view - probably something like my Celestron 8" - 10 x 10 arcmin. Not much good for widefield... This setup with a 6.3 reducer, you can get a FOV of 20 x 20 arcmin (ie 4 times as big). With a 3.3 reducer, its bigger again. But, there's a limit to how big a FOV you can get. I also read that the 3.3 reducer can cause vignetting problems on some systems...

What you are suggesting is probably what most of the (wealthy) astrophotographers do. They have a humungous scope and CCD doing the small FOV stuff - small deep sky stuff - planetary nebulae, small galaxies, asteroids etc. They (typically) piggyback a small refractor on top to do the guiding (with a seprate guiding CCD of course). But of course, you can 'invert' this setup by having your 32" Richey-Chretien doing the guiding and you 'guidescope' actually taking images - nice wide field images like M42 (Orion Neb) in one shot.

Of course, the quality of your images will depend on the quality of the kit you use. If you have, say, a 20" RC with an SBIG/FL top end CCD with a 4" apo and duplicate SBIG/FL top end CCD, then sky's the limit.

With the kit you have and the scope you intend to buy, you can work out your FOV's for both scopes and figure out if this is what you want. I would suggest you image with the DSI and guide with the LPI - the DSI will give better images. All you need to do, is make sure the DSI is mounted on the scope you want to image with at the time. Voila. You'll have two very different fields of view and can take wide images or narrow, detailed images as you please.

Most (wealthy) astrophotographers do exactly what you are proposing.

Personally, I have the Meade ETX70 piggybacked on the C8 - I can take wide field or narrowfield as I choose, just be swapping the DSI over. Not owning a second CCD at the mo, I'm not guiding. But then the AP1200 does what it says on the tin - I can now get 4 mins unguided exposures :shock: and there's more in this beast that I can eke out I'm sure.

Overall, what you suggest is most definately a plan. Just make sure you satisfy yourself of the quality of the scope you intend to buy and try and get an idea of images sizes you'll get. I can send you on a nifty calculator that'll do this for you if you like.

One point - see if you can get rid of the star diagonal on the finder and just pop the LPI/DSI straight in - reducing the number of surfaces light bounces off increases quality (by avoiding aberrations, dust-motes etc).

Hope this helps.

Cheers

Dave McD

Cheers Dave. I'm sure that through the finder scope I won't get as good quality as I would through an ETX or something, but I thought that with it being a reasonable sized finder scope I could temporarily use it for the wide fields until such times as I can afford a tracking scope, plus I do find the standard finderscope with the LX90 a bit frustratingly small.
Now, I just can't get my head around the tracking :shock: I know - as an example - that I can put the LPI on the finder and the DSI on the scope, and in this setup the finder scope will do the tracking with the LPI and allow me to image through the scope with the DSI. My brain short circuits when I imagine both the imager cables reaching the laptop. I can't get my head around connecting both these cables to the laptop and having both the LPI and DSI software open. Do I just connect both cables to the available USB2 slots then open the DSI software and when that is open, just open the LPI software.
I'm just hi-tech thick
Bill H.

Bill - you might be surprised and get very good images, as good as the ETX possibly (or even better - who knows!), from the finder scope. They'll certainly be wide-field. Also, I'd assume its a 'fast' focal ration and thus would be very forgiving of (marginally) poor focus and crap seeing. It could be a great imager - if you could get the low down on the optics etc you'll get a good idea of what you can expect.

As for LPI guiding and DSI imaging, it can be done. I've seen posts on the DSI board that outline the method. I think you attach the LPI to the laptop then get the software going. Then you attach the DSI and start that particular software program. After that, I glazed over...

I can trawl thoruhg the boards and try and find the details if you like....

Cheers

Dave

Cheers Dave, i tried the DSI boards but I glazed over at the point of connecting the LPI :lol:
Bill.

Sometimes I astonish myself and have some thoughts. I just realised, perhaps I won't be able to focus the finderscope with the DSI/LPI, or will it have a focus on it? does anyone have any knowledge of this piece of equipement?
BillH.