There ARE alternatives!

[strongmanmike]

Even though they are obviously good cameras too, IIS members
wondering what to get themselves when they are ready for the move
up in the imaging stakes shouldn't just think its an "SBIG" or nothing,
there "are" alternatives, great alternatives.

Once you know what you are doing, this is what you can do with the
beautifully compact, sensitive and light (about the size of a large eyepiece)
Starlightxpress SXV-M25C one shot CCD camera and a fast Newtonian he
he he :-)

http://www.heavenlyview.com/m45sxvm25a.htm (http://www.heavenlyview.com/m45sxvm25a.htm)

Perhaps technically the resolution is slightly less than a mono
camera but hey, no filter wheel, no filters, just point and
shoot...BANG, an image like this!

Alan hasn't mentioned it in his image credits but I bet he didn't
even use dark frames, he hasn't before with his SX cameras.

Mike

[Dennis]

You make a good point Mike. I occasionally go through the throes of “must upgrade my ST7E” and end up looking at the SBIG and Starlight Express line of ccd cameras.

I have tended to avoid the one shot colour because of the “resolution issues” continuously being spoken about in the ccd imaging forums. I guess if you are a Rob Gendler, it matters; but for the majority of potential users, they would be stoked to grab an image like Alan Chen's.

When spending $1000's on a ccd, there can be a tendency to “play it safe” and go for the SBIG models, yet you may not require those attributes that differentiate the SBIG models from the Starlight Express models.

The main reason I would chose SBIG is for the dual guiding design of their cameras, although there are alternatives in the Starlight Express range.

Cheers

Dennis

[strongmanmike]

Hi Dento :)

I certainly don't want to denegrate SBIG cameras as they are indeed fine instruments in their own right but the argument that the patented self guiding is such a bonus is a little over rated in my opinion. There are countless examples of piggyback guided images (like Alan Chens M45) that were taken using a seperate guide camera and guide scope, to clearly counter this percieved benifit. With a decent mount and well mounted guide scope with a rigid focuser, self guiding is just not necessary unless perhaps you want to take long sub exposures (in excess of 10 min) with a very long focal length scope (> 2500mm) and even then it wouldn't be impossible for piggyback guiding to return good results.

The myth of the importance of self guide was born from commercial Schmidt Cassegrains with floppy mirrors. If you are using one of these then self guide is very useful but otherwise it is over rated IMO.

Mike

[Lee]

From someone who has never guided, but is aware of the basics of it - to me the biggest advantage of self guiding would be not having to stuff about with guidescopes, double dovetails, extra camera etc etc - seems more elegant and streamlined..... my 10c (inflation)....

[strongmanmike]

Seems like that huh?..but the time will be easily taken up or exceded by trying to find a suitable guide star that still allows you to frame your image properly and/or can be seen through each filter! There are some objects that SBIG camera owners, without a guide scope, simply can't image becasue of this so they resort to getting a dedicated guide camera anyway. You will find most SBIG camera owners have or eventually get a guide scope and seperate guide camera anyway.

Mike

[Lee]

Never thought of that..... must be hard to find some guide stars through the narrow band filters..... ouch

[Doug]

Yes, there are always alternatives. It is interesting to compare this M45 image aquired over 200 minutes with a 10" apeture to an image of the same object aquired with a mere 80mm, and only 60 minutes with a canon 350d
this later image can be compared by looking at the link supplied at
http://www.iceinspace.com.au/forum/showthread.php?t=14429
Just think what could be achieved with background noise reduction by upping the ante to 200 minutes with that setup!

I guess it comes down to one's preference between imaging for accuracy or 'happy snaps', and there is nothing wrong with happy snaps.
looking at the 350d<<ED80 image of M45 and comparing it to the sx image, if I had a 350d (which I do), and was using it for astro-imaging(which I'm not), I wouldn't even think of upgrading to anything other than a mono full frame ccd such as an SBIG, and then only if I had the desire for going beyond happy snapping.

my take,
Doug

[strongmanmike]

Oh I agree totally. The work many on this group are doing with DSLR's is really good!

DSLR's are great and the latest article in AS&T proves they can produce cooled CCD like results (all be it with very long exposures).

I just thought some on this list might like to see what something other than the "Coke" , "Panadol" or "Wind Surfer" of CCD cameras can do :-)

Mike

[RB]

Yes I think it's great Mike that we know what alternatives are available and thanks for the link, awesome image by Alan.
Also what Doug said, because not all members will be in a position to own higher end equipment, so it's also great to see what guys are producing with the DSLR's.

Both valid points I think.

[Dennis]

And therein lies the beauty of this forum…hearing from experienced observers and imagers who have “been there” and “done that” and can thus save community members a lot of frustration, heartache and potentially unnecessary costs.

I welcome these posts and subsequent discussions for the issues they bring up and discuss, helping me arrive at a better informed decision. Does wonders in eliminating “buyer’s remorse”!

Cheers

Dennis

[RB]

Totally agree Dennis, we all can reach higher by standing on the shoulders of giants.

[avandonk]

The Starlightxpress SXV-M25C looks like a very nice alternative to mono CCD's. The only real advantage over a Canon 5DH is that the chip is cooled. It is fair to compare the two as they in the same price range. The Canon 5DH has a well capacity of 80,000 electrons compared with 25,000+ for the SXV-M25C. This means the 5DH has an inherently better signal to noise if you ignore the effect of cooling the chip in the SXV-M25C.
It would be interesting to do a comparison exposure of M45 with a comparitive optic. I will try with my Tal 200k (200mm dia) at F9 and see how it compares to 250mm diameter at F3. I will also see how the 5DH compares at 300mm focal length at F2.8.

I am of the firm opinion that any imaging system is better than none. All we individually then have to do is get the best out of it. Comparisons should only be made when thoughts of upgrading become seriously chronic.

It is coincidental that these were the two alternatives I considered when wanting to upgrade from my Canon 20D.

Bert

[asimov]

I'm still at stage one; a long exposure modded webcam. I intend on wringing its neck for all its worth, & then add cooling & do it all over again, lol.

[Garyh]

Interesting thread Mike,
There are some alternatives for us DSLR uses but you have to admit there is a huge gap in outlay to get to the next level of imaging. Also we are restricted to what we can get and brand. SBIG , SX or FLI or Apogee and thats about it for choice or maybe a Artemis top end camera? Thats all I now about myself and when it comes to one shot color the choice is even smaller.
The new SXV-M25C would be one I would consider as well as the new SBIG 11000 if I had money.
Yet a lot of DSLRs have the same ccd sensors etc as the dedicated ccd imagers have except for the cooling, maybe AO and a guiding port which we can use a cheap subsitute for.
So for me I will be using a DSLR for some time yet till prices come down on the dedicated ccds. Just all that noise really bugs me on warm nights..:mad2:.
So I say price and outlay holds most of us DSLR uses back from the next big step..
Thats my 2 bobs worth...
Cheers Gary