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Old 26-08-2013, 05:26 PM
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gregbradley
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Join Date: Feb 2006
Location: Sydney
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The choice is a bit easier than this really Houghy.

Not all scopes as has been pointed out can handle an 11002 chip.

Because you live in light pollution your option is narrowband. Narrowband requries strongish cooling to keep the noise down as the signal is weaker than broadband. You also ideally need to be able to do long exposures.

So there are 3 factors here:

1. What size chip can your scopes handle including weight of the final camera package? (11002 requires a largish focuser like 3 inches, 2.7 may not work as it did not with my FS152 Tak, I had to upgrade it to a 4 inch focuser and then all the accessories cost way more like reducers).

2. Narrowband filters are expensive. The 11002 will require 50.2mm round filters. These cost around $550 each or more. The QSI583 can get by with smaller filters per several recommendations. Those filters can cost half as much.

3. Guiding. Because you are going to do long exposures you need a good guiding solution. OAGs are proven to be one of the best. SBIG probably has the best range of autoguiding solutions then QSI. The latest STF8300 has a built in OAG, the later models have a guide chip in the filter wheel. The guide chip has to be in front of the filters as narrowband will block the guide stars badly with a self guiding camera and my experience was it made it impractical. So its OAG or chip in filter wheel. So that narrows it to SBIG or QSI. Both have good clean electronics and cooling. Or use a FLI or Apogee and buy an OAG and fit it in front of it (that's what I use).
FLI Microline is about $3500 I thought. A MOAG is about $900 add a few hundred for adapters and more for a filter wheel and filters. It adds up.
SBIG and QSI start looking good for the overall system.
You may already have autoguiding solutions - forget guide scopes though unless they are working really well. We are talking 20-40 minute exposures with narrowband. Not going to work well with a guide scope.

You also may get better results with 3nm Ha and O111 and save money on the smaller filters required for the QSI and get the higher rated ones.
I think QSI allows the smallest filters.

So to me 11002 would be out. QSI or SBIG would stay in. A 3rd may be the new Starlight Express 694 chip -its more sensitive than 8300 and SX also sell a filter wheel and OAG unit for it. You already have a lodestar.
The chip is a tad smaller than KAF8300 though but higher QE.

Greg.
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