Camera upgrade

[Entropy]

Hey guys,

Just got back from Wiruna, had an absolute ball. But, I came back with a few questions.
Ever since I bought my Tak I've had my eyes on the SBIG STXL-11002 camera. I currently use a 60D DSLR which I am getting fairly good results from. I would like to upgrade to a CCD and retire the DSLR but, after this weekend, monochromatic imaging scares the heck out of me.
I would just like to get peoples opinion if I should dive straight in the deep end and buy the STXL once I have the money (which could take quite some time) or by some sort of intermediary camera like, for example, the Atik 383L+ OSC and dip my toe in CCD imaging first? (Equipment: FSQ106, EQ8 with Orion ultimate auto guider package), Keeping in mind I live in the centre of Sydney and have difficulties getting to dark sites very often (A problem I'm looking to remedy)

Just a quick side question as well. QE... I've seen some camera advertise QE as high as 80% (With a relatively cheap price tag) while the STX-16803, SBIGs biggest and best camera, advertises a peak QE of only 60%...
Why the large difference? Do companies measure this differently or is it not very important by itself?

Thanks

[RickS (Rick)]

If you're serious and want to go mono ultimately then I wouldn't bother with OSC, especially if you already have some experience with a DSLR.

The 11K sensor and the FSQ-106 is a great combination and will give you a very wide FOV of approximately 3.9x2.6 degrees. It's great for large objects and fields. At an image scale of 3.5 arcsec/pixel guiding and seeing don't need to be fantastic to get a great result and the combination of fast scope and big pixels will collect data quickly. The only downside is that you won't have the resolution to do small objects justice.

Another option would be to go with a sensor with smaller pixels. That will get you better resolution at the expense of a smaller FOV. The ICX-694 and KAF-8300 sensors would be worth thinking about if you want the extra resolution.

QE does vary significantly across different sensors. As well as peak QE you might also want to look at the QE at different wavelengths and think about what you'll be imaging (e.g. Ha is important for emission nebulae, good QE for the blue region would be useful for galaxies.) Another important camera parameter is read noise - the lower the better.

Cheers,
Rick.

[Entropy]

Thank you for you help,
I have been re-assessing my buy list with all this information in mind.
I would like the option to take some half decent images of smaller objects. So I was thinking of buying the ICX814 (Atik 490EX) and keep saving for my dream camera (the 11K). Where do pixels start becoming 'too small' for my current setup (490EX is 3.69 square)

Now, here are my options.
Purchase a colour Atik490EX and whimp out of mono for the time being (Mono really does scare me )
Purchase a mono 490(with EFW) and practice while saving for upgrading to the 11k
Purchase the 11K and deal with my DSLR for quite a while (This is my least preferred option as my wife is showing an interest in time lapse and nightscape photography, thanks to the gentleman, who's name I cant remember, who showed that amazing montage on the Friday at Wiruna).
Which option do you think would be best? (I'm almost leaning towards the second but it seems a bit of a waste buying two filter sets and filter wheels)

So with QE, two sensors having a QE difference of 20% doesn't necessarily mean that the higher QE sensor is significantly better than the lower QE sensor?

Thanks again

[Paul Haese]

The STXL11002 is a good camera. I have one and it works well. It will mean you can do narrow band imaging from home. That way you will use the camera more often. You can also do some broad band imaging too but mainly for stars and brighter objects.

I would recommend you get the integrated filter wheel and guide camera. It works a treat and has 8 filter slots for narrow band and broad band filters.

No point economising here as you will wish later on that you had made the purchase in one hit.

The 11K sensor is a proven performer and while it has middle of the range QE it is widely used by many of the top imagers across the world.

The STXL will hold temperature of -30C on the sensor all year round including on very warm nights. MANY other cameras cannot do that as a matter of fact.

Mono is not hard and there are many good tuts on the net that will guide you through the process. Using a OSC in Sydney will limit you.

Feel free to ask me any questions you may have about the STXL.

[ericwbenson (Eric)]

Originally Posted by Entropy

So with QE, two sensors having a QE difference of 20% doesn't necessarily mean that the higher QE sensor is significantly better than the lower QE sensor?

QE is difference is important, that 20% is like having a 20% bigger telescope (in area, not diameter of course). But you can compensate, you just need to expose for 20% longer, that's it (if cooling and electronics quality is similar).

Best,
EB

[gregbradley]

FSQ and 11002 chip are an excellent combo and seem to work together beautifully.
The 50% QE is not that big of a deal. 80% QE is most likely a small chip and that has its own issues and may not match an FSQ very well which is after all a widefield imaging instrument so a large sensor is ideal and F5 is fast anyway so 50% is not problem.

QE is one of a string of factors to consider for what is best for a certain type of image. It may not that high a priority in widefield and quite high if you want to do long focal length narrowband (which you aren't intending per your post).

Greg.