wich ccd cam?

[Erwin Kats]

Hello,

i was thinking about buying a CCD camera.

The next 2 ccd's are in my mind.

a QHY 9 or a SBIG ST-10 XME.

the QHY 9 is around 2000 euro's and the SBIG ST-10 XME can i get 2nd hand for 3500 with 5 filters.

mostly i photograph with my vixen R200 SS 800mm F4.

2 advantages of the SBIG are: dual chip *build in guide chip*

and high QE ( 85% ) vs 56% of the qhy 9

i would like to get around the same FOV as i got now with my eos 40D that has a 22,2 x 14,8 mm chip size.

qhy9 is 19,7 x 15,04mm chip size

ST10 = 14.85mm x 10.26mm

link to QHY 9

QHY9 8.6mega pixel mono camera

link to ST-10

ST-10 Information

please let me know youre tips etc.

kindly regards, Erwin Kats

[Ben Ritchie]

Self-guiding is great, but is more limited through RGB filters and very hard with narrowband unless you have a high-end mount that can do 30s guide integrations. Even through a blue filter you may need 4 second or longer guide integrations to pick up a guide star. So there's a fair chance that you'll end up using an external guide CCD anyway.

Remember too that the -10XME is a NABG CCD, so bright stars will bloom, so it's almost useless for some targets (e.g. M45). Saying that it's still a superb CCD, very sensitive and great for narrowband. I'd love one, but would probably go for the QSI version rather than SBIG because of the limited use (in practice) of the self-guiding.

[narrowbandpaul]

ill back up that.....the sbig self guide system is in theory great, but through a blue filter or narrowband filter it is very limiting. You may find yourself moving the telescope from the ideal framing orientation, just to find a guide star.

and the SBIG will bloom....and becuase of the high QE, it will bloom quite quickly. M45 would be next to impossible I would think.

so for guided exposures, it is far more versatile to guide via separate guide scope and camera.

the QHY has an antiblooming chip. So you can throw as much light as you want at the pixels and they wont bloom. It has a larger area, but a lower QE. However the QE is still very respectable for an ABG chip.

there is a good figure of merit given to me, and that is how fast can you image a given area of sky. it turns out to be QE*area of sensor/price. The bigger the number the better

however, the qhy9 sensor has a lower full well, so the dynamic range is reduced, hoever high signal levels are not that common in deep sky imaging. M42 may be the only one, or M31.

if its my money. QHY9

[Ben Ritchie]

Another point i'd make is that with a NABG CCD, the wider the field of view, the more likely you'll pick up stars bright enough to bloom rapidly. So with your 800mm FL Newtonian and a ST-10 you'd be doing a fair bit of bloom-removal. It's not particularly hard to do, and things like CCDStack have good tools for helping, but it becomes more painful when the bloom overlaps nebulosity you want to image (which is why M45's pretty much impossible to image well using LRGB with a NABG CCD)

[Erwin Kats]

Thanks Guys,

the owner of the SBIG ST-10 XME , is also a friend of my ( Karel Teuwen www.karelteuwen.be )

He says , that he almost find everytime a guidestar with the onboard guidechip, but... he has a 2 time bigger apperture ( 16'' ) so he will catch more light then me with my 8''.

he will show me some pics about the blooming, and will show me some editing to get it away, but it still makes me nervous.

on google i also found that anti blooming chips like the QHY 9 will get fat stars do you guys know anything about that.?

Besides the ST-10 is also deleverid with CFW 8, and 4,5nm and rgb filters.

so its a completepackage...

but if the blooming is horrible then its still a bad investment i think.

thanks again,

regards erwin.

[Erwin Kats]

i received an e-mail from an other SBIG ST-10 owner

Arie Nagel from holland.

he send me this pic from the wodaski-debloomer.

its look pretty impressive, how much blooming is away.

so with not to bright stars it will work fine i think.