Posted by Andrea Tasselli at 16:45 on 2010 Dec 13
First question would be: is it a refractor or a reflector?If a refractor is it an apo or achromat?Achromats tend to produce large halos so they’re not best suited for ccd imaging unless you filter them. For photometry a V filter would do. Just keep this in mind.As for the CCD camera, I would tend to lean toward the SX lines as they’ve never let me down in so may years of near-continuous usage. If you want to cover an extended field then your best bet would be their monochrome camera based on the Kodak 8300 chip. For best response (highest sensitivity) I’d suggest the SXVF-H9. The former can be binned to boost the sensitivity and you would still get a decent pixel scale and you’d probably not needing a focal reducer as the field would be large enough to have enough comparison stars. The other side of the coin is that you might end up having to buy a more expensive set of filters because of the larger format of the CCD chip. With the other option you can use a focal reducer to achive a respectably fast f/ratio and use less expensive filter set and still enjoy the best sensitivity per £ in the market today. Obviously if you want to splash out than I’d suggest that the ST8-XE is a good compromise between pixel scale and FWC. I’d recommend to avoid pixel larger than 15 um as it would severely undersample the PSF.Hope it helpsAndrea T.