Dear Sir/Madam, This is Elham Ziaali, a PhD candidate in astrophysics in Research Institute for Astronomy and Astrophysics of Maragha (RIAAM) in Iran. I plan to equip an observatory to start photometry and spectroscopy of variable stars specially pulsating stars and Delta Scuti stars there. We have a 11 inches Schmidt-Cassegrain Telescope (from Celestron company) and we need a new CCD camera, proper filters, a focal reducer and a guider which will be another CCD camera with smaller pixel size which locate at the finder-scope. I visited your website and I selected STX-16803 CCD with FW7-STX filter wheel to do photometry. Since I am not very experienced, please let me know is it a suitable model for our goal with this kind of telescope? and what kind of filters will match with this CCD model and this filter wheel? I would appreciate that if I could ask you about the model of guider you suggest me? In case of spectroscopy, could you please suggest me the spectroscope models I can use with this telescope and STX-16803STX-16803 CCD? Yours Sincerely, Elham Ziaali
The STX-16803 has a very large image sensor, compared to the what is available in an 11-inch SCT. It is likely too large for that telescope. Only the centre of the field would be properly illuminated. Is this a C-11 or a C-11 EDGE HD ? I would recommend the Aluma-U3200. It has 6.8um pixels, which are an ideal match for that telescope if you have excellent seeing conditions (0.5 arcsecond), and it supports a Remote Guide Head or a Self-Guiding Filter Wheel. http://diffractionlimited.com/product/aluma-3200/ There is also an STF-3200 which is less expensive, but it does not cool as well and does not have self-guiding capabilities or a remote guide head option. You could get a small CCD camera for that. Another option would be the STF-1603, with 9um pixels. If your seeing is 1 arcsecond, it is also an excellent camera, smaller, less expensive. This is the modern version of the famous ST-8, but does not have self-guiding capabiliites. We have 1.25 to 36mm filter inserts, and Custom Scientific makes photometric filters in 1.25" threaded cells that can be used with these inserts for photometry. Many people buy our 3 Narrowband filters, and a set of photometric filters, so they can do imaging and photometry. We no longer make or sell spectrographs. I can put you in touch with Shelyak Instruments if you need a referral. Best wishes, colin
Dear Colin, Sorry for the super delay and Thanks for your reply. The telescope is C-11. I am not sure about the seeing value but I know the observatory is completely near to the Kerman city in Iran, a medium city at 30.2839° N, 57.0834° E. I suppose the seeing would be larger than 1 arcsecond. If there is any list or catalogue for seeing values (or at least approximate values) of different parts of world I would appreciate that if I could know about that by you. According to your explanations STF-1603, with 9um pixels, seems the best but since I am not sure about the seeing I can not decide. I would like to be put in touch with Shelyak Instruments for having more information about spectrographs. Thank you for that. Please let me know any further information which can help me to decide easier about the needed instruments. Best wishes, Elham
