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DSLR and telescope?
I've been following some of the progress the DSLR team has been making with regards to DSLR photometry and a couple of weeks ago I played around with my DSLR (Canon 450) in taking some shots of the moon and a couple of DSO's for grins and they came out ok. I've been thinking of how well this would work for doing photometry and if there are any specific things to look out for. I know the documentation and focus has been on using a DSLR on a tripod but what about using on an ALT-AZ scope? Has anyone tried it and what were your finding? I'm using a Celestron CPC 1100 and figure I'd probably need to use the 6.3 reducer to get a wider field and speed up the scope a bit but the hardest part is focusing, man it drove me nuts when trying to hit the DSO's.
Any suggestions or experiences from those who have tried this are appreciated!
Hi all, Fully agree with Heinz: 11" telescope would be a good candidat to chase exoplanet eclipse around 10+ mag stars !But difficult for 3~6 mag cases. It's also rightcontrolling the defocusing with the x10 Live-Viewworks superbly... even if framing at x1 is near impossible... (low resolution screen of the 450D) At 11" you will have to expose very short andneedmany shots to average the scintillation. A tele-lensabout 50~60 mm pupil diameter is probably the optimum for such stars. Your telescope gets 30 times the photons captured by such lens. Yours truly, Roger
Heinz and Roger, Thank you both for your input, it's greatly appreciated! Seems with my setup I'd be better off chasing exoplanet exclipses or possibly fainter (10+ mag)stars for photometry then. I could always do the tripod thing too, I was just hoping to find a way to use my current equipment to do photometry. When I got this scope and got back into astronomy last year after a brief foray years ago, Ididn't know 1/10th of what I know now (not that Iknow a lot now lol)but looking back, I'd have gone with a different setup and a GEMmount so Icould do astrophotgraphy and photometry. Then again, Ididn't know ANYTHINGabout how involved every day people can now be with science in astronomy. Ihope to get a small imaging setup in the future that will be dedicated to imaging for photometry but in the meantime I can at least do some things with what I have, along with the visual observing. Thanks!! Maurice
For epsilonyou could try to mount your camera pigyback on your telescope,you thenget a steady platform that follows the stars.
Yes, that is something else I was thinking of doing. Ijust need to get a piggyback mount, which I'll be looking for today.
Hi I guess when using a telescope and DSLR to do photometry, it's the same as thru a tele-lens: you don't want perfect focus, you want the star image to be spread across many pixels. Anyway, to find the right focus (or, in this case, the right amount of de-focus), a DSLR with a zoomable Live-View feature is infinitely superior. When I do astro photography (just for fun, nothing special) with my little 6" f/5 Newtonian reflector, I use either a bright star (or more exactly, the spikes it generates!) to focus, or Jupiter's brightest moons which happen to be just bright enough to be seen on the Live View of my DSLR when properly focused. It's a matter of seconds. Without live view....you have a problem. For epsilon aurigae, the main disadvantages of using a telescope seem to be that a) even with a reducer you'll have problems getting good (bright) comparison stars into the same field and b) it is difficult not to over-expose. CS Heinz