I am the king of "Ignorant Astro-Newbies," and can't seem to get my equipment to function. I have an old (don't laugh, I'm poor) Meade model 4400 4.5" Newtonian scope and have been trying to take some photos of moon craters without success. I am trying to use a Minolta Maxxum HTsi SLR camera, with a Meade camera adapter, and a Qualide T-mount adaptor for the Maxxum. I can't figure out what the problem is, but the camera won't seem to function with the T-mount and camera adapter, either on or off the telescope. It looks like the camera is looking for the actual lens, and isn't "happy" with the adaptive equipment or the telescope. Am I hopeless? Any help would be truly appreciated. If anyone has any answers, please e-mail me at [email protected]
T-Mount HELP!
Started by Steve1969, 09/11/2003 08:12PM
Posted 09/11/2003 08:12PM
Opening Post
Posted 09/11/2003 08:54PM
#1
It sound like you don't have enough back focus from the eyepiece holder to the film plane. With the scope pointed at the moon, hold a piece of paper in front of the eyepiece holder (with no eyepiece.) Move the paper back and forth until the moon is focused, then measure the distance from the holder to the paper. Compare this to the distance required to get the light to the film plane.
Posted 09/11/2003 10:53PM
#2
Hi,
Most electronic cameras (my Nikon included) will not work normally without the lens because the lenses are auto-focus and auto-focal ratio. If you try to use the camera in any of the auto modes the camera will just say its got some kind of error. You have to use the camera in full manual mode and just worry about exposure time (the focal ratio is fixed by the scope). You will need to estimate exposure times. With a full Moon, as with right now, and with ISO 100 film the exposure will be somewhere around 1/180 - 1/500 of a second on my F10 scope - your mileage might vary.
Take Care,
Jose Suro
Tierra Verde, Florida
Most electronic cameras (my Nikon included) will not work normally without the lens because the lenses are auto-focus and auto-focal ratio. If you try to use the camera in any of the auto modes the camera will just say its got some kind of error. You have to use the camera in full manual mode and just worry about exposure time (the focal ratio is fixed by the scope). You will need to estimate exposure times. With a full Moon, as with right now, and with ISO 100 film the exposure will be somewhere around 1/180 - 1/500 of a second on my F10 scope - your mileage might vary.
Take Care,
Jose Suro
Tierra Verde, Florida
Funding Member
