CCD vs Film? Lots of time vs no patience? Alright, this is your place to discuss all the astrophotography what's and what's not. You can discuss about techniques, accessories, cameras, whatever....just make sure you also post some nice photos here too!
Hi Friends. Clifford shot the following series of photos of the recent Venus Pleiades conjunction using a DSLR on unguided tripod. Upon closer inspection of the photos, there seems to be 2 unknown objects drifting across the photos.
Could they be due to some light/lens/camera effect? Or could it be some objects in our atmosphere or in space? A pair of ejected rocket booster?
Feel free to submit your guesses and your reasoning behind them to help Clifford solve this puzzle.
"The importance of a telescope is not how big it is, how well made it is.
It is how many people, less fortunate than you, got to look through it."
-- John Dobson.
Yes, it is lens internal reflection artifact. Orly and Alweek good guess, but no prize for you, haha
It moves because what Gary didn't show you (he cropped the photos) that Venus moved across the photo or the bright spot changes position, so the artifacts "moved" in the opposite direction at the "same speed".
In order for such artifact to take place, there must be a very bright spot of light, bright exposure (by aperture/time) and dark area in the photo as well as the bright spot need to be within about 50~60% coverage from the lens center. These Venus photos were take with 200mm f/5.6 + 2x teleconverter (400mm f/11), 6 seconds exposure, ISO 1600. Only photos with Venus nearer to the lens center have the artifact. Last night had proven the effect to Gary with Venus (with artifact, 5 sec), Moon (no artifact, 1/30 sec) and the stadium flood light (with artifact, 5 sec) with the same equipment.
Yes, both reflexes were created by one very bright light source, in this case Venus. Last night photo of Venus which was the only light source, there were 2 reflexes too. Depend on the lens and aperture, it can have even more reflexes. Once I took Jupiter with f/2 lens, it had 3 or 4 reflexes.