On 23 Dec 2008, at 14:13, Gary Bulk wrote:
I will definitely try the "Hat trick". My Nikon doesn't quite have mirror-lockup, but it does have a mode to flip up the mirror 1/2 sec. before the shutter opens. I'm not sure that is long enough. Maybe I will try a few comparison shots between the Hat Trick and the semi-mirror lockup.
Joe has more "hat trick" experience than me but I think if you cover up the front of the scope before opening the shutter and then open the shutter and then let the vibration settle out before removing the hat I don't think you need to lock the mirror up. Just be sure and cover the front again before closing the shutter.
I would really like to be able to get 2-5 minute exposures
Ummm, since the chip is not cooled I've a feeling that if you go more than a few seconds you're going to pick up an awful lot of background noise. Anyone here have experience with how long one can go with an uncooled chip before noise becomes objectionable? Also, is there some way to use a DSLR to make a master flat and use it to subtract the noise (like is done with CCD cameras)?
I'm a little hesitant to culminate the scope because I don't know what the before and after differences should look like, and don't want to make anything worse. I guess I will do some more reading on it first.
Best not to mess with it unless you have a manual to show you how (it's very easy to make a bad situation much worse). Might be best to bring it to a star party and have someone do it for you.
About the "piggyback" suggestion, I have an adapter/mount partially built to be able to piggyback my dSLR on the telescope. I am hoping to finish that today.
If that doesn't work, I donated tall and short C-8 piggy back mounts to SLAS for the loaner scope program. You could see about borrowing one.
I saw a picture of a pier (mentioned by Patrick) on a forum the other day, and that is definitely on my list. I can build one without a big $ outlay. I already have a concrete pad in my backyard, and I'm guesssing that a pier bolted to that would give me about the best foundation I could hope for.
Best to put the pier in the ground (dirt) such that it is isolated from the concrete. Concrete has the irritating habit of transmitting vibrations especially when using long focal length imaging systems.
I took golf lessons a while back, and felt that I had to remember and pay attention to 8 different things simultaneously while I was swinging the club.
But, as with golf, if you stick with it you'll get the hang of it. Cheers, patricjk