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A couple DSLR questions

Started by JeffinMd, 01/19/2006 05:14PM
Posted 01/19/2006 05:14PM Opening Post
First, I'm using a Nikon D70s.

I'm having trouble getting to focus on a Mak-Newt. (MN56) It seems like I need in-focus, is there a way around this problem? Is there a low power "barlow" type lens for this? Will I have as much trouble on a Schm-Newt?

Second, advice/recommendations on stacking, focusing software would be appreciated. Please keep in mind I have a Nikon. (I think some are Canon only)

Thank you all.
Posted 01/20/2006 01:26AM | Edited 01/20/2006 01:37AM #1
Your focus problem may be you need a focal reducer or an extension piece for your scope. A barlow would be undesirable as it lengthens the focal ratio and generally you want that shorted and flatter for imaging. Such as the wonderful Televue .8X flattener/reducer for different focal length scopes.

For example I use a Nikon D70 on a Tak FS152 or a William Optics 80mm or an RCOS 12.5 inch.

The FS152 has 2 configurations; 1 with an F6 focal reducer where the camera fit snugly behind it with no need of extension tubes.
1 without the reducer which requires an extension tube to come to focus.

The William Optics fits the camera with a TV reducer/flattener fitted to it without extenders. Without the reducer it still comes to focus but I think it is more in-focus from memory.

You need ScopeStuff part TA2P which is a 2 inch barrel that screws into a T Thread adapter screwed onto your Nikon D70s. If you need in-focus then the reducer/flattener is the way to go I am pretty sure.

I could check what effect with and without Televue .8X reducer/flattener makes as far as focus goes if you are interested to be sure.

Some use a Celestron or Meade F6.3 reducer on the TA2P and I have as well but the Televue unit is far superior even if it reduces less than the other.

As far as focusing goes, use Nikon Capture and use a laptop or computer. You control the camera from the computer and the images are downloaded and displayed and you can view the images at a larger size by adjusting the software. This way you can frame your shot and get the focus just right before imaging. You can also batch time lapse photos to take a series of up to 60 second shots using that software. Images Plus is the standard for image stacking and RAW file conversion software. It also can control the 70s like Nikon Capture but with a Hap Griffin infrared remote you can program a series of shots of any length and ISO setting. It has a focus aid as well. Also the images are saved in your hard disk and this saves the additional step of downloading shots from your camera to your computer later. It does however require a computer. Otherwise slew to a bright star and focus through the viewfinder and take an image and blow it up using the magnify function on the D70s display (see your manual about which buttons to push). I find I can normally get a sharp focus simply looking through the viewfinder (make sure the little slider next to it is set for your vision as it can move when travelling!). Just use a bright star and focus it.

Greg.