5400 vs. 5700 for astrophotography

[oswaler]

I am thinking about buying one or the other. The main issues as I see them for astrophotography are 1)The 5400 has a max exposure time of 10 minutes while the 5700 only seems to allow 5 minutes. 2) The optical zoom on the 5700 is twice that of the 5400.

Has anyone used one or both of these for astrophotography? Is there a problem with the 5400's noise reduction on exposures longer than 5 min.?

Any comments would be appreciated.

-Eric

[PeterP]

I bought the 5400 with astrophoto as one of my planned activites.

The ISO speed of the 5400 is 50-400 and the 5700 is 100-800,
so what you gain in bulb exposure time you partially loose in sensor sensivity.

I've only tried a few times with a handheld camera to the telescope and found that focusing was a major problem. You see very little or nothing on the LCD.
There are tricks to focusing but they usually require a camera attached to the telescope. I will have to get my order in to nextphoto to get the t-mount adapter.

I have also heard that these digital cameras (not only nikon) don't handle cold very well.

[oswaler]

Thanks - I didn't know about the big diff. in ISO range.

Just holding the camera won't get you much. I bought an afocal mount from Orion for only about $30.00 that works very well. It attaches to the camera's tripod screw hole and then holds the camera lense up to the eyepiece. I was surprised that the materials they used were so good and sturdy for a $30 item. I have been using my current digicam up at Mt. Pinos and haven't had problems with the cold yet. DUring the winter maybe but then there's too much snow to go up there anyway.

Focusing on a faint object is hard with a digicam but perhaps a flip mirror would help or maybe focusing first on a close-by bright star and then slewing to the object (which is where those Go To computers on the scopes are handy.

-Eric

[sjms]

the temp issue is no problem. an external battery pack under a coat with a reasonable length cord.

[Larry Loo]

Posted: Wed Oct 29, 2003 7:34 pm Post subject: 5400 vs. 5700 for astrophotography

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If you prefer the 5700 because of its longer zoom and higher ISO setting, then you should use the 5700's bulb setting with Nikon's electronic cable release. If you fabricated a homemade cable release post like mine, you'd have a cheaper alternative. With either one you can lock the shutter open and make an exposure for as long as you wish.

My homemade cable release post:

http://www.pbase.com/image/22365419/original

Colin F. also has a very nice one that is suitable for a 5700 that has an MB-E5700 mounted below it.

[PeterP]

Yes agreed
I ordered the t-mount adapter(part np0031) from nextphoto. To resolve the problem . It lets you connect the camera directly to the telescope.

Originally Posted by oswaler

Just holding the camera won't get you much

Yes that would work well, or a real long extension cord and the nikon external power supply. Though I think the LCD may still freeze up in the dark of winter.

Originally Posted by sjms

the temp issue is no problem. an external battery pack under a coat with a reasonable length cord.