8 replies to this topic

[kenny4090]

I am using an SkyQuest XT8, a Nikon D5100, and a 2X barlow.  Whenever I start processing the video I am taking, the planet is way too washed out and all the planet looks like is a white ball.  I can't seem to turn down my gain on the camera when I am shooting video.  Any suggestions on how to either turn down the gain on my Nikon D5100 during video or reduce the light coming into my telescope?

[CrazyPanda]

If you don't have flexibility to set exposure settings during video, then you have a couple of options with the optics:

 

1. Use a 3x barlow instead of a 2x. This will spread the light out over a larger area, reducing the intensity per pixel to less than half. You probably want more image scale than a 2x barlow can provide for that camera. Advantage is that you get more image scale. Disadvantage is the atmosphere may not be steady enough to support that kind of image scale and tracking/focusing will be harder without tracking.

 

2. Use a variable polarizing or ND filter to reduce the light hitting the sensor. Disadvantage is that you're just artificially killing signal without converting it to something useful like larger image scale.

[gstrumol]

I shoot Jupiter and Saturn using my C8, a Canon T7 DSLR, and a 2X Barlow. Doesn't the Nikon allow you to set the ISO for a video? There has to be a way ... take a look at this:

 

https://www.youtube....h?v=VX6sPFJQJSE

 

Here are some shots I took using the C8 and the Apex 90mm Mak on both (with the Canon):

 

 

For Jupiter on the C8 I found an ISO of 1600 was best.

[FRANKVSTAR]

Just a quick thought, you say you are using a 2x barlow. Have you tried something like an  Orion Variable Polarizing Moon 1.25" Filter, most often used when viewing the moon or imaging the moon. Or maybe a Neutral Density Filter, I have read some people use them to lower the bright light from the planets.  Hope you resolve the issue, as to you camera, I have never taken video with my DSLR on celestial objects.

[RedLionNJ]

When shooting video (at least through a Canon DSLR), you have several options you can tweak to alter the brightness. You can raise or lower the simulated ISO, or you can adjust the simulated exposure time. I'd be a little surprised if similar options don't exist for newer Nikons.

[RichA]

I am using an SkyQuest XT8, a Nikon D5100, and a 2X barlow.  Whenever I start processing the video I am taking, the planet is way too washed out and all the planet looks like is a white ball.  I can't seem to turn down my gain on the camera when I am shooting video.  Any suggestions on how to either turn down the gain on my Nikon D5100 during video or reduce the light coming into my telescope?

Just use an ND filter on the barlow.  The camera is pretty much limited to 1/24-1/30sec frame rates and has a native ISO of 200.  The auto-gain that probably boosts the video ISO to maybe 1600 is reacting to the black sky occupying most of the frame.  If you can set a narrow "spot metering" function to just included the planet, do that.

[kenny4090]

Thanks for the responses, I'll have to try some of these options.

[dcaponeii]

My best recommendation for a scope that is native f/5.8 is to quit trying to shoot planetary with a DSLR and spend $179 for an ASI715MC from High-point Scientific.  1.45 micron pixels  is 4x at the native f/ratio.  More expensive, but maybe more versatile would be to use a 2x barlow and go with the ASI678MC.

[kenny4090]

My best recommendation for a scope that is native f/5.8 is to quit trying to shoot planetary with a DSLR and spend $179 for an ASI715MC from High-point Scientific.  1.45 micron pixels  is 4x at the native f/ratio.  More expensive, but maybe more versatile would be to use a 2x barlow and go with the ASI678MC.

I have been looking into maybe getting a new camera.  Is the ASI715MC and ASI678MC something that can be used for DSO photography?