Am I missing something?

[spikkyboy]

So, last night was a lovely clear evening. I fired up the Celestron CPC925.

WOW! I had the best views of Saturn ever. With a 30mm eyepiece and x2 Barlow.

Previous views were an orange blob with a disc around it. This time I can see grey blue in the rings and rings within the rings so probably as good a visual as I will ever get.

I attach my Neximage directly to the rear of the scope using a 2" adaptor.  Using the supplied icap software the camera is recognised and connected. No image just a full hazy screen. Twiddle focus backwards and forwards, nothing. Suddenly right at the end of travel I notice a full screen sun spot type image. No more focus travel.

Luckily the adaptor is a fairly long tube and by loosening the screw I can eek bit more out of it by moving the camera further up in the adaptor.

We have some kind of focus. I see Saturn, and either some of it moons or nearby stars. They are in pretty good shape but the main planet is just a big white over exposed blob. Tried  a number of different filters but it did not improve.

My question is which setting must I alter to stop this over exposure? It seems I am almost there and am finally getting everything to work.

Just one final hurdle. (he hopes)

Any input would be most welcome and as always thanks in advance.

[wimvb]

First of all, put an extension ring between camera and scope. This will give a more stable configuraion than having the focuser all out.

Second, planets are bright and the 925 will collect a lot of light. You compensate by using short exposure times, measured in milliseconds rather than seconds.

[PeterCPC]

...and you might want to combine the short exposures with some longer ones that capture the moons - not easy.

[Elp]

Not familiar with your setup but both Firecapture and OAcapture have a gain setting which is useful for locating and framing the planet, but then turn it down as much as possible to "dim" the image and until the planet detail appears clearer. Only then your exposure time should be adjusted to get enough detail in the captures. Remember you can always brighten up an image to eek out detail but you cannot darken an image to resolve over-exposed images.

[Andy ES]

9 hours ago, Elp said:

dim" the image and until the planet detail appears clearer. Only then your exposure time should be adjusted to get enough detail in the captures.

Hi

I’m starting to use firecapture with a CPC925 similar to the OP above.

Is it possible to suggest what the gain and exposure settings should be for Jupiter?

I suppose there are loads of variables depending on seeing but perhaps there are average settings to start from?

I’m pretty happy about dimming down after  locating the planet, but really not sure what the exposure Time should be . I think it’s about 1-2ms?

 

thanks

[Elp]

Hello Andy,

Firecapture has default setting profiles depending on what you're trying to photograph (see screenshot below), haven't got it open in front of me but I think if you press the button where it says Jupiter they'll be around 5 options to choose from (Jupiter/Saturn/dso etc) which gives a good starting point. If your planet is a white dot some settings are too high.

I don't use Firecapture much as it crashes too much for me on my astroberry. In OAcapture however with the below JPG file settings were as follows:

Blue Balance: 99
Auto Blue Balance: on
Red Balance: 50
Auto Red Balance: on
Gain: 0
Auto Gain: off
Exposure (msec): 75

After stacking+sharpening with Autostakkert and a post process brightness+contrast edit I get a similar Jupiter image to the one on my profile.

Seeing conditions have a bearing on what settings I use, having auto settings enabled also affects what other settings such as gain I'd use, generally gain I try to dial it as close to 0 as possible.