help mars

Discussions of using SharpCap for Planetary Imaging
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luke.peda
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help mars

Post by luke.peda » Mon Oct 12, 2020 8:07 am

hi I have a ccd 183c qhy I have a problem with settings for the planet mars, my first doubt and if you see it being used directly to the "tube" of the telescope second question what kind of parameters should I use
:roll:

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admin
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Re: help mars

Post by admin » Mon Oct 12, 2020 5:47 pm

Hi,

yes, the camera goes straight in where the eyepiece usually goes with no extra lens required (the telescope *IS* the lens :) ).

A good starting point would be to set exposure to about 30ms (0.03s) and mid to high gain. Adjust the gain first to get the brightness right, only if you run out of gain adjustment change the exposure.

Robin

GSBass
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Re: help mars

Post by GSBass » Mon Oct 12, 2020 7:01 pm

Be careful not to zero out your gain though, it causes an onion style artifact with some camera so a healthy mix of low gain and exposures is best

luke.peda
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Re: help mars

Post by luke.peda » Tue Oct 13, 2020 7:09 am

So without diagonal and with a barlow as an initial setting to have an image on the PC :|

luke.peda
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Re: help mars

Post by luke.peda » Tue Oct 13, 2020 9:14 am

And use flop mirror?

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Re: help mars

Post by admin » Tue Oct 13, 2020 6:54 pm

Hi,

you can use a flip mirror if you want (it helps lineup the camera), but it's not essential.

You can also work either with or without a Barlow lens. The image will be bigger but dimmer with a Barlow lens.

A diagonal is also optional – taking it out may slightly improve the image quality as you have one less surface that might disturb the light, but you do need to make sure that you can compensate for the distance that the light travels in the diagonal otherwise you won't reach focus. That usually means you will need to add an extension tube unless you are using an SCT (SCT's have a very wide focus range).

Cheers, Robin

brenski
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Re: help mars

Post by brenski » Thu Oct 15, 2020 12:07 pm

hi Robin

is there a quick and easy setup for planetary imaging with sharpcap? this will be my first attempt this evening, if i can get setup in time...as I'd like to get some images of Mars - while it's still nice and bright.

my equipment:

Skywatcher 130p Alt-AZ, Zwo ASI 183MC pro (cooled) - or i can use a SVBony SV205.

what would I need to set sharpcap to to get possible images? is there a guide for this? and what can I expect image-wose?

thanks

Martin
Skywatcher 130p Alt-AZ (Starsense for skywatcher) ♦ Bresser AR90S 90/500 ♦ Bresser 70/350 ♦ Zwo ASI183MC Pro (cooled) ♦ SVBony SV205 ♦ Canon 200d ♦ Samyang 14mm F/2.8, ♦ Samyang 85mm F/1.4 ♦ Omegon Minitrack LX2 ♦ Skywatcher Star Adv Pro ♦ Fiji WS1 3D

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turfpit
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Re: help mars

Post by turfpit » Thu Oct 15, 2020 1:05 pm

Martin
is there a quick and easy setup for planetary imaging with sharpcap?
There is no quick and easy with astro-imaging - only pain and expense. You have to try things, evaluate the results, adjust and repeat.

This doc of mine might help viewtopic.php?f=35&t=1156. It is for a mono camera but the info will still apply to a colour camera. Also see my posts in here viewtopic.php?f=7&t=211.

Some images with an SV205 https://www.astrobin.com/search/?q=sv205.

Some images with a 183C https://www.astrobin.com/search/?q=183C&page=2. You will find some planets but not many and there is a reason for that with that sensor.

Good luck.

Dave

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Re: help mars

Post by admin » Thu Oct 15, 2020 5:54 pm

turfpit wrote:
Thu Oct 15, 2020 1:05 pm
There is no quick and easy with astro-imaging - only pain and expense. You have to try things, evaluate the results, adjust and repeat.
Hah! I like that. It really sums things up!

SharpCap tries to make things easier (when I started planetary imaging, the most common program in use at the time would overwrite the previously saved capture unless you remembered to change the file name before pressing capture again...), but there is still a learning curve. The trouble is that you are unlikely to bump into someone with the exact same equipment as you, which means that there will be no guides that can tell you exactly what settings to use - a little trial and error and learning is inevitable.

Robin

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Re: help mars

Post by turfpit » Thu Oct 15, 2020 7:01 pm

Robin
you are unlikely to bump into someone with the exact same equipment as you, which means that there will be no guides that can tell you exactly what settings to use
If you gave me any combination of scope/camera, this is what I would do for planetary:
  • Set Gain to 60% (70% if using a Barlow).
  • Turn on histogram and select Logarithmic checkbox.
  • Adjust Exposure until Right hand side of Histogram at 80%.
  • Run capture.
log-histogram-for-planetary-capture.JPG
log-histogram-for-planetary-capture.JPG (22.59 KiB) Viewed 331 times


It is a good starting point but that 4 point list took me 2 years and a lot of bad experiences/failures to develop. Using the histogram give a systematic way to approach planetary (or lunar or deep sky) imaging. For dimmer planets, I have gone as far as 90% gain especially if using a Barlow.

The higher gain leads to lower exposures which in turn produces higher frame rates. The rest is the lottery of the atmosphere.

The above is a starting point. In a planetary session I would end up with as much as 100Gb of data using various settings. The real understanding as to what works best comes form processing the data and evaluating the results.

Dave

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