#1  
Old 10-10-2020, 10:55 AM
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lazjen (Chris)
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Late to the Planetary Imaging game...

I've made some half-baked efforts to do some planetary imaging over the years, but I never seem to get all the pieces together.

Time to go fully baked.

Aim: To get decent images of the planets, e.g.: Mars, Jupiter and Saturn

For now, I'd like to either use my RC10 or Sharpstar 107PH scope. I have various barlows available for use, including a Baader FFC.

I have 2 cameras currently available, both mono. ASI1600 and a guide cam (usb 2, I think?) - ASI174

Now for the questions.

1. I've been thinking of getting a colour camera specifically for this purpose, as these targets are fairly bright and I think it would make image processing easier overall. However, would I be better off sticking with mono + filters instead? Either way, what camera(s) should I look at for my setup?

2. Setting it up. This is probably where I'm the most confused. Do I set up the image train like I would for deep space imaging, or should I be taking the image through eyepiece projection?

3. Capturing. I've used FireCapture in the past. Is this still worthwhile or should I use something different? SharpCap?

4. Processing. I've played with a few things, including AutoStakkert. What's the good choice(s) these days?

Thanks for any pointers.
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  #2  
Old 10-10-2020, 02:36 PM
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cometcatcher (Kevin)
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ZWO have brought out a new planet cam, the ASI462. It's a one shot colour cam with good dynamic range at high gain, which sounds good.

I have a 183mm Pro mono and a cheap Svbony SV305, which is the same as an ASI290mc. Both are good. Some people prefer mono with filters, some prefer OSC. Personally, I like my little OSC SV305. I find it a bit of a pain to refocus with filter changes when on the clock for something with a fast rotation rate like Jupiter.

Your present cameras will also work. The equation for optimal focal ratio is pixel size times 5. So my SV305 with 2.9um pixels is best at F14.5, and my 183 with 2.4um pixels is best at F12. This is just a guide. I often go a bit higher to F20. I just use a barlow in the imaging train.

I use Sharpcap since it supports the SV305. I like Autostakkert. It seems pretty good. V3 is about to be replaced by V4. So for me it's Sharpcap to capture, Autostakkert for stacking and Photoshop for levels and unsharp mask, although Gimp would wok just as well.
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Old 10-10-2020, 03:45 PM
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lazjen (Chris)
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Ok, sounds interesting. Thanks for the reply, Kevin.

The ASI174 mini has 5.86um, while the ASI1600 has 3.8um, so 5x is about F29 and F19 respectively.

To get that with the RC10 at F8 is about 4x or 2-3x (probably 3x?) and for the Sharpstar at F6.5, I'd need 5x or 3x respectively (for each camera). Looks like it might be easier to go with the RC10 and ASI1600 at 2x or 3x if I used my current gear (would obviously have to use filters and process appropriately).

If I got the ASI462, I'd only need 2x for the RC10 to hit optimal focal ratio formula. Might try more with my current gear first to see if I can get some results.

How do you go about focusing? How can I tell I've got the best focus for the current conditions? How much data do you capture (frames?) for an image?
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Old 10-10-2020, 04:14 PM
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Chris, I focus by viewing the object directly on the monitor. The 10" native F4 + barlow I have a focus motor on it, my 8" SCT has a Crayford and I just do it by hand. Electric focus is best as it avoids vibration and is fairly easy to hit the spot.

Capture is best done in a small ROI window to keep the frame rate up. The faster the better. I use 480x352 for Jupiter, similar for Saturn and smaller for Mars (unless I want to include moons).

I capture in 12 bit SER video files as it keeps artifacts down that often show in 8 bit captures.

For a single video file run I capture 2.5-3 minutes for Jupiter and Saturn, 6 minutes for Mars. The pro's do this multiple times and de-rotate in Winjupos, but I'm not up to that yet.

I think your RC10 should perform very well. Definitely give your current gear a go.
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Old 10-10-2020, 08:29 PM
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Camelopardalis (Dunk)
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Chris, your reflector should be fair game for planetary, but the refractor wouldn’t have the reach to show enough detail to be anything more than a novelty.

Since you’ve got the mono 1600 and filters already, why not give that a go. Be sure to make ruthless use of the Region of Interest (ROI) to be able to amp up the frame rate.

A 2x Barlow should be enough to get you in the ball park, and don’t be shy with the gain (just keep it within the analogue gain range).

I’ve been using a 462 this season and it has good QE and low noise, but it’s not essential to get results. Good collimation and focus is...
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Old 10-10-2020, 09:46 PM
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Quote:
Originally Posted by cometcatcher View Post
Chris, I focus by viewing the object directly on the monitor. The 10" native F4 + barlow I have a focus motor on it, my 8" SCT has a Crayford and I just do it by hand. Electric focus is best as it avoids vibration and is fairly easy to hit the spot.
Check, went to electronic focusing a long time ago and will never look back.

Quote:
Originally Posted by cometcatcher View Post
Capture is best done in a small ROI window to keep the frame rate up. The faster the better. I use 480x352 for Jupiter, similar for Saturn and smaller for Mars (unless I want to include moons).

I capture in 12 bit SER video files as it keeps artifacts down that often show in 8 bit captures.

For a single video file run I capture 2.5-3 minutes for Jupiter and Saturn, 6 minutes for Mars. The pro's do this multiple times and de-rotate in Winjupos, but I'm not up to that yet.

I think your RC10 should perform very well. Definitely give your current gear a go.
I'll have to look at my options again for the camera, but I think I could choose 8 or 16 bit. Or is the 12 bit SER chosen as part of the file output process?

Hrm, I might have to look at how much storage I have on the laptop and clean it up a bit.
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Old 10-10-2020, 10:00 PM
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lazjen (Chris)
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Quote:
Originally Posted by Camelopardalis View Post
Chris, your reflector should be fair game for planetary, but the refractor wouldnít have the reach to show enough detail to be anything more than a novelty.

Since youíve got the mono 1600 and filters already, why not give that a go. Be sure to make ruthless use of the Region of Interest (ROI) to be able to amp up the frame rate.

A 2x Barlow should be enough to get you in the ball park, and donít be shy with the gain (just keep it within the analogue gain range).

Iíve been using a 462 this season and it has good QE and low noise, but itís not essential to get results. Good collimation and focus is...
Yep, got it, get that ROI small to up the fps. Gain for the 1600 - what would be good - 200? Is it worth having the camera cooled since I have the option?

I'll try to get it working with the Baader FFC since it's probably the best glass I've got for the purpose, so it might be closer to 3x.

And I'll have to check the collimation first... It's been random clouds in recent nights, maybe it will give me a chance in the coming week.
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Old 10-10-2020, 10:22 PM
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Quote:
Originally Posted by lazjen View Post
Yep, got it, get that ROI small to up the fps. Gain for the 1600 - what would be good - 200? Is it worth having the camera cooled since I have the option?

I'll try to get it working with the Baader FFC since it's probably the best glass I've got for the purpose, so it might be closer to 3x.

And I'll have to check the collimation first... It's been random clouds in recent nights, maybe it will give me a chance in the coming week.
With the 1600, pretty much anything up to 300 is in the analogue range. It will depend on how much you need...aim for getting the histogram levels up to about 60%, by a combination of gain and exposure time. Cooling holds no advantage at such short exposure times. At high gain there's no advantage to bit depths beyond 8-bit either, as any lost precision is (re-)gained during stacking...and 8-bit can give you 2x the frame rate of 16-bit.

I usually let the ROI dictate the fps and dial up the gain accordingly, but the 462 is OSC and pretty sensitive, so that's a bit of a luxury. Some of my recent Martian experiences have been in excess of 300fps in an effort to try and capture some decent frames in the generally rough seeing...this past week down here has been pretty awful despite some promising forecasts

Regarding the Barlow...if you're starting out, I'd recommend being under rather than over as it's less tricky. The seeing will mess with you, and it's hard to separate bad seeing from poor focus and/or collimation. Remember you can get variable multiplication with practically any Barlow with a separable lens piece (one that threads off of a 1.25" barrel), and the optical quality only really matters in the centre since the planets are such tiny targets, in our apparent view. I hit roughly f/15 this way, which works well with 2.9 micron pixels.
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Old 11-10-2020, 10:22 PM
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lazjen (Chris)
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I think I'll follow a similar path re: ROI, fps then gain. Sounds like an easy process to remember and repeat.

I'll keep it in mind re: the barlow.

Looks like it's a moot point anyway for the next week, weather forecast is turning bleak.
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Old 12-10-2020, 10:10 AM
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Camelopardalis (Dunk)
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Yeah dreaded clouds are back

One thing that’s worth mentioning regarding software...while both FireCap and SharpCap have their following, checkout ZWO’s own ASICap. It’s a bit rough around the edges and doesn’t follow its target like FC, but one feature is that you can set “Runs” where you can set different gain, exposure time, filter and capture length into a sequence, and tell it how many times to loop around. Invaluable when using a mono camera.

Simple but effective.
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Old 12-10-2020, 12:54 PM
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lazjen (Chris)
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I did have a play with ASICap, but from memory it assumes you're using a ZWO filter wheel and ZWO focuser, which I am not. That was a bit annoying.

FireCapture did handle the filters ok. Have not tried SharpCap for that yet.
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