HOWTO: Capture a planetary imaging timelapse with Planetary Live Stacking

[AstroMathmo]

Ah indeed! I’d been focused on the conditional problem of optimising a still given my inputs were frames from a time lapse. I’ll give the time travel version a go. Ta!

It’s at this point I want a camera with a faster read out and Thunderbolt 5.

[AstroMathmo]

I managed another outing with the GRS visible and here is the video link. I saved TIFs for the frames which allowed me to do some batch processing in Pixinsight before reassembling.

https://app.astrobin.com/u/AstroBillUK?i=ne562i#gallery

[admin]

Hi,

thanks for sharing - lovely image and a good long period of rotation. I think I was trying to capture on the 1st March, but I was testing a new IMX715 camera with small pixels (no need for a barlow) - the camera worked fine, but I struggled with re-collimating after taking out the barlow and didn't really get anything worthwhile

cheers,

Robin

[Jean-Francois]

Hello Robin,

I tested yesterday evening for the first time the Planetary Live Stacking.
It works fine. But I did the same "error" as you with my camera QHY715C.
I installed it on my 10" Newton with a 2.7x Barlow ... that is too much.
I can say that the tool "Offset Plate Solve and Resync Target Position" is working very good.
So I will today repeat, but this time without the Barlow. If the seeing will allow, I can upload a result this evening.

Concerning the "715" camera ... was it a QHY or ZWO ?
Yesterday my QHY715C camera crashed several times SharpCap. It was slowing down and then no response and then crash.

Jean-Francois

[AstroMathmo]

The hardware choices for these time lapses are interesting . I’ve been using a 585C with a 2x on my f/10 C8. That gave me a lot of room for unattended ROI tracking* for an extended period and also a decent chance of plate solving goto working with PS3. But now I’m finding and centering with a well aligned guide scope and discovered that your handy button to freeze the time lapse allows me to do a quick manual nudge to the edge opposite the drift direction mid session and not notice it in the video. (I might put a bigger sensor cam on a flip mirror for the goto) With that confidence I was thinking of switching to an IMX664 for the frame rate benefits and then I can get a bit pickier over the seeing selection %. Of course the multiplier to my f/ratio is a constraint and for now I will be at effective 6.5X with the Barlow. I quite fancy losing my corrector plate and moving to a classical Cass running at around f/18. I have the APM 1.5 and 2.7 to play with as well as the 2X Powermate. The 2.7 on my SCT did work quite well for Mars but due to being less pixelly rather than any more true detail emerging.

*I have to set up every time so PA is an issue. I forgot to do it on a previous session and that’s how I discovered that using the SC scope controls mid time-lapse worked OK!

[admin]

Hi,

@Jean-Francois - the IMX715 camera I was using worked fine from a camera point of view, but having taken out the barlow, I think the scope was no longer properly collimated, and I struggled to get it back in collimation. The camera is neither ZWO or QHY - I have a pre-release sample from another manufacturer...

@AstroMathmo

I like the classical cass - mine is naturally at f/12, but takes a 2x barlow nicely. I think the lack of a corrector is an advantage (no dew magnet, faster cooling), but the focuser/barlow/extension tube/camera hang a long way off the back. Another thing I have been learning is that while collimation can be tricky, you don't need to worry about re-doing collimation like you do with an SCT, since the primary mirror is fixed and doesn't flop about with focus changes or slewing around the sky. There are some lovely 10" classical cassegrains with carbon fibre truss tubes - very tempting, but I would either have to single mount such a beast or go for a significant mount upgrade!

cheers,

Robin

[StarFlea]

Hello Robin,

I tried the described method for the current lunar eclipse, but unfortunately, the result wasn't what I would have hoped for.
Firstly, this was obviously due to the weather, which thwarted the first part of the eclipse...

Now I used multi-point stacking for the moon, which seemed more sensible to me than single-point. But you can see the result of this relatively short experiment in the attached MP4 (ZIP-File).
And now I'm wondering what I could do better to achieve a passable result for the next lunar or solar eclipse.

Screenshot 2025-09-12 224511.png (32.24 KiB) Viewed 1518 times

Screenshot 2025-09-12 224442.png (38.1 KiB) Viewed 1518 times

LunarEclipse.zip

(701.99 KiB) Downloaded 34 times

Secondly, I noticed that during a lunar eclipse, you work with an extremely high dynamic range. On the one hand, you have a very dark area in the umbra that you want to capture in detail, and on the other hand, the area outside the umbra is overexposed.
Is there a way to automatically and smoothly adjust the exposure throughout such an eclipse, e.g., from 0.25 ms at the beginning of the eclipse to 200 ms in the middle, and then back to 0.25 ms at the end?

Capture_00001.jpg (784.17 KiB) Viewed 1518 times

Capture_00003.jpg (424.78 KiB) Viewed 1518 times

Greetings!
StarFlea

[admin]

Hi,

sorry to hear that it didn't go well

I haven't seen anything exactly like the stacking anomaly in the video file before. Do you have any saved, unprocessed, video of the event that you could share? Even if only short, it would let me test multi point stacking and whether it works on the video. One thing that does occur to me... Did you have the 'Surface' align mode selected as well as multi point stack? The planet/full disc option could behave oddly as the illuminated part of the disc of the moon changes shape relatively rapidly during the eclipse, since it tries to cente the 'center of brightness' of the image.

On the exposure, the only automatic option that works in the background is the camera auto exposure (if that's available for your model of camera). The exact implementation is dependent on the camera SDK, but they *usually* try to avoid overexposed areas, so that may be sufficient. There are other things you could do with the sequencer, but they don't give a smooth transition, more allow an adjustment to be made at various points, which I think would cause other problems with brightness jumps.

cheers,

Robin

[StarFlea]

In this case, the stabilization mode was set to "Planet/Full Disc" and the stacking mode to "Multi Point."
Unfortunately, I don't have another video of the eclipse that could be used, so I limited myself to taking individual images.
But couldn't any video of a lunar eclipse be used?
I noticed that the position of the lunar disk seems to shift in time-lapse as the umbra moves outward. Perhaps the alignment is orienting itself along the edge of the shadow?

[StarFlea]

As for continuously adjusted exposure, I'm somewhat reassured that even semi-professional observatories can't do it any better:
https://www.youtube.com/watch?v=m13hxhL743o


But seriously: I'm wondering how to make such a difficult HDR transition smooth!
I haven't been able to find anything like automatic exposure on my camera (Omegon veTEC 571c) at a quick glance.
Would it be possible to implement such fluid adjustment via automatic histogram analysis? That would, of course, be a very specific matter for a time-lapse of a lunar eclipse (or are there other useful applications)?