Processing Mars Widefield Data Pleiades Astrophoto PixInsight · Chase Davidson · ... · 14 · 381 · 10

Hello fellow astrophotography masochists,

A buddy of mine said his little girl is learning about Mars in school so I decided to capture some data while it is in the general area of the beehive cluster. I don't have a good planetary setup so I thought I'd use my new UltraCat 91 and the ASI 2600MM w/ RGB filters to get an interesting widefield shot. I captured 2+ hours worth of data with 30 second subs (90 subs of RGB respectively) thinking I could process this as I would usually process a comet due to Mars moving so far in the 2 hours of capture. Here's where my problem lies, usually during a comet processing process, I'd run starxterminator on each sub to remove the stars and then stack the comet...but Mars comes across as a star in this case. I can stack Mars after comet alignment tool and it comes across as a decent red looking large star/planet(?) but i get the strange RGB star trails. I can't seem to get a good starxterminator of this to where it pulls out just Mars from the star trails, nor can I pull out the stars from the stacked mars unaligned combined pic (where mars looks like a large star trail).

So I come to you to ask, how would you get the star trails (Mars aligned) and the stars aligned (mars unaligned) pic together into one image? Please let me know if I need to clarify anything from this rambling.

Thanks!
Chase

andrea tasselli:
Quite unclear whether you managed to align the starless (bar Mars) images or not. Although is probably pointless as you don't need more than 1 (central in time) good image of Mars and, once Mars is removed from the remainder of the stack, the stacked and cleaned image of the Beehive. There is at least another possibility but let's leave this one for later. One final question though, why capturing 2 hours of the lot when 1 minute would have sufficed?

Great question, sorry I was unclear. I have both the stars aligned (mars unaligned) and the stars unaligned (mars aligned) images. I should have only captured 1 min of data but I'm so used to taking images of nebulas I mistakenly gathered 45 mins of each filter before I realized Mars moves much faster in the sky than anything else, thus the thought I would process it like a comet image. If I could remove Mars from each of the 30 second subs, stack the stars (baring Mars) and then remove all the star trails from the aligned Mars image, then i could combine them easily.

andrea tasselli:

Chase Davidson:

andrea tasselli:
Quite unclear whether you managed to align the starless (bar Mars) images or not. Although is probably pointless as you don't need more than 1 (central in time) good image of Mars and, once Mars is removed from the remainder of the stack, the stacked and cleaned image of the Beehive. There is at least another possibility but let's leave this one for later. One final question though, why capturing 2 hours of the lot when 1 minute would have sufficed?

Great question, sorry I was unclear. I have both the stars aligned (mars unaligned) and the stars unaligned (mars aligned) images. I should have only captured 1 min of data but I'm so used to taking images of nebulas I mistakenly gathered 45 mins of each filter before I realized Mars moves much faster in the sky than anything else, thus the thought I would process it like a comet image. If I could remove Mars from each of the 30 second subs, stack the stars (baring Mars) and then remove all the star trails from the aligned Mars image, then i could combine them easily.

But you can remove Mars from each frame if you align on Mars only (with maybe interleaving one frame out for each one frame in, to have a cleaner rejection) and use that as the "comet-aligned" frame.

I think I tried this. I'll have to post the two images I've created so far. I created one where Mars is aligned as if it is the "comet-aligned" which created a red-green-blue star trails (because of mono). I tried to starxterm on this to remove Mars but all the star trails were captured as stars still (unsure why these are still considered stars). When I aligned all the other stars and Mars looked like a Red-green-blue comet, the "comet" wasn't long enough to be removed from starxterm also.

I'll post pictures of both of these images and the starxterminator results once I get back home to make it more clear.

I realize the easiest thing to do here is to capture Mars again with much less data but it's going to be cloudy/rainy in south texas for the next week and I thought it would be fun to try to make this data work.

There is a technique promoted by Adam Block, which helps with rejection of irregularities in the images. The best is to refer to the Adam’s video on this topic, but in short, you paint pure black binary area (strict 0 values on the edges) and then tune the rejection in image integration process to reject the values that are truly zeroes.

It seems to me that you're making this a lot more complicated than it has to be. Why not just do a short enough stack so that Mars doesn't show any appreciable movement and then process that out?

Chase Davidson:

Tony Gondola:
It seems to me that you're making this a lot more complicated than it has to be. Why not just do a short enough stack so that Mars doesn't show any appreciable movement and then process that out?

Mostly because the rains down here won’t stop till the end of this week and my buddies daughters mars project is due today but also because I’m stubborn. I’ll definitely take shorter data once I get soclear skies.

I guess I wasn't clear. Don't stack all your subs, just a few min. worth. No reason to re-take the data.

Chase Davidson:

Tony Gondola:

Chase Davidson:

Tony Gondola:
It seems to me that you're making this a lot more complicated than it has to be. Why not just do a short enough stack so that Mars doesn't show any appreciable movement and then process that out?

Mostly because the rains down here won’t stop till the end of this week and my buddies daughters mars project is due today but also because I’m stubborn. I’ll definitely take shorter data once I get soclear skies.

I guess I wasn't clear. Don't stack all your subs, just a few min. worth. No reason to re-take the data.

Hi Tony, I don't think I can stack my existing data with less subs because I took my shots on my 2600MM with 45 mins of red filter, then 45 mins of green filter, and lastely 45 mins of blue filter. So no matter how little subs I stack, Mars moved quite a bit between each filter. Correct me if I'm wrong though.

Oh wow, so you took single 45 min. exposures? Now I understand the problem!

Regardless, you did good.