AstroPhoto-Milky Way w SkyTracking Image Stacking

[JohnB62]

In the last few years I've been enjoying astrophotography.  I particularly like to take images of the Milky Way with terrestrial landmarks in the foreground.  To get another level of sharpness in the stars I recently purchased an iOptron SkyGuider Pro sky tracker, to get my stars/planets sharper and to reduce both distortion and noise by using lower ISO and longer exposures.  However, I realize that using the SkyGuider Pro will cause blurring of the foreground terrestrial features, and the worse the longer the exposure. 

I've read that the way to fix this is to take an image first without turning on the SkyGuider and then another image using the SkyGuider on, and then merge or stack the images so both the stars/planets and the foreground are sharp.  Can someone or anyone explain how to do this in Affinity Photo?  Much appreciated.  I have Affinity Photo both on a Mac and on an iPad.  Most of my work I do on the Mac.  (I recently moved back to a PC because it's better for my job, and am deciding whether to buy another license to Affinity Photo on the Windows machine - I want to make sure I can do what I want to do before I buy another license.)

Thanks!

John

[Dan C]

Hi JohnB62

Without the exact program on my Mac, I can't directly test this for you, however I see no reason why it would not work in Affinity Photo using the Live Stack function. To find out more about stacking please see the tutorial videos below!

Live Stacking

• Maximum Stacking
• Big Stopper Effect
• Light Painting Blending
• Stacking: Long Exposure Simulation
• Stacking: Noise Reduction
• Stacking: Object Removal
• Stacking: Exposure Merging
• Stacking: Star Trail Effect

[JohnB62]

Thank you. 

[John Rostron]

I think that it is going to depend on your foreground/skyline subject. Taking a static photo of the foreground is essential. You will need to separate the foreground from the sky background and the ease of this will depend on how distinct they are.

For your sky images, are you going to have a single long-exposure image, or a series of shorter ones? In the former case I would expect you would have a blurred foreground which might be more difficult to remove. In the latter case, you would be able to remove the  foreground more easily, but there would be more images to process!

I would assume your SkyGuider will maintain the alignment of the sky, but not the foreground. The alignment algorithm in Affinity Photo Stack can sometimes be fooled if the foreground is more well-defined than the sky. For this reason, it may be worth your while to eliminate the foreground in these images.

I write this as one who has been able to help some astro-photographers on this forum. However, the only celestial object I have ever photographed is one image of the moon.

John

[JohnB62]

Thanks John, this is really helpful.  You've touched on a lot of the concerns I have.  I'd like to do just two images, the static with SkyGuider Pro turned off and one with the SkyGuider Pro tracking.  Some of the stacking discussions and videos that I think (or imagined) I've seen say that Affinity Photo takes the "best quality" pixels in a stack of images and merges them into one best image.  I would hope that would include as "best quality" non-blurred versions of the foreground. 

I usually like mountains in my foreground.  How much the mountain is illuminated by ambient light (or light pollution or both) seems to depend on the direction I'm shooting in, but it's hard to tell.  Mt. Rainier from Sunrise always has good illumination from ambient or pollution.  Mt. St Helens from the northeastern side the mountain was totally black and a silhouette only.  I think the reason Rainier was more visible may have been light pollution from the Seattle area.  

I will ask on some other forums and look at some free stacking programs to see if they work better in this regard.  (I'm neither any good at nor enjoy processing so the less images to process the better for me.) 

Thanks again. 

John

[ronnyb]

On 3/24/2019 at 2:40 PM, JohnB62 said:

In the last few years I've been enjoying astrophotography.  I particularly like to take images of the Milky Way with terrestrial landmarks in the foreground.  To get another level of sharpness in the stars I recently purchased an iOptron SkyGuider Pro sky tracker, to get my stars/planets sharper and to reduce both distortion and noise by using lower ISO and longer exposures.  However, I realize that using the SkyGuider Pro will cause blurring of the foreground terrestrial features, and the worse the longer the exposure. 

I've read that the way to fix this is to take an image first without turning on the SkyGuider and then another image using the SkyGuider on, and then merge or stack the images so both the stars/planets and the foreground are sharp.  Can someone or anyone explain how to do this in Affinity Photo?  Much appreciated.  I have Affinity Photo both on a Mac and on an iPad.  Most of my work I do on the Mac.  (I recently moved back to a PC because it's better for my job, and am deciding whether to buy another license to Affinity Photo on the Windows machine - I want to make sure I can do what I want to do before I buy another license.)

Thanks!

John

Why not just try stacking the photos on your Mac’s copy of Affinity Photo?

[JohnB62]

Fair question. Because I'm planning on wiping the Mac and giving it to my wife as it will be an upgrade from her Mac.    In the meantime if I get a chance to go out and take some images with the SkyGuider Pro I'll give it a go, but it's not a permanent solution.  And I'm not aware of Affinity providing any cross-platform transfer rights. 

[John Rostron]

On 3/24/2019 at 6:40 PM, JohnB62 said:

I want to make sure I can do what I want to do before I buy another license.)

Remember that you can download a10-day free trial of the Affinity products.

Let us know how you get on.

John

[JohnB62]

Thanks John, I didn't know about the free trial.  I will do that, and let you know if I figure this out.  

John

[S. Schraebler]

@JohnB62 @Dan C @John Rostron

Hi John, John & Dan,

there is a program custom made for so called TWAN images, The World At Night: Sequator! 

You need Win10, but you are able to run an earlier 32 Bit version under OS X using the Wineskin Winery Wrapper. It's free, you can donate a coffee.

https://sites.google.com/site/sequatorglobal/

http://wineskin.urgesoftware.com/tiki-index.php?page=Downloads

https://aurigaimaging.com/download/download.php (demo version is fine, cannot save, just make a screenshot, runs in Wineskin Wrapper too)

https://pixinsight.com (that's what I am using meanwhile, Win10, Ubuntu Linux, OSX)

Also have a look at Babak Tafreshi's TWAN page

http://www.twanight.org/newTWAN/article.asp?ArticleID=3003&page=1

You can do the post processing in Affinity Photo

https://www.sternwarte-hofheim.de/galerie/schraebler/Pixinsight/!!HDR Tone Mapping und starless Bearbeitung in Affinity Photo 1.8 V01 S. Schraebler.pdf

Best Sighard

 

Visual observing on Alain Maury's farm, San Pedro de Atacama 2009, bright trail on the left side are ALMA antennas being moved to Chajanantor plateau, greenish haze below the the meteor is Sociedad Quimica's 24/7 illuminated Lithium production facility. This is a single frame.

20-inch Fotonewton @ IAS Observatory, Hakos, Namibia 2011, LMC, SMC, Milky Way, single frame

The backbone of night, Hakos, Namibia 2011, 15mm f/2.8 @ f/3.5, EOS20Da, 16x5min, ISO800, registered with Registar (Fisheye is as bad as it get's, when it comes to image registration)

Same images, registered with "new staple" in Affinity Photo 1.8 (no postprocessing)

Orion, 85mm f/1.8 @ f/4, EOS5Da mkII (astro modified), 40x4m, ISO1000, Samos 2017, registered with PixInsight

Same images, registered with "new staple" in Affinity Photo 1.8 (no postprocessing). Let's just say Affinity Photo is not made to calibrate and register astro subframes.

But that's no problem at all! Affinity Photo is good to do the postprocessing. And I am happy with that. Affinity Photo has Layers, Tone Mapping, Dust&Scratches Filter, Repair Brush, high quality Denoising, Histogram Transformation, Masks, Selective Color, Macros and much more. There is no "single program" for everything. Serif could easily spent man years if not decades in software engineering to repeat just all that what has gone into specialized programs. And for what? A handful of people! No thanks, I am happy enough to do it in two programs.