Now available for pre-order.

My latest Astrophotography Image Processing Guide covering Pixinsight is now available to order with a £3:00 saving from my secure online shop until the end of this month.

http://www.star-gazing.co.uk/shop

On the 21st of August I was really looking forward to the Moon occulting Saturn in the early hours of the morning, reappearing as the sky was getting very bright.

I was really hoping to improve on the images I had managed on similar events in the past.

Here’s some of my previous attempts, where I always managed to get The Moon’s limb over-exposed.
But there’s a good reason for that.

24th July 2007.

18th April 2022.

Of course, the image I had in mind of producing of the event now that I had much so much more experience in taking this type of image.

We could say that this image was taken that morning, BUT the Saturn image was captured a couple of hours before the event started.
The Moon image was taken during the egress phase and I erased the not so good image of Saturn out of it, blending in the previous and better Saturn image to the same size and position as I saw and captured.
I know what you are going to say at this point, I’ve gone way too far in producing this.
Perhaps I shouldn’t have put the artificial dark Moon limb on top of Saturn, or even added Titan in its correct position top right?
Or maybe I should never have produced this at all? 😉

But just look around the Internet and on social media where people have posted plenty of these composite or montaged images.
Sadly, these images always get multitudes of likes and re-posted much more often compared to most other folks images that are “The Real Deal”.
Is it wrong or right to do this? As long as it is stated it’s a montage, I guess not, but many don’t.

An image like this from a single image capture is really not possible.
Saturn is a long way from Earth, so although looking reasonably bright in the night sky and through a telescope the amount of light that reaches us is much less than that of The Moon.
To capture Saturn, needs a reasonably long exposure or high gain setting just to make it visible.
This will over-expose The Moon, making it far too bright and washing out lunar surface details.

To capture my videos which will be used to create the final images, I adjusted both exposure and gain settings to just start to over expose The Moons bright limb.
The ingress was trickier as that side of The Moon’s limb was a lot brighter.
This overwhelms and washes out Saturn even more as it got closer to the limb.
The thin interfering cloud also made Saturn dim occasionally as it cut light off from reaching the camera.

On the opposite side, where Saturn will reappear, The Sun was setting over The Moon, creating long shadows on the surface to make that limb a bit darker.
As The Moon was just past full, Saturn also appeared from behind the dark limb.
This made it a lot easier to capture the egress as I could make Saturn a bit brighter during the capture, without overexposing The Moon.
BUT, this was also as dawn was breaking, so the sky was getting reasonably bright by the time Saturn reappeared.

So, how did I do?

Up all night, I made some mistakes and thin cloud did interfere, making getting the the exposures right a bit more of a challenge.
I captured a long video at ingress and egress, observing the event through my 10″ Dobsonian.
The view, especially of egress was exquisite. 🤩

The images were chopped and stacked into sections using AutoStakkert!
The colour was corrected using Registax RGB alignment Tool.
The  images were then sharpened using Astro Surface.
Final polish was using Affinity Photo.

Saturn was brightened in the final images by using the tone mapping tool in Affinity Photo, not a composite.

I’m really pleased with what I got in the end and I will probably try not to magnify the image quite so much next time.

I also managed to capture data to give me a “decent” composite image, which is almost as good as the best of them out there. 😉

Just before Ingress.

During Egress:

T Coronae Borealis (T CrB) is a red giant star lying 3,000 light years away.
This extremely interesting star is usually about magnitude +10, which is well below naked eye visibility, but it is reaching the end of its life. As a result, the star has regular outbursts about every 80 years, and when in outburst can reach magnitude +2, giving it the nickname of The Blaze Star.
At maximum magnitude it will be easily seen with the naked eye being about the same brightness as The Pole Star, Polaris. It will stay this bright for a month or two, before fading back to magnitude +10.

I took this wide angle image of Corona Borealis on the 2nd of June 2024, which indicates the position of T CrB, not far from Epsilon CrB. It was still a faint magnitude +10 at this time, so has not erupted yet.

Keep looking up folks, because you just never know when T CrB it might start coughing.
Good luck.

Coming soon…

Despite persistent and thin clouds trying to spoil the view, I managed to capture the ingress and egress of the occultation of Venus by The Moon on the morning of the 9th of November.

I couldn’t upload the full animation to social media as it was too big, so here it is.

https://www.star-gazing.co.uk/Images/Venus-Occultation-20231109/2023-11-09-0945.gif

This bright comet is starting to get quite exciting.

It is currently (7th September 2023) visible low in the north-eastern sky just before sunrise as it moves through the constellation of Leo and it is brightening.

I captured this image of it on the morning of the 4th of September.

.

Currently at magnitude +5.8 the comet is theoretically just becoming bright enough to be visible to the naked eye.
But as it is in deep twilight at that time of the morning so it is best viewed with binoculars or a small telescope.

This finder chart shows the path of the comet in the morning sky from the 7th to the 11th of September 2023.
It is getting lower in the sky each morning but is brightening and getting bigger as it approaches perihelion on the 17th of September..
Click on the image for a bigger view.

From around the 11th, Comet Nishimura will now be visible in the evening sky, low in the West-North-Western sky just after sunset.
It will set very quickly after the Sun though, so get out and make the most of it as the sky darkens before it sets.
If the tail is long and bright enough, this could be visible long into the darker sky after the nucleus of the comet has set.

This finder chart shows the path of the comet in the evening sky from the 11th to the 18th of September 2023 as it passes from Leo into Virgo.
Click on the image for a bigger view.

It will be even lower in the sky at that time, but just how bright will the comet get, and how long will that tail be?

The great thing about comets is that we just do not know, they can be very unpredictable.
It is predicted to achieve just greater than 3rd magnitude, and the tail has already been imaged extending up to 10° degrees.

The only way to make sure to see what happens is to get out and have a look and if it does perform, we could be in for a real treat.

Whatever happens, Enjoy!

Keep Looking up (but fairly low down for this one).

Dave

ON the 19th of May, I was taking an image of a supernova in a distant galaxy NGC 4995.

The results of that image is below.

While processing the image the next morning, I learnt that another supernova had gone off in the spiral galaxy Messier 101 in Ursa Major. The last time I imaged a supernova in this galaxy was in September 2011, but my images I took then left a lot to be desired with the equipment I had at that time.

I had to wait a few days for clear skies, but, clouds finally permitting, I got a decent image on the evening of the 24th of May, using a one-shot colour camera.

Trawling through my previous images, I had another fairly decent monochrome image taken on the 3rd of April 2021.
I have placed the two images together below.

I then made an animation of the two images to show the difference.

So what are we seeing?
The supernova was a massive star, much, much bigger than our Sun.

It has come to the end of its life, running out of fuel.

As the pressure from within the star has lessoned, the mass of the star is no longer supported.
Once this outward pressure stops, gravity becomes the over-riding force, pulling the stars mass toward the core.
The star collapses onto itself, producing a massive implosion.

The resulting massive shock waves rip through the star where it explodes in energy as the star is ripped apart.

It becomes a type II Supernova, outshining the galaxy itself, which is composed of at least 100 billion stars. 🤯

As if that isn’t enough, let’s get our head around more.
Messier 101 lies 21 million light years away from Earth.
So the supernova actually occurred 21 million years ago.
Light from the galaxy and supernova, travelling at 186,282 miles per second, is only just reaching after all that time.

This galaxy is also a relatively near neighbour compared to many we can see in the night sky.

It’ll be interesting following this over the next few weeks or months to watch as it fades back into oblivion.

We are seeing a revolution, or even a series of revolutions in our hobby, with “Smart” telescopes, ever better optics and the new Harmonic mounts.

Harmonic (or Strain Wave) Mounts really are a very different experience from traditional equatorial mounts.

I was fortunate enough to be allowed to test ZWO’s AM5 mount, courtesy of First Light Optics.

The mount also came with the TC40 carbon fibre tripod.
This comes with a change of metal feet, for use on different surfaces.
In the specs, ZWO claims that this amazingly lightweight tripod, at only 2.3kg, can support a payload of up to 50kg. 😲
Being so lightweight, it would be excellent for travelling, but it is still quite low, even when the legs are fully extended.
There is a Pier Extension available if you need the setup to be higher.

ZWO also claim that weighing just 3.9kg, the AM5 itself has a payload of 8kg-13kg without requiring a counterweight.

For such a lightweight mount and tripod, I really wanted to put it to the test, both for imaging, payload and focal length.

It easily managed my Sky-Watcher Esprit 120ED imaging rig, which is just under 13kg.
I got some very nice images of the recent comet using it, even managing to get it to auto-guide on the comet itself, as it was bright enough to be seen in the guide scope.

So far so good. The mount is easy to carry about, set up and use and so far has performed beautifully.
The handset disposes of the traditional screen, just a couple of buttons and a joystick and is a joy to use.

As expected, I found that I could get everything working nicely together with the ASIAIR, but also using a USB cable to the PC, with just a few clicks was being controlled using various planetarium software via ASCOM. The ASI mount app for a smartphone or tablet is also extremely good and very easy to use.

Using the built in WiFi, I could also attach it to the ASIAIR and my home network, so every device on my network could connect to and operate the mount if needed without having to use any wires.

As with most ZWO products I’ve had a play with so far, it just flipping works. 😃

If I was being picky and looking for a niggle, the mounts WiFi will not work unless the handset is attached to the mount.
But that’s not too big an issue.

ZWO recommend that the AM5 is suitable for imaging with scopes of up to 900mm focal length, so I really wanted to put it to the test. All the scopes I have used so far on the mount were of shorter focal length than this.

My Celestron C11 has a much longer focal length of 2,800mm, so this would really test the mount well beyond the recommended limits.

The C11 weighs a little over 13kg. So with the guide scope and cameras attached, it was above the mounts 13kg payload.

If a counterweight is added, the payload of the AM5 can be increased to 20kg.

Making the tripod heavier, by adding a weight to the weight bag (supplied with the tripod) will help, but to be safe a counterweight shaft and counterweight is recommended.

Unlike conventional mounts, there is enough torque in the gears not to have to counterbalance the scope as is tradition.
So why add a counterweight?
If a heavier payload is put onto the mount, when the scope is over to one side, and too much weight is over to one side of the centre of balance, the tripod could tip over.

With Harmonic mounts, you really do have to get into a different mindset about getting the scope balanced correctly.
You just don’t need to.
In fact, because the axes of the mount are not moveable manually, it is impossible to even try to get the scope balanced in the traditional sense.

But it does take a while to get your head around that. Old habits die hard.

After adding the counterweigh shaft, I put on a 5kg counterweight, so I could mount my C11 for a very long focal length test of the AM5’s guiding.
I also put the mount onto my EQ6 tripod to give it extra stability (and a bit more height for convenience).

I then managed to get the mount polar aligned using the ASIAIR PA routine.
This was a challenge in the bright twilight, but adding a larger chipped camera helped me obtain a wider field of view with the scope.
How accurately did I polar align?
Well, I got close enough to polar alignment, within less than a degree, but I wasn’t going to spend loads of time getting this absolutely exact. If you want to see my view on achieving very accurate polar alignment, see my post Here

I set the ASIAIR to take a series of images of different lengths to see how long the mount would track for without producing star trails.

I also purposely used the simplest and shortest focal length guide scope I had, a converted Sky-Watcher 9×50 finder.

While imaging, the guiding figures were between 0.2 and 0.7, which was excellent.

But of course, the real test is always in how the images looked.
Was there any star trailing? No there wasn’t.
So all was going well with the 60 second exposures.

That night I was going to do progressively longer exposures, to see how long it could successfully guide for, but this was soon ruined by the clouds rolling back in.

I managed to get 5x 60 second exposures on M13, which was in a clear part of the sky.

This is the result of that stack, with not a star trail to be seen.
So all in all, this mount is certainly exceeding all my expectations.

I wonder if FLO want this back? 😉

I would certainly recommend this mount to anyone in the market for a new mount and if you travel, another added bonus is its extremely portable.

Comet C/2022 E3 (ZTF) is starting to brighten, and could give us a great display over the next couple of months.
See my previous blog entry here for maps and what we MIGHT expect:

Comet C/2022 E3 (ZTF) Naked eye in the new year?

With this in mind, I thought I would write down the method I use to capture as much detail in comet tails as possible in my images.

First Problem – A moving target.
As a comet goes round The Sun, it, just like the planets, is constantly moving.
As a comet gets closer to the Sun, its proper motion increases, being at its fastest at Perihelion (closest to The Sun).

When a comet is in closer proximity to Earth, its apparent motion across the sky also increases.
The closest it is to Earth, the greater the apparent motion.
Over the next few weeks the motion of this C/2022 E3 accelerates rapidly, passing Polaris and down through Taurus within a few weeks

Second Problem – A rapidly changing target.
Comet tails are extremely tenuous and in constant change.
Being buffeted by the solar wind, kinks and disconnections can form in the tail very quickly and move swiftly away from the comet.

You can probably surmise by this, that comets are a very active objects. All this movement results in blurring our images.

See the animation posted on the 6th of January to see what we are dealing with:

The images used for this animation were taken over just 5 minutes.
You can clearly see the movement of the comet against the stars, and the kinks moving down the faint ion tail.

How can this blurring be avoided?

Cancelling Movement.
The proper motion of a comet gives its own problems. Most auto-guiding systems lock onto background stars.
Any long exposure guided on stars could reveal the comet moving and blurring as it moves in front of the stars during the exposure.

If the comet is bright enough to guide on the comet itself, then this problem is solved.

But if not, the gain on the camera needs to be increased and take shorter exposures to minimise the movement during the exposure.
The shorter the exposure, the less the comet will appear to move.
The faster the apparent motion of the comet, the shorter the exposure you’ll need to freeze its motion.

Experiment by taking various exposures to see which exposure has the sharpest comet image without it trailing.
Once decided on the ideal exposure each captured sub should then have minimum comet movement and reduced blurring.

Freezing Tail Structure.
Details in the tails, especially the Ion tail can change within minutes.
If a kink or disconnection forms in the tails, these move rapidly away from the comet nucleus along the tails length due to pressure from the solar wind.

If a long exposure is taken, or lots of subs are used to stack over a long period of time, detail within the tail will blur in your images as this material moves.

When taking an exposure, or a number of shorter subs to stack later, it is best to leave the interval between start and finish to no more than a couple of minutes.

This will give you the best chance to freeze and capture those ephemeral tail structures.

Stacking Subs.
When stacking images, you really do need to stack on the comets position in each image otherwise the stars will be nicely stacked, but the comet, having moved between each exposure, will appear blurred in the stacked result.

Locking on the comets position and stacking the subs on that freezes the comets motion and draws the stars into trails.
The faster the movement of the comet, the longer the star trails will appear.

The image of the comet at the top of this blog entry taken on the 6th of January was a result of only 3x 60 second subs.
I was auto-guiding on the comet and increased the gain on the camera to 180 to pull out a bit more of the faint ion tail during the relatively short exposure.

I found that if I stacked 4 or more of the subs that were taken, the detail in the resulting image started to blur and detail in the ion tail was lost.
In this case I found using no more that 3 minutes exposure span gave me the best balance between a nice smooth stacked image with sharp tail details.
Like most imaging, it’s yet another balancing act on getting the exposure and timings right to freeze as much detail as possible.
Stack too many subs over too long a period of time and all that nice detail will be blurred out of existence.

Affinity Photo stacks astrophotography images, but it does not currently have a Comet Stacking mode, so cannot be used for moving comets:
https://affinity.serif.com/en-gb/photo
I hear that PixInsight has a comet stacking feature, but I haven’t used this software yet.
https://pixinsight.com

The software I use for my comet Stacking is…
Good old Deep Sky Stacker, which is of course free: http://deepskystacker.free.fr/english/index.html
(I never seemed to managed to get a very good image when using the combined comet and star stacking method).
The process I use is outlined in my Deep Sky Stacker Guide, which is available from my online shop:
https://www.star-gazing.co.uk/shop

It can also be done in Astro Pixel Processor:
https://www.astropixelprocessor.com
I made a YouTube Video a while ago showing how to do this in APP here:

Comet C/2022 E3 (ZTF) is brightening.

This image was taken on the morning of the 6th of January 2023, fighting the Moonlight.

I managed to get enough subs before the dawn sky brightened to create an animation of the comet moving against the background stars in Corona Borealis.

I have uploaded some maps to help you find the comet on my blog below:

Comet C/2022 E3 (ZTF) Naked eye in the new year?

This evening, The Moon moves in front of (Occults) Uranus.

It won’t be as spectacular as December’s occultation of Mars, but will still be interesting to observe or image.

With Uranus being a lot smaller and fainter than Mars, the event will also be a bit more challenging.

From my location, the event starts at 22:43:30 UT, when the dark part of The Moon’s southern limb will start to move across Uranus’ tiny disk.

From my location, Uranus does not hide too deeply behind the southern limb of The Moon and reappears at the bright limb less than 10 minutes later.

The event is over for me by 22:51:55 UT.

If you are further north from me Uranus will disappear earlier and dive deeper behind the Moon and the occultation will last a bit longer.
If you are much further south from me in Northamptonshire, The Moon will either produce a grazing occultation or miss Uranus completely.

Start and end times will differ depending on your location.

The animation below shows the occultation as seen from my location
Animation produced using Stellarium.

Let’s hope we have some clear skies.

I have managed to get the ASIAIR App running on my PC using the Windows Subsystem for Android.

This is a real game-changer for me and last Thursday evening, it worked extremely well.

If you fancy having a go yourself, here’s how I did it:
https://www.star-gazing.co.uk/WebPage/asiair-pc-2022122

Dave

In the early morning of the 8th of December on the day of Mars reaching opposition, The Moon moves in front of (occults) Mars.

Timing is roughly…

Disappearance: 04:58 UT.
Mars disappears near crater Grimaldi.

Reappearance at the bright limb, by Mare Australe: 05:57 UT.

The timings shown are as seen from my location, so your timings may be slightly different from these.

The speeded up animation below, created using Stellarium, shows what we might be able to see at disappearance and reappearance.

On the evening of the 5th of December The Moon moves in front of (occults) Uranus.

Timing is roughly…

Disappearance: 16:45 UT. Moon and Uranus are low down in the eastern sky.
Uranus disappears at the dark limb, close to crater Pythagoras.

Reappearance at the bright limb, by crater Reimann: 17:20 UT.

The timings shown are as seen from my location, so your timings may be slightly different from these.

The speeded up animation below, created using Stellarium, shows what we might be able to see at disappearance and reappearance.

Comet C/2022 E3 (ZTF) is meant to become just about bright enough to be seen with the naked eye in the new year.

It is currently at about 7th magnitude (3rd January 2023) in the northern part of the constellation of Corona Borealis, low down in the early morning eastern sky.

Over January, it heads northwards, slowly picking up speed and brightening.

Image of the comet taken on the morning of the 20th of January.

Animation of C/2022 E3 (ZTF) moving northwards through Corona Borealis on the 6th of January in bright moonlight.

Colour image of Comet C/2022 E3 (ZTF) taken 3rd January 2023 through the murk.

At the start of the new year it is located just north of Corona Borealis.

It reaches Perihelion (closest to The Sun) on the 12th of January.

It reaches the middle of Draco’s body by the 24th of January, where it should now be a lot brighter.

By the end of January the comet is passing close to Ursa Minor and Polaris, so will be at a respectable altitude throughout the night.

It reaches its maximum magnitude of +5.4 on the 1st of February, when it should “just” be visible the the naked eye from a dark sky.
The beginning of February is when the comet will be at its closest to Earth.

A bright gibbous Moon will be visible in the evening sky, so may be best to observe or image the comet in the morning sky, once The Moon has set.
It’s not going to be a spectacular comet, but should give us something nice to look at or image.

On the 6th of February the comet moves through Auriga passings very close to the first magnitude star Capella.
The Moon rises a little bit later that night, so get out before that rises fairly quickly after dark.

Moving southwards by the 11th of February the comet passes to the east of Mars in Taurus.
The Moon is now well out of the way and visible in the morning sky, so will not interfere with viewing or imaging the comet in the evenings.

A few days later on the 14th & 15th of February it passes to the east of the first magnitude star Aldebaran and the Hyades open star cluster.

After passing through Taurus, the apparent motion of the comet is now slowing as it fades.

It passes just west of the shield of Orion the last two weeks of March and then on into Eridanus.
The comet is moving in a large retrograde loop, which swings it just south of the first magnitude star Rigel in the foot of Orion towards the end of April.

It’s developing very nicely now, so let’s hope for a good show.

🤞

The maps below show the path of the comet from January until March.

Star-Gazing Guide to High Resolution Lunar & Planet Imaging.
My latest imaging guide is now available to order from my online shop.
Click here to visit my online shop.

Almost 2 years in the writing, trying out lots of different techniques, this edition of my astrophotography guide leads you step by step through a number of tried and tested image capture and processing workflows to help you get the very best out of your lunar and planet imaging.

My guide covers the taking of video images and subsequent stacking and post-processing using a number of software packages.

Among the techniques covered within this guide are:

• Introduction to the planets and Moon.
• The equipment and accessories used to take images.
• Why we use videos to capture Moon and Planet images.
• Using SharpCap to capture Moon & Planet images.
• Stacking the video files using AutoStakkert! and AstroSurface.
• Sharpening the stacked images using Registax and AstroSurface.
• Colour correcting images using Registax and AstroSurface.
• Final image polishing using Photoshop and Affinity Photo.

Visit my online shop or the link below for more details:
https://www.star-gazing.co.uk/Shop

High Resolution Lunar & Planet Imaging

Mars is approaching Opposition.
As a result the distance between The Red Planet and Earth is decreasing, so the apparent size is getting bigger.
It reaches opposition on the 8th of December, when The Moon will also move in front of it (an occultation).
More details about this later.

As the disk gets bigger, it makes it a bit easier to view and image features on the planets surface.
Mars is high up in Taurus as well, so that really helps, keeping the planet clear of most of the clag in the atmosphere lower down.

It still has a fairly small disk compared to Jupiter and Saturn, but you can quite clearly see the north polar cap and the dark triangular-shaped feature of Syrtis Major in my image of the gibbous phase below, taken on the 8th of September 2022.

My images below taken under varying conditions, were taken in August.
This shows progress in growth even over just a month.

How big is Mars going to get?
I have used Stellarium to create the diagram below to show just how big Mars will get over the next few months and the changing of its phase, as the angle to The Sun changes.

In December the disk will be about the same size as Saturn’s.
But you do have to be quick!
The distance increases rapidly in the new year, so by February it will be almost half that size, making features much more difficult to make out.

Here’s to a good Mars apparition, and let’s hope we have some good clear skies for us to view it.

I managed to wake in time to catch Jupiter and Mars before the sky started to brighten.
I could see Saturn just about to dip below the neighbours roof, so was too low for me to get in the scope.

I easily got Jupiter in my sights, being a lot higher in the sky.
As soon as my first images were starting to focus, it was obvious something wasn’t quite right.

There were two shadow transits on the disk of Jupiter and I could clearly see that they looked strange.
In the over-processed first image below, arcs are visible on the satellite shadows and Io and Ganymede.

I’m definitely not going to get much detail with that right mess.

It was immediately obvious, that despite me thinking I had collimated my C11 the previous morning, it definitely needed tweaking again.
Collimation was was well out. SCT’s can be notoriously difficult to collimate.

I thought it was going to be one of those nights out with the scope when everything goes wrong as patchy cloud started to fill the sky.

Undeterred, I slewed the scope over to a bright star in the clear gap and de-focused to produce a bright ring.

Using the defocused star, I took quite some time using my trusted method to get the ring concentric, meaning that the scope was collimated.

I then sent the scope back to Jupiter, which was now peeking in and out of clouds.

Within half an hours, the clouds had mostly cleared. Game On!

The image now looked much, much better. The satellite shadow and satellites were now nice and sharp.

I could see the twilight starting to creep in, so didn’t try and use the Atmospheric Dispersion Corrector (ADC).
Setting that up properly would have eaten up even more valuable time, when I could be capturing images.

But I was now running out of time…

I ran off a few videos, before putting in a 2x Barlow lens to increase the image size of the disk on the camera chip.

I was still able to see that the focused image was much better than the last time I tried that, so should be able to get some decent enough images.

Once I had captured a few videos of Jupiter, in the brightening twilight, I pointed the scope towards Mars, centering it easily in the Barlow camera view.

The dark triangular feature of Syrtis Major was showing very nicely on the gibbous planet.

I then took a few images of Mars, which had  then packed away.

I turned out to be a great morning, plus I didn’t lose too much sleep either. ?
Next time I’ll leave enough time to use the ADC to try and sharpen the images a bit better.

Below are my images and at the bottom I have put an image showing the relative sizes of Mars & Jupiter, to show just how small Mars is at the moment.

As my last video turned out to be so popular, I have now recorded another one explaining about the other images the James Webb Space Telescope team released and what we are seeing.
Enjoy.

The James Webb Space Telescope is really out of the blocks with so much style.

It has imaged and worked out the distance of an extremely remote galaxy GLASS-z13.

Here’s my YouTube video about it.