[am1m]

Superb pictures and information, as always grajaa, thank you! Had a question about the colours seen in these space photos, are they captured by the equipment, or rendered by the software? How accurate is colour capture for these relatively deep space shots? I see most of the NASA pics captioned with 'false colour', or 'colour added by the software'. I guess colour is affected by the sheer distances involved.

Thanks in advance for any information!

[graaja]

Originally Posted by am1m

Superb pictures and information, as always grajaa, thank you! Had a question about the colours seen in these space photos, are they captured by the equipment, or rendered by the software? How accurate is colour capture for these relatively deep space shots? I see most of the NASA pics captioned with 'false colour', or 'colour added by the software'. I guess colour is affected by the sheer distances involved.

Thanks in advance for any information!

Thank you for the kind words am1m

The accuracy of the colors depends on the type of data acquired. If the image is acquired using a color camera, then the colors are real as we would see with our human eyes. Technically, the color information is present in these objects when we see them in a telescope, but as they are very dim, we see only in grey scale. But a camera integrates several minutes of light and hence can reproduce color. The same applies when we capture these objects using a monochrome camera with RGB filters. As these filters pass Red, Green and Blue in the visible spectrum, the output after combining the color channels will be in real color.

But when we shoot narrowband, and capture light spectrum corresponding to various elements (Oxygen, Hydrogen and Sulphur are the widely used filters), in the final image reconstruction, each of these outputs are assigned a color channel (also known as palette). For example, hubble telescope images use SHO color palette where Sulphur is assigned to Red, Hydrogen is assigned to Green and Oxygen is assigned to Blue. This is called a false color image as the final color is not the true representation. But this is used in scientific analysis as the color indicates the concentration of the elements in various areas of the object.

For example, below are two images of Rosette nebula. The right one is shot with a color camera and the left is shot with narrow band filters and created using Hubble's SHO palette. With the SHO image, we can easily identify that the blue regions are rich in oxygen and the golden regions are rich in Hydrogen and Sulphur.



Below picture shows how the individual channels are seen by the monochrome camera. When all these channels are combined, you get the final image I had posted in my previous post.



Also, research telescopes like JWST, Hubble, Chandra X-Ray telescope can also detect wavelengths which are not visible to the human eyes like infra red, ultraviolet, X-Ray etc. These data are also assigned some color in the visble spectrum while making images to be viewed by general public. These are also false color images.

Hope this clears your doubt.

[ampere]

You are killing it! Hobby is one thing, but you have taken this to the next level! Look forward to seeing more on this Ganesh!

[Carspook]

Very nice, great work. The car with the Milky Way photo is awesome, combines two the fields really well.The amount of work and dedication this needs is clearly shown in your post. Hats off to you sir

[theqca]

I do a lot of serious photography but nothing in astro. Enjoyed going through your post and viewing the images. Lovely work. Thanks for sharing.

[graaja]

Originally Posted by ampere

You are killing it! Hobby is one thing, but you have taken this to the next level! Look forward to seeing more on this Ganesh!

Thank you so much for the kind words, Ampere!

Originally Posted by Carspook

Very nice, great work. The car with the Milky Way photo is awesome...

Thank you so much for the kind words Carspook!

Originally Posted by theqca

...Lovely work. Thanks for sharing.

Thank you for the kind words, theqca!

[MT_Hyderabad]

Amazing clicks (if I can call them clicks :-))

I am now seeing your other images, clicked only the updates coming at the bottom of the thread and didn't realise that there are 12 pages!

[aviator1101]

Originally Posted by graaja

You can do wide field astrophotography with your Canon 90D with maybe a focal length of 200mm. Take very short exposures of less than 5 seconds. Take 100+ exposures like this and then use software like Deep Sky Stacker (DSS) to stack these images to get one single image. Then you can use regular photo applications like Photoshop or GIMP to work on brightness contrast etc. With this method, you can shoot some bright objects like Orion Nebula, star clusters like Pleiades, Hercules cluster etc.

graaja Sir, went through your posts and they actually opened my door to this new subject. I have been to various high altitude areas including Hanle where you get a perfectly clear sky, have seen such photographs on the internet which used to look good to the untrained eye, but the mechanics involved, read through your posts, was a revelation.

I'm sure there are many like me who are avid travellers and get an opportunity to lie down and observe a clear sky, but never had the opportunity to photograph it meaningfully either due to lack of knowledge or proper equipment.

For people like us, if you could share some tips of wide field astrophotography using normal photography equipment like a DSLR and a Tripod.

[graaja]

Originally Posted by aviator1101

For people like us, if you could share some tips of wide field astrophotography using normal photography equipment like a DSLR and a Tripod.

Apologies for the late reply.

When using a DSLR on a tripod, following are the steps to be followed.

1. Calculate exposure time:

There is a rule called "500 rule". To find the maximum exposure time you can use without star trails, you divide 500 by the focal length of your lens. If you have a crop sensor DSLR, then the focal length should be effective focal length including the crop factor.

For example, if you have a full frame DSLR with an 18mm lens, then the maximum exposure you can do is 500/18 = 27.7 seconds. If the same 18mm lens is on an APS-C sensor with a crop factor of 1.6, the maximum exposure time would be 500 / (18 x 1.6) = 17.3 seconds.

In practice, we do not use the maximum exposure time calculated from the 500 rule, but limit to about 60% of the calculated time. So, the exposure time for the above examples with 18mm lens would be 16 seconds for full frame and 10 seconds for APS-C.

2. Focusing

Once you have calculated the maximum exposure time for your camera, the next step would be to get the proper focus. If your lens has a focus scale with focus to inifinity, then you can directly set the focus to infinity and this will work. If the lens does not have focus to infinity, then you have to manually adjust the focus to get the stars as sharp as possible. If your camera has live view with zoom in function, then you can zoom in to a bright star and adjust the focus.

Another method is to use something called a Bahtinov's mask. With a bahtinov's mask, when you point the camera to a bright star and shoot it, you will see three lines, one horizontal and another two lines diagonal to this horizantal line. You need to adjust the focus ring till you get both the diagonal lines at equal angle to the horizontal line. Below is an example image (Image source: Google)



Bahtinov masks may be readily available for a specific lens. In case it is not available, there are several open source 3D models available where one can adjust the dimensions to match the lens and 3D print them.

3. Shooting the pictures and stacking

Once you get the focus right, it is just pointing the camera to the object you would like to shoot (like Milky way, Orion etc.), set the exposure time and shoot.

When you shoot with a wide angle lens on a full frame camera which allows long exposure times like 20 seconds, you will be able to get a good picture with just one exposure.

When you shoot with a slightly longer focal length or a crop sensor, which does not allow long exposures, you can do multiple exposures and stack multiple images using programs like Photoshop, Sequator etc. When you stack multiple images, the fainter details in each image get added to give you a final image with good details.

Hope this helps. Let me know if you have any other doubts.

[graaja]

Astrophotography Trip to Leh and Hanle

Last year (September 2022), I had been to Hanle for an astrophotography trip. I documented this trip in a separate thread, link below.

https://www.team-bhp.com/forum/trave...hanle-leh.html (In Search of Nebulae and Galaxies – An Astrophotography Trip to Hanle and Leh)

I had decided to come back to Hanle again but wanted to do a road trip this time. That wish was fulfilled last month when I did a 4-week road trip to Hanle for astrophotography.

Like last year, this year too several BAS (Bangalore Astronomical Society) members planned to visit Hanle. As we had residual monsoon clouds last September which washed out 4 out of 5 days in Hanle, this year we decided to visit in October.

The downside of this decision is that temperatures would be much lower than what we faced last year. The lowest temperature we faced was -8.5 degrees in most of the nights. This also resulted in water in the pipes freezing which gave rise to problems of its own!

The upside is that we would have a higher chance of clear nights. I got clear skies 3.5 out of 4 nights in Hanle.

Unlike last year when everyone in the team arrived and left on the same dates, this time everyone had different plans and different arrival and departure dates. We made a couple of groups with common arrival and departure dates. I had planned 3 nights in Leh and 4 nights in Hanle. A close friend accompanied me till Leh on the road trip. We left Coimbatore on 30th September and reached Leh on 6th October. On the 7th, we drove to Pangong and were back in Leh on the 8th. On 11th October, I started my solo journey to Hanle, while my friend took a flight back home.

I am updating the astrophotography part of the trip in this thread. I will write a separate travelogue covering the complete road trip.

Part - 1: Photography in Leh:

I set up my equipment where we stayed, a homestay called Dakpa House, which was in Thiksey far from the light pollution of Leh town. The plan was to shoot for 3 nights (8th to 10th October). Unfortunately, I got only one clear night on the 8th, of which the 2nd half was washed out by moonlight. The remaining two nights were washed out with clouds. So I could collect only a few hours of data on the 8th.

The equipment is set up outside the Home Stay.


Early morning, the equipment, Moon and Venus.


Just a few hundred meters in front of the Home Stay, there was a very good location with the Indus River and snow-capped mountains in the background. Thanks to my friend and fellow Astrophotographer Mahadevan for finding this spot.


Clicked a picture of the Milky Way with this beautiful scenery in the night.


The BAS team in front of the Leh home stay with the managers of the homestay.

[graaja]

Part - 2: Photography in Hanle

On the 11th of October morning, I packed up all the equipment, loaded the car, and drove to Hanle. In Hanle, we stayed in a place called Hor Cottages. This place is located about 6km outside the Hanle village, in the middle of nowhere. Below is a picture I shot of this place from a couple of kilometers using a telephoto lens.

Notice how there are no buildings anywhere nearby. There are 6 cottages and we had booked 5 of them, and the remaining cottage was used for the drivers of the two cars hired from Leh. So, we had the place all to ourselves. The dome-like structure is the dining room. Once dinner was done by 9:00, it was complete lights out throughout the property, and it was completely dark. The view of the Milky Way under Bortle-1 (the darkest on a scale that measures light pollution) sky was just breathtaking.

On the same evening, I set up the equipment and started shooting. The equipment set up in front of the cottages.


For three nights on the 11th, 12th, and 13th, the sky was crystal clear. On the 14th, we had clouds at the beginning of the night with very severe winds. The sky cleared up after 10PM, and I was able to collect some data from 10PM to 4AM. On the night of 13th, I also set up my Canon R6 mirrorless camera to record a timelapse of Milky Way. This timelapse can be seen in the YouTube video in a later post.

There were several improvements compared to last year's trip.

Equipment:

Last year, I had carried the EQ6-R Pro German Equatorial Mount. This mount is a beast of a mount and weights 17.5 kilos just for the main mount. Add 8 kilos for the tripod, 5 to 10 kilos of counterweight, the total setup without the payload (telescopes, cameras etc.) weighs 30 to 35 kilos. At the low oxygen levels in Hanle, setting up this mount involved lots of effort and took about 2 hours to set up.

This time, I had bought a ZWO AM5 which is a harmonic mount. Harmonic mounts have a very high payload-to-mount weight ratio. This mount is rated for the same payload weight as the EQ6, but weighs just 5 kilos. And it does not need counterweights for payloads up to 13 kilos. So, this makes the total weight of the setup without payload 12.5 kilos compared to 30-35 kilos of the EQ6. As this mount does not require balancing of the RA and DEC axes, it takes much less time to setup. It took just 30 minutes to set up both in Leh and Hanle and another 30 minutes to dismantle.

Place of stay:

Last year, we had set up equipment in front of IIA (Indian Institute of Astrophysics) guest house which was far from the place where we stayed. Because of this, we did not have a place to rest in the night once the equipment was set up and started capturing data. This made us astrophotographers miserable. This time, we had the luxury of the equipment set up just outside the cottages where we stayed.

Number of clear nights and quality data:

Last year, 4 out of 5 nights in Hanle were washed out due to clouds and I lost lot of data in Leh due to equipment failure. Below is the list of targets and data I acquired on each target last year.

Jelly fish Nebula: 2:25 hours
North American and Pelican Nebulae: 2:51 hours
Helix Nebula: 2:03 hours
Bubble Nebula: 50 minutes
Triangulum Galaxy: 2:18 hours
Eastern Veil Nebula: 2:00 hours
Witch Head: 0:20 hours

This is a total of 12 hours 47 minutes of data on 7 targets from 7 nights.

Below is the list of targets and data from this year.

North American and Pelican Nebulae: 9:55 hours
SADR Region: 2:00 hours
Heart and Soul Nebulae: 5:55 hours
Spaghetti Nebula: 4:50 hours
Veil Nebula Complex: 8:40 hours
Witch Head Nebula: 0:55 hours

This is a total of 33 hours 15 minutes of data on 6 targets from 7 nights.

Apart from these deep space targets shot with my main equipment, I also was able to capture a few Milky Way pictures and timelapses using the Canon R6 mirrorless camera. Overall, this turned out to be a very successful trip.

[graaja]

I will share the pictures of the deep-space targets and details on these targets now. Before that, below is the list of equipment and software used to capture and process these targets.

Equipment:
ZWO AM5 harmonic mount
William Optics Redcat51 refractor telescope with a focal length of 250mm
William Optics 30mm guide scope
ZWO ASI2600 MC Pro, color CMOS main camera
ZWO ASI224 guide camera
Pegasus power box - power distribution and USB hub
Intel NUC Mini PC to control all the above equipment

Software:
N.I.N.A for controlling the equipment and data capture. I used the advanced sequencer in N.I.N.A to program multiple targets in a night.
Pixinsight for stacking and processing the images
Lightroom for final edits

The North American and Pelican Nebulae

The Pelican Nebula (also known as IC 5070 and IC 5067) is an H II region associated with the North American Nebula in the constellation Cygnus. The gaseous contortions of this emission nebula bear a resemblance to a pelican, giving rise to its name. The Pelican Nebula is located near first magnitude star Deneb and is divided from its more prominent neighbor, the North America Nebula, by a foreground molecular cloud filled with dark dust.

The North America Nebula (NGC 7000 or Caldwell 20) is an emission nebula in the constellation Cygnus, close to Deneb (the tail of the swan and its brightest star). The shape of the nebula resembles that of the continent of North America, complete with a prominent Gulf of Mexico.
The distances to the North America and Pelican nebulae were controversial because there are few precise methods for determining how far away an HII region lies. Until 2020, most astronomers accepted a value of 2,000 light years, though estimates ranged from 1,500 to 3,000 light years.

But in 2020, the Gaia astrometry spacecraft measured the distances to 395 stars lying within the HII region, giving the North America and Pelican nebulae a distance of 2,590 light years. The entire HII region Sh2-117 is estimated to be 140 light-years across, and the North American nebula stretches 90 light-years

Exposure: This picture is an integration of 9 hours 55 minutes (119 individual pictures of 5-minute exposure each)



Heart and Soul Nebula - IC1805 and IC1848

Located about 7,500 light-years from Earth, the Heart and Soul nebulae form a vast star-forming complex that makes up part of the Perseus spiral arm of our Milky Way galaxy. The nebula at the right is the Heart, designated IC 1805 and named after its resemblance to a human heart. To the left is the Soul nebula, also known as the Embryo nebula (as it resembles a human embryo), IC 1848 or W5. The Perseus arm lies further from the center of the Milky Way than the arm that contains our sun. The Heart and Soul nebulae stretch out nearly 580 light-years across, covering a small portion of the diameter of the Milky Way, which is roughly 100,000 light-years across.

The two nebulae are both massive star-making factories, marked by giant bubbles that were blown into surrounding dust by radiation and winds from the stars. These stars are less than a few million years old - youngsters in comparison to stars like the sun, which is nearly 5 billion years old.

Exposure: This picture is an integration of 5 hours 55 minutes (71 individual pictures of 5-minute exposure each)



Witch Head Nebula - IC2118

IC 2118 (also known as Witch Head Nebula due to its shape) is an extremely faint reflection nebula believed to be an ancient supernova remnant or gas cloud illuminated by nearby supergiant star Rigel in the constellation of Orion. It lies in the Orion constellation, about 900 light-years from Earth. The nature of the dust particles, reflecting blue light better than red, is a factor in giving the Witch Head its blue color. Radio observations show substantial carbon monoxide emission throughout parts of IC 2118, an indicator of the presence of molecular clouds and star formation in the nebula. In fact, candidates for pre-main sequence stars and some classic T-Tauri stars have been found deep within the nebula.

Exposure: This picture is an integration of 55 minutes (11 individual pictures of 5-minute exposure each). I plan to collect more data on this target during the upcoming season to bring out more details on the dust clouds and reduce noise.



Veil Nebula Complex

The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus. It constitutes the visible portions of the Cygnus Loop, a supernova remnant, many portions of which have acquired their own individual names and catalog identifiers.

The source supernova was a star 20 times more massive than the Sun which exploded between 10,000 and 20,000 years ago. At the time of the explosion, the supernova would have appeared brighter than Venus in the sky, and visible in the daytime. The remnants have since expanded to cover an area of the sky roughly 3 degrees in diameter (about 6 times the diameter, and 36 times the area, of the full Moon). While previous distance estimates have ranged from 1200 to 5800 light-years, a recent determination of 2400 light-years is based on direct astrometric measurements.

There are three main visual components in this region:

The Western Veil: Also known as Caldwell 34, consisting of NGC 6960 (also known as the Witch's Broom, Lacework Nebula, Filamentary Nebula) near the foreground star 52 Cygni

The Eastern Veil: Also known as Caldwell 33, whose brightest area is NGC 6992, trailing off farther south into NGC 6995 (together with NGC 6992 also known as Network Nebula) and IC 1340;

Pickering's Triangle: Brightest at the north central edge of the loop, but visible in photographs continuing toward the central area of the loop.



Below picture shows the three main areas of the nebula.


For some reason, whenever I look at the picture of veil nebula, I see "Jabba the Hutt", a creature from Star Wars movies.


And the bottom part of the nebula resembles the creature from Aliens movie.

[graaja]

Spaghetti Nebula

Simeis 147, also known as the Spaghetti Nebula, SNR G180.0-01.7 or Sharpless 2-240, is a supernova remnant (SNR) in the Milky Way, straddling the border between the constellations Auriga and Taurus. It was discovered in 1952 at the Crimean Astrophysical Observatory by Grigory Shajn and his team using a Schmidt camera and a narrowband filter close to the Hydrogen Alpha transmission line. It is difficult to observe due to its extremely low brightness.

The nebulous area has an almost spherical shell and a filamentary structure, which resembles spaghetti, and hence the name. The remnant has an apparent diameter of approximately 3 degrees, an estimated distance of approximately 3000 (±350) light-years, and an age of approximately 40,000 years. At that distance, it spans roughly 160 lightyears.

It is believed that the stellar explosion left behind a rapidly spinning neutron star known as pulsar PSR J0538+2817 in the nebula core, emitting a strong radio signal.

Due to the filaments being very dim, it is very difficult to bring out the details of this nebula without bumping up the noise as well. I will be planning to get more hours of data on this target during the upcoming astro season.

Exposure: This picture is an integration of 4 hours 50 minutes (58 individual pictures of 5-minute exposure each)



SADR Region

Gamma Cygni (γ Cygni, abbreviated Gamma Cyg, γ Cyg), officially named Sadr is a star in the northern constellation of Cygnus, forming the intersection of an asterism of five stars called the Northern Cross. It is approximately 1,800 light-years from the Sun. With an apparent visual magnitude of 2.23, Gamma Cygni is among the brighter stars visible in the night sky. Compared to the Sun this is an enormous star, with 12 times the Sun's mass and about 150 times the Sun's radius. It emits over 33,000 times as much energy as the Sun, at an effective temperature of 6,100 K in its outer envelope. This temperature is what gives the star the characteristic yellow-white hue of an F-type star. The Sadr Region (also known as IC 1318 or the Gamma Cygni Nebula) is the diffuse emission nebula surrounding this star.

This frame also has many other objects, a few of them are:

Crescent Nebula: The Crescent Nebula (also known as NGC 6888, Caldwell 27, Sharpless 105) is an emission nebula in the constellation Cygnus, about 5000 light-years away from Earth. It is formed by the fast stellar wind from the Wolf-Rayet star WR 136 (HD 192163) colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 to 400,000 years ago. The result of the collision is a shell and two shock waves, one moving outward and one moving inward.

M29 Open cluster: Messier 29 or M29, also known as NGC 6913, is a quite small, bright open cluster of stars just south of Gamma Cygni. It was discovered by Charles Messier in 1764, and can be seen from Earth by using binoculars.

NGC6910 Open Cluster: NGC 6910 is an open cluster in the constellation Cygnus. NGC 6910 is located half a degree east-northeast of Gamma Cygni. It may be physically related to the nebula IC 1318 as it lies at a similar distance, behind the galactic Great Rift.

Exposure: This picture is an integration of 2 hours (24 individual pictures of 5-minute exposure each)



The annotated version of the picture with the objects marked.


Sagittarius arm of Milky Way from Hanle. This is the view towards the core of the Milky Way, and is very dense and rich in star fields and nebulae. As winter approaches, this view sets earlier. At the time we were in Hanle, this part of the Milky Way was visible from 7PM to around 9:30PM.


Venus rising over the horizon and Zodiacal light. The zodiacal light (also called false dawn when seen before sunrise) is a faint glow of diffuse sunlight scattered by interplanetary dust. Brighter around the Sun, it appears in a particularly dark night sky to extend from the Sun's direction in a roughly triangular shape along the Zodiac. Zodiacal light can be observed from locations with very low light pollution.


Winter Milky Way or Perseus arm from Hanle. This is the view of the Milky Way away from the center. As this part is away from the core of the galaxy, it is not as dense as the view of the Sagittarius arm.



The greenish glow towards the north is air-glow and is mistaken by many to be Aurora or Northern Lights. As per NASA:

Airglow occurs when atoms and molecules in the upper atmosphere, excited by sunlight, emit light to shed their excess energy. Or, it can happen when atoms and molecules that have been ionized by sunlight collide with and capture a free electron. In both cases, they eject a particle of light — called a photon — in order to relax again. The phenomenon is similar to auroras, but where auroras are driven by high-energy particles originating from the solar wind, airglow is energized by ordinary, day-to-day solar radiation.

Closing this report with a couple of vide compilations.

A compilation of various Timelapses shot in Pangong Tso lake and Hanle.

https://www.youtube.com/watch?v=PW1quJ-pM7s

A short video about Astrophotography in Hanle.

https://youtu.be/E_vblDjZ2j4

That's all folks I have for now. Will come back with more updates and pictures once the Astrophotography season starts in December. This year, the focus will be more on quality vs. quantity. I will be shooting less targets but collect more data on each target to get more details on the targets.

[Rajain]

Dear Ganesh

I remember the images you had taken last year and followed it up with the latest ones. I also saw and spent time researching the equipment. My God you have taken a hobby to the next level. Going through your thread is so immersive, so satisfying that I got myself a nice cup of tea, sat on the lazy boy and totally soaked in the entire thread again from the beginning. Stopping every now and then to check the equipment.

We will absolutely remain glued to the thread for the travelogue as well. a BMW going up to Hanle and back would be awesome.

Your pictures are so amazing that it has led me to do some more reading and checking on the constellations and the first few steps in the world that you are an accomplished artist in.

Cheers
Rajain

[aviator1101]

As always, fantastic photographs graaja Sir.
I always fall short of superlatives to describe your photography. Add to that the additional knowledge that you share with us. Only gives a feeling of how vast is the universe and how tiny we are.

Thanks again