Our Beautiful Universe - Photos and Videos

[timmdeeg]

Hi, I'm still a beginner, the Image of M31 above was my first trial (with some good luck).

I'm reading this and that and found to improve the image quality stacking is important and gathering light as well. I wonder supposed I want to invest one hour what's an optimization between those two strategies. One could e.g. take 10 pictures each exposed 6 minutes with ISO 1600 or 80 pictures each exposed 45 seconds with ISO 12800. Due to the ISO-invariance the visible noise doesn't change.
Lets assume that the dynamic range isn't an issue what do you think?

 

[Drakkith]

@timmdeeg Due to readout noise, longer exposures are usually better all else being equal. However, realistically you have to worry about saturation of brighter pixels, tracking and guiding errors, and many other little things that can affect longer exposures more than shorter. Bump your scope while taking 45 second exposures and you lose less than a minute of data at worst. Bump your scope near the end of a 10 minute exposure and you've lost nearly all of that time.

And if you're not autoguiding then you're probably limited to about 2 minute exposures at most, depending on the focal length of your scope and the quality of your tracking.

By far the most important thing is to simply accumulate photons, either through long exposures or through many shorter ones. 10 hours of 1 min exposures is probably better than 1 hour of 10 min exposures unless you have a very noisy camera.

 

[Devin-M]

I get good exposures about half the time with 90 second exposures at 6400iso (Nikon D800) at 2130mm f/14.2 tracked but unguided, but when I’m shooting at 300mm f/4.5 or 600mm f/9 I can consistently crank out 5 minute exposures at 6400iso, sometimes even 10 or 20 minutes with my sulphur narrowband filter but above 5 minutes at 600mm is risky territory unguided… you can lose a lot of frames to wind, tracking problems, planes, satellites etc.

 

[timmdeeg]

Ok, thank you for your comments. I will have to make my own experiences anyway but I think 30" to 60" depending on the object should be fine for starting.

 

[DennisN]

I got the Sony FE 4/70-200 G OSS.

Very cool! Here are two reviews of the lens:

• Sony FE 70-200mm F4 G OSS Lens Review (from The Digital Picture, which includes some usage suggestions)
• Sony FE 70-200mm f/4 G OSS (SEL70200G) - Review / Test Report (from OpticalLimits, a detailed test)

Features like the focus magnification are very helpful.

Yes, I agree . I've got that too on my camera (Sony A6000). And the autofocus is great too, and also the autofocus tracking (tracking moving objects) is quite impressive.

Hi, I'm still a beginner, the Image of M31 above was my first trial (with some good luck).

I'm reading this and that and found to improve the image quality stacking is important and gathering light as well.

I've posted some good tutorial videos in this thread which you may find interesting, see my post #1,472.

The two videos in that post is from this youtube channel which has a bunch of various tutorials on doing astrophotography with cameras and lenses (with or without trackers):

• Nebula Photos (by Nico Carver)

Another channel with good astrophotography tutorials is this one:

• Forrest Tanaka (e.g. this video in which he shoots the Andromeda galaxy)

 

[Andy Resnick]

Hmm. I'll have to check my source and get back to you.

The document I refer to is "Astronomical Seeing in Space and Time", a dissertation by David Saint-Jacques, University of Cambridge (1998). He presents an unusually clear (!) discussion about atmospheric seeing conditions, and some of the results demonstrate (as best I can understand) that susceptibility to seeing scales as the aperture diameter d^(1/3).

 

[Andy Resnick]

In deep sky astrophotography, where you're taking sub-frame images of at at least tens of seconds, but more typically several minutes, stopping down the aperture won't help more than they hurt (other physical abberations aside, i.e., chromatic, spherical, coma and astigmatism -- stopping down the aperture might help for those). The seeing changes are just way too fast.

Ignoring the other aberrations, you'll get more bang for the buck by increasing the aperture to raise the signal further above the noise floor.

A smaller aperture might have a slightly better effect on your guiding though, maybe, where exposures are only a couple of seconds. But I'm talking about the primary imaging here.

I think we are starting to talk past each other, and this discussion would be more broadly interesting if we focused on the essential aspect: refractive vs. reflective telescopes and the trade-offs. It's my impression that the folks that post here on PF fall into one of these two broad categories: DSLR folks are using refractors while the 'astronomy' folks are using reflectors.

For example, after accounting for the optical design differences between a finite-conjugate objective and afocal telescopes, my 400/2.8 lens is roughly equivalent to a 152mm refractor plus whatever accessories are needed (e.g. field flattener, focal reducer).

I'm fairly sure that none of the astronomy people posting here uses an actual refractor, which I find mildly interesting and wonder why. Similarly, while fast DSLR lenses are comparable to astrographs in terms of f/# and field of view, I don't think anyone here uses an actual astrograph.

 

[Drakkith]

I'm fairly sure that none of the astronomy people posting here uses an actual refractor, which I find mildly interesting and wonder why.

I have a William Optics refractor that I usually use. A good refractor is a joy to work with.

 

[timmdeeg]

Very cool! Here are two reviews of the lens:

• Sony FE 70-200mm F4 G OSS Lens Review (from The Digital Picture, which includes some usage suggestions)
• Sony FE 70-200mm f/4 G OSS (SEL70200G) - Review / Test Report (from OpticalLimits, a detailed test)

Yes, I agree . I've got that too on my camera (Sony A6000). And the autofocus is great too, and also the autofocus tracking (tracking moving objects) is quite impressive.
I've posted some good tutorial videos in this thread which you may find interesting, see my post #1,472.

The two videos in that post is from this youtube channel which has a bunch of various tutorials on doing astrophotography with cameras and lenses (with or without trackers):

• Nebula Photos (by Nico Carver)

Another channel with good astrophotography tutorials is this one:

• Forrest Tanaka (e.g. this video in which he shoots the Andromeda galaxy)

Thanks, very helpful for getting more knowledge. It's amazing, having been a convinced visual observer for more than 20 years - inspired by the Sony now things are changing rapidly. The desire to have more was too strong. Since a few weeks I have in addition a Photoline 102 mm FPL53 Doublet on Skywatcher HEQ5 and am trying to gain initial experiences.

 

[Andy Resnick]

Hmm. I'll have to check my source and get back to you.

Found another reference: Roggemann and Welsh, "Imaging through turbulence", CRC publisher, 1996- this book is quite authoritative. Their derivation results in the long-exposure PSF FWHM scaling as aperture diameter d^5/3, quite a bit worse than the other report.

Bottom line: larger aperture, more sensitive to seeing conditions.

 

[Drakkith]

@Andy Resnick Hmm. I must have misremembered my reference. It only talks about maximum magnification for visual use vs amount of scintillation in the atmosphere. I must have extrapolated the bit about photographic use myself.

 

[collinsmark]

Tadpoles Nebula (IC 410) and Letter Y Cluster (NGC 1893) in the constellation Auriga. Captured from my back patio in early 2022.

There's a lot going on in the image. If you're interested in the nebulosity, the nebula is called IC 410 (also called SH 2-236): The Tadpoles Nebula. It's about 12,000 light-years away and about 100 light-years across. To the upper right, there's a couple of dense structures visible that look like squirmy tadpoles. Those are composed of gas and dust leftover from the formation of the star cluster in the center of image (see below). Their wiggly shape is due to the star cluster blowing the gas and dust away via stellar winds and radiation pressure. Within the structures are stellar nurseries where new stars are burning and even newer ones are forming.

Now if you're interested in the star cluster in and around the center of the image, that's NGC 1893: The Letter Y Cluster. There's some fascinating patterns of star formation, where stars are grouped together in curved lines.

Here's the image rotated by 90 deg, so that the star cluster looks a little bit more like the "letter Y" (sort of).

Equipment:
Meade 10" LX200-ACF on an equatorial wedge
Baader 3.5/4nm Ultra-Narrowband filters (first light for these)
ZWO ASI6200MM-Pro (first light for this too)

Software:
Nighttime Imaging 'N' Astronomy (N.I.N.A.)
PixInsight
Topaz Sharpen-AI

Exposure:
SII: 82×600s (13.67 hrs)
Hα: 64×600s (10.67 hrs)
Oiii: 102×600s (17 hrs)
Total exposure time: 41.33 hours
SHO mapping. Bortle 7 (maybe 8) skies

 

[Drakkith]

Baader 3.5/4nm Ultra-Narrowband filters (first light for these)

A good set of narrowband filters makes a huge difference in image quality. I was narrowband imaging using an OIII filter designed for visual use for a number of years. It was disappointing to say the least!

 

[bruha]

Hello, here is my attempt of Orion trapezium (bad condition from window i suburb area) with eyepiece camera Ebony SV 105-just experiment

Lot of succes

 

[bruha]

Maybe this one is little better ...

 

[collinsmark]

The Whirlpool Galaxy (M51) captured from my back patio in Early 2022. The grand design type spiral galaxy (M51a, also called NGC 5194) is smaller than the Milky Way galaxy, sporting a diameter of only around 76,000 light-years across and having approximately 1/10 the mass. Although the galaxy resembles water spiraling down the bathtub drain, it's actually not part of a cosmic bathtub. It's a galaxy comprised of gas, dust, planets, black holes, dark matter, billions of stars, and everything else that makes up a whole galaxy.

M51a is interacting with an even smaller dwarf galaxy (M51b, also called NGC 5195), that resembles a rubber ducky spiraling down the bathtub drain. Of course, it's not a rubber ducky and there is no drain; M51b has been gliding past M51a for hundreds of millions of years.

Due to PF's image size restrictions, I can't post the full resolution image. So here's a cropped version that should reflect some of the detail I was able to capture with M51:

The galaxies (in M51) are in the constellation Canes Venatici, and are roughly 30 million light-years away from Earth.

Equipment:
Meade 10" LX200-ACF on an equatorial wedge
Baader 3.5nm Ha filter
Optolong L-Pro filter
ZWO RGB filters
ZWO ASI6200MM-Pro monochrome camera

Software:
Nighttime Imaging 'N' Astronomy (N.I.N.A.)
PixInsight
Topaz Labs Sharpen AI

Integration:
Bortle 7 (maybe 8) skies
L-Pro: 132×300s = 11 hours
Ha: 21×300s + 14×600s = 4.08 hours
R: 28×300s = 2.33 hours
G: 29×300s = 2.42 hours
B: 26×300s = 2.17 hours
Total integration time: 22 hours

No rubber duckies were harmed in the imaging of this object.

 

[fresh_42]

Relative rotation periods of planets in 2D

 

[DennisN]

The Whirlpool Galaxy (M51) captured from my back patio in Early 2022.

Gorgeous!

 

[Andy Resnick]

Leo Triplet (M65, M66, and NGC 3628) @ 800mm, 2.5 hrs integration time:

The field of view is just slightly larger than a DX format frame. Seeing conditions were poor/bad overall, but stopping the lens down to f/8 substantially improved the PSF. 10s subframes, ISO 500. All post-processing done with AstroPixel Processor.At 1:1 Crop:

 

[collinsmark]

The Horsehead Nebula (also known as Barnard 33) and Flame Nebula (NGC 2024, Sh2-277) in the constellation Orion, captured from my back patio in early 2022.

Here's a different crop:

The Horsehead Nebula proper is the dark region of thick dust in the shape of a horse's head. The brighter emission nebulosity of the surrounding regions are caused by ionized gas charged by Sigma Orionis, the star in the center of the first image (upper center in the second image). Magnetic fields channel the gas to form streaks against the background glow.

The Flame Nebula, to the left of the Horsehead, has the shape of those torches and pitchforks that the townsfolk sometimes bring over to my place when I attempt to try more science. Alnitak (which can be seen in the image, just above the Flame Nebula), the easternmost star in the Belt of Orion, shines energetic ultraviolet light into the nebula, ionizing the gas there.

Equipment:
Explore Scientific ED80-FCD100 piggybacked (horsebacked?) on a LX200-GPS mount, on an equatorial wedge.
Baader 3.5/4 nm ultra-narrowband filter set.
ZWO ASI6200MM-Pro.

Software:
Nighttime Imaging 'N' Astronomy (N.I.N.A.).
PixInsight.
Topaz Labs Sharpen AI.

Integration:
Bortle class 7 (maybe 8) skies.
SII: 47×300s = 3.92 hours
Hα: 53×300s = 4.42 hours
Oiii: 47×300s = 3.92 hours
Total integration time: 12.25 hours

 

[bruha]

excelent
(How far is this flame and horsehead nebula comparing to center of Orion Nebula-trapezium?)

 

[collinsmark]

excelent
(How far is this flame and horsehead nebula comparing to center of Orion Nebula-trapezium?)

I think they're about the same distance away from Earth: both are a little over 1300 light-years away. Both are a part of the Orion Molecular Cloud Complex.

 

[bruha]

Thank you .

 

[Devin-M]

Quick question about Bahtinov masks and the double slit experiment….

My understanding with the double slit experiment is we don’t know which slit a photon goes through or maybe it goes through both…

But with a Bahtinov mask there are a lot more slits and the slits are at different relative angles from each other… we might not know which slit a photon went through either, but can we narrow it down to say the photon went through a particular section of slits?

For example can we say the photons that made the central diffraction spike in the second picture went through the set of slits on the left hand side of the first picture?

https://en.wikipedia.org/wiki/Bahtinov_mask

 

[collinsmark]

But with a Bahtinov mask there are a lot more slits and the slits are at different relative angles from each other… we might not know which slit a photon went through either, but can we narrow it down to say the photon went through a particular section of slits?

For example can we say the photons that made the central diffraction spike in the second picture went through the set of slits on the left hand side of the first picture?

Not quite. I mean, not with certainty anyway.

If you were to cover (block) the right hand side of the Bahtinov mask (in the first picture), the central diffraction spike in the second picture would look almost the same. But it wouldn't look exactly the same. There would be subtle differences. If you were to trace the intensities along the central spike, it would look slightly different with and without the right side of the mask being covered.

Similarly, if you were to cover up the left side of the mask in the first picture, the 'X' diffraction spikes in the second picture wouldn't be exactly the same. Sure, those spikes would still have their 'X' shape, but there would still be some subtle differences in the intensities traced along any portion of the 'X' shape.

So since covering any particular side of the Bahtinov mask has at least a subtle effect on all three spikes, it doesn't really make any sense to say that a particular photon definitely went through one and only one side of the mask.

 

[bruha]

Hello, I attach two testing pictures of Sirius by camera eyepiece Bresser (SX1) and SV EBONY (S1).

Lot of succes.

 

[bruha]

An here three moon images -AG1 with Breesser and BG1,CG1 with SV Ebony eyepiece camera+Gimp little sharpening and denoising.

 

[Andy Resnick]

Rosette nebula (NGC2244):

1:1 crop:

Deets: 400mm f/4, 12 hrs @ 13s ISO64 frames. Stacking & post with APP.

 

[collinsmark]

Oh, man. I've been working on both the Leo Triplet and the Rosette Nebula over the last month or two. I was going to say it was a coincidence back when you posted the Leo Triplet photos, but now the Rosette pics?! and now I can't let it go. Nice work, btw. Images to come.

 

[Andy Resnick]

Another clear night, some more time on the Leo Triplet, now up to 3.25 hours integration time (800/8, 10s ISO 500 subs):

I'm now starting to be able to pull out rather dim objects, here's a 200% crop of a region near NGC 3628:

The 2 circled objects are IC 2725 (upper) and IC 2729 (lower). According to the NASA/IPAC Extragalactic Database, IC 2725 is a 14.8 magnitude object and IC 2729 is a magnitude 15.6 object (both visible waveband). Not bad for an urban location!

 

[timmdeeg]

Dear all, here are my first trials with new equipment. I took the chance after several weeks with cloudy nights.

My equipment

Sony A7III
Photoline 102 mm Dublet FPL53
Skywatchwer HEQ4
Photoline 3" 0,79x Reducer, focal length 570 mm
DeepSkyStacker, Siril, LightZone

Photos taken with SQM 21,2:

M81/82 with NGC2976/34/77 50x45", ISO1600
Horsehead Nebula 50x45" ISO1600
Rosette Nebula with star cluster NGC2244 50x30" (*) ISO4000
M38 with NGC1907 50x15" ISO20000 (mistake, not intended)
(*) not satisfying, cluster stars are blown up, not sure why (focus - stretching - ...)

 

[Andy Resnick]

Finished imaging the Orion Nebula (M42) for the year- 6 hours total integration time @ 800/8 (6s ISO 64 frames). NGC 1999 is visible near the bottom and the accompanying Herbig-Haro objects HH1/2 are just barely visible in the full-sized image.

One of the things I like about M42 is the 'painterly' quality to the nebula, here's a 1:1 crop-

As M42 moves out of my field of view, M51 is rising, so I expect (hope?) to get more imaging time during the next month... Here's M51, also 800/8, 3.8 hours (10s ISO 200 frames).

The color and sharpness are good, but the noise level is still high (1:1 crop):

 

[Drakkith]

As M42 moves out of my field of view, M51 is rising, so I expect (hope?) to get more imaging time during the next month...

I haven't gotten my equipment out in a long while, partly due to the awful skies here in Shreveport, partly due to a plethora of partially broken or malfunctioning equipment that I haven't been able to fix because I'm poor. (Or because Orion, for some reason, wasn't able to find the parts to replace the broken knobs on my mount's tripod legs)

So here's a pic of Thor's Helmet (NGC 2359) in hydrogen-alpha from an unfinished imaging session about a year ago. That I hope I haven't uploaded to this thread already.

 

[collinsmark]

Here's my recent capture of the Leo Triplet (also known as the M66 Group). (Captured from back patio, late February, early March 2022.)

The upper, center galaxy is NGC 3628, known as the Hamburger Galaxy. It's one of my favorite galaxies. I look forward to revisiting that one in the future with more focal length. Mmm. Hamburger.

To the lower left is M66 (also called NGC 3627) and to the lower right is M65 (also called NGC 3623).

Below is a different crop of the same data, and rotated about 90 deg.

Equipment:
Explore Scientific ED80-FCD100 piggybacked on an LX200-GPS mount on an equatorial wedge.
Orion Field Flattener for Short Refractors.
ZWO RGB filters.
Baader 3.5 nm Hα filter.
Optolong L-Pro filter.
ZWO ASI6200MM-Pro.

Software:
Nighttime Imaging 'N' Astronomy (N.I.N.A.)
Pixinsight
Topaz Labs Sharpen AI

Integration:
Bortle class 7 skies (maybe 8)
R: 84x180s = 4.2 hours
G: 66x180s = 3.3 hours
B: 95x180s = 4.75 hours
L-Pro: 197x180s = 9.85 hours
Hα: 29x600s = 4.83 hours
Total integration time: 26.93 hours

 

[DennisN]

Dear all, here are my first trials with new equipment. I took the chance after several weeks with cloudy nights.

Congratulations, very nice!