K-3 astrophotography first session

Unregistered User · 07-11-2015, 02:03 PM

Originally posted by ZeGaby

Some pics from my last session :

Look !

Starry Car

Impressive. I would love to shoot stars in the summer but the sun never sets fully here in the north...

JimmyDranox · 07-11-2015, 04:18 PM

The second picture is very, very good. No movement, no traces of coma anywhere (what lens is this, 18mm f1.8?), a very clear Andromeda, and the Milky Way, ... Superb!!

ZeGaby · 07-12-2015, 10:39 AM - **2 Likes**

Thanks for your comments !

Originally posted by Tjompen1968

Impressive. I would love to shoot stars in the summer but the sun never sets fully here in the north...

But you've got some aurora borealis

Originally posted by JimmyDranox

The second picture is very, very good. No movement, no traces of coma anywhere (what lens is this, 18mm f1.8?), a very clear Andromeda, and the Milky Way, ... Superb!!

It's the Sigma 18-35mm f/1.8 Art (i love this lense ! )

I've try a new way to enhance Milky Way on my two last pictures :

Look ! V2

Starry Car V2

And a new picture from my session

The blue Hour

Just before the night....
you can see when the stars appear (the smooth is natural, it's not an effect)

JimmyDranox · 07-12-2015, 06:00 PM

Very nice this Blue hour. And I like the name too.

About V1 vs V2, I like V1 more.

About ''Look''. It is something interesting in that picture. You have an aircraft at the left, and a satellite, at extreme left, just around the edge. Up, you have three satellites, with long and thin traces, and a very slow moving target. Much to slow to be satellite or aircraft, especially that is quite high in the sky, maybe 40-50 degrees. Ovni? Also, a slow target at the right, at a low angle. Again, a good choice of name for this picture.

ZeGaby · 07-14-2015, 12:58 AM - **1 Like**

Originally posted by JimmyDranox

Very nice this Blue hour. And I like the name too.

About V1 vs V2, I like V1 more.

About ''Look''. It is something interesting in that picture. You have an aircraft at the left, and a satellite, at extreme left, just around the edge. Up, you have three satellites, with long and thin traces, and a very slow moving target. Much to slow to be satellite or aircraft, especially that is quite high in the sky, maybe 40-50 degrees. Ovni? Also, a slow target at the right, at a low angle. Again, a good choice of name for this picture.

Thanks

Milky Way
I use the O-GPS1 module, Sigma 18-35mm @ 18mm f/2.0 Iso800 60sec

mikeSF · 07-14-2015, 08:51 AM

great work, ZeGaby!

ZeGaby · 08-09-2015, 04:29 AM - **2 Likes**

New pictures made with the Sigma 18-35mm f/1.8 and the O-GPS1 module

Sending from Andromeda

Iso 1600

Up above Moivre

Iso 800

ZeGaby · 08-11-2015, 12:40 PM

Up above - Panorama

A new version of "Up above Moivre" ! Made of 3 pictures, stich with AutoPano.
Made with OGPS-1 50s with the Sigma 18-35mm @ 18mm f/2.0 iso800

**Weevil** · 08-11-2015, 09:06 PM

I'd have a question for you astrophotos litterates:
in this link, they promote the usage of a SMC Pentax K 135mm f2.5 for astro photo, as one of the best lens...

The Best Telephoto Lenses for Astrophotography - Articles - Articles - Articles - Cloudy Nights

However, when they mention: "When the aperture is stopped down to 37mm using step-down filter rings, this lens produces incredibly tiny pinpoint star images from edge to edge."

I don't understand why they refer aperture in mm ???

Is this a typo or Am I missing something ?

Thanks in advance

**Pete_XL** · 08-11-2015, 11:02 PM

Originally posted by Weevil

I'd have a question for you astrophotos litterates:
in this link, they promote the usage of a SMC Pentax K 135mm f2.5 for astro photo, as one of the best lens...

The Best Telephoto Lenses for Astrophotography - Articles - Articles - Articles - Cloudy Nights

However, when they mention: "When the aperture is stopped down to 37mm using step-down filter rings, this lens produces incredibly tiny pinpoint star images from edge to edge."

I don't understand why they refer aperture in mm ???

Is this a typo or Am I missing something ?

Thanks in advance

I remember having read in some forum that it was commendable to stop down lenses at the front end using step-down filter rings instead of using the diaphragm of the lens. It said that keeping the rear aperture wide open and reducing diameter at the front end avoids/reduces diffraction patterns occurring at bright stars. Have not tried it.

JimmyDranox · 08-12-2015, 12:24 AM

Originally posted by Weevil

I'd have a question for you astrophotos litterates:
in this link, they promote the usage of a SMC Pentax K 135mm f2.5 for astro photo, as one of the best lens...

The Best Telephoto Lenses for Astrophotography - Articles - Articles - Articles - Cloudy Nights

However, when they mention: "When the aperture is stopped down to 37mm using step-down filter rings, this lens produces incredibly tiny pinpoint star images from edge to edge."

I don't understand why they refer aperture in mm ???

Is this a typo or Am I missing something ?

Thanks in advance

Because in astronomy 'aperture' means the diameter of the frontal element of the lens or telescope.

Quirky · 08-12-2015, 05:13 AM

My math: 135mm / 37mm = f/3.6 where f is the focal length. So they are using step down rings to build a funnel that is screwed onto the front of the lens with a 37mm diameter opening to get the desired aperture? I guess this prevents using light from the edges of the lens; sort of a light tunnel passing through the center of the elements.

I'm new to astrophotography (My K-3II is being delivered today!!), so I'm trying to summarize what I understood from this thread. Thanks,

Lee

**TedH42** · 08-12-2015, 11:57 AM

Originally posted by Quirky

My math: 135mm / 37mm = f/3.6 where f is the focal length. So they are using step down rings to build a funnel that is screwed onto the front of the lens with a 37mm diameter opening to get the desired aperture? I guess this prevents using light from the edges of the lens; sort of a light tunnel passing through the center of the elements.

I'm new to astrophotography (My K-3II is being delivered today!!), so I'm trying to summarize what I understood from this thread. Thanks,

Lee

This is correct, but not the full answer.

The step-down rings (having a completely round hole) PRIMARILY avoid the diffraction spikes that the regular diaphragm (non-round blades) would cause for imaging stars. These spikes are rarely visible for daytime photographs, but are quite prominent on brighter stars, which are pinpoints of light on a totally black background. Think of the "starbursts" so desired on the SMC (vs HD) DA 15mm ltd for nighttime and sunrise/sunset shots.

loco · 08-12-2015, 12:39 PM

Quick question .... I'm hoping to set my K-3 out tonight with the Rokinon 14 or maybe Samyang 8mm fisheye and try to get some Perseid shots. I thought maybe I'd set the interval shooting and let it go for as long as the battery lasts or the card fills up. But then I got to thinking ... what about dew?

If I put a couple handwarmers around the lens, will that keep dew off? And in your experience, will there be enough dew to damage the camera -- since neither of those lenses is weather sealed??

Thanks!

Nitrogliserin · 08-12-2015, 01:48 PM - **1 Like**

Originally posted by loco

Quick question .... I'm hoping to set my K-3 out tonight with the Rokinon 14 or maybe Samyang 8mm fisheye and try to get some Perseid shots. I thought maybe I'd set the interval shooting and let it go for as long as the battery lasts or the card fills up. But then I got to thinking ... what about dew?

If I put a couple handwarmers around the lens, will that keep dew off? And in your experience, will there be enough dew to damage the camera -- since neither of those lenses is weather sealed??

Thanks!

Dew won't damage your camera since the lens is attached but the visibility could affacted by water drops on the lens.

This article may also help you.

Dew Heaters for Night Sky Photography | Phil Hart

08-12-2015, 05:13 AM	#87
Quirky Forum Member Join Date: Feb 2013 Location: Hayes, Virginia Photos: Gallery \| Albums Posts: 96	My Understanding My math: 135mm / 37mm = f/3.6 where f is the focal length. So they are using step down rings to build a funnel that is screwed onto the front of the lens with a 37mm diameter opening to get the desired aperture? I guess this prevents using light from the edges of the lens; sort of a light tunnel passing through the center of the elements. I'm new to astrophotography (My K-3II is being delivered today!!), so I'm trying to summarize what I understood from this thread. Thanks, Lee

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07-11-2015, 02:03 PM	#76
Unregistered User Guest	Originally posted by ZeGaby Some pics from my last session : Look ! Starry Car Impressive. I would love to shoot stars in the summer but the sun never sets fully here in the north...

07-11-2015, 04:18 PM	#77
JimmyDranox Veteran Member Join Date: Oct 2012 Location: Ploiesti, Romania Photos: Gallery \| Albums Posts: 1,632	The second picture is very, very good. No movement, no traces of coma anywhere (what lens is this, 18mm f1.8?), a very clear Andromeda, and the Milky Way, ... Superb!!

07-12-2015, 10:39 AM - 2 Likes	#78
ZeGaby Pentaxian Join Date: Jul 2014 Photos: Gallery Posts: 308	Thanks for your comments ! Originally posted by Tjompen1968 Impressive. I would love to shoot stars in the summer but the sun never sets fully here in the north... But you've got some aurora borealis Originally posted by JimmyDranox The second picture is very, very good. No movement, no traces of coma anywhere (what lens is this, 18mm f1.8?), a very clear Andromeda, and the Milky Way, ... Superb!! It's the Sigma 18-35mm f/1.8 Art (i love this lense ! ) I've try a new way to enhance Milky Way on my two last pictures : Look ! V2 Starry Car V2 And a new picture from my session The blue Hour Just before the night.... you can see when the stars appear (the smooth is natural, it's not an effect)

07-12-2015, 06:00 PM	#79
JimmyDranox Veteran Member Join Date: Oct 2012 Location: Ploiesti, Romania Photos: Gallery \| Albums Posts: 1,632	Very nice this Blue hour. And I like the name too. About V1 vs V2, I like V1 more. About ''Look''. It is something interesting in that picture. You have an aircraft at the left, and a satellite, at extreme left, just around the edge. Up, you have three satellites, with long and thin traces, and a very slow moving target. Much to slow to be satellite or aircraft, especially that is quite high in the sky, maybe 40-50 degrees. Ovni? Also, a slow target at the right, at a low angle. Again, a good choice of name for this picture.

07-14-2015, 12:58 AM - 1 Like	#80
ZeGaby Pentaxian Join Date: Jul 2014 Photos: Gallery Posts: 308	Originally posted by JimmyDranox Very nice this Blue hour. And I like the name too. About V1 vs V2, I like V1 more. About ''Look''. It is something interesting in that picture. You have an aircraft at the left, and a satellite, at extreme left, just around the edge. Up, you have three satellites, with long and thin traces, and a very slow moving target. Much to slow to be satellite or aircraft, especially that is quite high in the sky, maybe 40-50 degrees. Ovni? Also, a slow target at the right, at a low angle. Again, a good choice of name for this picture. Thanks Milky Way I use the O-GPS1 module, Sigma 18-35mm @ 18mm f/2.0 Iso800 60sec

07-14-2015, 08:51 AM	#81
mikeSF Pentaxian Join Date: Jan 2009 Location: East Bay Area, CA Photos: Gallery Posts: 6,620	great work, ZeGaby!

08-09-2015, 04:29 AM - 2 Likes	#82
ZeGaby Pentaxian Join Date: Jul 2014 Photos: Gallery Posts: 308	New pictures made with the Sigma 18-35mm f/1.8 and the O-GPS1 module Sending from Andromeda Iso 1600 Up above Moivre Iso 800

08-11-2015, 12:40 PM	#83
ZeGaby Pentaxian Join Date: Jul 2014 Photos: Gallery Posts: 308	Up above - Panorama A new version of "Up above Moivre" ! Made of 3 pictures, stich with AutoPano. Made with OGPS-1 50s with the Sigma 18-35mm @ 18mm f/2.0 iso800

08-11-2015, 09:06 PM	#84
Weevil Site Supporter Join Date: May 2012 Location: Near Montréal, Québec Photos: Gallery Posts: 4,445	I'd have a question for you astrophotos litterates: in this link, they promote the usage of a SMC Pentax K 135mm f2.5 for astro photo, as one of the best lens... The Best Telephoto Lenses for Astrophotography - Articles - Articles - Articles - Cloudy Nights However, when they mention: "When the aperture is stopped down to 37mm using step-down filter rings, this lens produces incredibly tiny pinpoint star images from edge to edge." I don't understand why they refer aperture in mm ??? Is this a typo or Am I missing something ? Thanks in advance

08-11-2015, 11:02 PM	#85
Pete_XL Site Supporter Join Date: Mar 2010 Location: Germany Photos: Gallery Posts: 335	Originally posted by Weevil I'd have a question for you astrophotos litterates: in this link, they promote the usage of a SMC Pentax K 135mm f2.5 for astro photo, as one of the best lens... The Best Telephoto Lenses for Astrophotography - Articles - Articles - Articles - Cloudy Nights However, when they mention: "When the aperture is stopped down to 37mm using step-down filter rings, this lens produces incredibly tiny pinpoint star images from edge to edge." I don't understand why they refer aperture in mm ??? Is this a typo or Am I missing something ? Thanks in advance I remember having read in some forum that it was commendable to stop down lenses at the front end using step-down filter rings instead of using the diaphragm of the lens. It said that keeping the rear aperture wide open and reducing diameter at the front end avoids/reduces diffraction patterns occurring at bright stars. Have not tried it.

08-12-2015, 12:24 AM	#86
JimmyDranox Veteran Member Join Date: Oct 2012 Location: Ploiesti, Romania Photos: Gallery \| Albums Posts: 1,632	Originally posted by Weevil I'd have a question for you astrophotos litterates: in this link, they promote the usage of a SMC Pentax K 135mm f2.5 for astro photo, as one of the best lens... The Best Telephoto Lenses for Astrophotography - Articles - Articles - Articles - Cloudy Nights However, when they mention: "When the aperture is stopped down to 37mm using step-down filter rings, this lens produces incredibly tiny pinpoint star images from edge to edge." I don't understand why they refer aperture in mm ??? Is this a typo or Am I missing something ? Thanks in advance Because in astronomy 'aperture' means the diameter of the frontal element of the lens or telescope.

08-12-2015, 11:57 AM	#88
TedH42 F/8 & Somewhere Join Date: Dec 2011 Location: Colorado Photos: Gallery Posts: 1,412	Originally posted by Quirky My math: 135mm / 37mm = f/3.6 where f is the focal length. So they are using step down rings to build a funnel that is screwed onto the front of the lens with a 37mm diameter opening to get the desired aperture? I guess this prevents using light from the edges of the lens; sort of a light tunnel passing through the center of the elements. I'm new to astrophotography (My K-3II is being delivered today!!), so I'm trying to summarize what I understood from this thread. Thanks, Lee This is correct, but not the full answer. The step-down rings (having a completely round hole) PRIMARILY avoid the diffraction spikes that the regular diaphragm (non-round blades) would cause for imaging stars. These spikes are rarely visible for daytime photographs, but are quite prominent on brighter stars, which are pinpoints of light on a totally black background. Think of the "starbursts" so desired on the SMC (vs HD) DA 15mm ltd for nighttime and sunrise/sunset shots.

08-12-2015, 12:39 PM	#89
loco Veteran Member Join Date: Mar 2011 Location: Virginia Photos: Gallery \| Albums Posts: 2,846	Quick question .... I'm hoping to set my K-3 out tonight with the Rokinon 14 or maybe Samyang 8mm fisheye and try to get some Perseid shots. I thought maybe I'd set the interval shooting and let it go for as long as the battery lasts or the card fills up. But then I got to thinking ... what about dew? If I put a couple handwarmers around the lens, will that keep dew off? And in your experience, will there be enough dew to damage the camera -- since neither of those lenses is weather sealed?? Thanks!

08-12-2015, 01:48 PM - 1 Like	#90
Nitrogliserin Senior Member Join Date: Apr 2013 Location: Turkey Posts: 246	Originally posted by loco Quick question .... I'm hoping to set my K-3 out tonight with the Rokinon 14 or maybe Samyang 8mm fisheye and try to get some Perseid shots. I thought maybe I'd set the interval shooting and let it go for as long as the battery lasts or the card fills up. But then I got to thinking ... what about dew? If I put a couple handwarmers around the lens, will that keep dew off? And in your experience, will there be enough dew to damage the camera -- since neither of those lenses is weather sealed?? Thanks! Dew won't damage your camera since the lens is attached but the visibility could affacted by water drops on the lens. This article may also help you. Dew Heaters for Night Sky Photography \| Phil Hart