All Forum Comments
Comment by JForeigner posted on Aurora at 15/05/2024 - 09:14
Spad wrote:
JForiegner and myself have been conflabbing about a problem with using camera lenses for DSO photography. Because of the iris blades, which cause stars to throw off a wierd sprayed out refraction pattern.
Example - Look at the star below the Nebula.
To get rid of this, you can run the lens wide open. Unfortunately depending on the lens used, this can lead to CA being quite bad. The longer the exposure, the worse it will get.
This lead me to go gawking at Astrophotography forums. This lead to an answer, which lead to me creating this contraption...
It connsists of - step down rings from 86mm to 62mm. On top of that is a Cokin medium filter mount, with a Cokin ClearSky LPF. Then its all mounted on my Sigma 150-500mm, which in turn is stuffed on my K5ii. I have also stuffed on 3 Cokin lens hoods.
This lot will them be mounted on a tracked, and guided EQ mount.
The main bit of kit here is te step down rings. The reduction from 86mm to 62mm will reduce the aperture down to abuot f8 while leaving the actual lens aperture wide open. According to all the info I consumed, it "should" get rid of the distortion caused by the iris blades.
For those interested, and if I read it all correctly... to get the desired aperture you use this formula:
Lens focal length divided by the require aperture.
You then use the step down the rings to get close to that figure. So I am goin to use 500mm and want f8. So this gives me 62.5mm. Hence the step down to 62mm.
Images will be shot tonight, and results posted when I have processed them!!
Thank yiu for you attention, and you can now all bugger of so I can start fannying !!
Small steps forward to improve your final product.JForiegner and myself have been conflabbing about a problem with using camera lenses for DSO photography. Because of the iris blades, which cause stars to throw off a wierd sprayed out refraction pattern.
Example - Look at the star below the Nebula.
To get rid of this, you can run the lens wide open. Unfortunately depending on the lens used, this can lead to CA being quite bad. The longer the exposure, the worse it will get.
This lead me to go gawking at Astrophotography forums. This lead to an answer, which lead to me creating this contraption...
It connsists of - step down rings from 86mm to 62mm. On top of that is a Cokin medium filter mount, with a Cokin ClearSky LPF. Then its all mounted on my Sigma 150-500mm, which in turn is stuffed on my K5ii. I have also stuffed on 3 Cokin lens hoods.
This lot will them be mounted on a tracked, and guided EQ mount.
The main bit of kit here is te step down rings. The reduction from 86mm to 62mm will reduce the aperture down to abuot f8 while leaving the actual lens aperture wide open. According to all the info I consumed, it "should" get rid of the distortion caused by the iris blades.
For those interested, and if I read it all correctly... to get the desired aperture you use this formula:
Lens focal length divided by the require aperture.
You then use the step down the rings to get close to that figure. So I am goin to use 500mm and want f8. So this gives me 62.5mm. Hence the step down to 62mm.
Images will be shot tonight, and results posted when I have processed them!!
Thank yiu for you attention, and you can now all bugger of so I can start fannying !!
I have this problem with my images as well. I am going to approach this problem in a slightly different way. A large fat bloke dressed in red left me a 3d printer under the tree. My way of producing an aperture mask will be to print a donut shaped item that will either fit snug or be able to be threaded into the front of the lens.
[quote:3496ace15f="Lubbyman"]Aren't you in good company? Doesn't the JWST produce spikey stars due to its hexagonal mirrors, spikes have to be removed in post-processing?
Steve
By all means if someone wishes to correct me, please do. But my understanding of the hubble/jwst spikes is that they are caused by the veins in front of the mirror. It is an artifact of the design of these sorts of telescopes.
Gary
Comment by JForeigner posted on An Experimental Contraption at 18/01/2024 - 07:24
Thank you for the warm comments.
I will add to this thread. Sadly, this is not a type of photography where you can't rattle off a load of images in one session.
Just to add one more thing. With this image, I used the Pentax 645 600mm f5.6.
Gary
I will add to this thread. Sadly, this is not a type of photography where you can't rattle off a load of images in one session.
Urbanmeister wrote:
But yes, the final image looks good, but there is room to improve. If I can make forward progress with my data collection, I have more than happy to share and explain what I am doing.LennyBloke wrote:
Great to some some more top quality Astro images, this one is stunning - keep 'em coming Gary
Absolutely! Fantastic images. Btw, 'room for improvement' comment, ahem, why? It looks great to me.Great to some some more top quality Astro images, this one is stunning - keep 'em coming Gary
Just to add one more thing. With this image, I used the Pentax 645 600mm f5.6.
Gary
Comment by JForeigner posted on 645 Astro at 12/12/2023 - 06:17
Inspired by Spad's efforts I will start to post some of my images.
I too dabble in astrophotography. I shoot with a Canon camera for now, but at some point that will be changing. But I use some Pentax 645 glass. Namely a 300mm f4, the manual version, and a 600mm f5.6. The 300mm has no tripod foot which creates a problem, but it is a problem that has been overcome with the help of a 3d printer.
My workflow is along the same lines as Spad's, but slightly different. I used an equatorial mount that is controlled by a laptop, I collect my data, and I have a friend process it for me in PI. At the moment, I am focusing my efforts on improving the raw data that I collect before I go down the rabbit hole of processing this data. I am based in NZ, so my images may appear upside compared to how you are normally used to seeing them, I kid you not. I don't use a telescope, just camera lenses.
But I will post images as I get the chance. Life, work, the moon, and clouds all hinder this.
But here is my first image. The Horsehead and Flame nebula. As you will see, it has room for improvement, and we will get there. It is a bit of try something, and see how it works, or not.
Gary
I too dabble in astrophotography. I shoot with a Canon camera for now, but at some point that will be changing. But I use some Pentax 645 glass. Namely a 300mm f4, the manual version, and a 600mm f5.6. The 300mm has no tripod foot which creates a problem, but it is a problem that has been overcome with the help of a 3d printer.
My workflow is along the same lines as Spad's, but slightly different. I used an equatorial mount that is controlled by a laptop, I collect my data, and I have a friend process it for me in PI. At the moment, I am focusing my efforts on improving the raw data that I collect before I go down the rabbit hole of processing this data. I am based in NZ, so my images may appear upside compared to how you are normally used to seeing them, I kid you not. I don't use a telescope, just camera lenses.
But I will post images as I get the chance. Life, work, the moon, and clouds all hinder this.
But here is my first image. The Horsehead and Flame nebula. As you will see, it has room for improvement, and we will get there. It is a bit of try something, and see how it works, or not.
Gary
Comment by JForeigner posted on 645 Astro at 10/12/2023 - 01:04
Ian,
Very impressive images. Well done. I like your Andromeda image the most. But I too have been out shooting Orion as well as it is that time of the year.
Like you, I shoot astro with a Canon, but I use some of my Pentax 645 glass as well with using an adaptor.
I am more than happy to post some images tacked onto this thread if you are happy with that.
Gary
Very impressive images. Well done. I like your Andromeda image the most. But I too have been out shooting Orion as well as it is that time of the year.
Like you, I shoot astro with a Canon, but I use some of my Pentax 645 glass as well with using an adaptor.
I am more than happy to post some images tacked onto this thread if you are happy with that.
Gary
Comment by JForeigner posted on Past week of Astro at 09/12/2023 - 03:54
I do like these landscape and Milky Way type of images. Do I like it? I think that the idea is there, and you are heading in the right direction. Can it be improved? I am sure it can be. The sign on the tree could be cloned out. It depends on how fussy you are, or what you're aiming to trying to achieve as a final image. The star colours are a little off, but overall, a good effort. I know it is not easy.
Is this a single image? What gear did you use and what were your settings?
Gary
Is this a single image? What gear did you use and what were your settings?
Gary
Comment by JForeigner posted on Cannot Decide..... at 11/07/2023 - 07:45
A great result and well done.
It is easy to get addicted once you start to produce images like this.
If you haven't already, download something like Stellarium, it's free. You can then use the ASCOM software that runs with PHD, and you then tell the mount what object you want to point at, and off it goes.
Gary
It is easy to get addicted once you start to produce images like this.
If you haven't already, download something like Stellarium, it's free. You can then use the ASCOM software that runs with PHD, and you then tell the mount what object you want to point at, and off it goes.
Gary
Comment by JForeigner posted on The first of many... at 26/05/2023 - 08:03
For a change, we actually had clear skies. The first time that I have ever tried to photograph one.
K3 and a Sigma 18-35mm art.
Gary
K3 and a Sigma 18-35mm art.
Gary
Comment by JForeigner posted on Aurora Australis at 28/04/2023 - 09:36
Are you using a wired cable release to trip the shutter, so not physically touching the camera.
I am not sure that the using the crop factor is going to do anything, but I am opening to learning something new. It looks as if you getting two images on the same image. Everything sounds normal, that is the shutter only opens and closes once by listening to the camera?
What happens if you use a different shutter speed? Shorter, or longer? Move away from the house if possible. Maybe your gps unit can't lock onto enough satellites in different directions. Try in a more open area.
Let us know how you get on.
Gary
I am not sure that the using the crop factor is going to do anything, but I am opening to learning something new. It looks as if you getting two images on the same image. Everything sounds normal, that is the shutter only opens and closes once by listening to the camera?
What happens if you use a different shutter speed? Shorter, or longer? Move away from the house if possible. Maybe your gps unit can't lock onto enough satellites in different directions. Try in a more open area.
Let us know how you get on.
Gary
Comment by JForeigner posted on K-3 II Astrotracer Weirdness at 28/03/2023 - 08:17
brenski wrote:
hi, yes, correctly calibrated. no, didn;t bump/catch the tripod (catching/bumping the tripod would result in a "line" between each "double-star"?
this is almost as if it captured the whole image twice - it's like a double-exposure?
It has been a while since I used my astro tracer. hi, yes, correctly calibrated. no, didn;t bump/catch the tripod (catching/bumping the tripod would result in a "line" between each "double-star"?
this is almost as if it captured the whole image twice - it's like a double-exposure?
But how sturdy is your tripod, and tripod head? If you have a tv aerial in the image, you are shooting at a lowish angle. By any chance, did you shoot anything nearer the zenith? And if so, did you have the same problem?
Gary
Comment by JForeigner posted on K-3 II Astrotracer Weirdness at 28/03/2023 - 07:35
The first image is looking towards Christchurch, and I like it as I have captured the Milky Way in the image as well.
The next two are looking south over our local town.
and
The last two are looking east, and I do like the colours of these.
and
These images were taken with a K3 and a Sigma 18-35mm f1.8. Off the top of my head, I think that the exposures were at 6 seconds, and at f2.2.
Gary