Ed, I like you video and you had great information from a high altitude. I been working on my astrophotography skills for several years now. It does take time and patience. I learn a lot of good information from your video and please keep them coming. Thanks again!
Rule of 500: I disagree with your claim that a cropped sensor behaves differently than a full-frame sensor. Here’s why: Using a non-tracking camera: Consider the _rate_ (in, say, arc-seconds per unit time) that a stellar image sweeps across the sensor. This rate determines how long the exposure may be without star trails being visible. This rate of stellar image drift across a non-tracking sensor is determined solely by the lens’s focal length. Reductio ad absurdum thought experiment: Let’s say: (1.) we have a 300mm lens on a film camera with 8”x10” film (200mm x 300mm). I think we can agree that our exposure is limited to 500/300 = 1-2/3 seconds (≈1.7 s.). (2.) Let’s say we have a microfilm spy camera with a 300mm lens. And the frame size is 2x3mm. In example 2, crop factor is 100. Will we be limited to 0.017 s. exposures without star trails? No. The stellar image in an undriven camera will sweep across the film or sensor at the same rate in _any_ camera with a 300mm lens. Concluding: the pixel density on the sensor may affect whether star trails are visible. (a) Coarse pixel density: less likely to see star trails in a given exposure time. (b) Fine pixel density: star trails are more likely to be visible after that same exposure time.
Hi Ed, this is off subject but I need your opinion. If u don't mind, of course. I'm looking to add an 8 inch newtonian to my collection and have narrowed it down to between a meade or the apertura. They look similar to me, but the meade is $100 more. The only difference I can find is that the meade is 1 pound lighter. Visual use.
Good video as always, though from my experience I'd recommend people to research the NPF rule for better results than the 500 rule. Modern DSLRs and mirrorless cameras have much higher resolution and the star trailing remains apparent if you use the 500 rule. Replacing the 500 divided by focal length variable with a value of 200 or 300 is also a good alternative.
Good point. I sometimes recommend the "Rule of 400" to be safe. If you think about, the reality should be the "Rule of Zero". The sky is always moving.
An off topic question. There is something I don’t understand about refractors and DSO. If I use for visual observations for example a 150/750 mm F5 achromat and a 150/1200 F8 FPL53 APO, I understand that with the APO the Moon and planets will look 10x better and sharper but how about galaxies ? Will the galaxies look better in a high-quality APO than in a same-aperture short F5 achromat ? (For visual observations only, not astrophotography). Also is the contrast on galaxies better in the APO than in the same size achromat ? Thank you!
With an achromat you not able to correct the abberation over the whole spektrum. As with an good Apochromat these errors on "both ends" of the spectrum are reduced further. So this is why you have these red and blue edges opposide each other with an achro but, at least much less, with an APO. These errors are apparent at high contrast edges the most. Like on stars you can see them very easy. Its maybe even hard to not see it :)) As you are also always have stars in every picture you take from a nebula, galaxy or supernova remnant you will see it there. But the effect doesnt only apply to pointy lights and magicly dissapear on galaxies. It is also there. You just can not see it easily but you dont get the image really sharp because you can only focus on a part of the spectrum, ie. red. Thus the other end, ie. blue, gets blurry and this lower the resolution over all ;)
Try the Orion Observer 134 (review somewhere on this channel). It isn't perfect but it's my new favorite choice in the ultra-budget category. If you want a more permanent scope, get a 6" or 8" Dob.
Mirrors have no false color, so if that's your criteria, get yourself a Newtonian. If it's a refractor you want, you have to define "no chromatic aberration." Do you want the false color to be below what's commonly accepted to be perceptible by most people? And do you want that in both the visual and photographic regions? If yes to the latter, be prepared to pay...
@@edting So, basically, If I don't want to see any aberration (chromatic, spherical etc.) or other image "imperfections", I have to spend quite a lot as it seems. Fine. I'll just stick with something that isn't too costly... ...with some imperfections. So, what telescope would you suggest with the following criteria: 0-700$; easy to setup, maintain and transport; able to see the moon as clearly as possible... ...Or, would binoculars be good enough?
Not to forget the Freeware "Siril" for stacking... Very, very powerfull and now in Ver.1.2.3 nearly an all-in-one solution for beginner, with the prewritten scripts also very easy to use. Giving them a nice result with close to no need for learning to stack, at least... Find the results better as what I got/get with DSS. Stretching and Postprocessing is another story, though :D Thanks Ed for this leading guide to new hobby-astronomes ;)
Correcting the white balance of a modified camera in post-processing is pretty simple and fast. Any decent processing software can do it (Photoshop, etc.). It's still a bit of pain in that you can't get usable pictures right out of the camera, but since any "keeper" image is going to have some post-processing, throwing in a white balance adjustment is simple.
this was well over my head, but i gained an appreciaton for the work involved- And most important of all i learned not to sleep in the desert because i do not want snakes as my bed buddies!
Interesting. I've never been able to get that to work. Are there different filters for the different kinds of mods? In my experience the balance never quite gets back to the camera's original color science. There's always one color that's a little bit off (not surprisingly, it's usually red).
@@edting Probably something to experiment with, basically, you need match the transmission profile of the removed internal filter with whatever you're attaching to the lens, and while if you have a NIR spectrometer you could just measure it, it's unlikely the manufacturer will just have one publicly available. Since cameras are using silicon sensors, they can only be sensitive to around 1050 nm or so (at best, if best is lots of IR response), so wavelengths longer than that don't really matter in your chosen filter, and really, if you can get rid of about 700-950 nm, you probably remove the vast majority of what a normal sensor can see. As with using a warming filter or another with your camera that blocks some portion of the incoming light, it will need to be rebalanced, it's just that the camera's calibration settings already compensated for the internal one. Any sort of IR blocking filter on the lens should block a good portion of the IR getting to the sensor, which then makes it easier to find that correct looking balance point with internal camera settings or with rebalancing in software, and IR blocking filters (or short pass filters) are pretty well understood and available, so you should have a number of good options with only minimal blocking of any visible light. There's a second reason to have an IR blocking filter for regular photography and that's actually chromatic aberration. Basically, most lenses are corrected for low dispersion in the optical band, but IR at longer wavelengths needs additional corrections to end up in exactly the right place on the sensor, so if you leave the IR cut off and just rebalance for normal optical work, you get more chromatic aberration in your image (the color of which depends on the IR transparency of each Bayer filter mask on the sensor it's got, which actually can be white if all three color filters are transparent to IR.)
Great video, Ed! Quick question: Is 42mm a large enough aperture for binocular observation? I'm getting binos for my young son and I, and I'm afraid a larger pair will be too heavy and not fit his face comfortably.
I have Vortex Viper 8x42, they are great (with lifetime warranty). Don't take binoculars with magnification more than 8 if you will look at the sky holding them in hand. View will become very unstable. Every move of your body will be magnified by the magnification number. 7x or 8x magnification maximum for doing this holding binoculars in hand is sweet spot. Anything bigger and you will need a tripod enjoy watching a sky.
@@edting I believe @marcinmorun meant their 70mm model, which is not blue or plastic. Unrelated, I have already ordered the blue plastic model for 65 dollars, it's in the mail.
If you're going to make a bunch of exposures for stacking, can you leave the camera stationary and use the stacking software to align the images to correct for Earth's rotation?
On paper, yes. In practice, the stacking software may have trouble "keeping up" and you may wind up with nothing. Even if it works, you are going to have to start cropping as stuff moves off the edge of the frame. And here's another dirty little secret - the tracking mount you bought (and may have paid a lot of money for) isn't perfect. Periodic error can creep in. Astrophotography is exacting and difficult - you want to minimize any chance of errors creeping in. Sometimes I wonder why I do it myself!
It depends on how long you're shooting. Stacking obviously can't help if the object moves out of frame, but in my short experience that's the only real limitation. I'm kinda new to stacking and Deep Sky Stacker (the freeware Ed mentioned), but I've never had a problem doing just that - lock the tripod and let the camera click away. Always follow the rule of 500 (another youtuber said best to make it 400, so I do, and it's helped). You can adjust the sensitivity in DSS to track and register the stars better. I think it works really well, though like I said, I'm still kinda new. Still, I've never had a problem with DSS not registering everything correctly. You can also set it to stack only your best images (best 80%, best 15%, whatever), which can really improve your final picture - if you start with a lot of images. I've been starting with about 50 images and having it stack my best 60-80%. One thing though - turn of your camera's image stabilization! That makes all the stars appear a bit off, and it doesn't give DSS the really sharp images it needs to stack only the best. From one beginner to another, good luck!
Sounds awesome! Can you give any direction what to warch out for? How to repurpose a commercial model for use with a telescope? Thanks!! @@astralfields1696
I challenged myself to do just that with my new Sony Alpha-6100 + 2 kit lenses that I bought for the eclipse in April, and I've been really surprised at what it can do! A happy surprise I got with my really cheap kit zoom lens (215 mm) came when I caught the M92 star cluster in Hercules (not M13). The chromatic aberration made it look cool and all colorful! It's fake color from a cheap lens, but it made me smile! I'm enjoying the challenge, in dark rural skies and also deep in the city where I live. Ed has cautioned against people going from looking at the stars through their telescopes to astrophotography too quickly, but I'm kinda going the other way. I only have a camera, and no telescope. I'm starting with the astrophotography. 🙂 And I appreciate all of Ed's tips.
Can you try astrophysicist 254mm F14.5 Maksutov-Cassegrain with c11 sct please ❤
Ed, I like you video and you had great information from a high altitude. I been working on my astrophotography skills for several years now. It does take time and patience. I learn a lot of good information from your video and please keep them coming. Thanks again!
Modern telescopes make the hobby somewhat affordable!
I'm hoping this is at least a 10 part course. I have a lot to learn. Thanks Ed.
The video ive been waiting for. Thanks ED!
Rule of 500: I disagree with your claim that a cropped sensor behaves differently than a full-frame sensor. Here’s why:
Using a non-tracking camera: Consider the _rate_ (in, say, arc-seconds per unit time) that a stellar image sweeps across the sensor. This rate determines how long the exposure may be without star trails being visible.
This rate of stellar image drift across a non-tracking sensor is determined solely by the lens’s focal length.
Reductio ad absurdum thought experiment:
Let’s say:
(1.) we have a 300mm lens on a film camera with 8”x10” film (200mm x 300mm). I think we can agree that our exposure is limited to 500/300 = 1-2/3 seconds (≈1.7 s.).
(2.) Let’s say we have a microfilm spy camera with a 300mm lens. And the frame size is 2x3mm.
In example 2, crop factor is 100. Will we be limited to 0.017 s. exposures without star trails?
No. The stellar image in an undriven camera will sweep across the film or sensor at the same rate in _any_ camera with a 300mm lens.
Concluding: the pixel density on the sensor may affect whether star trails are visible.
(a) Coarse pixel density: less likely to see star trails in a given exposure time.
(b) Fine pixel density: star trails are more likely to be visible after that same exposure time.
Hi Ed, this is off subject but I need your opinion. If u don't mind, of course. I'm looking to add an 8 inch newtonian to my collection and have narrowed it down to between a meade or the apertura. They look similar to me, but the meade is $100 more. The only difference I can find is that the meade is 1 pound lighter. Visual use.
Good video as always, though from my experience I'd recommend people to research the NPF rule for better results than the 500 rule. Modern DSLRs and mirrorless cameras have much higher resolution and the star trailing remains apparent if you use the 500 rule. Replacing the 500 divided by focal length variable with a value of 200 or 300 is also a good alternative.
Good point. I sometimes recommend the "Rule of 400" to be safe. If you think about, the reality should be the "Rule of Zero". The sky is always moving.
An off topic question. There is something I don’t understand about refractors and DSO. If I use for visual observations for example a 150/750 mm F5 achromat and a 150/1200 F8 FPL53 APO, I understand that with the APO the Moon and planets will look 10x better and sharper but how about galaxies ? Will the galaxies look better in a high-quality APO than in a same-aperture short F5 achromat ? (For visual observations only, not astrophotography). Also is the contrast on galaxies better in the APO than in the same size achromat ? Thank you!
With an achromat you not able to correct the abberation over the whole spektrum. As with an good Apochromat these errors on "both ends" of the spectrum are reduced further. So this is why you have these red and blue edges opposide each other with an achro but, at least much less, with an APO.
These errors are apparent at high contrast edges the most. Like on stars you can see them very easy. Its maybe even hard to not see it :)) As you are also always have stars in every picture you take from a nebula, galaxy or supernova remnant you will see it there. But the effect doesnt only apply to pointy lights and magicly dissapear on galaxies. It is also there. You just can not see it easily but you dont get the image really sharp because you can only focus on a part of the spectrum, ie. red. Thus the other end, ie. blue, gets blurry and this lower the resolution over all ;)
Can you recommend me an equatorial telescope under or near $350 (Aperture at least 5 inch)?
Try the Orion Observer 134 (review somewhere on this channel). It isn't perfect but it's my new favorite choice in the ultra-budget category. If you want a more permanent scope, get a 6" or 8" Dob.
Is there such a thing as a telescope with ABSOLUTELY no chromatic aberration?
Mirrors have no false color, so if that's your criteria, get yourself a Newtonian. If it's a refractor you want, you have to define "no chromatic aberration." Do you want the false color to be below what's commonly accepted to be perceptible by most people? And do you want that in both the visual and photographic regions? If yes to the latter, be prepared to pay...
@@edting So, basically, If I don't want to see any aberration (chromatic, spherical etc.) or other image "imperfections", I have to spend quite a lot as it seems.
Fine. I'll just stick with something that isn't too costly... ...with some imperfections.
So, what telescope would you suggest with the following criteria: 0-700$; easy to setup, maintain and transport; able to see the moon as clearly as possible...
...Or, would binoculars be good enough?
Not to forget the Freeware "Siril" for stacking... Very, very powerfull and now in Ver.1.2.3 nearly an all-in-one solution for beginner, with the prewritten scripts also very easy to use. Giving them a nice result with close to no need for learning to stack, at least... Find the results better as what I got/get with DSS.
Stretching and Postprocessing is another story, though :D
Thanks Ed for this leading guide to new hobby-astronomes ;)
Correcting the white balance of a modified camera in post-processing is pretty simple and fast. Any decent processing software can do it (Photoshop, etc.). It's still a bit of pain in that you can't get usable pictures right out of the camera, but since any "keeper" image is going to have some post-processing, throwing in a white balance adjustment is simple.
this was well over my head, but i gained an appreciaton for the work involved- And most important of all i learned not to sleep in the desert because i do not want snakes as my bed buddies!
You can correct a Ha mod DSLR with an external lens filter. I do it with my Canon 6D.
Interesting. I've never been able to get that to work. Are there different filters for the different kinds of mods? In my experience the balance never quite gets back to the camera's original color science. There's always one color that's a little bit off (not surprisingly, it's usually red).
@@edting Probably something to experiment with, basically, you need match the transmission profile of the removed internal filter with whatever you're attaching to the lens, and while if you have a NIR spectrometer you could just measure it, it's unlikely the manufacturer will just have one publicly available. Since cameras are using silicon sensors, they can only be sensitive to around 1050 nm or so (at best, if best is lots of IR response), so wavelengths longer than that don't really matter in your chosen filter, and really, if you can get rid of about 700-950 nm, you probably remove the vast majority of what a normal sensor can see.
As with using a warming filter or another with your camera that blocks some portion of the incoming light, it will need to be rebalanced, it's just that the camera's calibration settings already compensated for the internal one. Any sort of IR blocking filter on the lens should block a good portion of the IR getting to the sensor, which then makes it easier to find that correct looking balance point with internal camera settings or with rebalancing in software, and IR blocking filters (or short pass filters) are pretty well understood and available, so you should have a number of good options with only minimal blocking of any visible light.
There's a second reason to have an IR blocking filter for regular photography and that's actually chromatic aberration. Basically, most lenses are corrected for low dispersion in the optical band, but IR at longer wavelengths needs additional corrections to end up in exactly the right place on the sensor, so if you leave the IR cut off and just rebalance for normal optical work, you get more chromatic aberration in your image (the color of which depends on the IR transparency of each Bayer filter mask on the sensor it's got, which actually can be white if all three color filters are transparent to IR.)
Why not just a UV IR cut?
I'd love to be good with nightscapes but light pollution is so bad here in Florida
Interesting.
Thanks, Ed! I'm enjoying the series as I enjoyed your book!
Great video, Ed! Quick question: Is 42mm a large enough aperture for binocular observation? I'm getting binos for my young son and I, and I'm afraid a larger pair will be too heavy and not fit his face comfortably.
I have Vortex Viper 8x42, they are great (with lifetime warranty). Don't take binoculars with magnification more than 8 if you will look at the sky holding them in hand. View will become very unstable. Every move of your body will be magnified by the magnification number. 7x or 8x magnification maximum for doing this holding binoculars in hand is sweet spot. Anything bigger and you will need a tripod enjoy watching a sky.
The signal to noise ratio goes as sqrt(n), not the noise itself.
Hi.
I know it's off topic, but could you give me your honest opinion of the SARBLUE Mak701000 telescope?
Don't buy those blue plastic Maksutovs. They go by many different names (to keep running away from reviewers?)
@@edting I believe @marcinmorun meant their 70mm model, which is not blue or plastic.
Unrelated, I have already ordered the blue plastic model for 65 dollars, it's in the mail.
Great video Ed
Ed, where can I find the first two lessons?
Check links in description to this video.
If you're going to make a bunch of exposures for stacking, can you leave the camera stationary and use the stacking software to align the images to correct for Earth's rotation?
On paper, yes. In practice, the stacking software may have trouble "keeping up" and you may wind up with nothing. Even if it works, you are going to have to start cropping as stuff moves off the edge of the frame. And here's another dirty little secret - the tracking mount you bought (and may have paid a lot of money for) isn't perfect.
Periodic error can creep in. Astrophotography is exacting and difficult - you want to minimize any chance of errors creeping in. Sometimes I wonder why I do it myself!
No. That's why we spend thousands on quality EQ mounts.
It depends on how long you're shooting. Stacking obviously can't help if the object moves out of frame, but in my short experience that's the only real limitation. I'm kinda new to stacking and Deep Sky Stacker (the freeware Ed mentioned), but I've never had a problem doing just that - lock the tripod and let the camera click away. Always follow the rule of 500 (another youtuber said best to make it 400, so I do, and it's helped). You can adjust the sensitivity in DSS to track and register the stars better. I think it works really well, though like I said, I'm still kinda new. Still, I've never had a problem with DSS not registering everything correctly. You can also set it to stack only your best images (best 80%, best 15%, whatever), which can really improve your final picture - if you start with a lot of images. I've been starting with about 50 images and having it stack my best 60-80%. One thing though - turn of your camera's image stabilization! That makes all the stars appear a bit off, and it doesn't give DSS the really sharp images it needs to stack only the best.
From one beginner to another, good luck!
Come on now Ed. Nobody uses a webcam for planetary imaging any longer.
I am using a security webcam with Sony IMX415 for like 50$, 4K with 30FPS with great results.
Sounds awesome! Can you give any direction what to warch out for? How to repurpose a commercial model for use with a telescope? Thanks!! @@astralfields1696
@@astralfields1696 Could you share the name of your particular model?
Ok, so I pick up my camera and then...?
Just kidding a "little"! Thank you for this informative video.
Yeah, this isn't easy and I'm not that great at nightscapes. Maybe you will be better than I...
@@edting Please don't misunderstand me. I humbly say that in no way could I do better. I really meant thank you for the informative video.
Go ahead and try it. You might be a prodigy at this. I've seen it happen.
I challenged myself to do just that with my new Sony Alpha-6100 + 2 kit lenses that I bought for the eclipse in April, and I've been really surprised at what it can do! A happy surprise I got with my really cheap kit zoom lens (215 mm) came when I caught the M92 star cluster in Hercules (not M13). The chromatic aberration made it look cool and all colorful! It's fake color from a cheap lens, but it made me smile! I'm enjoying the challenge, in dark rural skies and also deep in the city where I live.
Ed has cautioned against people going from looking at the stars through their telescopes to astrophotography too quickly, but I'm kinda going the other way. I only have a camera, and no telescope. I'm starting with the astrophotography. 🙂 And I appreciate all of Ed's tips.
@@beenaplumber8379 Maybe I've just given up. I don't know. But I agree, I like Ed's videos too.
1st
Sooo much knowledge here!
I enjoy Mr's Ting's vids so much. However, I am still getting my Mewlon 180c!!