Think I had a 10" refractor dropped on my head, so I came back to listen again. Lot to unpack in these tutorials. They are great. If I can get through these, I will reward myself with an opaque donut
At around 2:02 you say to keep your camera orientation the same as your light frames. In the very next breath you say to reorient your scope to point straight up to facilitate flat frames. This seems contradictory, no?
Hi Ray, thanks for pointing that out! To clarify, you'll want to make sure that you do not rotate or adjust the camera in any way. The scope can be pointed in any direction towards the sky to take sky flats because the scope, camera sensor, filters, optics, etc. are all moving together in unison. Nothing in the imaging train is being changed. When you change the orientation of the camera only, any dust specs that may reside on your filters or field flatteners are now in a different position when you take your flats frames. Since your flats frames are used to simply reverse the effects of vignetting and dust specs, if you rotate your camera, these specs are now in a different location when you take the flat frame and now they cannot be properly subtracted out
Goes from simple white T-Shirt with elastic band 😀to an unknown concept called "ADU" in 30 secs flat 😅. When we get to "unity gain" a minute later I had to lie down in a foetal position 🥵
Thanks Teagan! I like the idea of taking Darks with the astronomy camera not attached to the telescope. Makes it much easier. Also easier to just block off some time and shoot/create a whole library of darks at different temps, gains and exposure lengths. Thanks for the video. Dr B from Manitoba, Canada
Hi Bob, ADU is an Analog to Digital Unit, and is the representation of the charge stored in a pixel (an analog signal) in a format useful for creating images (digital information). Essentially this refers to the brightness of a pixel, or in the case of Mean ADU the average brightness of the image. Mean ADU is what we're referencing here as that is common way for dedicated astrophotography programs to relay that brightness information - but if you're using a program like SharpCap which also can display a histogram, you can absolutely follow our DSLR histogram guidelines and ignore ADU. For a bit more context: ADU can range from 0 (no signal) to about 64,000 (max signal). Accordingly a Mean ADU of 15,000 to 30,000 corresponds to an image that averages out to 25% to about 50% of the max brightness.
Boarding up the door to the room was a nice touch. :)
We think so too!
Hi, If you make qa tutorial I think it would be good to get rid of the background music which only dystracts from the talking. Thanks
Think I had a 10" refractor dropped on my head, so I came back to listen again. Lot to unpack in these tutorials. They are great. If I can get through these, I will reward myself with an opaque donut
Glad to help!
At around 2:02 you say to keep your camera orientation the same as your light frames. In the very next breath you say to reorient your scope to point straight up to facilitate flat frames. This seems contradictory, no?
Hi Ray, thanks for pointing that out! To clarify, you'll want to make sure that you do not rotate or adjust the camera in any way. The scope can be pointed in any direction towards the sky to take sky flats because the scope, camera sensor, filters, optics, etc. are all moving together in unison. Nothing in the imaging train is being changed.
When you change the orientation of the camera only, any dust specs that may reside on your filters or field flatteners are now in a different position when you take your flats frames. Since your flats frames are used to simply reverse the effects of vignetting and dust specs, if you rotate your camera, these specs are now in a different location when you take the flat frame and now they cannot be properly subtracted out
Goes from simple white T-Shirt with elastic band 😀to an unknown concept called "ADU" in 30 secs flat 😅. When we get to "unity gain" a minute later I had to lie down in a foetal position 🥵
In using a DSLR and 135 mm lens, are the calibration frames shot in RAW or JPG?
This guy is real good.
Thank you!
Thanks for your presentation. Very concise and to the point.
Glad it was helpful!
Awesome vedios!!.
Thank you!
Thanks Teagan! I like the idea of taking Darks with the astronomy camera not attached to the telescope. Makes it much easier. Also easier to just block off some time and shoot/create a whole library of darks at different temps, gains and exposure lengths. Thanks for the video. Dr B from Manitoba, Canada
Thanks for watching!
how do you take dark flat frames
How about bias frames
Hoe do you keep your focus while stretching the tshirt and rubber banding it?
Everybody like Texan
When taking those flat frames, the focus should remain the same. And when putting the shirt on it, focus ring can easy be moved on
Don't know what you mean by ADU ??? This is not explained on the High point Scientific website
Hi Bob, ADU is an Analog to Digital Unit, and is the representation of the charge stored in a pixel (an analog signal) in a format useful for creating images (digital information). Essentially this refers to the brightness of a pixel, or in the case of Mean ADU the average brightness of the image.
Mean ADU is what we're referencing here as that is common way for dedicated astrophotography programs to relay that brightness information - but if you're using a program like SharpCap which also can display a histogram, you can absolutely follow our DSLR histogram guidelines and ignore ADU.
For a bit more context: ADU can range from 0 (no signal) to about 64,000 (max signal). Accordingly a Mean ADU of 15,000 to 30,000 corresponds to an image that averages out to 25% to about 50% of the max brightness.