Altair Hypercam 26C- My first CMOS Camera

Discussion of features and issues relating to Altair Astro Cameras
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Brian1973
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Altair Hypercam 26C- My first CMOS Camera

Post by Brian1973 »

I have been imaging for about two years using the Canon T6I. I decided to transition to a dedicated astro-camera and purchased the Altair Hypercam 26C.

Although I have reviewed all the documents on the Altair site regarding the use of a CMOS camera and have been watching many Youtube video's (mainly by Dr. Robin Glover) I find that I have many questions.

I received the camera about three weeks ago and haven't had much of a chance to use it because I live in Oregon where the haze, heat and smoke has wreaked havoc on imaging opportunities.

Questions-
1) What is ultra low mode and what purpose does it serve?

2) Should I shoot in Ultra low mode all the time?

3) The hypercam 26c offers 8 and 16 bit depth, is there a selection for 12 bit depth?

4) Are there any scenarios or reasons to shoot in a lower bit depth than 16?

5) How does Gain and Exposure Length intersect?

6) Many people attest there is no longer a need to take dark frames, flats and bias with this camera. Is this true?

7) Are there periodic firmware or other updates that I need to do? If so, where are these located?

8) Any other information or resources that are helpful with learning how to use this camera?

Thanks

Brian
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Re: Altair Hypercam 26C- My first CMOS Camera

Post by admin »

Hi Brian,


1) What is ultra low mode and what purpose does it serve?

ULN mode reduces (by about 10% or so) the amount of electronic read noise that gets into every image from the camera electronics.

2) Should I shoot in Ultra low mode all the time?

You should use it for deep sky imaging or for live stacking (EAA) - anything where your exposures are longer than a second or two. Do not use it for high speed imaging if you do any with the camera (lunar/solar/planetary) as it reduces frame rates a lot and the read noise reduction is not really significant for those types of imaging

3) The hypercam 26c offers 8 and 16 bit depth, is there a selection for 12 bit depth?

No, just 8 or 16.

4) Are there any scenarios or reasons to shoot in a lower bit depth than 16?

Yes, high speed imaging (lunar/solar/planetary) does not benefit from 16 bit mode, and would suffer because of reduced frame rates.

5) How does Gain and Exposure Length intersect?

Increasing both will increase the brightness of your image, but the exposure does it by collecting more photons over a longer time while the gain basically brightens up the signal that is already there (like turning up the volume on a radio). Turning up the gain will increase the noise in the image more than turning up the exposure for the same increase in brightness.

You can use the SharpCap Pro 'smart histogram' functionality to get more detailed suggestions on the correct gain/exposure to use for deep sky imaging.

6) Many people attest there is no longer a need to take dark frames, flats and bias with this camera. Is this true?

No, you still need to take dark frames if your exposures are of a significant length (more than a few seconds). It might be less critical than with some other cameras, but they will still help. Your dark frames should be taken at the same settings (gain, exposure, black level and temperature) as the light frames.

Flat frames help deal with vignetting (darkening of the frame corners) or dust shadows on the image - depending on your optics and whether you have any dust you may or may not need them. If you do use flat frames you should also use 'dark flat' frames to ensure the correction is OK. In most cases the flat frame is short enough exposure that a bias frame can be used in place of a dark flat.

The other use for bias frames is to try to correct for your dark frames using a different exposure length than the light frames - if your dark and light frames have the same exposure length and other settings then this type of bias frame is not required.

7) Are there periodic firmware or other updates that I need to do? If so, where are these located?

No, there are usually no firmware updates for these cameras (very rare for an update to be needed). The drivers usually do not change much either. Any changes are usually located in the camera SDK, which comes as part of the SharpCap install, so by keeping SharpCap up-to-date you will be keeping up-to-date for the camera.

8) Any other information or resources that are helpful with learning how to use this camera?

There may well be some other 26C users on here as it is a popular camera, otherwise there is often good content on Youtube - watching someone who has the same camera run an imaging session using it can be very instructive.

cheers,

Robin
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