Possibly Silly questions for DSLR users

[Newforestgimp]

Hi all,

I wonder if someone can clear my confusion and doubts.

I'm very new to AP & I’m currently using a crop sensor DSLR an old EOS30D & a newer 1300D for my Astro shots, both are APS-C crop sensor.

1) If i were to buy a new DSLR for mostly AP should I look for Full Frame, APS-C, micro 4/3 format ?

2) am I worrying unnecessarily about the number of LONG exposures the sensors are ‘exposed’ to having a detrimental effect on the sensors themselves ? Is there such thing as ‘sensor burn’ like there is with OLED & LCD TVs had screen burn from exposure to static images ?

many thanks 

[wxsatuser]

Full frame means you need a scope or lenses that can cover the sensor

APS-C is most likely the best way to go.

Long exposures as such will not hurt the sensors but be careful when it's really hot outside.
Obviously you don't want the sensor temperature going to high.

My Canon 60Da has done hundreds of exposures of 10minutes with no problems.

[Newforestgimp]

7 minutes ago, wxsatuser said:

Full frame means you need a scope or lenses that can cover the sensor

APS-C is most likely the best way to go.

Long exposures as such will not hurt the sensors but be careful when it's really hot outside.
Obviously you don't want the sensor temperature going to high.

My Canon 60Da has done hundreds of exposures of 10minutes with no problems.

My current scope for imaging is a WO Zenithstar 61, would that change the advice ? thanks for the reassurance on the sensor front.

[wxsatuser]

49 minutes ago, Newforestgimp said:

My current scope for imaging is a WO Zenithstar 61, would that change the advice ? thanks for the reassurance on the sensor front.

Not sure, does it cover full frame?

It appears with a flatner it does 43mm which is close if that is correct.

[Tommohawk]

I did quite a lot of long exposure stuff with Canon 550D with ambient 30 deg and sensor didn't suffer any problems - well, not that I could see. BTW you can check chip temp in EXIF data. 

Full frame sensor might put real demands on the peripheral image and you may get some shape changes or CA even if manufacturer says imaging circle is OK. Plus of course full frame sensor camera is typically much more expensive.

Re 4/3 format - probably biggest issue is just with  mechanical / software compatibility, though TBH I'm not sure of the latest on this. Also if you have a scope with a 43mm imaging circle and use it on a 4/3 sensor (22.5 mm diagonal) you are wasting a lot of image. Most hybrid imagers ie astro/non-astro go for Canon APS-C which I used for some years and works well.

[rnobleeddy]

I'm not aware that it's possible for the sensor to get so hot that it's damaged. It's just that the hotter it is, the noisier it is. 

[rickwayne]

The choice of sensor size can really be driven by what you want to image, your optics, and the image scale.

You can use a tool like Telescopius to previsualize what various targets will look like with different-sized sensors. It's not always a case of bigger is better. You can  calculate the image scale for a combination of focal length and sensor with the astronomy.tools CCD Suitability page.

Simply put, smaller sensors usually have finer-pitched pixels, so you might achieve the same (e.g.) 20 megapixels on a smaller target with a smaller sensor.

Smaller pixels means more noise, though with today's gear, software, and techniques that's largely a solvable problem.

Most vendors publish an image-circle size spec for their scopes.

Edited January 15, 2021 by rickwayne