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Beginner DS CCD/CMOS question

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#1 Ben Cartwright SASS

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Posted 21 April 2017 - 12:43 PM

I am a Solar Imager, you may have seen some of my stuff, I also do Lunar.  I find Solar extremely easy and use a ZWO ASI174mm (not cooled)

 

I originally purchased a ASI120MC before realizing it wouldn't work for solar as it is color.  I also have a ASI120mm-s for solar.  I have started to do some deep sky stuff, not much due to the reason I am into solar, my light pollution where I live, skies are usually worse than mag 2.4 and need averted vision to see Polaris which is over the shopping mall 300 feet from my location.

 

I drive to the Seagrave Observatory in RI to do imaging where they are about 4.5

 

I have been using my Canon 70D and now my 80D with Backyard EOS and that is easy, although not cooled, 8 months of the year it really doesn't matter the temps at night are in the 40's and 50's F and much colder also.

 

I was thinking of getting a cooled ASI camera and was thinking of a color camera for the one shot ease, but having the 120mm and the 174mm was also wondering about a filter wheel for them. They would handle most of the Messier's and the 80D would handle the big stuff like M31.

 

A few questions,

 

1) First a filter wheel, If I thought that a 120 minute exposure (total for stacking) would give me what I needed, with the filter wheel is it 120 minutes for each color and the clear so 480 minutes, or the 120 divided by the number of filters, so 30 minutes each?

 

2) Would a cooled camera make a big difference especially in the summer time where temps at night can be in the high 60's F.?

 

3) I may be getting a cooled ASI174mm for solar in the summer, have to see how bad the noise is when it gets in the 90's and the camera temp climbs to over 50C.  If I did that then a filter wheel might be the way to so since I am 90% a solar imager but the question is exposure - see question 1, I don't have hours to spend getting captures I have to work my day job.

 

4) if I decided on a ASI1600 or ASI071, would they give better results than the 70/80D Canon cameras or be comparable except I could get them cooled?

 

Most bank for the buck might be a ASI174mm with a filter wheel, useful for my solar and for DS but worry about exposure times with a filter wheel

 

 

Responses are appreciated



#2 Ben Cartwright SASS

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Posted 21 April 2017 - 12:46 PM

Here a couple of my images, solar and DS

 

10_05_38_g5_ap61%20reg6%2050-50%20color%

 

20-11-18%2010-31-33%20plages%20color-jpg

 

M31%20DSS%20third%20good%20PS%201-LR%20a



#3 bobzeq25

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Posted 21 April 2017 - 02:17 PM

I am a Solar Imager, you may have seen some of my stuff, I also do Lunar.  I find Solar extremely easy and use a ZWO ASI174mm (not cooled)

 

I originally purchased a ASI120MC before realizing it wouldn't work for solar as it is color.  I also have a ASI120mm-s for solar.  I have started to do some deep sky stuff, not much due to the reason I am into solar, my light pollution where I live, skies are usually worse than mag 2.4 and need averted vision to see Polaris which is over the shopping mall 300 feet from my location.

 

I drive to the Seagrave Observatory in RI to do imaging where they are about 4.5

 

I have been using my Canon 70D and now my 80D with Backyard EOS and that is easy, although not cooled, 8 months of the year it really doesn't matter the temps at night are in the 40's and 50's F and much colder also.

 

I was thinking of getting a cooled ASI camera and was thinking of a color camera for the one shot ease, but having the 120mm and the 174mm was also wondering about a filter wheel for them. They would handle most of the Messier's and the 80D would handle the big stuff like M31.

 

A few questions,

 

1) First a filter wheel, If I thought that a 120 minute exposure (total for stacking) would give me what I needed, with the filter wheel is it 120 minutes for each color and the clear so 480 minutes, or the 120 divided by the number of filters, so 30 minutes each?

 

2) Would a cooled camera make a big difference especially in the summer time where temps at night can be in the high 60's F.?

 

3) I may be getting a cooled ASI174mm for solar in the summer, have to see how bad the noise is when it gets in the 90's and the camera temp climbs to over 50C.  If I did that then a filter wheel might be the way to so since I am 90% a solar imager but the question is exposure - see question 1, I don't have hours to spend getting captures I have to work my day job.

 

4) if I decided on a ASI1600 or ASI071, would they give better results than the 70/80D Canon cameras or be comparable except I could get them cooled?

 

Most bank for the buck might be a ASI174mm with a filter wheel, useful for my solar and for DS but worry about exposure times with a filter wheel

 

 

Responses are appreciated

More exposure is always better, but color data doesn't need to be as good as luminance.   Most people would do something like 120 on lum, 40 each on RGB.  240 total, 1/2 lum.  RGB will need more exposure, of course.

 

This is, as always, subject to personal taste, but that's a mainstream way to go about it.  Reducing the color data too much makes it hard to get good color.  See:

 

http://astroimages.w...good-color.html

 

Funny thing.  Mono plus filters takes less time to get to the same signal to noise ratio as OSC.  Having all the pixels working all the time is a big deal.  It may not appear that way at first glance, because serious imagers doing mono plus filters also tend to do serious total imaging times.  That's not required because it's mono plus filters.

 

So you're not really saving time in acquiring data with OSC.  You may be saving processing time, depending on how you do processing.

 

Cooled cameras are always best, but a modern camera like the 80D is pretty good.  The older 70D - not so much.  I don't do darks with my Nikon D5500 (also have an Atik 460EXM).  The general thing people do to step up from a DSLR is the whole deal; cooled, mono, filters.  That's a major improvement, especially in light polluted skies.

 

That's a nice M31.  You did that with an ST80?  The noise could be addressed by more total imaging time, or advanced processing, like:

 

https://jonrista.com...duction-part-1/

 

Or best by both.


Edited by bobzeq25, 21 April 2017 - 02:29 PM.


#4 Ben Cartwright SASS

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Posted 21 April 2017 - 03:14 PM

The M31 was taken with my 70D and the ST80 guide scope on the Seagrave's Meade LX200 16".  It was 20 - 25 second exposures.  The solar images were with my ASI174mm, the first one with my Lunt LS80 and the second with my Quark Chromo and Celestron XLT120.

 

I am now leaning towards a ASI174mm cooled as that would give me the most bang for the buck, I can use it for solar in the summer and deep sky with a filter wheel. I am doing a lot of reading and learning.

  The 80D would do for the large objects like Orion or M31.  My current 174mm would be a good winter camera.  the other day I was shooting using sharpcap and watching the temp on the camera in 45 minutes it never got above 35C, tends to be cool here most of the year.




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