M45

[brrttpaul]

alays look roreward to it appearing

[tooth_dr]

24 minutes ago, brrttpaul said:

alays look roreward to it appearing

Lovely. This is really whetting my appetite for M45

[Knighty2112]

That’s great! What settings did you use to get the nebulisity to show? Excellent work!  

[brrttpaul]

ed80 scope, heq5 pier mount, Asi1600 mono,  captured with SGPRO,I find the best setting for me is gain at 50 offset 15 ( right or wrong no idea but seems ok with me),  Lum 10 secs x 42, RGB 60 secs, x42

[bobro]

1 hour ago, brrttpaul said:

Lum 10 secs x 42, RGB 60 secs, x42

Love the star colours! Though I'm a bit puzzled by the exposure - isn't Lum supposed to be longer than RGB to capture detail as our eyes aren't that sensitive to colour?

[brrttpaul]

I dont think so but then again im still a beginner,  I have always been lead to believe lum binned 1x1  and rgb binned 2x2, 

[SIDO]

Very nice image...

[wimvb]

Lovely.

An old truth in ccd imaging is to shoot a little rgb at bin 2x2, to keep the noise down, and lots of lum at full resolution to get detail. But with low noise cmos, there's little use to bin rgb. Some imagers don't even collect lum at all. But if you do, get loads more, whatever exposure time you use. Maximum exposure time should be determined by gear (guiding) and sky conditions rather than old truths.

[SIDO]

I observed this visually in the scope last night, the Full Moon had it all looking pretty bland without the typical glare and shimmer of the brighter stars. Keep M45 coming you guys, can't wait to see more of these especially with the inclusion of nebulous components ?

[Guest]

Just for reference - I've got the same camera and use these settings for LRGB

Gain  = 139 (unity gain)

Offset = 10

L = 1min

RGB = 2min

Like you, I'm not sure if these are the best but I've never had to use any different settings to get superb results ?

I'm surprised that there isn't more nebulosity showing between the stars in your image.

It looks like it should be there based on the amount around the stars themselves - what software did you use to process this?

Very nice image - especially like the colour of the background stars.

David

[brrttpaul]

I like unity gain, but the nifty fifty (thats what i call it lol) just gives me a cleaner image and my stars are not as likely to be blown out, also I do suffer with amp glow (think all zwo cameras do)  so when i do the stretch in PI i always ease back a tad rather than have it fully stretched, the dynamic background extraction seems to make it worse  in most cases so usually use the automatic extraction

[wimvb]

2 hours ago, brrttpaul said:

also I do suffer with amp glow (think all zwo cameras do)

They all seem to suffer from that, to a certain degree. But darks usually work very well.

[brrttpaul]

I always use darks, still makes no difference, wonder if there is a rule of thumb percentage wise? i use about 50 darks on my images

[geordie85]

26 minutes ago, brrttpaul said:

I always use darks, still makes no difference, wonder if there is a rule of thumb percentage wise? i use about 50 darks on my images

I use darks with my qhy183c and still have amp glow present unless I use flats and dark flats too. Then it's completely calibrated out. 

[brrttpaul]

I have never understood  darkflats , I take flats but been told not to take any bias , maybe I should look into dark flats

[geordie85]

1 hour ago, brrttpaul said:

I have never understood  darkflats , I take flats but been told not to take any bias , maybe I should look into dark flats

They're exposures taken at the same length as your flats but with the dew cap on. 

[wimvb]

(You may already be familiar with this, but anyway.)

The ASI1600 has a different sensor from other ZWO cameras. I believe it's a Panasonic sensor, while other cameras have Sony. Sony sensors have generally more amp glow.

Amp glow is the build up of signal in the pixel wells, due to dark current and a local increase in temperature. Since it's electronic in nature, it's calibrated out with darks. (But this doesn't explain why flats would be needed too). Flat frames at "longer" exposure times, need their own darks for the very same reason. That's why with cooled CMOS, you normally shoot lights, darks, flats and dark flats (= darks for flats). If there is no amp glow, you can use bias frames to calibrate flats, rather than dark flats.

[brrttpaul]

Ah thx both the penny drops, I will get onto that tonight when I get home thx very much for explaining it