m31

[cardconvict]

Had a second try at this just compare this result with the last one i did with the canon 450.

Also was seeing as well how much of a improvement i could make at iso 1600 just had to tame the noise in processing.

21x10min lights 40 darks 80 flats and 100 bias.

stacked in DSS and processed in photoshop, telescope was the ED80 on a EQ6 pro mount ,camera canon 500 full spectrum cls ccd astronomik clip in filter.

and here is the attempt from the last time with a canon 450.

[namreg]

Looks pretty superb to me! blumming sight better than the one I posted the other day!

Is the noise at 1600 vastly more than 800? I generally use 800 but as I'm unguided I was thinking of having a go at 1600. Do you think stacking more subs would alleviate the extra noise a little?

[cardconvict]

the noise on the canon 500d is very low anyway but yes stacking alot more images together will produce a cleaner image just get as many lights darks bias and flats as possible more the better,if you do not use a filter then i would stick at iso 800 but the clip filter i have is very aggressive so i have decided to go for iso as a experiment to try to add more signal.

[msinclairinork]

That is one mother of an M31! Well done.

And a very interesting test with ISO's somthing all us DSLR users will benifet from, so thanks for that

Thanks for sharing,

Michael

[peter shah]

superb shot....wow thats a lot of calibration frames:eek:

[cardconvict]

superb shot....wow thats a lot of calibration frames:eek:

thanks peter yeah i know but also running at that iso does give off a bit more noise so more calibration frames the better, it just smoooths it out alot more

[namreg]

Don't the darks already include bias? If you subtract darks and bias (or whatever you do with bias!) aren't you effectively applying bias twice?

Doug

[cardconvict]

Don't the darks already include bias? If you subtract darks and bias (or whatever you do with bias!) aren't you effectively applying bias twice?

Doug

on m31 i always try different ways of stacking and i have heard about not stacking the bias and i did try as well but after stacking there was some wierd results so i restacked with the bias and it was fine

also i have reprocessed this with the red channel tuned down a bit

[namreg]

Oh OK. I might give that a go as well then, as bias are the easiest to take! I've given up on flats.

[cardconvict]

Oh OK. I might give that a go as well then, as bias are the easiest to take! I've given up on flats.

i would,nt give up on flats they are very important to get a good final result how do you normally take them

[namreg]

I don't. I know they're important - I get horrendous vignetting using prime focus which I take out during the processing, which I know isn't ideal. My sensor probably isn't the cleanest either, but I haven't yet found a way to do it. I've read loads of suggestions, like using the twilight sky and such, but I take my photos at night(!) when the twilight sky isn't in sight, and as I understand it you should really take flats immediately after or before the lights, to catch the dust in the same place. Any suggestions that don't involve buying a horrendously expensive lightbox?

[cardconvict]

when i started to take flats i used to use the white T-shirt pointing at the blue sky the next day but sod law i always had i speck of dust move when i packed away my equipment so now i use my lap top screen, so first set your camera on AV mode and the iso has to be the same iso as your lights put your laptop screen in front of scope and push half way down on the trigger to calculate the exposer time and fire loads of them off i take about 100 more the better.

[namreg]

That's worth a crack. Just measured my screen and it's just 9" top to bottom, so should cover my 8" newt. Hope this isn't a silly question, but how do you get a blank, bright laptop screen without your windows desktop, or something else, on display?!

[cardconvict]

oh yeah sorry what i do is bring up note pad and auto hide the task bar hope that helps you oh and if you do that you don't have to use a t-shirt

Ian

[namreg]

Ah. Makes sense. Cheers Ian - that could've solved something I've been puzzling over for months (as long as I've been doing this in fact). Next clear sky I will be out there with my laptop!

Superb image (getting back on thread). Something for me to aspire to when I've sussed all this out - but not with this kit. I get the middle bit of that image in my FOV at prime focus, and focal reducers are out of my budget. But one day.

Cheers mate.

Doug

[Beyond_Vision]

A great result with the dim outer extents and the dust lanes showing up well. The rework looks better less red it would be worth trying to give the colour a bit of lift. Have a look at the Gabany method of colour enhancement

Stargazer - A Private Observatory In The Heart Of Europe

Regards

Kevin

[cardconvict]

A great result with the dim outer extents and the dust lanes showing up well. The rework looks better less red it would be worth trying to give the colour a bit of lift. Have a look at the Gabany method of colour enhancement

Regards

Kevin

wow thanks for that kevin that makes a huge difference after reading that i'am going to start from scratch and take my time and not use saturation cheers Ian

[cardconvict]

ok thanks to kevin i have reprocessed this again and boy i think that is a big difference in using Gabany method.it has also help me in keeping noise down also i have taken 2 min subs and added to this to preserve the core more hope you like.

[SlipperySquid]

It's a little bit good innit I've bookmarked that site and will give some of my data another go! But that sir is a cracking m31!