Noise and bloat

[Shimonu]

So I went out and got 60x60s on M33 with my NEQ6, WO Z73, camera is a Canon Eos 700D modified. I would say this was probably a bortle 5 sky.

I've run through some post-processing in APP and I need to know what more I can do or what I'm doing wrong. I feel like the picture is pretty noisy and the stars are quite bloated.

In APP I let it use all the default settings for integration and for the post-processing I've just gone through background calibration and star colour calibration and then cropped it. I had some dust motes and I haven't gotten to taking flats yet.

I just used my 60x60 lights and 15 darks here and I'm wondering how much difference some bias would do. I thought I had some but I seem to have misplaced them. Obviously I could stretch this more but the noise gets a bit crazy. This is the 10% BG, 5 sigma, 2,5% base preset option

I'm certainly learning just how faint galaxies are

Here's one where it's cropped and stretched more. This is starting to feel like too much even if there's certainly a lot more detail.

Edited January 11, 2021 by Shimonu

[Budgie1]

You may be a little out of focus, but that aside, try stacking without the darks and see what the noise is like. Sometimes the darks make the noise worse, rather than better and I stopped using them, just using flats, dark flats & bias frames for calibration.

If you go for M33 again, try longer exposures. If you're not guiding then try extending the exposure time until you start to see the stars trailing and then bring it back. You should be able to get 90-120 seconds with an unguided NEQ6.

Also, what ISO were you using? With my modded EOS 1300D I tend to use 800 ISO for most targets.

[rnobleeddy]

Using a similar setup, I found M33 didn't really work until I had at least 3 hours of 5 minute subs, with relatively little moon. 

On the star bloat - if the astro mod removed both filters, did you use a IR cut filter?

Edited January 12, 2021 by rnobleeddy

[alacant]

14 hours ago, Shimonu said:

how much difference some bias would do

Hi

Good effort.

You're gonna need a long time for m33; 60x5 minute frames would be better;)

Noise: lose the dark frames. On a 700d, they will introduce more noise. Instead, take bias frames at 1/4000s and stack them to make a master bias. Use this to calibrate both the light and (when you can) flat frames. For the noise to diminish, dither between light frames and then stack using a clipping algorithm.

Stars: dunno. Maybe focus drifted or wasn't locked?

Cheers and HTH

 

 

[ollypenrice]

An hour on M33 really isn't anywhere near what you need, especially with so little aperture. If you've been looking at M33 images you like on the net, check their exposure times. Plenty of images out there have over 20 hours. I agree with Alacant's advice on calibration. Stars: yes, check focus regularly and keep an eye on the sky. However, there are lots of post-processing techniques to control star size. First, get much more data.

Olly

[Aramcheck]

This was 117 mins in Bortle 6 with a SW 130dps & a Canon 600d (astromodified):-
https://stargazerslounge.com/topic/369470-m33-130dps-odd-light-artifact/

It would have been longer but clouds stopped play (again) & at the here at the moment clear skies are few and far between.

IMHO Bias / Flats & Darks are a must. (You'll have to check processing with & without darks - I find it's better to use darks). Vertical lines on the 2nd image looks (to me) like bias.

If APP does deconvolution then try that to reduce star bloat... It took me a while to get settings right in Pixinsight...

Noise is inherent with a DLSR, unless cooled. You can eliminate it to some extent in processing.

Cheers
Ivor