Noisy galaxies from the city

Maurice · #1 18-10-2013, 08:01 PM

Ok, I know that its probably not a good idea to take Luminance data of galaxies from the suburbs of Melbourne (and with a bit of the moon out), but I needed to play with the new EQ8.

Attached are a rather noisy pair of NGC253 that had 70min of L and an NGC1365 with 100min of L - no sky glow reduction filters.

I tried taking more data of 253; it got smoother, but no deeper. The one thing that this exercise does, is to make you brush up on your flat fielding skills....

VC200L at f/9, QHY9, ASI120MM guider @ 270mm, EQ8
Poor seeing, so binned 2x2

Comments welcome..
Cheers

Maurice

alpal · #2 18-10-2013, 11:04 PM

Hi Maurice,
The detail is there.
I think only RGB should be taken from city suburbs or where there
is any light pollution?
The RGB data ends up sharper & my latest flickr photo has some proof of that
although it is just a bright part of a nebula - not a galaxy.
Will you try some RGB with an anti light pollution filter?

cheers
Allan

Maurice · #3 19-10-2013, 03:13 PM

Hi Allan

Thanks for your comments.

I'm keen to try something like a CLS filter with luminance next.
Hopefully that will be a direct comparison to using L on its own.
After that, I'm sure that RGB will also be a challenge..

cheers

Maurice

Phil Hart · #4 19-10-2013, 03:22 PM

Good to see you out imaging Maurice! Results look good to me.

What's the verdict on the EQ8 so far?

Phil

astronobob (Bob) · #5 19-10-2013, 03:26 PM

Interesting stuff Maurice, very resolved for 2x2, & never a lost cause imaging in any conditions, & something i should be doing a bit of actually

Good show !

Maurice · #6 19-10-2013, 03:52 PM

Hey Phil.... its been a while...

So far the EQ8 has been great, except for the darned axes locking levers! Even after adjustment I can't seem to get quite enough locking force out of them.
Its too easy for things to move with the slightest nudge.. not good.
Tracking-wise though its great; the difference in error on a good night between RA & DEC is about 0.1"( RMS). Overall tracking errors are about 0.3" to 0.7" RMS depending on conditions.
I have been using it lately with EQMOD which is a breeze, & hope that they implement the homing function soon (very useful).

Overall I'm happy with it so far..

Hope to catch up soon.
Cheers
Maurice

Maurice · #7 19-10-2013, 03:57 PM

Hi Bob

Thanks for your comments. I am going to make an effort to get out there whenever possible.

You are right - got to make the most of what you've got.

BTW, the sampling on 2x2 binned was 1.2"/pixel & I had 3"to 3.5" seeing.

Cheers
Maurice

Maurice · #8 19-10-2013, 04:24 PM

I should be more specific...
these are guided tracking errors...not un-guided.
Unguided PE is about 5" P-V with no nasty fundamentals.

Maurice

Quote:

Originally Posted by Maurice

Hey Phil.... its been a while...

So far the EQ8 has been great, except for the darned axes locking levers! Even after adjustment I can't seem to get quite enough locking force out of them.
Its too easy for things to move with the slightest nudge.. not good.
Tracking-wise though its great; the difference in error on a good night between RA & DEC is about 0.1"( RMS). Overall tracking errors are about 0.3" to 0.7" RMS depending on conditions.
I have been using it lately with EQMOD which is a breeze, & hope that they implement the homing function soon (very useful).

Overall I'm happy with it so far..

Hope to catch up soon.
Cheers
Maurice

Stevec35 (Steve) · #9 20-10-2013, 04:44 PM

I think they are both good shots and I certainly take luminance from my outer suburban location. The biggest light pollution problem I have is with gradients.

Cheers

Steve

Maurice · #10 20-10-2013, 04:58 PM

Quote:

Originally Posted by Stevec35

I think they are both good shots and I certainly take luminance from my outer suburban location. The biggest light pollution problem I have is with gradients.

Cheers

Steve

Hi Steve
I agree. Gradients are a pain.
As an old fan of IRIS, I find that its polynomial background fit tool combined with its level masking tool works wonders in eliminating gradients.

Cheers
Maurice

Arthur Coombs (Arthur) · #11 21-10-2013, 11:46 AM

Hi Maurice, good to see the "old master" finding enough time to image again, even if in a light polluted area. Very nice images. Trust you will be able to improve the locking devices on the new EQ-8 mount.
Regards Arthur

Maurice · #12 22-10-2013, 09:07 PM

Quote:

Originally Posted by Arthur Coombs

Hi Maurice, good to see the "old master" finding enough time to image again, even if in a light polluted area. Very nice images. Trust you will be able to improve the locking devices on the new EQ-8 mount.
Regards Arthur

Hi Arthur
I don't know about 'old master'.... I think that just plain 'old' is more accurate!
Glad you like the shots. Will catch up soon.

Regards
Maurice

trek1701 (Mark) · #13 27-10-2013, 06:16 PM

Maurice.

Incredible images from light polluted Melbourne.

I'm looking forward to seeing your excellent planetary work again when the opportunity arises

Cheers Mark

Maurice · #14 28-10-2013, 11:01 PM

Quote:

Originally Posted by trek1701

Maurice.

Incredible images from light polluted Melbourne.

I'm looking forward to seeing your excellent planetary work again when the opportunity arises

Cheers Mark

Thanks Mark.
I do enjoy imaging the planets, but deep sky is a lot of fun too!
I hope to do a lot more of it with the new mount.

Cheers
Maurice