A first DSO image - M81

I'm humbled by the quality of some of the images I've seen on this site - and kudos to all who set the bar so high.

I captured my first (and only DSO). It's poor - but It's a personal accomplishment - I actually captured a DSO. Focus appears off - I captured an image of saturn immediately afterwards and that appeared fine.

The image is unguided. 20 stacked images on 60s frames.
I took about twice this number of frames and rejected about half due to star-trails.

Skywatcher 8" f/6 scope on an EQ6Pro. Imager was an Atik 16IC.
Dark subtracted (but - if I can recall - only one dark of 60s meadian combined with two copies one displaced by one pixel in x direction and the other likewise in y dierction in an attempt to elliminate some hot pixels). I know this aint the way to do it.

No flats.

Really can't recall how I scaled it but I did do a little wavelet sharpening.

Rotated etc to compare features with a reference image from Hubble - and it was nice to see that there was a correspondence.

Mark

Mark, your atempt at this is very good, it's nice to get that personal 1st Ok the focus is ever so sligtly off, but I would'nt be picky about it, I could'nt even do that with my cg5 mount, the tracking is very poor. I like the dust lanes caught there.

How is the eq6 for tracking?

Keith..

Mark - the fact that you captured dust lanes suggest to me that your focus was pretty good. Also, the fact you say your image of Saturn turned out well, suggests focus is not your main problem.

It might be that tracking is the bigger issue. As far as I know, the EQ6 is a good mount with a reasonable periodic error - and with an 8" scope I can't imagine it being overloaded to the detriment of tracking.

Here's a few suggestions that you might try out:

1. Balance your scope correctly - both RA and DEC axes. This will reduce any unbalanced load on the motors and will help them run more smoothly
2. Polar align as best you possible can - drift alignment with your imager is best but if you tear down your setup each night, it might not be practical.
3. If you can (and if the facility is available with the mount) record periodic error (PE) and see what it looks like. Not sure if the EQ6 is programmable, but if it is, you can reduce PE this way.
4. Focus - try a Hartmann mask or similar or even, at the start of the night, get your focus on a bright star, planet or even the moon. If you can lock focus, then do so. Unfortunately, as the optical train cools down, focus will shift. If you want great results, you'll need to check focus periodically - on a stable night, every hour should be OK. On a night where temperature fluctuates a lot, maybe every 30 minutes. If you want brilliant results, and electronic focuser is the way to go - but you'll need to ensure you can lock the primary mirror if its an SCT. If its Newt, not an issue (not sure what the Skywatcher is...). Note that Hartmann mask is not obligatory - if you're comfortable doing your focus by eye, that's fine too.
5. Ensure any connections in your system (e.g. imager to draw-tube) are tight and don't jiggle around.
6. Try and figure out the maximum exposure you can take without seeing trailed stars - then limit yourself to this exposure time. Even if its only 15 seconds, you'll not be throwing away 50% of your images and the more images you have, the better your results will be - even if the individual frames show little detail. When stacked, you'll be surprised at how much detail is actually there.
7. I'd personally recommend you lash into the items above before worrying about calibration frames. Sure, they will make a difference if you have a nice tight well tracking, well polar-aligned setup. But if you don't have those, calibration frames will serve no useful purpose. Of course, when you have the above items sorted, let us know and we'll give you the lowdown on darks, flats, flat-darks and bias frames

HTH

Dave

p.s if its any consolation, your first DSO capture is waaaaay better than my first

Hi,
I like it, it represents the eyepiece view of it to some extent.
Keep up the good work, looking forward to seeing more .

Thanks for all the responses. Dave et al I respect your wisdom and acquired knowledge on the imaging process(es) - so thanks for the input and encouragement.

Mark