NGC1491 in Ha

[swag72]

This has been a really frustrating image taken in my new obs with everything now I think finally working. I eventually got the focus sorted in narrowband, which was difficult enough in itself.

So here is an Ha image of NGC1491, I would absolutely welcome any thoughts with regards the processing as I have found this really difficult. Perhaps it was just a tricky image to process!!

Mount: HEQ5

Scope: SW Evostar 120ED

Camera: Atik 314L, Baader 1.25" 7nm Ha filter

Subs: 12 x 1200s (4 hours total)

[Shibby]

Very nice, I've never seen this one before. So thanks for posting it!

[swag72]

Cheers Lewis - There's some major problems with it regarding noise - I hope to get some pointers!!

[RobH]

Looking good Sara....nothing wrong with the focus!!

It's surprisingly noisy for 4 hours....I don't know this target....did you have to stretch the image quite hard?

There's a bit of a gradient showing....any flats used?

Cheers

Rob

[swag72]

Cheers Rob - Stretched and processed to within an inch of it's life, which is clearly showing, but I couldn't see it at the time!!

No flats used and no gradient removal in PI either, this is just as it was.

Having another play now!!

[Tim]

Not too shabby at all Sara

Like Rob I don't recall this target, so not sure what it "should" look like. You quite often get a lot of noise when you stretch narrowband targets. There are things you can do to lessen the effects.

How are you focusing? Manually? If you have a bahtinov mask, select a really bright star, not necessarily in your target, centre it, and then run your focus routine. With a Ha filter in place the mask will produce a series of dots, and by going in close to the star check out the first 3 dots. When they are equally spaced your focus will be perfect, lock it and then move to target. Apologies if I am teaching granny to suck eggs

If the temperature is varying much through the night, then do check the focus from time to time, as it will vary.

Cheers

Tim

[ollypenrice]

No flats? Naughty. Get 'em done!!! Totally, absolutely, 226%, utterly essential. Super scope, fine observatory, the mighty Atik CCD... flats.

Olly

[swag72]

I used the very good Bahtinov grabber programme to check focus. Although I didn't check it during the 4 hour run. Temp didn't change too much really.

Yes, yes Olly!! I did do some flats but when I stacked the first 900s batch they made the gradient really bad, so then I read and learnt that I need to do bias as well - So it ALL got binned!!

These were aligned and integrated in PI - Must see how to add flats and bias.

[prokyon]

Very nice,

I did a widefield of this area with Sh2-205 some weeks ago. So I know, no easy object.

Cheers

Werner

[swag72]

Cheers Werner - What did you find so tricky about this area? The processing, lack of data? Maybe I should just pick an easier target and work on processing from there!