M45 (my first LRGB image)

[Carole]

This was an exercise to practice using LRGB filters for the first time.  I probably haven't done enough subs, or maybe even not long enough, but I wanted to complete the exercise, and this time the filters lined up OK.

Having heard lots of people complaining about terrible dew and dew heaters not doing the job properly, I was wondering what I was going to find as I never even checked mine as they always seem to work OK.

There was a nasty gradient in the bottom left corner which I have tried to process out as best I can, I am still concerned this is to do with the Atik Shutter when doing flats, despite following relevant instructions.

Atik 383L with Skywatcher ED80 Pro, Guided with NEQ6

Luminance 300 x 16 (1h 20mins)
Red & Green 6 x 300 secs
Blue 9 x 300 secs

No LP filter (I've got one somewhere but mislaid it  )

[Ivor]

There appears to be quite few patches especially the transistion from top left to M45 gas region, but I'm not sure whether that the JPG compression you've used. Were you using H or Clear for Luminance? I would have thought H would have been better for your location?

With my ST8300M I've found I need at least 10 subs per channel for RGB and even more for SII & OIII, I'm not sure how your location compared to mine (T. Wells) will impact the sub count.

[RobertM]

Hi Carole,

That's good as a first LRGB but it looks like you may have a spacer issue as corner stars are all equally, and evenly, elongated.  The gradient is most likely due to light pollution.

Robert

[Carole]

Hi Ivor,

Do you mean Ha as I don't know what H is.
a) I didn't think that Pleiades would have Ha.
b) I only have four holes in my 2" filter wheel one each for LRGB, the Ha is in a separate narrowband filter wheel.

I actually used the Blue filter for the luminance as it seemed to have much better nebulosity than the luminance.

Hi Robert, yes there is a slight amount of elongation in the corners, but no-where near as bad as it was when I first got the camera.  I tried to purchase a spacer exactly the right size, but no-one seemed to do exactly the right size, so this is very slightly out.  Not being too technical I am not sure what I can do about it, I am assuming it is the distance of the flattener lens to the sensor that is the deciding factor.  I have tried both Ian King and Bern.  Bern supplied the existing spacer.  Bit of a pain really.  

Maybe I could get JonH to do a custom spacer for me.

Carole

[Ivor]

Sorry, yes I meant Ha, a quick google found this example

http://stargazerslounge.com/gallery/image/2702-m45-081008-les-granges-france-9x120sec-rgb-ha-atik-314l-wo-zs66-no-darks-or-flats/

I thought it would be a perfect example considering the poster

[Fay]

Gosh Ivor, do you know I dont remember using an HA filter, but just goes to show!!!!

[Carole]

I'm not sure whether that the JPG compression you've used.

Talking about that, this was a PNG file uploaded to my website and then linked to here and it has turned into a Jpeg en-route, so no compression applied.  How does this happen?  Why doesn;t it stay a PNG?

Carole

[Ivor]

I've gone to your website and it is a JPG there, I'm not sure how your website is setup but the upload process could be converting it.

http://www.caroleastronomy.webspace.virginmedia.com/_wp_generated/wpeb5433f5_0f.jpg

[Carole]

I had better re-check that Ivor, in case I have loaded the wrong image.

Carole

[Mac]

Gosh Ivor, do you know I dont remember using an HA filter, but just goes to show!!!!

Dont worry Fay, its not really your photo anyway.

Mac.

[JonH]

Hi Carole,
Looking good so far, wish i had a camera to do LRGB with!

Do i hear mention of my name and something custom?......

[Carole]

Do i hear mention of my name and something custom?......

Yes please Jon, I'll E Mail you to discuss if that's OK with you.
Not urgent but something I should get sorted out.

Carole

[JonH]

No problem

[Carole]

Just to say having seen this image displayed at BEECHE last night, it looked terrible and shows where I rubbed out one layer to show the one below and made a right pigs ear of it, but doesn't really show on my monitor.

I am therefore going to re-process it.

Carole