Deneb

[neil groves]

Hi guys...

   Well i'm more than a bit chuffed with this although there is still an issue that I could use some advice on please.

Overall I am satisfied with this as my second image using DSS, BUT.........

In an effort to bring out any nebulosity in the area which (looking at other peoples images) i know to be red during the stretching bit of the processing, I pushed up the reds in curves which added a redness to Deneb, since Deneb is a blue/white star, this is obviously wrong, do I need to boost any colours specifically during processing or just concentrate on what is in the data as recorded by the camera?

  I went out into the yard and was disappointed to see clouds, however they were thin high cirrus clouds through which the stars were showing and every now and again there would be a clear patch of sky appear so i decided to go ahead and shoot anyway, details below:

45 lights

11 Darks

5D

70-200L @ 200

f/4

3 sec exposures

I kept the exposures short to ensure round stars since i was on a static tripod, every now and again thin cloud wisps would cross Deneb but never thick enough to completely blot it out, i guess this is what has caused the slight shadow appearing down and to the right of the brighter stars?

Is the red patch to the top left of Deneb nebulosity or just artifacts introduced during processing?

any advice appreciated

thanks

Neil.

p.s oh and why do bright stars appear as big blobs in images when through the FOV they appear as pin sharp lights?

[neil groves]

now i see why i need bias files also to take away the vignetting, or is that flat files?

Neil.

[jambouk]

I tried Deneb the other night at 50mm on an equatorial mount, 120 second exposures, and did a load of them, but the next day found out the focus was off It's a project for another night to try again.

I suspect you've got gas cloud there. Have you added flats to get rid of vingetting?

On this sub, Deneb is the star nearest the middle, just north (up) from the centre.

James

[ollypenrice]

Flats for vignetting. This thread should help you orientate yourself. http://stargazerslounge.com/topic/198910-around-deneb/

Olly

[neil groves]

ok so it's flats I need, i'll take some and reprocess.

I can definitely see nebulosity in your shot James, it seems further from Deneb than it appears in my shot so I don't know if mine is what I think/hope it is lol

love those wide views.

Neil.

[jambouk]

I'm just waiting for a new zero percent interest credit card, then i'm getting a better dslr

Yes, the wide views are lovely.

Thanks for the link olly, i need to do those too eventually.

James

[Stu]

I tried Deneb the other night at 50mm on an equatorial mount, 120 second exposures, and did a load of them, but the next day found out the focus was off It's a project for another night to try again.

I suspect you've got gas cloud there. Have you added flats to get rid of vingetting?

On this sub, Deneb is the star nearest the middle, just north (up) from the centre.

James

North American Nebula showing nicely in that one near Deneb, plus a few others.

Is it a focus problem or something else? Looks ok at the top but strange star shapes towards the bottom?

Stu

[jambouk]

I think it may be related to the EOS filter clip I've got. It might have a finger print on it, or not be seated correctly... I'm just having a quick go at M45, and have pushed the clip in harder in the dark, and maybe there was a slight bit of movement, but not sure. I'll have a look at what 30 minutes of widefield data on M45 looks like. It's hard to get good focus, as smaller fainter stars can look like pin points of light, but brighter ones just go blobby for me.

James

[Astrosurf]

I've not used it recently, and am not at home to check, but I think I used a Star Mask in Photoshop to isolate the brightest stars while stretching so they didn't get blown out and larger. Have a look on the Web for tutorials.

It's a great pic though!

EDIT: I think it was something like this: http://starmatt.com/articles/StarShaping.html

Alexxx

[lensman57]

Hi guys...

   Well i'm more than a bit chuffed with this although there is still an issue that I could use some advice on please.

Overall I am satisfied with this as my second image using DSS, BUT.........

In an effort to bring out any nebulosity in the area which (looking at other peoples images) i know to be red during the stretching bit of the processing, I pushed up the reds in curves which added a redness to Deneb, since Deneb is a blue/white star, this is obviously wrong, do I need to boost any colours specifically during processing or just concentrate on what is in the data as recorded by the camera?

  I went out into the yard and was disappointed to see clouds, however they were thin high cirrus clouds through which the stars were showing and every now and again there would be a clear patch of sky appear so i decided to go ahead and shoot anyway, details below:

45 lights

11 Darks

5D

70-200L @ 200

f/4

3 sec exposures

I kept the exposures short to ensure round stars since i was on a static tripod, every now and again thin cloud wisps would cross Deneb but never thick enough to completely blot it out, i guess this is what has caused the slight shadow appearing down and to the right of the brighter stars?

Is the red patch to the top left of Deneb nebulosity or just artifacts introduced during processing?

any advice appreciated

thanks

Neil.

p.s oh and why do bright stars appear as big blobs in images when through the FOV they appear as pin sharp lights?

Hi Neil,

Well done, good start, I strongly suggest that you download APT, even in the unlicensed form, fully functional, the FWHM focus aid will help  you get better focus and reduce the star  bloat. Using any on camera aids for focusing AP type objects is a waste of time IMHO. You MUST take the flats at the same time as you take the lights with exactly the same focus position on your lens or scope, this the only way to make sure that the out of focus images of the dust bunnies and othstuff such as vignetting can be corrected otherwise you'd end up with wired and wonderful effects on your images, as for bias you need a lot of them and I mean a lot between   50~100of them for the darks try and get atleast 20~30 frames.

PS: You have captured  your  first nebular image , well done, there is nebulasity  around deneb.

A.G