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Equipment Discussions >> Video and Electronically Assisted Astronomy

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mclewis1
Thread Killer
*****

Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Veil NGC6992 , 105mm / F5.6 new [Re: John59]
      #6029914 - 08/16/13 09:22 PM

Nice shots Kevin and Matt.

Matt, exposure times? (I suppose 1024x), and AGC/gain info?
Sky conditions (limiting mag)?

Edited by mclewis1 (08/16/13 09:25 PM)


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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Veil NGC6992 , 105mm / F5.6 new [Re: mclewis1]
      #6029947 - 08/16/13 09:39 PM

x1024 , gain 1/3 to 2/3 of max (for the fainter targets) . Cherry Springs State Park, mostly blue zone . Just first light photos, no attempt to optimize anything else except gain and integration . All other adjustments (sharpness, color balance, noise reduction, gamma etc) were left to default this time.

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GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Veil NGC6992 , 105mm / F5.6 new [Re: mattflastro]
      #6030111 - 08/16/13 11:40 PM

Matt,
Some of Keven's images you posted here seem to be among those Keven has posted in another thread. But these here have a darker sky, suggesting some post adjustment on the black level. In the case of M17 (which Keven has not posted, yet anyway), the degree of blackness in the sky is really suggestive of some after adjustment carried to an exaggerated degree, and is probably not what the camera would ever output.


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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Veil NGC6992 , 105mm / F5.6 new [Re: GlennLeDrew]
      #6030156 - 08/17/13 12:11 AM

Quote:

Matt,
Some of Keven's images you posted here seem to be among those Keven has posted in another thread. But these here have a darker sky, suggesting some post adjustment on the black level. In the case of M17 (which Keven has not posted, yet anyway), the degree of blackness in the sky is really suggestive of some after adjustment carried to an exaggerated degree, and is probably not what the camera would ever output.



Glenn,
My current theory suggests that because the camera uses a 1/3" ccd, which is known to have less output than the better 1/2" ccd's , the sky is darker. I can actually prove this hypothesis thru induction. If we could make a 1/6" ccd, the sky would be even darker. And in a 1/infinity sensor, which would be a point sensor with no dimensions, the sky would be a perfect value of 0 counts . No read noise, no dark current, just perfect background even without cooling. Although cooling a point sensor might be easy since it would have no area, therefore no volume and given fninte density it would result in 0 mass, and that would take 0 BTU's to cool to any arbitrary temperature . Presto, perfect black 0 count dark sky . Although I've seen such skies in many previous images posted here by many illustrious dudes and was under the impression that it's one of the desirable traits of a camera to chop off the left side of the histogram, because video is different than CCD .


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GlennLeDrew
Postmaster
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Veil NGC6992 , 105mm / F5.6 new [Re: mattflastro]
      #6030172 - 08/17/13 12:23 AM

Matt,
I was pointing out the *difference* between the same images posted by Keven and yourself. If they were unaltered, they should be indistinguishable. But your versions had a notably darker sky.

A smaller chip (with smaller pixels) does not result in a selectively darker sky. While the output for the sky is lower, so it is for all other elements of the image, too. And so intrinsic contrast is not altered. What is altered is the S/N ratio, which is lowered, all else being equal.


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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Veil NGC6992 , 105mm / F5.6 new [Re: GlennLeDrew]
      #6030176 - 08/17/13 12:25 AM

Glenn,
I was pulling your leg. There was a for a hint.


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mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Veil NGC6992 , 105mm / F5.6 new [Re: GlennLeDrew]
      #6031527 - 08/17/13 06:34 PM

Glenn,
You were correct and it was my error. His original files were in TIFF format and my conversion to JPG was the problem.
I replaced the offending file with the original (or at least with a jpg that looks like his original tiff on my monitor). I did not do any monitor color calibration recently so YMMV. Your keen eye is appreciated.


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JimT
sage
*****

Reged: 08/13/05

Loc: Milky Way Galaxy
Re: Veil NGC6992 , 105mm / F5.6 new [Re: mattflastro]
      #6057368 - 09/01/13 10:20 AM

Matt

I have stumbled in to this before also. JPG can change different formatted images a lot sometimes when converted over. No idea why , but it does.


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JimT
sage
*****

Reged: 08/13/05

Loc: Milky Way Galaxy
Broadcast on NSN from SNAKE VALLEY new [Re: JimT]
      #6059632 - 09/02/13 04:36 PM Attachment (19 downloads)

Mr. Snake Valley, Ken James was broadcasting today and I caught this one.
NGC 3372

It was a real crowd WOW'er for sure.


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Dragon Man
Carpal Tunnel
*****

Reged: 03/07/06

Loc: Snake Valley, Australia
Re: Broadcast on NSN from SNAKE VALLEY new [Re: JimT]
      #6060881 - 09/03/13 11:21 AM

Hey, thanks for posting that Jimbo, I didn't think to take any screen grabs while I was broadcasting last night.
I was probably laughing too much because it was a fun broadcast.
Glad you got one for me

That is the Keyhole Nebula in Carina Nebula (NGC 3372), a large naked eye nebula see all night every night from here because it is circumpolar.

That really bright star just left of centre, right under the Keyhole Nebula, is Eta Carina, the brightest known star in the sky.
It is about to Supernova any day now (or maybe in another 100 years ).
They estimate that when it does go off it will be as bright as a full Moon illuminating the ground for about 3 weeks then will gradually start to fade over the next 3 months.

Even though Eta Carina is classed as the brightest known star, the reason it doesn't look as bright as Sirius is because it is covered by the Humunculous, the remains of it's last explosion.

The whole Carina Nebula is very easily seen by naked eye and is about the size of a Full Moon.

I was using a Mallincam Xtreme, and a 0.6x Focal Reducer, in an ED80 mounted on an EQ6 mount.


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Gavin Bray
sage


Reged: 12/31/06

Loc: Australia
Some Lodestar images new [Re: Dragon Man]
      #6069098 - 09/08/13 09:20 AM Attachment (16 downloads)

I took these tonight with the Lodestar mono attached to my 14" Meade at F3.3. All are single shots with no processing.

M8

Edited by Gavin Bray (09/08/13 09:21 AM)


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Gavin Bray
sage


Reged: 12/31/06

Loc: Australia
Re: Some Lodestar images new [Re: Gavin Bray]
      #6069099 - 09/08/13 09:22 AM Attachment (10 downloads)

M16

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Gavin Bray
sage


Reged: 12/31/06

Loc: Australia
Re: Some Lodestar images new [Re: Gavin Bray]
      #6069102 - 09/08/13 09:23 AM Attachment (10 downloads)

M17

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Gavin Bray
sage


Reged: 12/31/06

Loc: Australia
Re: Some Lodestar images new [Re: Gavin Bray]
      #6069104 - 09/08/13 09:24 AM Attachment (7 downloads)

M20

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Gavin Bray
sage


Reged: 12/31/06

Loc: Australia
Re: Some Lodestar images new [Re: Gavin Bray]
      #6069106 - 09/08/13 09:25 AM Attachment (6 downloads)

M22

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Gavin Bray
sage


Reged: 12/31/06

Loc: Australia
Re: Some Lodestar images new [Re: Gavin Bray]
      #6069108 - 09/08/13 09:25 AM Attachment (11 downloads)

M27

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Gavin Bray
sage


Reged: 12/31/06

Loc: Australia
Re: Some Lodestar images new [Re: Gavin Bray]
      #6069110 - 09/08/13 09:26 AM Attachment (9 downloads)

Part of the Veil Nebula

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Gavin Bray
sage


Reged: 12/31/06

Loc: Australia
Re: Some Lodestar images new [Re: Gavin Bray]
      #6069118 - 09/08/13 09:30 AM Attachment (14 downloads)

Something not so bright - NGC6822, a barred irregular galaxy

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Chris A
scholastic sledgehammer


Reged: 02/03/07

Loc: Toronto, Canada
Re: Some Lodestar images new [Re: Gavin Bray]
      #6069359 - 09/08/13 11:47 AM

Lots of very nice Ha images Gavin!! My only question is what is causing the horizontal streaks in all brighter stars in every image? Thank you.

Chris


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Gavin Bray
sage


Reged: 12/31/06

Loc: Australia
Re: Some Lodestar images [Re: Chris A]
      #6069938 - 09/08/13 05:07 PM

Hi Chris

These were with an IDAS light pollution filter. I don't have an Ha filter.

I'm not sure what's causing the streaks. Any suggestions?

Regards
Gavin


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