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Horwig

Just how deep can you go in one sub?

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For no sensible reason I can think of, just it was clear for a short while back in Nov and I'd been playing about with the setup, so I tried a 60 minute sub in luminance.

Here's that single sub, stretched in PS:-

M31, FSQ106 at F5, with an SXVR-H35, using an OAG with Lodestar on an AZ-EQ6

m31-deep_3600sec_1x1_L_frame1.thumb.jpg.241527278f2b0688c97791a3e1d7f76d.jpg

As I said, no real reason, but OK, there's probably a bit of bragging going on, I'm quite proud, the stars are ROUND!:icon_biggrin:

Huw

 

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What a glorious thing to have attempted.  I salute your indefatigability. 

Edited by gnomus

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A good testament to your sky as well as your guiding :) 

I'd have a horrible white (orange) out in luminance after 20 min :( 

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Is it a general question, or a personal one?

If general, the answer is "it depends". If personal, the longest individual sub I have done is 3 hours, just because :) ( I use my Ha filter for these long exposures due to bad LP where I live.

Your pic nicely demonstrates that conventional thinking needs challenging from time to time to see what happens. If you get a chance, do the same experiment on M13, it'll blow you away :)

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Mine is a 60min on M57 in ha and it was not very different from the 30 min subs I did.

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I went after the upturned outer shell of M31 a few years ago. I'd seen it on just one picture on the web at that time. I had endless luminance subs in 15 minutes but it was the 30 minute subs which found it. I only needed seven of them as well. I'm a fan of the long sub but have never gone beyond 30 minutes. Time to try! (There are countlmess folks who will tell you at length why it is a waste of time but I'm satisfied from experience that it isn't.)

Olly

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13 hours ago, RikM said:

A good testament to your sky as well as your guiding :) 

I'd have a horrible white (orange) out in luminance after 20 min :( 

Thanks, yes my sky here is all right, I get some LP from town, which is to my North East, but overhead and West is quite clean, this is the view from my ASC, North is down.

Capture_0002.thumb.jpg.3c53e71ef6ace6cf59c7b48ca0e21803.jpg

The main reason I tried the silly long sub was that I'd started to experiment with PA in SharpCap, think it proves how valuable a tool it is.

 

Huw

 

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Very impressed Huw.

Your post will give me the encouragement to extend out my Lum subs.  I plan to capture a widefield M81/82 with my new FSQ106 and long Lum subs will be just what I need.  I also fancy just proving what Per enthused about the 10 Micron mounts, super long unguided subs.  The longest to date unguided is 30 minutes with perfect stars, so I ought to push out to 60 minutes if only in a fond tribute :headbang:.

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1 hour ago, Barry-Wilson said:

Very impressed Huw.

Your post will give me the encouragement to extend out my Lum subs.  I plan to capture a widefield M81/82 with my new FSQ106 and long Lum subs will be just what I need.  I also fancy just proving what Per enthused about the 10 Micron mounts, super long unguided subs.  The longest to date unguided is 30 minutes with perfect stars, so I ought to push out to 60 minutes if only in a fond tribute :headbang:.

...but what do round stars tell you? Not all that much. A random error on both axes will give you round stars. (Not just a pedantic quibble. We actually had this when setting up the guide parameters with the Mesu. Stars were always round but they got smaller as we refined the guiding.) Assuming good PA, if the wheel will go round once (what, 8 minutes or so?) it should go round twice or thrice or ... what's the word for four times??? (We need an English teacher...)

Ah me, but how we miss Per. Imagine how I felt when I put the lens cap on his TEC to keep the dust off it.

Olly

Edited by ollypenrice

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13 hours ago, ollypenrice said:

I had endless luminance subs in 15 minutes but it was the 30 minute subs which found it. I only needed seven of them as well.

Interesting point, anybody done a comparison, equal total integration, lots of short vs a few long subs?

Huw

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Just now, Horwig said:

Interesting point, anybody done a comparison, equal total integration, lots of short vs a few long subs?

Huw

I think Sara did this a while back.

Olly

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I only do long exposure One Shot Color imaging. Most typically I'm in the 20 minute to 30 minute range. But I get there often in 300 second steps.

But if it is something I'm revisiting, and I know 1200s or 1800s worked before, I can tend to jump into it.

My Dad always said, "Nothing ventured, nothing gained."

One night I got a wild hair and went 5400 seconds. (90 minutes)

But you have to get your guiding down good to venture out there.

1800s of NGC 1893 from recent play: (07-03-2017, 1800s YCbCr HA7nm Denoised in Photo Shop (filters))

Mine is 1. Upside down 2. HA only. But if I knew how, I love to get this color.

 

1800s YCbCr HA7nm DN.jpg

Edited by SonnyE

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On 09/03/2017 at 23:09, Horwig said:

For no sensible reason I can think of, just it was clear for a short while back in Nov and I'd been playing about with the setup, so I tried a 60 minute sub in luminance.

Here's that single sub, stretched in PS:-

M31, FSQ106 at F5, with an SXVR-H35, using an OAG with Lodestar on an AZ-EQ6

m31-deep_3600sec_1x1_L_frame1.thumb.jpg.241527278f2b0688c97791a3e1d7f76d.jpg

As I said, no real reason, but OK, there's probably a bit of bragging going on, I'm quite proud, the stars are ROUND!:icon_biggrin:

Huw

 

Some people - mmm, how can I say this politely.

Nope cant think of it.

That's one h*** of a light.

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