jbell
sage
Reged: 04/09/10
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Redneck Astronomy
#5370925 - 08/16/12 12:19 AM Attachment (41 downloads)
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Being impressed with scout's milkyway on the garage.... Here's my redneck version.
Nec projector lens, F1.7 25mm zoom to F2.2 32mm
Lodestar C
Microphone stand
Pointed up at the milkyway.
12 seconds, single frame no external post processing, straight from the screen.
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scout72
Pooh-Bah
Reged: 05/12/08
Loc: SF Bay Area
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Re: Redneck Astronomy
[Re: jbell]
#5371027 - 08/16/12 02:40 AM
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Microphone stand??? Nice work- I am sure duct tape was involved.
Looks like maybe there is some star bloat- do you have an ir filter on the camera?
At least you were able to get it to come to focus, so good effort.
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scout72
Pooh-Bah
Reged: 05/12/08
Loc: SF Bay Area
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Re: Redneck Astronomy
[Re: scout72]
#5371032 - 08/16/12 02:42 AM
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Oh sorry- didn't see the gear setup image when I first posted- I guess no duct tape- but zip-ties are also high on the redneck "cred" scale.
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jbell
sage
Reged: 04/09/10
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Re: Redneck Astronomy
[Re: scout72]
#5371256 - 08/16/12 09:07 AM
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At least I got to confirm what I thought I knew....
I need 100mm for the scale I want.
12 seconds is the max integration time at 25mm, so once I go 100mm... I need F1.
There is no way a cctv cam is as sensitive as the lodestar. The cctv will need some help.
What's the easiest way to get that? I don't know if there is any practical way to stack 0.5x reducers on a starblast 4.5. (maybe a 2" reducer rigged to the bottom of the focus tube? or replace focuser entirely, and the 1.25 reducer on nose of camera?)
any ideas for me?
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scout72
Pooh-Bah
Reged: 05/12/08
Loc: SF Bay Area
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Re: Redneck Astronomy
[Re: jbell]
#5371527 - 08/16/12 12:23 PM
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Quote:
There is no way a cctv cam is as sensitive as the lodestar. The cctv will need some help.
Aw man- we were getting along so well in here and then you had to go throw this baby-ruth bar in the pool... 
Same CCD chip- ICX428/429 I believe in your cam as in the SCB-4000 Samsung...
But I know what you were getting at...
But also at 100mm you are also going to hit up against the limits of a non-tracking mount over a few seconds.
If you want 100mm FL at close to f1 I still think your best bet is going to be a lens (but won't be cheap cheap)- but I haven't messed around with stacked reducers on a newt enough to comment on your approach
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bhuvfe
member
Reged: 01/14/11
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Re: Redneck Astronomy
[Re: jbell]
#5371640 - 08/16/12 01:57 PM Attachment (25 downloads)
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Jbell,
If you have a spare 50 mm finder and a 0.5 focal reducer you can easily go to the FOV you need (more or less) but not at f1. See attached M31 (45 s, raw file). This setup cost less than a new lens but I wouldn't call it cheap...
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jbell
sage
Reged: 04/09/10
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Re: Redneck Astronomy
[Re: scout72]
#5371683 - 08/16/12 02:26 PM
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Quote:
Quote:
There is no way a cctv cam is as sensitive as the lodestar. The cctv will need some help.
Aw man- we were getting along so well in here and then you had to go throw this baby-ruth bar in the pool...
Same CCD chip- ICX428/429 I believe in your cam as in the SCB-4000 Samsung...
But I know what you were getting at...
apology, should have been more specific... 1/3" 512x cctv that I'm considering....
yes, once I go 100mm, then I can no longer do 12seconds, more like 3 or 4. Which makes a 512x work perfectly fine in terms of integration.
However with a 4x increase in Focal length,
means a 4x reduction in integration time for non tracking mount,
means a 4x improvement in F ratio to offset --
means I need F1...
100mm at F1 -- that's the goal.
And I think THIS is too expensive... but on the right track.
makes me kinda want to reconsider the camera tripod... and start thinking astroboy, or the cheapy celestron mount, etc..
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jbell
sage
Reged: 04/09/10
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Re: Redneck Astronomy
[Re: jbell]
#5374349 - 08/18/12 09:05 AM Attachment (16 downloads)
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more....
BTW scout... yes I use nashua aluminum tape... so high tech duck-tape.
This lens is in the 100mm range, and gets me pretty good scale. I had a bunch of fun last night just running from one end of the milky way to the other. Too bad it's not anywhere close to F1... but the lodestar brought out the colors in 8seconds. 8 was pushing it a bit... I 'footballed' stars a little, but where I was concerned that I was going to be limited to 4 seconds on a non tracking mount... well, I think this works.
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jbell
sage
Reged: 04/09/10
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Re: Redneck Astronomy
[Re: jbell]
#5374360 - 08/18/12 09:11 AM Attachment (17 downloads)
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Here is for scale difference vs first post. I "think" this is the same area... but I wasn't being very careful about labeling things. Also my color balance isn't quite the same... didn't go back and try to tweak it.
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