From: Mark Gaffney <markgaffney@mac.com>
Date: February 1, 2009 12:19:35 AM MST
To: Astro_IIDC@yahoogroups.com
Subject: Re: [Astro_IIDC] Re: M37 Image
Hi Milton, Actually perhaps you`re right & I should hold off on the Meade OAG & go for a Celestron (they`re $185). In the meantime I can get some of those Mogg parts. Mark.
On 01/02/2009, at 4:49 PM, Milton Aupperle wrote:
Hi Mark;
I would not recommend the Meade OAG, even if it is cheap.
You can not tilt the prism, which means your area for finding guide
stars is far narrower than with either the Celestron OAG or the Orion OAG.
HTH..
Milton Aupperle
--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:
Hi Alberto, I was asking about f3.3 FRs before buying anything but the
general consensus I got both here & the SCT & Autoguiding groups was
that getting things into focus might be difficult. The set-up I`ve
decided on with the OAG I`m about to purchase is an f6.3 FR (probably
Antares as they`re supposed to be as good as Celestron maybe better
for a cheaper price.) Also I was looking at a 0.6 Mogg FR attaching to
the imaging camera along with a 0.3 extender from the same place. I`ve
been offered a barely used second-hand Meade OAG for only $90 +postage
of $10 which is a great deal I think! Here`s the site for the Antares
f6.3 FR as given to me by a guy called Don D`Egidio;
http://www.agenaastro.com/Antares-f-6-3-SCT-Focal-Reducer-p/ofr-an-sctfr.htm
& here`s the Mogg site in Adelaide Australia where I live;
http://moggadapters.com/astro/adapter.asp
just click on Focal Reducers on the left. I was thinking also of
another 0.6 Mogg FR & a TM- 1.25. F adaptor also from Mogg to connect
to the OAG T-thread. Just go to accessories on the left & scroll down
the page. In the Future perhaps I may even get a Moonlite CS focuser
but things tend to move glacially in the land of Mark Gaffney
purchases! Mark.
On 01/02/2009, at 1:03 PM, albe albo wrote:
Very nice, patient and ICY work!
I noticed you used a OAG (i'd like to try it too) but i also figured
out that the OAG should work at its best into a star cluster!
Normally I heard that the OAG is terrible in order to catch a star.
Example around M51 or M82 i guess that it should be very hard.
Is it?
In addition i would use the OAG on a f. 3.3 reducer but it is less
forgiving than the 6.3reducer.
Time ago i read that even Mark Gaffney would use the OAG on a f 3,3
reducer but i couldn't read if he or someone else succeeded in this
task.
Ii fully agree about decent RGB even if it seems impossible.
All my color images done with TIS DMK exploited very old color
imagery i did years ago (at my beginning) with my EOS300D.
They were absolutely filthy, noisy and blurry but they worked fine
as RGB!
http://www.makina.it/SAA/DSO_%28DMK+EOS%29.html
For this reason now i'm experimenting the double TIS camera
grabbing: DMK =Luma + DBK binned = one-shot-RGB (i did only M1
because since i own the DBK the sky is permanently cloudy here).
The result was encouraging in order to continue further experiments.
This is the link with the reprocessed M1:
http://www.makina.it/SAA/DSO_%28DMK+DBK%29.html
About M37: I guess that you correctly left the natural result "as
is" so I did a little aesthetic experiment trying to reduce the
already small horizontal ovalization of the stars .
I tried with 0,67 px at center but it is different at the corners.
Do you want to see it?
TTYL
From: Milton Aupperle <milton@...>
To: Astro_IIDC@yahoogroups.com
Sent: Saturday, January 31, 2009 11:18:13 PM
Subject: [Astro_IIDC] M37 Image
Hi Folks;
I think I finally have my L R G B exposure times and processing
figured out for the EXHAD Grasshopper camera.
Check out M37 (taken at -22°C ambient temperature) :
http://groups. yahoo.com/ group/Astro_ IIDC/files/ DSO/M37_20090125
_MJA.jpg
Details are embedded in the image. I did have an electric blanket
turned on and wrapped around the gear box of the HEW 5 mount, which
eliminates the "grinding gears" issues below -15°C when slewing at
900x times siderial for the GotTo.
I found that when using the Hutech IDAs LPR filter with the AstroDon
"E" series LRGB filters, I need to use exposure times of roughly 1.3
Red, 1.0 Green, 1.0 Blue. I may increase the blue color channel a bit
more in future imaging session (I think it's a bit low), if the wind
ever stops blowing.
It's amazing how much you can underexpose, blur and soften the RGB
color channels and still get decent colors out in the LRGB combined
image.
TTYL..
Milton Aupperle
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