From: Mark Gaffney <markgaffney@mac.com>

Date: January 31, 2009 8:06:52 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] M37 Image

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@outcastsoft.com>

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