M81 - Lum (8 x 15 min)

Dear Friends,

Everything that could go wrong did go wrong last night (actually early this morning). Transparency was so bad that I could not get an initial good focus; once I focused seemingly right, the first 15-min exposure was immediately deleted due to the poor focus (due to the changing transparency). This went on for the initial three exposures and it was only on the fourth 15-min exposure and an hour later that the result was acceptable. Of course, a couple of exposures later the sky REALLY cleared up (fog and/or high-level clouds) and I needed yet another finetuning in the focus.

Everything seemed to be rolling along until the CCD camera bumped into the telescope pillar as M81 crossed the meridian. Well, this put a stop to my RGB exposures and after nearly five hours of freezing cold, humidity and fatigue, all I had to show for my efforts was eight exposures (above average quality) of 15-min duration each.

Without further adieu: www.astrovox.gr/forum/album_pic.php?pic_id=2963 ....

I am hoping that in approximately three weeks time when the moon is not a factor, there will be at least one clear night for the proper and complete imaging of this wonderful galaxy.

Clear skies to all of my buddies (yeah, yeah, Seanie too) here on Irishastro.

Anthony that is a wonderful result. Lovely detail. I can't wait to see it when you capture RGB data for it. I have no doubt that it will be simply stunning. However it looks like it will be towards the middle of the month before the moon allows such data to be captured.

I have a nice new set of interference filters arriving any day now. One of the first things I want to do is capture RGB data for my own luminance image of M81 I took a while back. I would love to compare notes with you once we both have a final result.

One thing I came across a couple of days ago was this item from Rob Gendler

www.robgendlerastropics.com/LLRGB.html

The technique he describes looks very interesting. It could help a lot in producing accurate colour renditions of such targets.

That's still a very good shot for all your effort Anthony, I like the dust detail in there, a beautiful galaxy.

Keith.

Hi Dave,

It will indeed be interesting to compare notes on each other's LRGB versions! As for the interference filters you are expecting, I trust you are aware of the G2V star calibration that you should pursue (one-time exercise) so that you will know the QE efficiencies for your camera in conjunction with the filters. For anyone interested, I have prepared the following text: www.perseus.gr/Astro-Tips-G2V-Star-Calibr.htm ....

Also, thanks for the link to Rob Gendler's article. I do remember reading it but I did forget the interesting technique he describes. As a result, thanks for the reminder which is also very timely in lieu of M81.

Keith: Thanks for the kind words. I am convinced there is a better version on the way once things get back to normal with the weather. It is not very much fun when you are having trouble focusing and which was the case last night?!

Very good image Anthony! Can't wait to see the colour one!

Regards,

You got a really great result there Anthony. It looks as stunning in black and white as I guess it would in colour. Well done!

Seanie.