First Light RC8 - Horsehead (7hrs of data)

[swannies1983 (Dan)]

This is my first attempt at imaging the Horsehead nebula with my new RC8 in combination with my modded (un-cooled) Canon 30D. It was taken over 4 nights. I fought high winds one night (still produced round stars...don't know how) and high temperature for one evening (~28 degrees C...hot pixels...yuk!) I was getting more star trails on the nights with no wind but this is likely to be due to me not sorting out balance in DEC yet.

Details
Scope: GSO RC8
Mount: EQ6
Imaging camera: un-cooled, modded Canon 30D
Guide scope: 60mm f/11 refractor
Guide camera: unmodded toucam
Guided using PhD
Sub details: 7hrs of data (84x5mins @ ISO1600)
Stacked in DSS and processed in PS.

First image is my attempt and second shows RAW sub. As you can see in the final, there is a annoying reflection which is likely to be due to LPS filter.

Not completely happy with colour so feedback is more than welcome

Merry Xmas all

Link to higher resolution image (3MB)

[LewisM]

That's a very odd reflection artifact around Alnitak. Certainly never seen it before.

[tilbrook@rbe.ne (Justin Tilbrook)]

That's nice Dan!

I quite like the colour, and looks like plenty of detail.

The reflection is quite odd seems to scribe a full circle, never seen that before.

Cheers,

Justin.

[swannies1983 (Dan)]

Thanks guys. Mario also had the same reflection issue with his RC8 as shown here.

[swannies1983 (Dan)]

Updated original image as I noticed a green gradient. Removed with HLVG plug-in.

[allan gould]

If you look carefully at your image in the reflection from Altinak you can see each pixel ampified in the reflection just outside the first blue halo of Altinak.. Seen this previously with OSC cameras around very bright stars. The dark spur at 4 oçlock is due to your secondary arm.

[Ross G]

Hi Dan,

Apart from the reflection, a very nice looking photo.

Ross.

[swannies1983 (Dan)]

Thanks Ross.

I actually came across a poster on Stargazers Lounge talking about reflections with their RC8. I thought it related to the earlier problems that Paul Haese helped rectify but apparently this is another issue. This is a post from the other person:

Hi all !
FYI, I've finally solved the reflection problem for good on my GSO 8" RC. And as a matter of fact, it had to go all the way up back to GSO. After several testings I did with a friend of mine, painting the inside of the focuser, flokking the adapters and so on to no avail, they aknowledged that there was a design flaw with the primary mirror baffle tube, and they redesigned it on our request.
The existing RCs can benefit from this new design, because the baffle tube actually has a thread at its end. So you just need to screw the extension they made to the existing baffle tube and here you go, no need to take the thing apart, just find some small hands that can reach the baffle tube through the spider.
I did some testings using a CCDT67 reducer, a configuration that was completely unusable beforehand (I used to have these big hallows all over the place, shooting with a DSLR) and well, I must say it solved my problem.
From there on, I have no clue how one can get the extension. I dealt this problem with a reseller here in France, and since we were the ones to hit the nail on that one, we got our extensions fo free. Maybe just see with whoever sold you the RC. GSO knows about all this, so I guess any reseller should be able to get hold of this item.

[stevous67 (Steve M)]

Very nice result Dan, and good saturation levels - I like it!

Steve

[Rigel003 (Graeme)]

Well done Dan. That's a lot of data and you've controlled the noise pretty well for these warm Adelaide nights. Halos around Alnitak are the nemesis of everyone who images this field. A lot easier with a refractor.

[swannies1983 (Dan)]

Thanks Steve and Graeme. Yeah, one night was hot but that others were around 15 degrees. Hot weather coming up but clear skies predicted. Do I bother imaging?