Scorpio Region on 15/5

[JohnH]

I could not make it to the session this w/e (hope it went ahead), the conditions here were good. I took the attached, it is a stack of 9x2 min exposures at 40mm F9, ISO 1600 with the Canon 20D piggybacked on my ETX 90. Processing is still a bit raw and the compression is not helping but I am pleased with the result...

[seeker372011]

very nice. What do you use to piggy back the Canon on to the ETX?

[rumples riot]

Despite compression the image is still very Nice John. Keep them coming.

[ving]

my god! its full of stars!!!
great shot :)

I think a good idea for images on this board would be to have a tumbnail or a smallish image linking to the full size on a photobucket acct. that way the smaller vers is availiable for 56kers and linked to the normal for LPBs.

[atalas]

Nice work John!


Louie:cool3:

[rowena]

why did u use a F9 appeture at iso 1600?

or is that as low as the lens will go?

did you have any other attempts at a lower iso and lower appeture?

[JohnH]

Thanks to all for the nice comments and I am very glad you like the image, what a spectacular piece of sky.

To answer the questions raised:

I use a Scoptronix ETX90 Piggyback adapter, I did try to make my own but it was not strong enough, the bought one cost $99 - a little high for a metal hoop and a thumb screw! If you have the tools and some basic metal working skill (that is me out by the way - I'm ok with a compiler though....) then I am sure you could make one for $20 or so.

I used F9 because the lens was the kit 18-55 F4-5.6 lens that came with the 20D. It is NOT a good lens for astro work, soft at best and with strong coma and sperical abberations. Come to think of it this is just not a good lens! The only way to use it for astro is to stop it down at least two stops, it would be better at f16 but then I would have to expose longer and my mount (ETX90 remeber) limits me to about 4 mins max at this focal length. This also dictates the ISO. This does not seem to be a problem as, so long as you are doing dark frame subtration and stacking, ISO is not so important as signal to noise ratio thus I always shoot at ISO 1600 to get to mid histogram and stack to average away the noise.

The acquired images were then processed in Registax 3 (stacking), Photoshop Elements (levels) and Neat Image (noise removal).

[acropolite]

Nice work John. How did you release the shutter, cable or self timer and did you use the mirror lock first?.

[JohnH]

Phil,

I used the TC-80N3 timer remote - this means I can image without my laptop attached or being tied to the scope, both are a big plus for me. The gadget is horribly expensive in Australia, I bought mine over the net from Hong Kong and got it for half the cost here (still expensive though!). I did not use mirror lock on this shot but do when shooting at prime (shorter exposure and longer focal lenght seem to demand it!).

[iceman]

I can't believe how great that looks! For someone who hasn't been at this for long, you are producing spectacular widefield shots. I just love them. You must've been a photographer in a previous life.

Sorry about the detail lost through compression, all I can suggest is using the webspace provided by your ISP to upload a less-compressed one, and link to it in your post. If you need help with that, let me know and i'll try and explain it further.

Shame you missed coming on Saturday night, hope you can make the next one.

[h0ughy]

Great shot. I am impressed with anyone who can get shots like that and make it look easy!