My first DSO - M13

[SteveL]

Now, I now that taking long exposure image sequences require a EQ mount, and that using an AltAz mount (like on my NS8GPS) will cause image rotation. I was under no illusion about that, it will cause problems for imaging (but fine for visual work). But the chance was too good to miss, so I pointed my scope at M13 and started taking images with my Meade DSI Color.

Despite this being my first imaged DSO, and the images will look terrible to the experts out there, I was pleased that I actually managed to get the shots. Stacking the sequece just causes image rotation blurs (as expected), but what did suprise me was just how much the sky does rotate when imaging on an AltAz platform. Want to see? Just take look at the animation below.

30 x 20sec images, Meade DSI-C, unguided, dodgy focus, and because its AltAz, no PEC training has ever been done on this scope. Oh, and it was VERY windy too

Thats effectively 20 seconds between each frame, and 10 minutes total.

[legion48]

I like it Steve. Very good effort.

[Kaptain Klevtsov]

Looks great Steve. If you have maxim, you can stack the rotated images as it works that bit out as well.

Anybody know how to extract the BMPs from an animated GIF? Or you could e-mail me the images Steve, and I'll have a stack at it for you if you don't have Maxim.

Captain Chaos

[Astronut]

quick question: what are the 3 bright 'stars' on the left of the image (there are also some fainter greenish(?) coloured ones to the right of these) that appear to be static compared to the image itself? Are these noise pixels?

[SteveL]

CC (aka KK) - GIFS are ony 256 colors, I`ll bundle the TIFs into a zip and make the availble somewhere. I dont have Maxim (its on my "astro list").

AN - hot pixels on the DSI. I didnt remove them using dark frames because i didnt think i needed to, and...err... i`ve never done DSO stuff befoe so dark frame removal is new tome (I have my DSI Dark frames around somewhere from last night)

[Kaptain Klevtsov]

Ace, I'll look forward to playing with them then.

Captain Chaos (another 3 or 4 weeks before the KK thing kicks in)

[SteveL]

Image sequence (TIFs)

http://zorlac.peonic.net/images/m13_20sec_003_seq.zip

Dark Frames (FITS - taken last night)

http://zorlac.peonic.net/images/current_darks.zip

Am looking forward to seeing what magic you can do with these.

[MartinB]

Superb effort Steve. Looked good on the avi. You can download deep sky stacker for free http://deepskystacker.free.fr/english/index.html That handles rotation. I've never used it myself and it's a bit slow apparently but will sort out your alt az subs nicely.

I stacked your images with Maxim DL. Rejected a few shaky ones - wind probably. Did a bit of stretching and sharpening. Compare your effort with my 1st M13 http://stargazerslounge.co.uk/index.php?topic=3341.msg36744#msg36744

[GordonCopestake]

Just shows how much you can learn in a year Mart!

[SteveL]

wow! That post-processed image is a great improvement... maybe there is hope for me and AltAz imaging 8) Do you have a link to your most recent M13 (as a comparison)?

DSS - I was recommended that by another friend, but didnt get a chance to play with it. I instead spent some time getting to know my 350D last night, so hopefully I`ll be imaging with that in the near future.

[Kaptain Klevtsov]

I had to have a play too.

Captain Chaos

[SteveL]

and another cracker... OK, Maxim DL has just moved up several positions on my astro list

[Dippus]

Hi Steve , am i right in thinking that you are using the autostar envisage software to capture your images??

If so , after a bit of fiddling i have found that the software can stack ,align and derotate the frames for you. see below

Have not subtracted the dark frames , as you can see by the fuzzy hot pixels on the left.

Also i don't know what version of envisage you have .If it has the "Drizzle" option that's the ticket.

If so PM me and i can talk you through the process . If you don't have the software with the drizzle option PM me anyway and we can sort something out.

I have a AltAz setup the same as you but that darn rotation problem can be sorted just by using the software bundled with the DSI.

Just takes some figuring out as the meade manual is about as clear as mud .

Also , if you save your frames as FITS the autostar imaging software is really good at stacking and derotating also.

Hope this helps and it could save you a bit of cash.

Cheers. Mark

[SteveL]

I used the Envisage app (with Drizzle) until now, but just trying K3CCD Tools at the moment as well. As it was my first long-ish exposure image, I had a lot to learn, but as usual, the SGL members have done me proud with their help.