Second night with Ultrastar C

[jorman]

Tonight it was a typical Miami muggy and hazy night, but I wanted to try the stacking function on Starlight V3. As you guys told me, once I set the Max Pixel Displacement to a value, the alignment fixed itself, even though I have to say that I did not see much improving do to stacking the images. It became clear , as with anything that has to do with astrophotography, that not all images were going to work well with my set up. Some images I had to exposed for 45 seconds. I do not consider this exposure near live anymore. Not to mention the fact that for an unguided SCT C14 with a light pollution filter, 45 seconds is really pushing the limit. I will have to experiment with my ED127 and a focal reducer  to bring the focal length to about 500mm at F/3.5. I will attach some of the images.

PS: I am totally confused about how this program handles the file sizes !!!

[laudropb]

Nice captures.

[RobertI]

Thanks for posting, glad to see you are making progress with the software. Strange that you did not see much improvement with stacking? I'm sure more experienced EAA'ers will give their views, but the blacks on your captures look very black, I wonder whether you have clipped out some of the detail that you would otherwise see improving with stacking? 

Rob

[HiloDon]

Hi Jorman,

If my calculations are right, you are at about a 1200mm focal length.  That's tough to track at 45 seconds without guiding.  Your ED127 should work much better.  I have posted comments about the Ultrastar C and it's lack of speed without fast optics.  I found that without Hyperstar at F1.9, I need 45 to 60 seconds with my 8" SCT at F4.5 and the images are not quite as good.  The C14 setup I use with Hyperstar will give very good images at 30 seconds or less, but I usually have near perfect skies.  You'll also find that for dimmer images, stacking will be required.  I don't see much improvement either on bright objects or star clusters.

Here are a few I got the other night.

Don

Here's one with my C6 w/HS at F1.9.  5x30s

[jorman]

Hi Don,

I just posted a frustration thread based on my experiences this week. Your images look wonderful. Unfortunately I had a Hyperstar lens and sold it a couple of years ago because it kept getting stuck to my corrector plate ( I think I explain this on a prior thread...). I am an astrophotographer and I went into this live imaging scenario thinking that I could use it on our outreach programs here in Miami, but frankly I would be embarrassed to take my set up to this outings. I wish I would have done more research into this matter before I plunged $1,000 into this camera. Maybe someone will invent a fast reducer for the SCT C14 that will attach to the visual back ! Even with my Meade 3.3 I could not get anything near what you are showing.

Regards,

Jorman

Ps: Are these images processed or enhanced in any way or are they screen shots ? They are impressive if they are....

[Hibou]

2 hours ago, jorman said:

Hi Don, Even with my Meade 3.3 I could not get anything near what you are showing.

As Don remarked, the background in your images looks very dark compared to his where you can see the noise. Are you sure you have adjusted your levels correctly :-)  Sorry for this naive question, but you did say you were unfamiliar with the software. Perhaps you should post a raw 16-bit FITS file that you are unhappy with together with imaging times and conditions. These jpeg files are not all that informative. I can't believe that other people find the Ultrastar-C and the similar Infinity-C just "very expensive toys" as you write in your frustration thread :-)

[HiloDon]

Jorman,

I posted a link to a post from Hiten regarding the 825 based cams in your frustration thread.  The images I posted were processed only with the Starlight Live on the fly controls.  As I commented in a post after Hiten's, the Hyperstar and good seeing make a big difference.  I don't get the same performance using my Meade 8" SCT and Optec focal reducer.

Hibou brings up a good point.  If you post a stacked fits file, I can open it in SLL and see if adjustment is your problem.

Don