First light and no images

[rambrosi]

Hello Everyone,
5 hours after first light with the Atik 414EX OSC and Celestron 9.25 XLT at F10 I packed it in defeated.
I could not find M101 due to possible underexposure?
My question is this.
What are the best settings and technique for finding a faint object for astrophotography?
The tutorials are mysteriously lacking this information from what I've seen. I just hope it's a fine camera as I do not want to return it.

[Jo]

What did the images you were getting actually look like? Was it the case that you were seeing stars but couldn't find M101, or were you not getting anything at all?

Before trying to find an object, I'll point the telescope at a pretty bright star, or even the moon if it's about, and take probably a 0.1s exposure at binning 3/4 just to get an image on the screen. If that comes up as expected, I'll then focus the camera on it (back at binning 1), before slewing to my desired object. There can then be a bit of zooming about to try and find things - I'm mostly looking for a slightly brighter patch somewhere on screen, using a looped exposure of between about 1 and 5 seconds, depending. Is this sounding like your process?

You make a good point that it's not covered in any of our tutorials, I'll see if I can change that. We do want to do some more videos showing real imaging sessions but the weather and the moon have made it a bit difficult!

I'm sure some of the experts here will have some good tips on finding faint objects.

Jo

[rambrosi]

What did the images you were getting actually look like? Was it the case that you were seeing stars but couldn't find M101, or were you not getting anything at all?

Before trying to find an object, I'll point the telescope at a pretty bright star, or even the moon if it's about, and take probably a 0.1s exposure at binning 3/4 just to get an image on the screen. If that comes up as expected, I'll then focus the camera on it (back at binning 1), before slewing to my desired object. There can then be a bit of zooming about to try and find things - I'm mostly looking for a slightly brighter patch somewhere on screen, using a looped exposure of between about 1 and 5 seconds, depending. Is this sounding like your process?

You make a good point that it's not covered in any of our tutorials, I'll see if I can change that. We do want to do some more videos showing real imaging sessions but the weather and the moon have made it a bit difficult!

I'm sure some of the experts here will have some good tips on finding faint objects.

Jo

Hi Jo,
What I am doing is focusing on a bright star then slewing back to my object.
I loop for 5 seconds and bright stars show but no faint fuzzy.
Is it the F/10 long focal length?
Alignment maybe? (Although I tested by slewing to a couple of objects in the 40,000 object database on the Celestron mount.)

[Jo]

You are pretty long at f/10 so I would consider getting a focal reducer, but you should still be able to get M101. Did you try using any exposures longer than 5s? It could be that as your system's fairly slow and M101 fairly faint, one of those bright stars is the core - did you try changing the histogram to see if that made things any clearer, or sometimes looking at it in negative can be more obvious?

How accurate do you feel your alignment is? Even with pretty good alignment, sometimes I find I still have to have a little search around!

[rambrosi]

You are pretty long at f/10 so I would consider getting a focal reducer, but you should still be able to get M101. Did you try using any exposures longer than 5s? It could be that as your system's fairly slow and M101 fairly faint, one of those bright stars is the core - did you try changing the histogram to see if that made things any clearer, or sometimes looking at it in negative can be more obvious?

How accurate do you feel your alignment is? Even with pretty good alignment, sometimes I find I still have to have a little search around!

Thank you Jo for your fast response.
I will try all of the above when I get back from Las Vegas.
More tutorials certainly might help with more sales although the brand is already highly regarded in the community.

[Jo]

Let me know how you get on when you get a chance to try again, and I'll start looking to put some more tutorials together.

Enjoy Las Vegas!

[patthehorse]

Hi Rambrosi.
I would do your 3 star alignment, then go to Alkaid. The nearest and brightest star to M101. If Alkaid is close to the centre of your FOV, when you slew to M101 it should be on your screen aswell.
M101 is the faintest of all the Messier objects, but the core should show up a on 3-5 second loop.
After a 3 star alignment. Alkaid is not in your FOV, use your finder scope to help centre the Star and remember the directional buttons you use. I.e north to get the star centred. M101 will be the same error in alignment, so using the same directional button should bring it into view.
It doesn't make up for a good Polar alignment but it'll get you imaging.
Hope this helps a bit.
Good luck.

[Chris]

I'd go along with the assessment that a C9.25 at F10 is pretty slow and M101 has a low surface brightness.
A focal reducer will help a lot, I'd also bin the camera and try a longer exposure, more like 30 seconds.

Also try something bright, such as M3, M13, M51.

The small field of view can easily mean that the object is slightly off the field, as people say check by slewing to a bright nearby star.

Chris