Ultrastar C v Lodestar X2c

[HiloDon]

Hi All,

I have recently been testing the new Ultrastar C with Paul's Starlight Live. I thought I would share some initial results as compared to the Lodestar X2c. My initial impression is that the Ultrastar is probably about one stop slower, but in no way is my assessment definitive. It is noisy and requires stacking to produce an acceptable image. A single exposure is not pretty. The color and resolution are excellent. Attached is a capture of the North America and Pelican Nebulae with the Ultrastar as compared to my earlier Lodestar captures (rotated to give similar perspective). I used my Orion Mini 50mm guide scope and a 7nm NB Ha filter.

I plan on doing considerably more testing, and will post results as I get them. I will be using the Ultrastar on the Mauna Kea VIS center's C14 with Hyperstar next week.

Any thoughts or suggestions will be appreciated.

Don

[Martin Meredith]

Hi Don

Although slower, its a very fine image for 8 x 45s and worth anyone's time waiting. The difficulty is comparing across different sessions. I think it was Paul who suggested using a binoviewer to collect data from two cams simultaneously (albeit with a slight transmission loss). That would be a nice test, although live image manipulation from a pair of cameras might require some gymnastics….

In any case, I think you've shown convincingly that the Ultrastar + StarlightLive is a very capable combination. I still find it amazing that these are possible with a 50mm guide scope.

Martin

[nytecam]

Excellent results Don via the Ultrastar C - the colour is more pleasing than the Lodestar C on these targets but that's a minor issue. The resolution of the U-C is excellent. Keep up the good work and await the Hyper star efforts :-)

Nytecam

[aparker]

Fantastic results with the Ultrastar. I have one of those 50mm scopes and should try it out as an imager someday. I only ever use it as an e-finder scope.

[Astrojedi]

Very nice captures.

The Ultrastar is actually quite a good image considering you used a h alpha filter with an RGB matrix vs. the Lodestar with a less obstructive matrix.

I would be interested in seeing equal exposure stacks on the same evening with and without H alpha.

[HiloDon]

Martin, Nytecam, Alex and Hiten,

Thanks for the feedback. You have confirmed my initial impression. I plan on a more controlled test this week, but I was so happy with this result that I wanted to see what others thought. Hopefully I can get some comparative images with the C14 Edge w/HS by simply switching cameras on the HS adapter. I don't think I need to refocus because the sensor position should be identical. I think Hiten did the same with his mono comparisons. I would appreciate some suggestions on objects. Keep in mind that we're at 20 degrees latitude. The focal length I'll be at is 675mm. I was thinking Helix Nebula and Sculptor Galaxy. I can only stay to 10pm, so I can get the Orion objects later in the session. I won't use any filters.

Thanks,

Don

[RobertI]

Great work Don, I am following this with interest as I am looking for a reason to buy an Ultrastar and in particular a colour if it is sensitive enough.

I would be using it with my RC6 or C8 + reducers and my particular interest would be in what is achievable with regard to:

• Sensitivity for brighter galaxies and nebulae in exposures of 60 seconds or less
• Star size and colours in open and globular clusters and even doubles (which would open up a new range of objects for me)

Looking forward to seeing your results.

Rob

[HiloDon]

Thanks, Rob.

Last night I took a few captures with the Ultrastar C and my Meade 8" SCT at about F4.5. I think I can answer your question on brighter nebulae with these results. On dimmer ones like the Horsehead, results weren't as good, but I need to experiment more before drawing conclusions. A couple of weeks ago, I did also get some decent captures of the Sculptor and NGC891 galaxies as well.

The skies I have here are really dark, so that needs to be taken into account. I am very optimistic now that the Ultrastar C can be a viable EAA cam, but am concerned about getting good results with dimmer objects.

Don