First Light w/C11 Hyperstar on Mauna Kea

[HiloDon]

Hi All,

I've been busy working on a broadcast from Mauna Kea at 9200' here in Hawaii.  We are now using our own equipment that includes a CPC 1100 HD with Hyperstar, Ultrastar M and C cams, and a Verizon mifi to connect to the Internet.  Last night was the first night we had everything working.  Just received the Hyperstar late last week.  We did the broadcast last night and viewed 18 DSO's.  Had viewers from all over the world, including some from the UK.  Here are some of the captures.  The ones that aren't stacked are single images at 15 seconds (clusters at 5s).  Attempts to stack images with dense star fields resulted in a weird distortion of the field.  I need to ask Paul about this.  Has anyone else experienced this with Starlight Live?

We plan on doing the broadcast every Tuesday evening for about three hours.  We are using Nightskiesnetwork.com and our channel is White Mountain Skies.  Please join us if you get a chance.

Don

[Stu]

Amazing shots Don, I shall try to catch your 'show' whenever I can. Hyperstar seems like an ideal system for VA, was the setup very tricky?

[baggywrinkle]

Beautiful shots...

[HiloDon]

Thanks, Stu and Baggy.

Stu, the setup is relatively simple.  The AZ mount eliminates the need for polar alignment and the Hyperstar is easy to install.  The short exposures eliminate the need for a GEM or guiding.  Technical issues were mainly with ensuring enough power for the evening and getting the wifi setup.  I learned last night that balance is important with the CPC mount to ensure good tracking.  The 11" is a bit heavy, but I can still handle it.

And, you are correct.  Hyperstar is the way to go for VA/EAA, no matter what cam you're using.

Don

[Stu]

Many thanks Don. I assume you still have a cable running across the face plate to the camera, is that correct? Could you post a picture of your setup so we can see how you've done it?

I have a C9.25 but it's a shame the Hyperstar is so expensive!

[DoctorD]

Hi Don

Fantastic images - I particularly like the detail in the triffid nebula, looks like you got the focus spot on.

Is it difficult to achieve and keep focus at F2 with the hyperstar?

CS

Paul

[HiloDon]

8 hours ago, Stu said:

Many thanks Don. I assume you still have a cable running across the face plate to the camera, is that correct? Could you post a picture of your setup so we can see how you've done it?

I have a C9.25 but it's a shame the Hyperstar is so expensive!

Stu,

There is a single USB cable to the Ultrastar.  If you look closely at the bright stars, you will see two minor diffraction spikes that are created by the cable.  Next time out I will snap a pic and post it here.

Don

[RobertI]

Fantastic results Don, the colour, sharpness and details are top notch. The single exposures are remarkable, especially M8. 

I would like to get Hyperstar on my C8 at some point, ideally with the colour Ultrastar.  I have always been worried that mirror flop would be a problem at F2, ie: when slewing to another object, it loses focus/collimation due to mirror moving? Is this in fact the case?

What time are your broadcasts likely to be in GMT or UT so I can tune in?

Rob

[HiloDon]

8 hours ago, DoctorD said:

Hi Don

Fantastic images - I particularly like the detail in the triffid nebula, looks like you got the focus spot on.

Is it difficult to achieve and keep focus at F2 with the hyperstar?

CS

Paul

Thanks, Paul.

I find the focus easier than native or standard focal reduction.  I don't even use a focusing mask or fine focuser.  I think it may have something to do with the Hyperstar optics requiring a larger movement of the mirror to get the same change in focus as standard reducers.  Dean at Starizona told me that there's no need to use the mirror locks either.  I did notice that I have to turn the focuser quite a bit to get a small change in unfocused star size.  I do a rough focus on a bright star with a short 500ms exposure.  Then I increase the exposure to five seconds and fine focus on all of the smaller dim stars that pop up.  With Hyperstar they all come to a pinpoint similar to visual focusing.

Don

[HiloDon]

2 hours ago, RobertI said:

Fantastic results Don, the colour, sharpness and details are top notch. The single exposures are remarkable, especially M8. 

I would like to get Hyperstar on my C8 at some point, ideally with the colour Ultrastar.  I have always been worried that mirror flop would be a problem at F2, ie: when slewing to another object, it loses focus/collimation due to mirror moving? Is this in fact the case?

What time are your broadcasts likely to be in GMT or UT so I can tune in?

Rob

Thanks, Rob.

I haven't had a problem with mirror flop on the three scopes I've used with Hyperstar, Evo 6, C11 HD and C14 HD.  And I don't use the mirror locks on the HD scopes.  My response to Paul gives more detail.

This time of the year we are starting about 8pm HST which is 6am UTC the following morning.  As we get into fall and winter months, we'll start earlier.

[Paul81]

Wow - amazing captures! I'll try to tune in next week!

[Martin Meredith]

Simply amazing shots Don! I love all of them but the Barnards in particular are incredibly dense.

I occasionally see the distortion in dense star fields which I put down to a mis-registration. I just undo the last frame and change the max pixel displacement (often making it smaller helps).

Martin

[HiloDon]

Thanks, Martin.

You were the one who got me interested in the Barnards a couple of years ago with your image of the Snake.

I wrote to Paul about the registration problem with dense star fields and he suggested the same thing.  I think the perfect clear skies we had that night made the problem worse.  I'm going to try lowering the MPD more and see what happens.

Don

[aparker]

22 hours ago, Martin Meredith said:

Simply amazing shots Don! I love all of them but the Barnards in particular are incredibly dense.

I occasionally see the distortion in dense star fields which I put down to a mis-registration. I just undo the last frame and change the max pixel displacement (often making it smaller helps).

Martin

I've observed the same thing.  Setting the max pixel displacement to a small value like 3-4 will eliminate the distortion.  

[faulksy]

that is amazing thank you so much for posting and well done. hats off to you

[HiloDon]

7 hours ago, aparker said:

I've observed the same thing.  Setting the max pixel displacement to a small value like 3-4 will eliminate the distortion.  

Thanks, Alex.  Last night I set the MPD to 5 and the stacking worked perfectly on the same objects with the same setup.  Paul wrote to me that the program limits the MPD minimum to 16 and I had it at 15, so I'm not sure what's going on, but it did work.

Don

[Paul81]

My mistake, with regards to star matching between the key frame and the latest frame, the application limits the MPD to a minimum of 8 pixels. The MPD value is used to define a bounding box, centered on the position of the reference star in which the correspondence algorithm will search for a match. When there are a lot of stars, a smaller bounding box means the algorithm is less likely to make a false positive match.

Regardless of this, values of MPD below 8 still effect when a key frame is generated, so in short focal length dense star fields a value of 5-8 is sensible. For long focal length less dense star fields such small values might not yield sufficient matches, so you need to increase the value to say 16-32.

[HiloDon]

29 minutes ago, Paul81 said:

My mistake, with regards to star matching between the key frame and the latest frame, the application limits the MPD to a minimum of 8 pixels. The MPD value is used to define a bounding box, centered on the position of the reference star in which the correspondence algorithm will search for a match. When there are a lot of stars, a smaller bounding box means the algorithm is less likely to make a false positive match.

Regardless of this, values of MPD below 8 still effect when a key frame is generated, so in short focal length dense star fields a value of 5-8 is sensible. For long focal length less dense star fields such small values might not yield sufficient matches, so you need to increase the value to say 16-32.

Thanks, Paul.

Your software and support is so valuable to the VA/EAA community.  Your commitment to us is very well appreciated.

Don

[Paul81]

Always welcome! I am happy the app is proving to be useful for people and making more of the night sky accessible :-)

[laudropb]

Fantastic set of images.

[Owmuchonomy]

Very interesting and enlightening outreach set up.

[orion25]

Amazing images, Don. Love the outreach work you're doing  

[HiloDon]

On August 16, 2016 at 13:08, orion25 said:

Amazing images, Don. Love the outreach work you're doing  

Thanks, Reggie.  

We're now trying to set up a regular broadcast, but had a few technical problems.  We'll work them out though.  Just had to send back our new CPC 1100 HD to Celestron to get checked out.  Azimuth tracking is not right and the wifi module won't connect to the scope.  They think it's the main board.  We're still going to try broadcasting with other scopes, weather permitting.  We do our visitor show every Friday.

Don