Starizona Hyperstar for C11 XLT (Note not Edge HD).

[WicklowSkies76]

Hi there. Despite getting lots of advice telling me not to bother, I have dabbled in Deep Sky Astrophotography with my Celestron C11 XLT and a f6.3 focal reducer and have had some surprisingly good results. There is a pretty significant amount of vignetting in my images as per image below but I am not looking to win any awards or get APOD :).

I opted for the C11 as I decided to focus on Lunar and Planetary imaging but that was a mistake in hindsight as my seeing is worse than poor at 53 degrees North and in Ireland.

In any case, I am stuck with it now. I am contemplating saving up for a Hyperstar which would take the f stop down to f/2 from f/10 and potentially eliminate the need for a guidescope once I get my Polar alignment nailed. The scope will be pier mounted in a few months.

Is opting for Hyperstar on a non-Edge a daft thing to consider? Would I be better served spending the money on a Refractor and guidescope etc? WIll the vignetting still be so poor with Hyperstar on the C11 that it's a waste of time?

[ollypenrice]

My two penn'orth...  The Hyperstar website, in my view, treads a very thin line between the 'just about justifiable' and the fraudulent. Read it very carefully and then read plenty more about the system from other sources. Note, for example, that M52 with the Hyperstar will be tiny and nothing like what you've posted above.

Note also that the only place on the Internet where you will find 'easy' and 'F2' mentioned together will be on that site. F2 will never be easy for perfectly simple reasons. It has an incredibly shallow depth of field so finding and holding focus will always be difficult. Add to this the fact that the focus is by means of the crude moving mirror system so that compounds the problem. And a shallow depth of field means that any mechanical tilt in your system will have one side of the chip in focus and the other not. And then there's collimation at F2 on a system you cannot look through. 

You see reasonable and sometimes good results from Hyperstars but delete the word easy right from the start and replace it with very difficult.  A Hyperstar setup can be built up at less expense than a top refractor setup of similar focal length but check out the forums and see what people choose to use... That said, the original non-Edge SCT is not to be dismissed for conversion. 

Vignetting. You need to know the corrected circle or image circle of the scope and the length of the diagonal of your chip. The chip diagonal must not be larger than the corrected circle. Check out the manufacturers' spec sheets to find them.  We cannot tell much about the vignetting in your image because it's a stretch. Instead open your linear (unstretched) image in a program which will allow you to read off the ADU values (the brightness) of the background sky in the dark corners and in the brighter middle. Only measure the background, away from stars and nebulosity. If the corners are vignetted (darkened) by no more than 25% it should be possible to rescue them by shooting flat fields. I have a 23% fall off in the corners of one rig and flats fix it. I check these values in AstroArt but most of the stacking/calibrating programs should let you do it.

Olly

[WicklowSkies76]

Thank you Olly that sounds like really good advice. A lot of what you called out there re: vignetting is something that's unknown to me but I know how to  figure out based on your instructions. Thanks. Very helpful. I could arguably get a widefield f/6 refractor plus CCD for similar price to the Hyperstar but then I would need to also invest in autoguiding equipment etc. The Hyperstar is tempting but they sell it as though you can get a great image in seconds and save hours but as you say conveniently leave out all of the other potential complications!

[stash_old]

While what Olly says may or my not be 100% true if you look on the EAA section here and Cloudy nights you will see excellent results as it is being used in a specific way - to have very short stacked exposures.

IMO - It might not fit "astrophotographers" requirements but Hyperstar ,on various Celestron Scopes (c6 upwards) , is well used and liked by the EAA community.

[ollypenrice]

1 hour ago, stash_old said:

While what Olly says may or my not be 100% true if you look on the EAA section here and Cloudy nights you will see excellent results as it is being used in a specific way - to have very short stacked exposures.

IMO - It might not fit "astrophotographers" requirements but Hyperstar ,on various Celestron Scopes (c6 upwards) , is well used and liked by the EAA community.

Yes, that's a different environment and one about which I know nothing.

Olly

[noah4x4]

Just came across this thread and I am a Hyperstar user.

If your interest is observing and you are dissatisfied with looking at indistinct "grey faint fuzzies" through an eyepiece you will love Hyperstar. Images at f/2 will form in two to twenty seconds and if you live stack them you will enjoy great views and even capture credible images in under five minutes of total integration time.

You don't need polar alignment, guiding or wedge/GEM. But you do need a high resolution, medium sensor, small pixel camera and 4K UHD resolution display for best results as you will require Zoom having removed your secondary mirror.

You won't win Astrophotographer of the Year, but if your interest is seeing stuff "near live" rather than creating astro-art, then Hyperstar is for you. It's incredibly easy too. The FOV is so wide you can succeed with a crummy alignment as it's impossible to miss a target. Then it's down to Zoom and decent tracking or plate-solving, a feature of Sharpcap. It's perhaps not for astro-artists, but I love it.

[ollypenrice]

On 18/08/2020 at 11:54, noah4x4 said:

Just came across this thread and I am a Hyperstar user.

If your interest is observing and you are dissatisfied with looking at indistinct "grey faint fuzzies" through an eyepiece you will love Hyperstar. Images at f/2 will form in two to twenty seconds and if you live stack them you will enjoy great views and even capture credible images in under five minutes of total integration time.

You don't need polar alignment, guiding or wedge/GEM. But you do need a high resolution, medium sensor, small pixel camera and 4K UHD resolution display for best results as you will require Zoom having removed your secondary mirror.

You won't win Astrophotographer of the Year, but if your interest is seeing stuff "near live" rather than creating astro-art, then Hyperstar is for you. It's incredibly easy too. The FOV is so wide you can succeed with a crummy alignment as it's impossible to miss a target. Then it's down to Zoom and decent tracking or plate-solving, a feature of Sharpcap. It's perhaps not for astro-artists, but I love it.

I think you're using some quite loaded terms, there, like 'astro artist.' Rather than react by guessing what you mean, maybe you'd like to clarify? Let's remind ourselves that the OP declared an interest in 'Deep Sky Astrophotography' and said nothing whatever about 'seeing stuff "near live."'

Olly

[noah4x4]

My post Olly reflects what I believe Hyperstar best fulfils and it isn't traditional deep sky astrophogography. It produces images incredibly fast at f/2 but its FOV is so massive you need Zoom on many objects, which inevitably impacts on image (and viewing) quality (ultimately pixelation). So I think we are on the same page. I'm not interested in the artistic aspects of AP so Hyperstar suits me. But it might not satisfy the OP and a solution between f/4 and f/6 is probably better for AP.

[ollypenrice]

38 minutes ago, noah4x4 said:

My post Olly reflects what I believe Hyperstar best fulfils and it isn't traditional deep sky astrophogography. It produces images incredibly fast at f/2 but its FOV is so massive you need Zoom on many objects, which inevitably impacts on image (and viewing) quality (ultimately pixelation). So I think we are on the same page. I'm not interested in the artistic aspects of AP so Hyperstar suits me. But it might not satisfy the OP and a solution between f/4 and f/6 is probably better for AP.

Yes, I'm sure it's a great system for your purposes. I've never tried real time photographic observing.

Olly

[noah4x4]

On 21/08/2020 at 08:04, ollypenrice said:

Yes, I'm sure it's a great system for your purposes. I've never tried real time photographic observing.

Olly

That suggests you don't suffer much light pollution Olly.  If you lived in a dismal overly illuminated location like so many of us you might find Electronically (camera) Assisted Astronomy to be the only viable way to observe, then AP using live stacking is merely a step away. 

[ollypenrice]

7 hours ago, noah4x4 said:

That suggests you don't suffer much light pollution Olly.  If you lived in a dismal overly illuminated location like so many of us you might find Electronically (camera) Assisted Astronomy to be the only viable way to observe, then AP using live stacking is merely a step away. 

I do live at a dark site, yes: we sometimes sometimes beat SQM22. We know from regular imaging that, with sufficient integration time, it's possible to mitigate LP.  I'm heartily in favour of anything which helps, including EAA.

Olly

[Sever603]

I am a new hyperstar user, and new to deep sky imaging. I won't say that anything in this hobby has been easy, but I don't find the hyperstar difficult at all, you can monitor focus relatively easily when starting a sequence on a new object, and the exposures are short enough that the chances of mirror shift aren't that high (confirmed when monitoring HFR in sgp), I'm not saying you'll get the same results with a hyperstar that you will with a high quality refractor shooting narrowband, but the results are more than acceptable for me personally. These are the first light shots that I captured from some fairly dark skies, no filters, stock dslr.