Starizona hyperstar 4

[Boese1978]

Considering this for my C8 / CGEM II. Searched the forums here but found nothing. Any input, suggestions , pros / cons welcome! Anyone with hands on experience? F2 sounds pretty cool!

[Sureshks]

Hi Steve,

I did a lot of research on the Hyperstar 8" & RASA 8" last year. The Hyperstar is an amazing system. I think it is f/1.9 for the 8" version. The nice thing is that you can remove the Hyperstar unit if you want to observe or shoot at f/10 (or something in-beteeen).

Ultimately, I decided to go with the RASA 8" f/2 instead of the Hyperstar. I liked the single focal length system vs components. While both the SCT and the Rowe-Ackermann have corrector plates, I just felt that the RA is an inherently better design optically than the SCT. Finally, I read that the Hyperstar needs to be collimated fairly frequently. I haven't needed to collimate my RASA since I got it.

Both are amazing systems. Youll be happy with either choice. I will tell you that shooting at f/2 requires different capture and processing than shooting at slower speeds. I normally shoot 5-minite subs at f/5.2 with my RC. But my RASA seems to over saturate with 5-minute subs, so I've been experimenting with 3-minute subs. In processing I've been struggling with walking noise. This is something I had never experienced before shooting at f/2. Fortunately, GraXpert seems to remove quite a bit of it.

Also, there is a nanometer shift with f/2 systems, so you'll need to get special high-speed filters that mitigate this shift. I use an Antlia Triband filter, which works pretty well. I've also heard of people using an L-Extreme with a RASA too.

I've also experienced issues shooting Flats when I don't use a filter. My flats panel is just too bright and the exposures end up around 4/10 second. I've added t-shirts but that hasn't helped. However, when I use the Triband filter I can shoot nornal Flats fairly easily.

I hope this helps!

Suresh

[Boese1978]

Hi Suresh,
Great info and help-
New endeavor for me so bear with me-
I ordered the hyperstar v4 over the RASA -didn’t want another scope- already have a ZWO ASI 585 mc pro, c8 on a cgemII-
Any info on capture and process would be helpful- I’ve used the ZWO once on the moon and struggled a bit to”see” on the laptop. Can you steer me towards filters needed? Is it one and done or diff filters for diff situations? All in all please comment on the learning curve for a newbie. Is it fairly easy to collinate the hyperstar? And, I’m apprehensive to remove the secondary and replace with the HS ETC. did you need rear counter weights on the sct ota? Thanks!!

[clayton]

You also might reach out to Conrad Sanders on MAS Slack or here on the forums for input. I believe he uses a C8 with a Hyperstar.

[Sureshks]

Hi Steve,

Sorry I'm camping this weekend and thought I sent you a response earlier. But I don't see it now.

I can't speak for the Hyperstar, since I have a RASA. Alan Touchberry and Conrad Sanders use Hyperstars and I know they really like them They can probably answer those questions you asked specific to the Hyperstar.

Shooting at f/2 is different than shooting at f/5. I normally shoot 5-minute subs at f/5 but that seems to saturate my RASA subs so now i shoot 3-minute subs. And processing is different as well. I get bad walking noise on my RASA subs, even when dithering across 10 pixels. GraXpert seems to mitigate the problem, but it's annoying. The captured light is just more intense at a given exposure vs f/5 so you'll have to do some additional steps during processing to make it look right. And shooting Flats without a filter is difficult with my RASA because my Flats Panel is apparently too bright to shoot optimal Flats, even when using t-shirts.

As mentioned, fast scopes cause nanometer shifting, so you need to get special filters that compensate for this. I did some research, and also connected with Starizona. Steve wrote the following:

At the moment our two favorite filters that don't cause halos for color cameras are as follows:

Antlia Triband RGB Ultra - $179

the narrowest broadband filter you can get, if you can only own one filter this one is it. Great for every target and zero halos. I know you wanted dual band but this is worth a mention. 

Optolong L-Para - $259

We've just recently been recommending the Optolong L-Para. Previously we would have said the IDAS NBZ-II at $318, both are great at fast and slow f/ ratios without halos. From our tests the L-Para seems to give slightly more signal, while keeping all the other benefits the same and being a good amount less expensive.

I ended up getting the Antlia Triband filter. It works pretty well overall on nebulas. But it leaves a brownish tinge on galaxies that I don't like. But my Flats turn out well with thos filter.

I also contacted Astro Hutech, and Ted wrote the following about the new IDSAA LPS-D3 filter:

https://astrohutech.store/product/lps-c1-2/

The comparison image shows LPS-C1 vs LPS-D3. The scope was pointed to the white LED-dominant sky like your sky. The lower image(LPS-D3) is brighter background and lose RGB color balance too. So, that's another option.

Duo-band or tri-band filters are particularly important for either the Hyperstar or RASA because it is not easy to change monochrome filters during a night because of Flats. Some people shoot multiple targets with, say H-alpha, and then return on other nights to fil in the OIII / SII.

We can discuss more at the next BSIG on July 19th. Bring your Hyperstar and we can work thru your issues.

Suresh

[Boese1978]

Thanks Suresh, the hyperstar is back ordered, if I receive it in time, I’ll bring it to the July BSIG.
How is it that the weight of the camera and hyperstar do not affect the corrector plate? Do you suspect I’ll need additional counter weights?
Steve

[defalkner]

I have a Hyperstar for my 8" Evolution. It work great, though I'm still a beginner. I think if you handle it carefully It should stay collimated. You will need a counterweight for the visual back but they usually send one with the Hyperstar. The Hyperstar and camera is a little heavy but it doesn't seem to affect the corrector plate.

[Sureshks]

Hey Steve,

I used to wonder about that very same question re: the corrector plate. But they are pretty strong and rigid. The corrector plate on my RASA doesn't flex... at least I don't see it in my stars. As mentioned, I'll let the Hyperstar peeps chime in re: that system.

Suresh