C925 Hyperstar V4 or RASA 8

[Oliver Berresford]

Hi everyone,

I'm currently considering going either a Hyperstar V4 for my C925 or the RASA 8.  I understand there are certain compromises to be made moving to one of these systems and I have a few years experience imaging and processing images.  

My real question here is for people who have real experience with a Hyperstar V4 on the C925 XLT and how they find it, how much messing around does it take to dial in.  I also have the Starizona reducer for my system which I use and really like and wonder do you find it hard changing over from one system to the other.  This naturally leads onto should I simply consider a RASA 8? although I have heard these can be hard to dial in and people have expressed reflection issues.

Any advice, pointers and especially real experience would be much appreciated.

Cheers Ollie

 

 

 

[Elp]

Ive been using a HS6 for a while, it's quite straightforward to use tbh though I'm not too picky about edge star shapes, being an SCT a refractor will always result in better in this respect which is what I usually use for star field input in my images (also because the HS mainly performs narrowband duty). I setup and breakdown every time and also don't have much issue with this either.

Whether it's better than a Rasa, maybe not because the Rasa is designed to do one thing, and one thing well. But this is one benefit of the HS system, you can still use the scope for visual and planetary imaging, long FL reduced imaging and fast wide imaging via the HS, so gives the rare use scenario of being a one scope system.

If you do decide on getting a Rasa 8 in particular, make sure it's a new batch one been resent to astro retailers recently after their manufacturing quality issue affecting a few scopes (enough for them to do a recall and spend over 12 months to resolve), the issue I believe was bright stars causing an uneven star flare pattern caused by the optics. If buying used, be certain the owner hasn't had this issue before paying. It only affects the 8 as far as I'm aware.

[Oliver Berresford]

Thanks for this information much appreciated 👍

[ollypenrice]

Another Olly (but with a 'y') here.  Greetings.

I've been using a RASA 8 for two years, now. It really is a scope from which there is no going back. No F2 system is going to be dead easy but the RASA is very remarkable in some key respects, most notably focus. Incredibly, it autofocuses easily and holds focus better, if anything, than the premium refractors I've used. Tilt is going to be an issue at F2 as well, but it is just as likely to come from the camera as from the scope. Patience in the early stages is all. A good dealer like FLO will give you chapter and verse on the bad batch of optics Celestron received from China.

I haven't used a Hyperstar but have read many tales of woe regarding setup and I'm very rarely impressed by the stars in posted images, especially broadband. RASA stars are pretty good, especially using star removal and replacement in post processing. (I think almost anyone working at short focal lengths is going to want to use this method these days.)  Personally I would not buy a Hyperstar but that's me. I also find their marketing blurbs borderline illegal and in contravention of advertising standards, which does annoy me.

Sample RASA 8 images:

https://www.astrobin.com/eolyxc/

https://www.astrobin.com/rwyqce/

https://www.astrobin.com/bubqfe/

https://www.astrobin.com/vlomu9/

Olly