Hi and SCT advice needed.

[Ramius (Bill)]

Hi all from Canberra - Ok now the ice is broken!

I am a month into this with the primary objective of Nebula astrophotography but interest also in planets, galaxies etc. Its already clear that my small refractor is not going to do it all and have been contemplating adding something (RC or more likely SCT) with more aperture and focal length.

It occurs to me now that a hyperstar C6 seems to make a fair stab at all the bases. 300mm at F2 for nebula sounds brilliant with options for 950mm with F/6.3, 1500mm "bare" and 3000mm with barlow for smaller DSO's, moon and planets.

Is there any obvious downside to this approach that I am missing? I know a C8 would do some of this better but weight and $$ are an issue.

Any input appreciated.
Cheers

[iborg (Philip)]

Hi Bill


I am not going to comment on your suggested scopes, I don't know enough to do so.


But, based on what I have read, think about the mount, at least as much as the scope.


My understanding is that a mediocre scope can give an acceptable result on a good mount, but, not so much the other way around.


Have fun.


Philip

[Ramius (Bill)]

Thanks Philip
I have a mid range AZ-5EQ thats seems to be tracking well with my small refractor and i think it is adequate for the time being provided I don't overload it.
Cheers

[Dave882 (David)]

If you can stretch the budget to get an 8” sct I think you’re going to have a lot more fun imaging/observing the planets. An az-eq5 should carry that too.
But I’m not sure this mount will be sufficient for good long focal length dso astrophotography. I think I’ve owned almost every size sct over the years from 4”-14” (except the 6” lol). IMHO 8” is the entry level for satisfying planetary viewing/photography.

If it were me, I’d get a second hand c8 and play with the planets for a bit, perhaps get into some short exposure eaa imaging of dso, and you also have the small frac to do wider angle stuff which will be so so so much easier than wrangling a Hyperstar. Then if I’m enjoying that, upgrade the mount to an eq6 or az-eq6 or cgem or similar down the track, then that opens up your options if you want to go a bigger aperture for planetary imaging, or perhaps even get a 8-10” newt for some more advanced dso imaging. A Hyperstar on a larger aperture sct can be amazing. I seriously love mine. But comes with many headaches compare with a newt and imo will never be able to provide the same image quality as other systems. so just know what you’re getting into before you make that commitment.
Good luck with your decision!

[Doogs38 (Alex)]

Hi Bill. I have no experience with the C6 but will offer a point of view regarding an 8” SCT. I have a couple of scopes for imaging: 80mm and 120mm refracs, and an EdgeHD 8” SCT which accepts HyperStar too. I’ve been using the SCT for imaging since Dec 22 and love it - it has great optics and its long focal length is terrific for ‘up close and personal’ imagery of galaxies and DSOs, but I’ve not yet used it for planetary imaging. I use an AZ-EQ6 mount and its performance has been more than adequate with the SCT. I did however learn imaging and guiding basics (with Ekos/KStars) using my refractors (shorter focal length = more forgiving) before tackling an SCT imaging system as there’s a bit of a learning curve with the long focal length, ‘slow’ imaging system and AOG. I also suggest some research as there is a cost to convert any SCT into an imaging system, eg. I use the EdgeHD specific 0.7 reducer (which actually degrades the EdgeHD’s optics), a Celestron AOG, ZWO ASIAIR, EFW and EAF, and various filters with OSC and mono cameras, a Pegasus powerbox micro and some mounting hardware for the accessories. But once setup, very little tweaking is necessary except for occasionally checking/tweaking the SCT’s collimation. Alex

[Ramius (Bill)]

Hi David & Alex
Thanks for the input.

Plan A was the small refractor for widefield DSOs and an 8inch SCT for planets and smaller DSOs. I got interested in C6 hyperstar based on Cuiv's (lazy geek youtuber) enthusiasm for his and then one appreared here for sale (which for better or worse i missed out on).


I recognise that i have a LONG way to go with the refractor before i need another scope - but i want to plan ahead so that i can build up a system methodically and get equipment used where possible. So based on input I will keep an eye out for 8in SCTs - with OSC the weight should be ok for the AZ-EQ5.

Still one question on Hyperstar. David mentioned they can be a headache. With that focal length i assume its not guiding related so what is the issue?
Bill

[Dave882 (David)]

Originally Posted by Ramius

Still one question on Hyperstar. David mentioned they can be a headache. With that focal length i assume its not guiding related so what is the issue?
Bill

Just my experience that while guiding is very much easier (often not used at all), small errors in collimation, secondary alignment, sensor tilt can be troublesome causing poor star shapes or other image defects. This will get progressively more influential the bigger you go in aperture or sensor size, and it also depends on how fussy you are for that kind of thing.

For a small 6” sct, which probably has an effective aperture similar to a 4” frac, these difficulties will be minimal, but I’m just not sure why you wouldn’t just use a short focal length frac which will give much better quality images, much simpler to set up, and probably a similar overall cost. Your mileage may vary, as they say, but just my 2c. Now once you go to an 8” sct or larger, with a Hyperstar, you’ve now got a system that (while still bringing the above challenges) a refractor will struggle to match in light gathering ability and speed. And also, you can use it at native focal length for planetary shots.

[Ramius (Bill)]

Thanks Dave
I will continue to get some hours up with the small refractor - i really need some hands on time as most of my effort to date has been spent learning basic theory and comparing equipment specs. In the meantime i will be keeping an eye out for an 8" SCT (and dedicated OSC but thats another discussion).
Cheers

[entr0py (Dan)]

I got an C8" Evo and am currently converting the setup from live viewing to EAA. I've been looking at the hyperstars but at the current exchange rate I am going to wait (like everyone else) to see if I can find a used Hyperstar 8 and for the time being only a reducer/corrector which will bring the f10 down to f6.3 (or until the Starizona Night Owl is available. Which would get the f10 down to f4.x (https://starizona.com/products/night...ucer-corrector). You could look into those options too?

[Ramius (Bill)]

Dan
If (when) i find a C8 an F6.3 is a given - great added flexibility for the price. The Night Owl is intriguing. It will be very interesting to see price and performance.

[kris85au]

Originally Posted by Ramius

...Is there any obvious downside to this approach that I am missing? I know a C8 would do some of this better but weight and $$ are an issue.

Any input appreciated.
Cheers

Yes, there are:

1. You will have to assemble and dissemble the setups to rotate between different FoV/fX. Unless you plan to stay rather stationary for extended periods. Lurking danger here is that, once novelty wears of and you become lazy, you will just stick with one setup.

2. With Hyperstar you will not be able to do visual and AP at the same time, but I stand to be corrected.

Many people dont care doing both at the same time, many do want to stay connected with the sky. I can make nice, detailed picture of Jewel Box that goes weeeell beyond my eyes resolution. But still, direct visual observation of the same cluster looks waaaaay better, for me. It is like watching fireworks vs watching video recording of fire works. Two completely different experiences.