I own two refractors that I would like to use for astrophotography, an Orion 80ED and a William Optics 80FD. I want to purchase a mount to allow me to use these two telescopes and to leave some room for future expansion.
The budget: max 3000AUD.
I am looking for the following features: good value for money, compact, portability, accuracy, GOTO, built quality, etc.
From my own research I am inclined for a HEQ5 (EQ6?) and Sphinx SXW(SWD?). Can anybody have any experience with these mounts? Can you point to me any reviews regarding these mounts? Thanks.
I have a heq5 with synscan but cant vouch for teh rest... it works fine with my 8" f6 newt, but i wouldnt go heavier. should handle you lil' 80s' easy. one again dont know how they compare to the sphinx but the eq6 is just a heavier heq5.
I have been looking into mounts as I am in the process of upgrading what I have. I currently use a GP mount with a SS2000PC that is the light weight predecessor of the sphinx. The sphinx and starbook seem good but have their limitations compared to the SS2000. See http://www.groupeastronomiespa.be/SSvsSB_V1.02.doc.pdf
I have just bought a new EQ6 (and hopefully it will arrive tomorrow) for ~$2000 as I needed the extra weight cpapbility over my GP mount.
The vixen mount will be better made than the EQ6 but I will wait and see.
You don't seem to need such a big mount with the 80mm refractors and if portability is important then the lighter mount would be the way to go.
PS. I will be selling my GP mount and SS2000 if I am happy with the EQ6 for much less than the $3000 of your budget. PM me if you are interested.
While I can't comment on either mount, as I haven't had them, one thing most seem to forget is the weight.
Yes, the "lill 80's" won't weigh all that much, but if you mount them like I do, with a side by side, this adds a fair bit as well. The only saving grace is the C of G is close to the mount, and without the long lever arm. Good luck.
Gary
I am looking for the following features: good value for money, compact, portability, accuracy, GOTO, built quality, etc.
You don't mention PE/PEC, Backlash or Autoguiding capability. Make sure you factor those 3 in. (I realise they might be in your "etc"). They are important for photography.
I assumed that all the three mounts can be guided, and this is what I am going to do with the second refractor. The PE I understand it is much bigger at HEQ5 and EQ6 than at Vixen. This will impact the time you can take a picture with no guiding at all. From this point of view the Vixen mount will allow you a longer exposure without guiding. Except for the new released model, Vixen was not having PEC. Another astrophotographer told me that PEC is not easy to use, less reliable then guiding and conflicting, if activated, with the guiding. As a result I thought that is not a must. I must admit I do not know much about the backlash.
Vixen looks better and I am sure is also better quality, but is over 30% more expensive than HEQ5, takes less load than the EQ6, and the GOTO system doesn't allow you to enter coordinates and I think that this is a disadvantage.
Usually you don't buy the best quality but the best value for money. What would you buy in my place and why? The ultimate goal for me is to be able to take good pictures of the sky. Are there any issues with the above telescopes that will make them unsuitable for astrophotography?
The Vixen - plain and simple much higher quality if you want to do careful astrophotography.
You can control starbook using free ASCOM drivers from software like Cartes du Ciel (Charts of the sky), I do almost all of my pointing of my Celestron with that bit of software - not the Celestron CG5 hand controller.
You can guide many scopes but every correction costs you something - its a bump you have to correct for. That bump will still be evident in your image. So a long shot with 200 corrections should not expect to look as good as a shot with 20 corrections. Also its important to get your backlash tuned well, so you don't over correct and start a rocking on your guide corrections. Finally the better your celestial South pole alignment the few corrections you will have.
For a permament observatory - or long runs of high calibre astronomy - PEC makes sense. Its annoying that the Vixen doesn't remember its PEC settings - but there is hope a firmware upgrade could fix that soon accoprding to american sites (Cloudynights). But PEC is all about minimising non random error in your gears. Random + non random errors = tracking capability. Higher quality mounts have better tracking.
So either you go for heavy load - and use it anyway you wish, or you lower the load slightly and get better motors and gears and go for better tracking and goto. Quality costs - so what are your priorities - load allowance or pointing and tracking?
Any mount whose motors have a gearbox are inherently going to give you grief even when autoguided due to the random micro jumps produced by the gears. Never mind PEC.
I replaced the motors on my HEQ5 with Astromeccanica motors. These are belt drive and are microstepped. I have no backlash on either axis on a standard out of the box HEQ5. The tracking is superb.
I am not interested in goto as I think it puts to much load on the mechanicals especially when near the 'limit'. The astromeccanica motors will give you goto from a standard HEQ5 or EQ6. I found it too painful to use as I can generally find what I want almost instantly without wasting time slewing etc.
Here is a crop from a 15minute autoguided exposure at 1800mm F9 JPG straight off the camera. Image scale is one about one (0.94) second of arc per pixel.
This was taken with a TAL 200K and all up weight of the optics was 13.5 KG.
This is one alternative it may not be correct for you. For astrophotography at any focal length though it works very well and is portable.
The image is of the core of Omega Cent. The EXIF data is there apart from the focal length.
I recently got a Sphinx SXW mount from one of the forum members and so far quite impressed. I haven't had much time to use it and it is currently mounted on an slightly undersized tripod (I do intend to get a pier) so keeping this in mind these are my first observations:
- Build and finish excellent, minimal cables and fuss which is also excellent.
- Light, excellent transportability.
- Polar alignment scope works very well (even though the alignment stars are only mag 5-6) provided the polar scope illumination is set its faintest illumination level.
- 90 second exposures with a 7kg Takahashi E160 (sharp 530mm focal length scope) showed tight round stars unguided. Periodic error is problably around +/-10 arc sec over 8 minutes or so .
- With polar alignment GOTO appears to be quite good, even with star alignment.
- I briefly tested Peter Enzerink's ASCOM driver using a simple Perl script and a crossover cable and it seemed to work well, although I need to do more testing.
When I get it all properly setup I'll do a proper review.
