I have a SkyWatcher EQ6R-Pro mount and looking to get a scope for planetary imaging. The max load of the mount is about 20kg. My budget for the scope is $3k... What do you suggest I get?
The Skywatcher 7" Mak I would say for a mass production instrument the best optically I have seen. Their quality has been increasing over the years, yet from the very start their standard quality has been outstanding and consistent. The first I looked through was an original gold coloured OTA. That instrument showed the Encke Division in Saturn's rings, though it struggled with average seeing. I've looked through two of the current model, with the second one being better than the gold scope, and the last and newest one I looked through rivaled my 7" Intes Mak. You can find the occasional outstanding SCT, but you really do need to test these units as optical quality does vary greatly. I do know of one particularly outstanding SCT in the Blue Mountains. SCT or Skywatcher Mak sight unseen? I'd go the Mak.
Now, if you want top shelf, then you can make a look for a Russian made 7" or 8" Mak like from Intes, or a Questar, but the Questar is very expensive. A star test I did with my own 715 Deluxe Mak showed me 5 diffraction rings around Arcturus, with glimpses of a sixth. The 9" Santel Mak I've just picked up, now that's the big brother of the Intes, with the same outstanding optics but larger aperture. Rare as hen's teeth, but ooh, so nice!
Hi Greg, The 7" f/15 maks from skywatcher (sold as celestron in the US) are readily available. These are a bargain and will do better than 8" SCTs. You'd have to look at a C11 Edge to do significantly better.
As Alex indicated there are other exquisite maks - notably from Intes, Santel, AP, TEC or APM/Wirth, but they're seriously rare and won't be within your budget, even secondhand.
Other alternatives:
- a long-focus Newtonian eg an 8" f/9 or 10" f/7, sheer size and mount will be a pain;
- classical cassegrains with small secondaries (ie not the fast RC ones from GSO).
Nice pics Martin, but the big difference here is, where your 6" is maxed out with barlows the fore mentioned cassegrains are just starting out at prime focus.
Rick
C9’s $2,500 + ( 8 times the cost of mine )
C11’s $3,500 + ( 11 times the cost of mine )
My HEQ5 mount $1200
Celestron mounts $ 3000 to $5000
I think for a budget low cost rig , my images are pretty darn good considering the above cost differences ( first time I’ve given myself a pat on the back )
There is no doubt that a 6" OTA can produce good planetary images, I myself recently upgraded from a 6" SCT to the 9.25" SCT. For planetary, an OTA with larger aperture and longer focal length can really bring out the details in a planet like Jupiter and Saturn. Bigger is better, but comes at a price.
With the original poster's specs of a A$3k budget, a C9.25 OTA, ZWO ASI224MC camera and 2x Barlow should come to around $3k new, and should be more than capable of producing high quality images of the planets. Given that he appears to be posting from the USA, an ADC would also be recommended as the planets are so low there.
I reviewed all of your suggestions and then checked images produced by each on Astrobin. At this point the minimal resolving power I would settle on would be 9.25" and really prefer 11"....
There is a guy on Astrobin using the C11 on the EQ6 mount and capturing great lunar detail. I just wonder if that combo is taxing the mount a bit.
At this point I am leaning towards the C11 or something similar. If anyone has any other suggestions I am all ears. :-)
It has been my understanding that it is ideal to run the mount around 50% of the rated capacity. So with the tube weighing in at 27.5lbs, add another 5-10lbs for gear, the total will be around 38lbs. The rated load is for 44lbs. I'm not sure how the counter weights are calculated in. They are another 22lbs. So if they are also supposed to be added in then I'm quickly at 60lbs.
I would hope that the rated payload would be more than able to be handled appropriately by the mount when properly balanced, with a bit extra for a safety margin.
My C11 fully loaded.....four cameras, spectrograph etc, five 5Kg counterweights sits OK on the NEQ6PRO.
I can easily work with 10 min subs on a 20 micron Slit gap.
