PDA

View Full Version here: : Planetary scope advice...


AstroApprentice
05-10-2017, 03:31 PM
I currently use an ED120 refractor for planetary visual & imaging, but I'm considering an upgrade to see/capture more detail. I dream about Marcus' TOA-150 in the classifieds, but I would need a new mount...and a pay rise!

I've read some good things about Intes Micro 715 F/15 Mak, particularly the Deluxe II version with 1/10 wavefront. A 7" scope would fit comfortably on my mounts, plus I don't think my seeing warrants much bigger aperture.

Just wondering if anyone has any experience with Intes Maks, or have an opinion if they are worth the high price tag (for a Mak)? The 715 Deluxe II is twice the price of a new Tak Mewlon 180c which although differs in being F/12 Dall-Kirkham is a similar aperture & weight.

Any advice would be greatly appreciated - I've only ever owned refractors, so I'm not even sure I will see much more than with my ED120.
Thanks!

raymo
05-10-2017, 03:45 PM
I'd go with the SW180 Mak. Terrific scope.
raymo

Wavytone
05-10-2017, 04:22 PM
Jason, I’ve owned an M703 and two SW 180 maks, and also looked through several more. Quality of all is variable and this is true also of the Russian scopes, ie there are few outstanding ones, a lot of fairly average ones and some poor ones.

The only exception to that is Questar but you’ll have to sell both kidneys to buy a 7”. Then there is TEC, they make a few invariably excellent but also expensive, and occasionally a big one comes up secondhand (an 8” and 10” recently on astromart).

As per below look for a SW180mm Mak, learn how to tell good from not so good because a good one can be very very good indeed - better than 8” SCTs or a 150mm APO.

However the SW quality is variable:
Some are excellent, as near as dammit to perfect in all respects and better optically than 8” SCT’s;
On some the optics aren’t quite fully polished and appear a bit grey near the edges when you point a torch at them;
On some the diffraction image isn’t perfect at high power (300X).

If buying secondhand always ask to star-test the scope at high power and try to ascertain it’s age. If optically excellent but the mirrors look a bit grey (10 years or more) it might be worth considering having the mirrors recoated - this is possible, and doesn’t cost a fortune.

Of the Russian scopes, Intes, Intes Micro and Intes Alter are all different companies and production is dependent on what the Russian military allow. Intes ceased to exist some years ago, and of the rest production stopped 2 years ago for the time being. So be wary of websites claiming to sell them as they’re probably just not maintaining the webpage.

Of the one I had and the others I’ve seen through, the Russian maks are optically OK to good, but mechanically the OTA are relatively heavy and fairly crudely built. In this respect the Skywatcher ones are distinctly preferable. The Russian finders are junk, and if it has a fixed mirror and rack & pinion focusser be prepared to replace that too.

You’ll find the Intes Micro scopes from time to time secondhand. A few new ones might still be possible from APM in Germany depending on what optics sets they have left (they are built to order) but the prices are eyewatering.

Some years ago Meade built LX200 7” f/15 maks, if you find one buy it because optically these were pretty good. Why they stopped production I have no idea.

Another rare oddball one is the Saxon 200mm mak, either f/15 or f/20. Occasionally one comes up on IIS secondhand though I have no idea what these are like, though quite possibly a bargain.

Orion Optics in the UK, Bosma and iOptron are also selling smaller maks up to 150mm, I’ve had a brief look at a couple of the iOptron ones, nothing wrong (the iOptron ones are Bosma rebranded).

Then there are also Maksutov Newtonians around 150-190mm aperture from various sources, might be of interest to you.

Lastly there are a few rare legendary ones - the Santel 9” f/13 Rumak I have being an example, this being the sole reason I sold my smaller SW 180mm mak.

AstroApprentice
05-10-2017, 05:28 PM
Thanks for the detailed info - helps a lot.
I emailed APM and they can order the 715 Mak in standard, deluxe or deluxe II configs with a few months wait & 35% deposit, but the prices are high. It worries me that the quality can vary so much. Apparently they come with a zygotest report - I assume that means they passed! ;)
I'll have a look at the SW Mak as you both suggested and think about Intes.
Thanks again.

Wavytone
05-10-2017, 05:40 PM
Ah ok. Expensive but no better optically than the SW.

A Zygo test is all very well, but meaningless unless the pass/fail criterion is defined, either peak or rms wavefront error, strehl etc...

Another trap with the Russian scopes is how to fit it onto a mount - the Russians often fit some nonstandard base - make sure it comes with a vixen or Losmandy dovetail rail or you have to add this yourself.

AstroApprentice
05-10-2017, 06:42 PM
Thanks - I think I'll give Intes a miss - sounds like a very expensive gamble.
It would be great if SW could guarantee the quality of their Maks - still an expensive gamble...

Kunama
05-10-2017, 07:29 PM
what about a TEC, they come up occasionally on various sites.... simply superb!

Mamba
05-10-2017, 07:34 PM
May be worth pointing out that Atmos has a Mewlon 210 up for sale at $2000, no mean planetary scope at all.
Dave Cooke

SkyWatch
05-10-2017, 08:25 PM
... and if you want a new one, Claude has the Tak Mewlon 180-C for $2595

- Dean

John K
06-10-2017, 10:01 AM
Hi Jason,

My advice would be you get a 10"+ SCT or quality reflector. This will give you more light to play with and higher frames per second when you image.

With Jupiter in particular you need more light to shorten captures as the planet rotates very quickly. 60 to 90 seconds imaging per channel max.

The Celestron SCT's seem to have a good reputation or a custom made newtonian with good optics will give you years of satisfaction.

Don't stress too much as well with mount quality if you need to get a new mount. The current software allows perfect tracking for planetary imaging.

Next year will be a great year for planetary imaging in OZ.

Clear skies.

John K.

issdaol
06-10-2017, 10:54 AM
The TOA150 and a Mewlon 210 is a big jump in visual performance over your ED120 so you will definitely see more (and better)

If you dont like diffraction spikes though a Mak like the TEC200 will be better.

Having owned SCT's in the 8 inch and 11 inch class before ...a Mewlon or TEC Mak in 8 inch or 10 inch easily outperforms the SCT's visually.

The only real advantage you get with SCT is you pay less but in my experience sacrifice both optical and mechanical quality.