6 inch refractor: A sense of scale

[michael.h.f.wilkinson]

hopefully I can squeeze in my 6" f11 dob too - will be a good trio!

My money is on the 180 Mak, at least for planets, and certainly for compact DSOs. The other two will tie for second place

[nicks90]

My money is on the 180 Mak, at least for planets, and certainly for compact DSOs. The other two will tie for second place

Narrr, my money will be on the long range artillery piece - I mean the 6" frac! No central obstruction and immense focal length will be beautiful on planets. And will the extra 30mm aperture of the Mak make up for the central obstruction for dso's?

[dweller25]

John, nice scope.

Have you considered making a wooden "Berry" alt az mount for it ??

[michael.h.f.wilkinson]

Narrr, my money will be on the long range artillery piece - I mean the 6" frac! No central obstruction and immense focal length will be beautiful on planets. And will the extra 30mm aperture of the Mak make up for the central obstruction for dso's?

Yes, it will. The Mak has a small central obstruction, from images I have seen, not much more than 20-25% (by diameter = 4-6.25% by area). This is has minute impact on resolution (central obstruction isn't anything like the problem many people think it is). The light gathering surface ignoring central obstruction is (180/150)² or a massive 44% higher. The notion that slow focal ratios are good for planets mainly stems from the fact that aberrations are more easily controlled. Still, an F/15 achromat may be beaten by an F/6 apochromatic scope, simply because the latter still has better chromatic correction. Anyway, the mak is also F/15, so equally lenient on EPs.

[bingevader]

Fantastic!

[LeeB]

I guess they would. I'm hoping not to have to spend that much though and, ideally, I'd prefer an alt-az solution. The APM Maxload alt-az would do the job on a massive wooden tripod but I'd need to budget around £1.5K I guess. The Skytee II actually holds the weight of the scope surprisingly well but the 2" steel tubed CG5 tripod allows too much twisting movement from the long tube. 

I knew mounting this would not be a straightforward exercise and it's certainly not but I wanted a challenge and I think it can be solved without having to spend £thousands.

......the tripod can be greatly improved with an extra spreader, I made mine from ply and it sits lower than the standard one, this takes a lot of the twisting moment from the head of the tripod. and is a cheap upgrade, also one of my eq6 tripods has had the lower inner legs removed and replaced with thick wall scaffold tubing, again a stiffer alternative.

[John]

John, nice scope.

Have you considered making a wooden "Berry" alt az mount for it ??

Yes, thats another option I'm considering David   

Thanks to everybody for the suggestions and feedback. This is a project that will run for a bit so I'll report further when I've made some more progress. 

I'm not getting drawn into the Mak 180 V's refractor debate though I did have one for a few weeks recently to play with

[Marki]

I'm not getting drawn into the Mak 180 V's refractor debate though I did have one for a few weeks recently to play with

Very circumspect, John .  Lots of interesting suggestions on mounting though - might look into the extra/lower spreader thing Lee mentioned myself.

Look forward to your next report!

[John]

Very circumspect, John .  Lots of interesting suggestions on mounting though - might look into the extra/lower spreader thing Lee mentioned myself.

Look forward to your next report!

Cheers Mark   

BTW, have you joined the Istar forum yet ?. It's not exactly over active but they are very welcoming !. Here is a link:

http://www.istarscopeclub.proboards.com/

Might be a good way to keep in touch with Istar developments.

[emadmoussa]

Good stuff. If you dont mind me asking, how much one of these cost on average?

[JamesF]

A simple wooden tripod would work nicely I reckon.  You wouldn't want anything too conspicuous.

James

[John]

.....  You wouldn't want anything too conspicuous.....

Absolutely not 

[John]

Good stuff. If you dont mind me asking, how much one of these cost on average?

http://www.istartelescopes.co.uk/page_2413941.html

Mine was not new though. 

[emadmoussa]

Thanks!!

[AndyWB]

Hye, hey, hey, I LIVE in France!!! 

 

That is simply glorious. Adorable.

 

Olly

But not near the coast! (I did think of that!)