Should I upgrade from a 5" Maksutov Cassagrain to a 9.25 Schmidt Cassagrain?

[mattd2222]

Hey everyone,

I currently own a Celestron Nexstar 127 (5") Maksutov Cassagrain and have been really tempted to upgrade to a Nexstar Evolution 9.25. I am wondering if you could share your opinion as to what kind of gains I will get with the bigger aperture. I am a visual observer and not planning on getting into astrophotography anytime in the near future. I mostly enjoy planetary viewing but want to be able to enjoy some DSO's as well. If I'm looking at Jupiter for example through my 5" and then looked through a 9.25" will I be blown away by the difference? I haven't had the opportunity to look through anything bigger than my 5". I am sure this question, or a variation of it has been asked several times but I appreciate any help you can provide. Thanks so much! 

[Anthonyexmouth]

not helpful but i have to say, going from my old 150mm orion europa newt to a tiny 90mm mak i was amazed at the improved views of jupiter. 

[dweller25]

Would strongly advise that you visit your local astronomy club to look through a few scopes - hopefully someone may have a C9.25 to look through.

Someone may even have a 10" Dobsonian which will give you great views of the planets and deep sky for a lot less money than the 9.25 Evo

[RT65CB-SWL]

Hi Matt and welcome to SGL. 

Again not really helpful, but I own a Celestron C6/xlt and a Meade ETX105 ['re-modded' as it fell off one of my mounts at a star party]. Both do good for what they do in my opinion. That said, I am also visual and mainly observe the Moon and planets.

 <--- my 're-modded' ETX105 with an SCT adapter ring so I can use accessories from the C6 too.

My advice is go to a local astronomy club/society star-party and see what others are using then decide. If you do a lot of travelling to find a dark site, then the Nexstar 127 maybe your best bet.  

[nightfisher]

Never used a 9.25, so all i can say is going to a larger scope is going to require a larger more expensive mount, (maybe the one your looking at comes as a kit), i would say get a 150 f5 newt and use it with same mount as you have (if suitable) and see if this wets your appetite for more aperture, you could always get a used newt and then sell it for about what you would pay for it if going to 9.25

[Stu]

The evolution includes the mount so that bit is sorted

I've owned a C925 for a while. It's a lovely scope, quite a big beast and needs to be properly cooled and collimated to deliver its best.

You will notice a big increase in resolution and brightness moving between the two. One challenge with planets currently, and for quite a few years to come is that they are very low from the UK. This means the advantage of larger scopes is somewhat muted due to the much thicker layers of atmosphere we are having to look through.

You probably would not get a dramatically bigger image of Jupiter, but when the seeing is good, you should see alot more fine detail. It tends to be that you have to want longer for the moments of good seeing but the detail and colour seen should be much better.

The 925 should be dramatically better on globular clusters, showing much deeper resolution of stars, and planetary nebulae such as m57 should also be much more satisfying. It will struggle on the larger clusters due to the long focal length and inherently narrow field of view.

As others have said, there are much cheaper routes to more aperture such as a 10" dob. This would probably give you similar performance, with less cooldown required and more versatility due to the shorter focal length. You obviously lose the goto, unless you get a goto dob!

It is always good advice to 'try before you buy', whether that is visiting a show room or a club or an outreach event.

Take your time, but also don't get frozen with uncertainty. I hope that helps a little

Stu

[Stu]

This is mine side by side with a 4” frac to give you a sense of scale for the OTA

[Trikeflyer]

I Agree with the comments above. If you observe from the UK and the conditions are not predictable, the benefit of a scope with faster cooling is worth considering. If you have predictable weather where you are and can therefore leave the scope out to acclimatise for a while that may not be a consideration.  Also depending on your observing location, as Stu has said, planets may be low in the sky and the atmosphere will have effect on what you see.  Also sct scopes are prone to dewing up so a good dew solution is needed at certain times of year.

If you were asking me, I think a Newtonian with a dob base would be worthy of consideration.  That said, Having used a non goto dob I'd say that for me, at High mags, tracking planets can be tricky because you are constantly having to touch the scope and this can cause a bit of wobble which spoils the image. I'm sure this isn't the case for everyone as it's a bit of an acquired skill I think.  Deep sky objects don't have the tracking challenges that planets do (for me anyway) and I have to say the the ring nebula and M13 globular have never looked anywhere near as good in any scope I have than with the 12 inch dob. If I had my choices again I'd have a 10 or 12 inch flex tube goto dob. I've never used an sct so I'm not talking from a highly authoritative point of view regarding the specific scope you asked about. These are only my opinions and others will I am sure have a different perspective which is what is so great about SGL... 

[Louis D]

6 hours ago, Stu said:

ou will notice a big increase in resolution and brightness moving between the two. One challenge with planets currently, and for quite a few years to come is that they are very low from the UK. This means the advantage of larger scopes is somewhat muted due to the much thicker layers of atmosphere we are having to look through.

The OP might want to investigate the ZWO 1.25″ Atmospheric Dispersion Corrector / ADC to improve planetary views before going to a larger scope.  I haven't tried one myself because I'm about 20+ degrees latitude south of y'all, so the planets are never all that low on the horizon from my backyard, but they reportedly work well.

One thing to consider with a Dob and low targets is the need for a clear sight-line to the horizon.  Fences and shrubs are a much bigger problem when aiming a Dob low compared to a tripod mounted scope.

[Cosmic Geoff]

I own a 5" Mak and also 8" telescopes.  I'd say that the 9.25" will offer a useful gain when looking at planets - my 8"SCT is always better than the 5" Mak when conditions are fair to good.  Also consider getting an ADC for looking at low-altitude planets.  My 8" Newtonian is not so impressive but that's a sample of 1.

I should point out that I have found that a good planetary video camera records views significantly better than what I can usually see directly with the same telescope. I have found planetary visual observing to be something of a disappointment.

For deep-space objects, a larger telescope of 8" or 9.25" aperture (it doesn't have to be a SCT) will provide a striking improvement in the view.  I would advise that you be sure to get one with GoTo, otherwise what you will mainly experience is frustration at being unable to find any faint object.

[Louis D]

2 hours ago, Cosmic Geoff said:

I would advise that you be sure to get one with GoTo, otherwise what you will mainly experience is frustration at being unable to find any faint object.

Or digital setting circles.  I use Sky Commander DSCs with my Dob when hunting faint fuzzies.