Refractor or dob for viewing the bright planets

[Stu]

They do come up used every now and then

https://www.astrobuysell.com/uk/propview.php?view=150505

[Mike_S]

I was looking at that but can’t get down to Essex anytime soon. 

[JOC]

FWIW I too my 8" Dob out about 12 days ago and I thought I got a lovely view of Jupiter.  Mind you I didn't have another telescope on the go to compare it with.

[Stu]

13 minutes ago, JOC said:

FWIW I too my 8" Dob out about 12 days ago and I thought I got a lovely view of Jupiter.  Mind you I didn't have another telescope on the go to compare it with.

You ain't seen nothing yet, wait till you see Jupiter and Saturn at 60 degrees, they will knock your socks off 👍👍

[Geoff Barnes]

3 hours ago, Stu said:

You ain't seen nothing yet, wait till you see Jupiter and Saturn at 60 degrees, they will knock your socks off

I just have , and they did!  

[Stu]

24 minutes ago, Geoff Barnes said:

I just have , and they did!  

Geoffrey, I may have to issue a 'planetary teasing' warning soon 🤣🤣🤣🤣

[Greymouser]

20 hours ago, John said:

The bottom one is a Takahashi FC-100DL and the top one is a TMB/LZOS 130 F/9.2 triplet. The scopes that Stu has suggested earlier in this thread are similar in concept to the Takahashi but at somewhat less cost.

 

Two excellent scopes there, but these you post, along with other posted suggestions, raises a question in me: There is a huge price difference in those two scopes, but is there a corresponding improvement in quality, experience at the eyepiece? Or is it a case of diminishing returns? Never mind when compared to other cheaper options.

I ask because the Tak is on my wishlist, as soon as I can persuade my wife,  but now I am wondering if I should aim higher, or indeed lower, considering the great reviews of the Skywatcher Pro and Esprit.  Then again the same goes for even cheaper ones. Just how are we all supposed to balance performance with cost? Where does it all end?

https://www.baader-planetarium.com/en/astro-physics-130mm-f6.3-starfire-gtx-refractor.html?___SID=U

🤔 Or even higher?

[jetstream]

Not the one asked but all I can say is that I'm extremely pleased with the TSA120- it will not show more than my dobs though- last night around 275x I had a remarkable view of Jupiter with the 24".

However, the refractor will give very pleasing views and some of them offer seemingly endless mag (TSA120 etc) so when seeing is good you have a great option at your disposal. To me the fracs give an aesthetically pleasing planetary view and a good mount (thanks @Stu) with tracking gives a big advantage IMHO.

[Stu]

Whilst searching for something else, I came across this old report of mine which has some pertinent comments about aperture for planetary observing at different altitudes.

 

[John]

1 hour ago, Greymouser said:

Two excellent scopes there, but these you post, along with other posted suggestions, raises a question in me: There is a huge price difference in those two scopes, but is there a corresponding improvement in quality, experience at the eyepiece? Or is it a case of diminishing returns? Never mind when compared to other cheaper options.

I ask because the Tak is on my wishlist, as soon as I can persuade my wife,  but now I am wondering if I should aim higher, or indeed lower, considering the great reviews of the Skywatcher Pro and Esprit.  Then again the same goes for even cheaper ones. Just how are we all supposed to balance performance with cost? Where does it all end?

https://www.baader-planetarium.com/en/astro-physics-130mm-f6.3-starfire-gtx-refractor.html?___SID=U

🤔 Or even higher?

Where does it all end ? - thats a good question !

I guess budget is the determining factor at the end of the day. There is a law of diminishing returns and a £2,500 scope will not deliver twice the performance of a £1,250 scope of course. In fact I used to have a Skywatcher ED100 which cost £300 on the used market and that probably gave me 80%-90% of the performance that the Tak FC-100DL does.

So why did I buy the Tak ? - well I've been in the hobby for many years now and I wanted to experience something that was at or close to the top tier of performance for myself rather than just reading about other peoples experiences of them I suppose.

I intended to buy one top end scope but then the TMB/LZOS 130 F/9.2 came up on the used market, within collection distance and from a seller that I knew and at a price that I found hard to ignore (I'm a bit weak like that though ) and I had the money available. I knew that LZOS objectives were something rather special and at a similar level to Astro Physics and Tak triplets so I could not resist the chance to see for myself.

In all honesty though, I could have had a heck of a lot of enjoyment from the hobby if I had not been able to own these scopes and for many years when my budget was tighter thats just what I did of course

 

 

 

[Greymouser]

53 minutes ago, John said:

I'm a bit weak like that though

I would be surprised if, in context, many people could deny that on this forum. Certainly not me...
( Curiosity can kill the cat though! Or would that be my wife in some circumstance? )

[Steve Clay]

If its for planets what about a Mak

[Sunshine]

I think the OP has more than he expected in response to his question lol, its ok MSammon, sometimes  posts turn into cerebral wrestling matches.

[SIDO]

5 hours ago, Sunshine said:

I think the OP has more than he expected in response to his question lol, its ok MSammon, sometimes  posts turn into cerebral wrestling matches.

Even worse my wife won't let me buy the Ts let alone the Tak and this thread has me wanting them both...

Edited June 27, 2019 by SIDO

[Mike_S]

It’s okay I like the science part even though can’t take it all in that quick. A bit better viewing tonight. Could make out some faint orange bands on Jupiter. Saturn was pretty sharp too. On the sticky thread “what can you expect to see”. The images it shows for a 4 inch frac are better than what I am getting from my 10 inch dob. Do you expect to see as clear as this through the eyepiece? 

 

[jetstream]

My 10" f4.8 dob gives much much better views than those images...

Cooling, collimation and dealing with local thermals are where to concentrate efforts IMHO.

[MarsG76]

On 25/06/2019 at 08:27, vlaiv said:

Can I point to the obvious?

You have 10" dob - and one important aspect for planetary viewing is aperture - it provides resolution.

Smaller aperture can be less affected by poor seeing, so yes under some circumstances 90mm aperture will look more pleasing than 10" one, especially if you try to push magnification on dob over the limit of the seeing. Slower scopes have another advantage in poor seeing - they have wider critical focus zone, so any disturbance of the wavefront is less likely to produce defocus blur.

Having said all of that - why don't you just do an aperture mask for that dob - you can easily have 90mm F/13.3 scope that way that has zero chromatic aberration.

That is by far the cheapest option - you can make it out of some cardboard. Here is an example:

What exactly seems to be a problem with view thru that dob? Maybe rechecking collimation would be a good thing to do. What magnifications are you using?

+1.. definitely a better solution.... 

[Stu]

I've posted this one many times before, and bear in mind it was taken when Jupiter was at high altitude so I don't get results as good currently. This is a smartphone image through the 4" Tak at around x200. The visual view was much better with fine detail visible but it gives some sort of idea of what is possible with a 4".

[Mike_S]

4 hours ago, jetstream said:

My 10" f4.8 dob gives much much better views than those images...

Cooling, collimation and dealing with local thermals are where to concentrate efforts IMHO.

Is this from northern hemisphere and this time of the year? What magnification please?

[John]

I think it's not sensible to make any judgements about the relative performance of scope types on Jupiter when the planet is positioned as it currently is from the UK. It's the worst it's been that I can recall and I've been observing it for 40 years. All the sketches and images you will see date from when the planet was much better positioned so won't bear comparison to what can be seen now.

My 1st observations of Jupiter date from the late 1970's when Jupiter was up in Taurus and back then I could see 4-5 cloud belts with my Tasco 60mm refractor which cost me £45.00. When I observed Jupiter a few nights back with my £2K+ Tak I could see little more detail than the 60mm frac showed all those years ago. Is the Tak a lousy planetary scope ? - nope, it's superb, but Jupiters position is currently scrubbing much that performance potential away.

If you have a low and uncluttered southern horizon and a period of steady seeing or if you can move yourself and your equipment 500 or more miles south you might start to see more of what your scope can deliver but otherwise I think we have to accept that a planet at this altitude in the sky is a very awkward target and not one that is a sound basis for judging scope capabilities I suggest.

 

[Mike_S]

At the moment I want to spend as little as I can to rule out problems. I want to try a Pentax XW7mm but can’t see any second hand or can get a SW Evostar 102 F9.8 on an EQ3 mount and use my 5mm eyepiece for X200 magnification. Next month maybe. Will probably go with the lower power eyepiece first or even a cheaper one if a decent one comes up second hand.

Edited June 27, 2019 by MSammon

[John]

The Vixen SLV's have performance very much like Pentax XW's albeit with a smaller field of view. You can pick those up used for well under £100, sometimes a lot under that !

[Mike_S]

Also seen a Celestron Nexstar 102 GT for £135. Tempting but could wait and get a 100-102mm apo for £400 used. 

[Cosmic Geoff]

Jupiter is looking particularly bland lately - with a small telescope one might be able to make out just one cloud belt. I have never acquired the knack of seeing much planetary detail - tried various scopes and eyepieces. Eventually having several scopes and a spirit of 'what's to lose' I tried planetary imaging and pretty soon had an image of Jupiter taken through the 127mm Mak that was far better than anything I had seen visually.  I then had a season imaging with a C8 and ASI 120MC.

I also found that my binoviewer + Skywatcher x2 Barlow lens worked surprisingly well for planetary viewing on Mars- possibly because as well as using two eyes it cut down the glare at each eye by more than half.

For visual use, the C8 SE is the best planetary scope in my collection, seeing permitting.

[jetstream]

6 hours ago, MSammon said:

Is this from northern hemisphere and this time of the year? What magnification please?

I live in northern Ontario Canada with different seeing conditions possibly. I can get good views between 200x-250x when seeing is up there but the planet is so low its not really worth pursuing much (to me).  This is current, last night actually. The 10" dobs are typically great lunar/planetary scopes, as @dweller25 pointed out to me years ago.

Test yours on the moon, when at about 1/4 full- you should be getting very sharp, clean views..

I would hold off on any purchases with the thought of improving Jupiter views at this time...