Skywatcher Startravel 150 f/5 vs Skywatcher Evostar 150 f/8

[MarsFirst]

I bought recently a Skywatcher Startravel 102 f/4.9, and having liked it, now I want to go a step up to either Skywatcher Startravel 150 f/5 or Skywatcher Evostar 150 f/8.

I want to use the scope primarily for observation and photography of Mars, Jupiter and it's moons, Saturn and Titan, but perhaps also for observation and photography of DSO.

Can you please advise which one to go for? (both are the same price, so it's only about the suitability).

P.S. I was reading this post: https://stargazerslounge.com/topic/134287-f5-versus-f8/ but that was only a general question f/5 vs f/8 - my question is about the two specific scopes, so perhaps someone uses them and has a better idea of their suitability for the above.

Edited November 2, 2020 by MarsFirst

[johninderby]

You might also consider the Bresser 152. Has a great CNC focuser which can be upgraded to dual speed and is a huge improvememt over the very basic focuser on the SW. Excellent build quality and good optics.

The longer focal length will have less false colour so is the one to go for if used for planetary observing but the shorter focal length will have a wider fov and more false colour but not a problem for low power observing. You have to decide which is more important, planetary or DSOs.

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-ar-152l-1200-refractor-ota.html

or

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-ar-152s-760-refractor-ota.html

I use the Bresser 127L mainly for solar observing and is an f/9.45 so less CA than the 152 f/7.9.

The152 is quite a big scope so will need a solid mount.

Edited November 3, 2020 by johninderby

[Space Hopper]

An F8 150mm refractor is a big beast of a scope, and quite a handful.

What are you mounting it on....??

[Space Hopper]

Worth a watch to give you an idea of a big refractors mass.

This is a 152 F6.5, so the F8 option will b e bigger still.

I'm not trying to put you off or anything, just trying to give you an idea of size and mounting requirements.

 

[John]

For observing the planets the F/8 will be much more effective than the F/5 because of the amount of false colour that the F/5 focal ratio in this aperture generates. 

As has already been said, these are big scopes which require substantial mounts.

[messier 111]

to take into consideration, the weight, the length.
the f8 is by far the best for planets.
the focus being longer, the light is therefore focused farther away, therefore less aberrations.

[johninderby]

You might consider the Bresseer 127L. Decent aperture and at f/9.45 even less false colour that the f/8. Lighter and easier to mount as well.

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-ar-127l-1200-refractor-ota.html

Edited November 3, 2020 by johninderby

[MarsFirst]

12 hours ago, Space Hopper said:

An F8 150mm refractor is a big beast of a scope, and quite a handful.

What are you mounting it on....??

It comes with a quite sturdy EQ5 Deluxe Heavy-Duty Equatorial Mount, so that shouldn't be an issue.

[MarsFirst]

11 hours ago, John said:

For observing the planets the F/8 will be much more effective than the F/5 because of the amount of false colour that the F/5 focal ratio in this aperture generates. 

As has already been said, these are big scopes which require substantial mounts.

 

10 hours ago, messier 111 said:

to take into consideration, the weight, the length.
the f8 is by far the best for planets.
the focus being longer, the light is therefore focused farther away, therefore less aberrations.

Thanks for confirming that guys, that's what I thought too, but what about the photography? Will f/8 be equally good for imaging too? (Both when using SLR adapter and digital camera in stead of an eyepiece).

[messier 111]

33 minutes ago, MarsFirst said:

 

Thanks for confirming that guys, that's what I thought too, but what about the photography? Will f/8 be equally good for imaging too? (Both when using SLR adapter and digital camera in stead of an eyepiece).

I am not able to answer you, I do not take photograph of the sky.

Edited November 3, 2020 by messier 111

[Peter Drew]

I have a 150 F5 Startravel and 150 F8 Evostar.  Either is at the limit of an EQ5 equatorial for visual use, an EQ6 would be more suitable for imaging.  The two telescopes are both a compromise when it comes to visual and imaging, the best choice boils down to which aspect the interest is biased.  There are a lot more DSO's than planets!     🙂 

[MarsFirst]

28 minutes ago, Peter Drew said:

I have a 150 F5 Startravel and 150 F8 Evostar.  Either is at the limit of an EQ5 equatorial for visual use, an EQ6 would be more suitable for imaging.  The two telescopes are both a compromise when it comes to visual and imaging, the best choice boils down to which aspect the interest is biased.  There are a lot more DSO's than planets!     🙂 

That's what I am inclined to think Peter. I am a Mars fanatic, but am under no delusion on how much more detail I can see (once every 2 years, when the Mars is at its closest, that is) with f/8 compared to f/5 scope

So I will go, with heavy heart, for Skywatcher Startravel 150 f/5

[Rusted]

Psst! Anyone want a "little used" Kaleidoscope?

Will trade for an f/8! 

[John]

I've owned a few of the 150mm F/8's and they show enough CA and SA for my tastes. I would not personally opt for the 150mm F/5, even for just deep sky observing. I can't imaging that it would be good for imaging either - the CA bloat around stars would be substantial.

Actually the F/8 is a pretty good deep sky observation instrument.

 

Edited November 3, 2020 by John

[MarsFirst]

2 hours ago, MarsFirst said:

That's what I am inclined to think Peter. I am a Mars fanatic, but am under no delusion on how much more detail I can see (once every 2 years, when the Mars is at its closest, that is) with f/8 compared to f/5 scope

So I will go, with heavy heart, for Skywatcher Startravel 150 f/5

Or not!

I just called the shop, and they told me about the Focal Reducers, so it looks like with one of those, with Skywatcher Evostar 150 f/8 I can have my cake and eat it at the same time !!!

[MarsFirst]

24 minutes ago, John said:

I've owned a few of the 150mm F/8's and they show enough CA and SA for my tastes. I would not personally opt for the 150mm F/5, even for just deep sky observing. I can't imaging that it would be good for imaging either - the CA bloat around stars would be substantial.

Actually the F/8 is a pretty good deep sky observation instrument.

 

Yeah John, thanks for concuring - I changed my mind and go for the 150 f/8 after all - see above why.

[Rusted]

Sorry, my earlier post may have been a bit too cryptic.

I have owned an [already secondhand] 6" f/8 Celestron for many years and never used it without a Fringe Killer for white light.
It's upper limit was about 120x on average on the sun [solar foil filtered] and moon and planets.
It was used for solar H-a before finally being retired in favour of a shiny new f/10 achromatic objective and DIY tube.

My new f/10 iStar objective, in a thin, steel, duct tube, can manage double the old f/8's power on average on the moon and planets.
I was shocked to discover I could actually use over 200x routinely on a 6" after many years of being so handicapped.

A 6" f/15 [or possibly an f/12 at a push] achromat would make a far better planetary and lunar instrument but is very difficult to mount affordably.
An old Fullerscopes MkIV mounting would do if you can find one in fair condition with drives.

If you have any DIY skill that would also provide an affordable mounting.
A Berry style, counterbalanced plywood fork ALTAZIMUTH would carry any instrument you can physically lift at very low cost.

I have no experience of any other make of 6" f/8 but chromatic aberration is function of aperture and focal ratio.
You may find this chart useful: Red is VERY BAD. AVOID! Yellow just manageable with specialist filters. Green is better.
An APO [or ED] break these rules as well as the bank.

 

Edited November 3, 2020 by Rusted
New image

[Rusted]

Don't forget that you have to mount a refractor so you can get under it at high altitudes.
Even with a star diagonal you need a tall pier or tall, very sturdy tripod.
Though you can sit at a telescope it means your minimum eyepiece height is at eye level [when seated] when the OTA is vertical.
Unless you have an adjustable height chair this can mean contortions at different pointing altitudes.
My old 6" f/8 on a tall and massive pier on a Fullerscopes MkIV:   The 7" thick wall pipe is far too heavy for one person to lift but rock solid.

 

Edited November 3, 2020 by Rusted
typo

[Owmuchonomy]

On 03/11/2020 at 02:53, johninderby said:

You might consider the Bresseer 127L. Decent aperture and at f/9.45 even less false colour that the f/8. Lighter and easier to mount as well.

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-ar-127l-1200-refractor-ota.html

Hi John, what is the OTA weight for the 127 please? Thanks, Chris.

[johninderby]

The 127L OTA weight is given as 7.9kg.

[Louis D]

On 03/11/2020 at 12:44, Rusted said:

Don't forget that you have to mount a refractor so you can get under it at high altitudes.

This is even an issue with smaller refractors.  I have an adjustable height stool so that I can sit mere inches above the ground with my legs straight out when the scope is pointed near zenith.  It makes me wonder why people complain about the "contortions" it takes to view through a Dobsonian by comparison.

[Stu1smartcookie]

I "second " Johns post regarding the Bresser scopes ... they , in my experience are a cut above the skywatcher ones ... i briefly used a breser 127/L . A really nice scope .

[John]

I've owned a Bresser 127L and a Meade AR5 - they were identical. The Bresser had better optics than the Meade did but I think that was sample variation as the scopes clearly came from the same manufacturer.

The 127L was a nice 5 inch achromat refractor. False colour well controlled at F/9.4 and a collimatable objective cell. They have changed the colour scheme now but I think it's the same scope. The focuser on the current version is better than the one that I had I believe. The 127L is the middle one of these:

 

 

 

Edited November 6, 2020 by John

[johninderby]

The addition of that lovely CNC R&P 2.5” focuser has been a great upgrade to the 127L  Add the optional dual speed knob and you have  got a great focuser. 👍🏻

Edited November 6, 2020 by johninderby

[John]

Does the new version have the 3 nuts and bolts holding the objective cell onto the tube with the nuts on the inside ?