Newbie - expectations for sharp images

[Duotwr]

Evening everyone. My daughter and I are pretty new to astronomy. We’ve got a skywatcher heritage 130p flextube which we’re enjoying using and starting to learn to navigate the stars. 

Of course we’ve been trying to do some planetary viewing - but I’m really struggling to get any kind of sharp images of, for example, Jupiter. I’ve bought some BST Starguider eyepieces which seem pretty reasonable. We can see four moons sharply with the 6mm EP and a couple of times we’ve discerned some faint bands on Jupiter - but it’s still looking pretty fuzzy all round. 

Am I missing something? I’ve tried collimating the telescope and testing this on a star seems to indicate collimation is pretty good. We’ve tried from a dark sky area in Scotland in the last couple of weeks. 

Am I being unrealistic in my expectations of what we’ll see with this scope and EP?

Thanks

Keith

[Elp]

It highly depends on atmospheric seeing, most of the time you'll have to put up with wobbling and blurring due to the moisture, temps and moving air. Try not to view directly over buildings or sources of heat, yes even grass and water bodies can contribute but you make do.

But you do have to concentrate your vision and stare at what you're looking at for a bit (like 30s to a minute), your brain will start to resolve details as it interprets what its seeing.

Also I've found on occasion when they appear bright to either use a variable polarising filter, or you can Barlow the eyepiece which will increase the f ratio making the view dimmer, which can help with seeing surface detail, but will exasperate any seeing issues due to the increased magnification. But you don't really need to buy anything more than you already have.

Your reflector scope should give sharp views, also make sure theres no dew on the eyepiece, secondary mirror or primary mirror when using it.

Edited January 5 by Elp

[John]

Unless the seeing conditions are really good (which is rare) you will only get the occasional glimpses of what your telescope is really capable of. These can only be momentary lasting a second or two. That is why you need to spend quite a lot of time observing a target such as Jupiter - you get more chance of seeing one of those fleeting moments. Our atmosphere is responsible for these variations.

 

[bosun21]

To add to what has already been said above,  dew formation on the secondary mirror is pretty common with the Heritage scopes especially if you are not using some sort of shroud on the scope. The secondary mirror is basically exposed to the air so will dew up if the dew point is reached. A home made shroud would be beneficial.

[Duotwr]

Great thanks everyone. It’s still amazing what we’re seeing!

I’m pretty keen on the tinkering so I’ll have a look into sorting some kind of shroud. This evening I did literally take the scope out the house and start looking within about 1 minute so not surprised if there was some dew forming. 

We’ll have a play around and see how we get on. I’ve got a basic Celestron omni Barlow so we’ll try that too. 
 

many thanks!

keith

[John]

Jupiter's disk features do not respond well to the very high magnifications that can be used on Saurn and the Moon, for example.

Generally I've found 130x-160x has delivered the best contrast on the giant planet on nights when 200x plus has been good for Saturn or the Moon.

So "throttling back" the power is often a good approach 🙂 

[Nikolai De Silva]

Hi @Duotwr! 

We also have a 130p, a SW Starquest 130p (I think the same optics as the heritage). Only having the two eyepieces, 10mm and 25mm Kellners, we got with the scope, and got a 5x Barlow (not a branded one). The views of the moon and Saturn are great for us. Saturn is sharp.

Jupiter is also good with its two bands clearly visible. As you have told Jupiter is not sharp like on the internet, but good. When spending times out, views are getting clearer. The eyes are adjusting for the dark and then views are really impressive. We don't get any aberrations anyhow.

Good luck and clear skies!

Nikolai.

Edited January 6 by Nikolai De Silva

[bosun21]

25 minutes ago, Nikolai De Silva said:

The eyes are adjusting for the dark and then views are really impressive.

It's often best not to be fully dark adapted when viewing Jupiter as it can be too bright to allow the details to show.

[Stu]

11 hours ago, Duotwr said:

Great thanks everyone. It’s still amazing what we’re seeing!

I’m pretty keen on the tinkering so I’ll have a look into sorting some kind of shroud. This evening I did literally take the scope out the house and start looking within about 1 minute so not surprised if there was some dew forming. 

We’ll have a play around and see how we get on. I’ve got a basic Celestron omni Barlow so we’ll try that too. 
 

many thanks!

keith

You have a very capable scope, despite its ‘beginner’ tag. I have owned one and it at times put other more expensive though smaller aperture refractors in the shade!

Totally agree with what has been said already. Making a shroud should make a difference for a few reasons; it cuts out glare and protects the mirrors from few, but I also used to find that my breathing disturbed the views as it goes straight through the light path. Adding a shroud stops this happening and steadies the views.

Whilst your scope won’t need that much cooling, it will still benefit from say 20 mins to let it acclimatise to the ambient temperature and stop convection currents.

For some reason I never really spent much time on Jupiter with mine, but I got some excellent views of Mars with it when it was at opposition, dark markings and the polar cap visible which was a great result for such an affordable scope. I see no reason why you shouldn’t get some more detail out of Jupiter with practice. Keep your collimation right, get the scope cooled, observe when the planet is at its highest and as often as you can so you catch the good seeing conditions when they occur. Nail the focus, then just spend time at the eyepiece. Your brain is very clever and over time it combines the best moments of seeing so that you see much more after, say half an hour, that a short one minute look.

There are plenty of improvements which can be made to the scope. Wrapping PTFE plumbers tape around the threads of the focuser helps give it a firmer movement and stay where you put it. You can also put the scope on a mount using the dovetail, which puts it at a much more convenient height. I never actually used mine on the dob mount, putting it straight on a mount.

If you search for Heritage 130p posts by @Mark at Beaufort then you will find plenty of great examples of how to lodge scope to improve it, like this one:

Enjoy! 👍

[Ricochet]

Jupiter is very susceptible to atmospheric seeing, which is the stability of the atmosphere, not the darkness of it. In fact many people report that their best planetary views occur when there is a light haze in the air as there is no wind to blow the water vapour away. Due to this requirement for stable air, observing from a dark site will not necessarily show better results than observing from home, other than avoiding any negative effects from the heat haze coming off roof tops. Given the recent weather I would not be too concerned about any potential lack of sharpness over the last couple of weeks and would simply continue to observe without worrying too much about the collimation of the telescope or any other tweaks that may improve its performance. 
 

One important section of atmosphere that is often overlooked is the air inside the telescope itself. When moving a telescope from a warmer location to a colder one there is a cooldown period where the components are cooling and this leads to air currents inside the telescope. For a 5” Newtonian this isn’t very long but within the first half an hour of observing I would consider this a possibility and see if the sharpness improves later in the session.

 

 

[inedible_hulk]

Personally I’m finding the moisture laden turbulent atmosphere associated with this seemingly endless series of storm fronts means that, even when I get a clear night, my views of Jupiter have been pretty poor. Maybe the forecast cold weather will bring some more stable skies and better visibility. Coloured and specialist filters can help tease out the details (see here), but I’d say 99% is down to the state of the atmosphere. Hang in there!