What should I see when seeing is good?

[West End Wendy]

I've been a telescope owner for nearly 2 mnths now and I've had many opportunities to see Jupiter and now Saturn too if I can bring myself to get up early enough.

90% of the time I observe a planet it fluctuates in and out of focus. This is no problem for me - I'm really ecstatic to get a few fleeting moments of excellent clarity, but I get the impression from more experienced posters that in genuinely good seeing conditions I should get less of the "in and out of focus" effect. Having only been observing since the end of October, I have no point of reference.

What does a planet look like in really good seeing, and how much does seeing affect lower-power observing?

Thanks,

Tim.

[Revs]

Seeing will effect the sharpness, detail and contrast of your view, not to be confused with atmospheric turbulence, which is what makes objects distort and shimmer. The lower and power the less it's noticeable

EDIT: In the 5-6 months I've had my 'scope I've only had one, maybe two nights of good seeing, and several nights of patchy good spells. I'd say more than half the time it's poor/average, but it's still worth getting the 'scope out to find out

[BAZ Senior]

Iam not sure what scope you have, but are you allowing it to cool down when you go out?

This can make a dramatic difference, as the air currents within the tube are all moving about, and settle down when they reach the same temp as the air. This can take a while, so be patient, but it will improve your viewing.

[WayneR]

Excuse me jumping in, but another newbie question - how long would you usually leave the 'scope outside to cool down? (Assuming ambient indoors around 20 degC and below freezing outside at the moment)

[Dai150PL]

I allow 5 minutes per inch of aperture. So for me 30 minutes.

[Nexus 6]

Hi Wayne,

I would leave it 30 mins to an hour before I started observing. Depending on what type of scope you have will determine how long. I leave my sct for about an hour.

Alan

[WayneR]

Thanks guys!

[West End Wendy]

5 mins per inch of aperture? Not heard that before. I reckoned on 20 mins for my 4" refractor so it seems to make sense.

I have tried using the scope straight out of the house so I appreciate how awful things can look with a warm tube and cold air.

[Moonshane]

I've been a telescope owner for nearly 2 mnths now and I've had many opportunities to see Jupiter and now Saturn too if I can bring myself to get up early enough.

90% of the time I observe a planet it fluctuates in and out of focus. This is no problem for me - I'm really ecstatic to get a few fleeting moments of excellent clarity, but I get the impression from more experienced posters that in genuinely good seeing conditions I should get less of the "in and out of focus" effect. Having only been observing since the end of October, I have no point of reference.

What does a planet look like in really good seeing, and how much does seeing affect lower-power observing?

Thanks,

Tim.

Hi Tim

as you probably know, there's two elements to how things look and cooling is essential as others have said (even for refractors).

transparency - this is basically how much cloud cover/haze etc there is in the air - i.e. how clear the sky is. the air is often more stable when there is a little bit of thin cloud/haze and thus it's sometimes the best conditions for planetary / high power views.

ironically, the seeing is often worse when the transparency is high although on rare nights you get a combination of good seeing and good transparency - make the most of these. good transparency / poor seeing is great for low power faint targets like galaxies etc. if the moon's not up so there's always something to do unless the transparency is so bad you cannot see the sky!

seeing is affected by either local or atmospheric turbulence and in my experience has been quite poor of late. it's possible that local factors such as everyone having their heating on in the houses around you could also affect this so many people choose the early hours to observe planets when the heating is off and the air is generally a bit more stable. many observers have reported being able to observe at not much more than 100x with a sharp image. your experiences seem normal.

in the UK we are cursed with unstable skies and the best you can hope for on a regular basis is a few seconds over each observing minute of really sharp detailed views with the rest ranging from fuzz to sharp; popping in and out of focus is quite normal - finding the point where the sharp views when they come are sharp is the tricky bit and when you find it don't change the focus unless you choose eyepieces (EPs).

on this point, I prefer a smaller sharper view and therefore tend to use less magnification than the seeing will possibly allow as the lower the magnification, the more prolonged the sharper views. it's about finding the balance that suits you, the scope and the conditions.

planetary observing is the most challenging as you need to observe for long periods to build up the detail and concentrate the tease out the finer contrast etc. I love it.

if you have good transparency and poor seeing you sometimes have to change your targets and go for faint stuff at low power - this is great too

experience definitely helps (and I am still a relative novice to many here) but I find some of the reports of detail seen and magnifications used a little surprising. local conditions can have a lot of impact though.

just enjoy what you can when you can is the way I look at it.

if you are still awake then well done - sorry for waffling on a bit.

[West End Wendy]

Thanks for that comprehensive and informative answer Shane. That's all extremely helpful info for me.

Tim

[brantuk]

Processing astro photos from a webcam is a good indicator of "Seeing" conditions. The idea is to get as many continual frames as possible in a short space of time in order to capture e.g. a planet.

The software will select and align all the good frames (when seeing was good) and throw away any bad ones (poor seeing). You can then tweak what's left by "throwing away" yet more frames to get the best possible picture.

If you lost 80% of the frames from a 20 minute filming session, then the seeing was only good for about 4 mins total. This would've occurred in odd fleeting seconds spread over the whole period.

If you were capturing 5 frames per second, that would mean only 1200 good frames (at 1/5th sec each) out of 6000

[Revs]

Wayne, if your scope is a closed tube type, ie a SCT or a Maksutov, I'd recommend a good hour for cooling, especially if it's been kept at room temps.

[WayneR]

Cheers Revs.